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freebsd-dev/sys/vm/vm_page.c
Konstantin Belousov ee06cffcd2 vm_page_free_prep(): correct description of the required page and object state. 
Reviewed by:	markj
Sponsored by:	The FreeBSD Foundation
Differential revision:	https://reviews.freebsd.org/D25482
2020-06-27 02:31:39 +00:00

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/*-
* SPDX-License-Identifier: (BSD-3-Clause AND MIT-CMU)
*
* Copyright (c) 1991 Regents of the University of California.
* All rights reserved.
* Copyright (c) 1998 Matthew Dillon. All Rights Reserved.
*
* This code is derived from software contributed to Berkeley by
* The Mach Operating System project at Carnegie-Mellon University.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* from: @(#)vm_page.c 7.4 (Berkeley) 5/7/91
*/
/*-
* Copyright (c) 1987, 1990 Carnegie-Mellon University.
* All rights reserved.
*
* Authors: Avadis Tevanian, Jr., Michael Wayne Young
*
* Permission to use, copy, modify and distribute this software and
* its documentation is hereby granted, provided that both the copyright
* notice and this permission notice appear in all copies of the
* software, derivative works or modified versions, and any portions
* thereof, and that both notices appear in supporting documentation.
*
* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
* FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
*
* Carnegie Mellon requests users of this software to return to
*
* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
* School of Computer Science
* Carnegie Mellon University
* Pittsburgh PA 15213-3890
*
* any improvements or extensions that they make and grant Carnegie the
* rights to redistribute these changes.
*/
/*
* Resident memory management module.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_vm.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/counter.h>
#include <sys/domainset.h>
#include <sys/kernel.h>
#include <sys/limits.h>
#include <sys/linker.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mman.h>
#include <sys/msgbuf.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/rwlock.h>
#include <sys/sleepqueue.h>
#include <sys/sbuf.h>
#include <sys/sched.h>
#include <sys/smp.h>
#include <sys/sysctl.h>
#include <sys/vmmeter.h>
#include <sys/vnode.h>
#include <vm/vm.h>
#include <vm/pmap.h>
#include <vm/vm_param.h>
#include <vm/vm_domainset.h>
#include <vm/vm_kern.h>
#include <vm/vm_map.h>
#include <vm/vm_object.h>
#include <vm/vm_page.h>
#include <vm/vm_pageout.h>
#include <vm/vm_phys.h>
#include <vm/vm_pagequeue.h>
#include <vm/vm_pager.h>
#include <vm/vm_radix.h>
#include <vm/vm_reserv.h>
#include <vm/vm_extern.h>
#include <vm/uma.h>
#include <vm/uma_int.h>
#include <machine/md_var.h>
struct vm_domain vm_dom[MAXMEMDOM];
DPCPU_DEFINE_STATIC(struct vm_batchqueue, pqbatch[MAXMEMDOM][PQ_COUNT]);
struct mtx_padalign __exclusive_cache_line pa_lock[PA_LOCK_COUNT];
struct mtx_padalign __exclusive_cache_line vm_domainset_lock;
/* The following fields are protected by the domainset lock. */
domainset_t __exclusive_cache_line vm_min_domains;
domainset_t __exclusive_cache_line vm_severe_domains;
static int vm_min_waiters;
static int vm_severe_waiters;
static int vm_pageproc_waiters;
static SYSCTL_NODE(_vm_stats, OID_AUTO, page, CTLFLAG_RD | CTLFLAG_MPSAFE, 0,
"VM page statistics");
static COUNTER_U64_DEFINE_EARLY(pqstate_commit_retries);
SYSCTL_COUNTER_U64(_vm_stats_page, OID_AUTO, pqstate_commit_retries,
CTLFLAG_RD, &pqstate_commit_retries,
"Number of failed per-page atomic queue state updates");
static COUNTER_U64_DEFINE_EARLY(queue_ops);
SYSCTL_COUNTER_U64(_vm_stats_page, OID_AUTO, queue_ops,
CTLFLAG_RD, &queue_ops,
"Number of batched queue operations");
static COUNTER_U64_DEFINE_EARLY(queue_nops);
SYSCTL_COUNTER_U64(_vm_stats_page, OID_AUTO, queue_nops,
CTLFLAG_RD, &queue_nops,
"Number of batched queue operations with no effects");
/*
* bogus page -- for I/O to/from partially complete buffers,
* or for paging into sparsely invalid regions.
*/
vm_page_t bogus_page;
vm_page_t vm_page_array;
long vm_page_array_size;
long first_page;
static TAILQ_HEAD(, vm_page) blacklist_head;
static int sysctl_vm_page_blacklist(SYSCTL_HANDLER_ARGS);
SYSCTL_PROC(_vm, OID_AUTO, page_blacklist, CTLTYPE_STRING | CTLFLAG_RD |
CTLFLAG_MPSAFE, NULL, 0, sysctl_vm_page_blacklist, "A", "Blacklist pages");
static uma_zone_t fakepg_zone;
static void vm_page_alloc_check(vm_page_t m);
static bool _vm_page_busy_sleep(vm_object_t obj, vm_page_t m,
vm_pindex_t pindex, const char *wmesg, int allocflags, bool locked);
static void vm_page_clear_dirty_mask(vm_page_t m, vm_page_bits_t pagebits);
static void vm_page_enqueue(vm_page_t m, uint8_t queue);
static bool vm_page_free_prep(vm_page_t m);
static void vm_page_free_toq(vm_page_t m);
static void vm_page_init(void *dummy);
static int vm_page_insert_after(vm_page_t m, vm_object_t object,
vm_pindex_t pindex, vm_page_t mpred);
static void vm_page_insert_radixdone(vm_page_t m, vm_object_t object,
vm_page_t mpred);
static void vm_page_mvqueue(vm_page_t m, const uint8_t queue,
const uint16_t nflag);
static int vm_page_reclaim_run(int req_class, int domain, u_long npages,
vm_page_t m_run, vm_paddr_t high);
static void vm_page_release_toq(vm_page_t m, uint8_t nqueue, bool noreuse);
static int vm_domain_alloc_fail(struct vm_domain *vmd, vm_object_t object,
int req);
static int vm_page_zone_import(void *arg, void **store, int cnt, int domain,
int flags);
static void vm_page_zone_release(void *arg, void **store, int cnt);
SYSINIT(vm_page, SI_SUB_VM, SI_ORDER_SECOND, vm_page_init, NULL);
static void
vm_page_init(void *dummy)
{
fakepg_zone = uma_zcreate("fakepg", sizeof(struct vm_page), NULL, NULL,
NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE);
bogus_page = vm_page_alloc(NULL, 0, VM_ALLOC_NOOBJ |
VM_ALLOC_NORMAL | VM_ALLOC_WIRED);
}
/*
* The cache page zone is initialized later since we need to be able to allocate
* pages before UMA is fully initialized.
*/
static void
vm_page_init_cache_zones(void *dummy __unused)
{
struct vm_domain *vmd;
struct vm_pgcache *pgcache;
int cache, domain, maxcache, pool;
maxcache = 0;
TUNABLE_INT_FETCH("vm.pgcache_zone_max_pcpu", &maxcache);
maxcache *= mp_ncpus;
for (domain = 0; domain < vm_ndomains; domain++) {
vmd = VM_DOMAIN(domain);
for (pool = 0; pool < VM_NFREEPOOL; pool++) {
pgcache = &vmd->vmd_pgcache[pool];
pgcache->domain = domain;
pgcache->pool = pool;
pgcache->zone = uma_zcache_create("vm pgcache",
PAGE_SIZE, NULL, NULL, NULL, NULL,
vm_page_zone_import, vm_page_zone_release, pgcache,
UMA_ZONE_VM);
/*
* Limit each pool's zone to 0.1% of the pages in the
* domain.
*/
cache = maxcache != 0 ? maxcache :
vmd->vmd_page_count / 1000;
uma_zone_set_maxcache(pgcache->zone, cache);
}
}
}
SYSINIT(vm_page2, SI_SUB_VM_CONF, SI_ORDER_ANY, vm_page_init_cache_zones, NULL);
/* Make sure that u_long is at least 64 bits when PAGE_SIZE is 32K. */
#if PAGE_SIZE == 32768
#ifdef CTASSERT
CTASSERT(sizeof(u_long) >= 8);
#endif
#endif
/*
* vm_set_page_size:
*
* Sets the page size, perhaps based upon the memory
* size. Must be called before any use of page-size
* dependent functions.
*/
void
vm_set_page_size(void)
{
if (vm_cnt.v_page_size == 0)
vm_cnt.v_page_size = PAGE_SIZE;
if (((vm_cnt.v_page_size - 1) & vm_cnt.v_page_size) != 0)
panic("vm_set_page_size: page size not a power of two");
}
/*
* vm_page_blacklist_next:
*
* Find the next entry in the provided string of blacklist
* addresses. Entries are separated by space, comma, or newline.
* If an invalid integer is encountered then the rest of the
* string is skipped. Updates the list pointer to the next
* character, or NULL if the string is exhausted or invalid.
*/
static vm_paddr_t
vm_page_blacklist_next(char **list, char *end)
{
vm_paddr_t bad;
char *cp, *pos;
if (list == NULL || *list == NULL)
return (0);
if (**list =='\0') {
*list = NULL;
return (0);
}
/*
* If there's no end pointer then the buffer is coming from
* the kenv and we know it's null-terminated.
*/
if (end == NULL)
end = *list + strlen(*list);
/* Ensure that strtoq() won't walk off the end */
if (*end != '\0') {
if (*end == '\n' || *end == ' ' || *end == ',')
*end = '\0';
else {
printf("Blacklist not terminated, skipping\n");
*list = NULL;
return (0);
}
}
for (pos = *list; *pos != '\0'; pos = cp) {
bad = strtoq(pos, &cp, 0);
if (*cp == '\0' || *cp == ' ' || *cp == ',' || *cp == '\n') {
if (bad == 0) {
if (++cp < end)
continue;
else
break;
}
} else
break;
if (*cp == '\0' || ++cp >= end)
*list = NULL;
else
*list = cp;
return (trunc_page(bad));
}
printf("Garbage in RAM blacklist, skipping\n");
*list = NULL;
return (0);
}
bool
vm_page_blacklist_add(vm_paddr_t pa, bool verbose)
{
struct vm_domain *vmd;
vm_page_t m;
int ret;
m = vm_phys_paddr_to_vm_page(pa);
if (m == NULL)
return (true); /* page does not exist, no failure */
vmd = vm_pagequeue_domain(m);
vm_domain_free_lock(vmd);
ret = vm_phys_unfree_page(m);
vm_domain_free_unlock(vmd);
if (ret != 0) {
vm_domain_freecnt_inc(vmd, -1);
TAILQ_INSERT_TAIL(&blacklist_head, m, listq);
if (verbose)
printf("Skipping page with pa 0x%jx\n", (uintmax_t)pa);
}
return (ret);
}
/*
* vm_page_blacklist_check:
*
* Iterate through the provided string of blacklist addresses, pulling
* each entry out of the physical allocator free list and putting it
* onto a list for reporting via the vm.page_blacklist sysctl.
*/
static void
vm_page_blacklist_check(char *list, char *end)
{
vm_paddr_t pa;
char *next;
next = list;
while (next != NULL) {
if ((pa = vm_page_blacklist_next(&next, end)) == 0)
continue;
vm_page_blacklist_add(pa, bootverbose);
}
}
/*
* vm_page_blacklist_load:
*
* Search for a special module named "ram_blacklist". It'll be a
* plain text file provided by the user via the loader directive
* of the same name.
*/
static void
vm_page_blacklist_load(char **list, char **end)
{
void *mod;
u_char *ptr;
u_int len;
mod = NULL;
ptr = NULL;
mod = preload_search_by_type("ram_blacklist");
if (mod != NULL) {
ptr = preload_fetch_addr(mod);
len = preload_fetch_size(mod);
}
*list = ptr;
if (ptr != NULL)
*end = ptr + len;
else
*end = NULL;
return;
}
static int
sysctl_vm_page_blacklist(SYSCTL_HANDLER_ARGS)
{
vm_page_t m;
struct sbuf sbuf;
int error, first;
first = 1;
error = sysctl_wire_old_buffer(req, 0);
if (error != 0)
return (error);
sbuf_new_for_sysctl(&sbuf, NULL, 128, req);
TAILQ_FOREACH(m, &blacklist_head, listq) {
sbuf_printf(&sbuf, "%s%#jx", first ? "" : ",",
(uintmax_t)m->phys_addr);
first = 0;
}
error = sbuf_finish(&sbuf);
sbuf_delete(&sbuf);
return (error);
}
/*
* Initialize a dummy page for use in scans of the specified paging queue.
* In principle, this function only needs to set the flag PG_MARKER.
* Nonetheless, it write busies the page as a safety precaution.
*/
static void
vm_page_init_marker(vm_page_t marker, int queue, uint16_t aflags)
{
bzero(marker, sizeof(*marker));
marker->flags = PG_MARKER;
marker->a.flags = aflags;
marker->busy_lock = VPB_CURTHREAD_EXCLUSIVE;
marker->a.queue = queue;
}
static void
vm_page_domain_init(int domain)
{
struct vm_domain *vmd;
struct vm_pagequeue *pq;
int i;
vmd = VM_DOMAIN(domain);
bzero(vmd, sizeof(*vmd));
*__DECONST(const char **, &vmd->vmd_pagequeues[PQ_INACTIVE].pq_name) =
"vm inactive pagequeue";
*__DECONST(const char **, &vmd->vmd_pagequeues[PQ_ACTIVE].pq_name) =
"vm active pagequeue";
*__DECONST(const char **, &vmd->vmd_pagequeues[PQ_LAUNDRY].pq_name) =
"vm laundry pagequeue";
*__DECONST(const char **,
&vmd->vmd_pagequeues[PQ_UNSWAPPABLE].pq_name) =
"vm unswappable pagequeue";
vmd->vmd_domain = domain;
vmd->vmd_page_count = 0;
vmd->vmd_free_count = 0;
vmd->vmd_segs = 0;
vmd->vmd_oom = FALSE;
for (i = 0; i < PQ_COUNT; i++) {
pq = &vmd->vmd_pagequeues[i];
TAILQ_INIT(&pq->pq_pl);
mtx_init(&pq->pq_mutex, pq->pq_name, "vm pagequeue",
MTX_DEF | MTX_DUPOK);
pq->pq_pdpages = 0;
vm_page_init_marker(&vmd->vmd_markers[i], i, 0);
}
mtx_init(&vmd->vmd_free_mtx, "vm page free queue", NULL, MTX_DEF);
mtx_init(&vmd->vmd_pageout_mtx, "vm pageout lock", NULL, MTX_DEF);
snprintf(vmd->vmd_name, sizeof(vmd->vmd_name), "%d", domain);
/*
* inacthead is used to provide FIFO ordering for LRU-bypassing
* insertions.
*/
vm_page_init_marker(&vmd->vmd_inacthead, PQ_INACTIVE, PGA_ENQUEUED);
TAILQ_INSERT_HEAD(&vmd->vmd_pagequeues[PQ_INACTIVE].pq_pl,
&vmd->vmd_inacthead, plinks.q);
/*
* The clock pages are used to implement active queue scanning without
* requeues. Scans start at clock[0], which is advanced after the scan
* ends. When the two clock hands meet, they are reset and scanning
* resumes from the head of the queue.
*/
vm_page_init_marker(&vmd->vmd_clock[0], PQ_ACTIVE, PGA_ENQUEUED);
vm_page_init_marker(&vmd->vmd_clock[1], PQ_ACTIVE, PGA_ENQUEUED);
TAILQ_INSERT_HEAD(&vmd->vmd_pagequeues[PQ_ACTIVE].pq_pl,
&vmd->vmd_clock[0], plinks.q);
TAILQ_INSERT_TAIL(&vmd->vmd_pagequeues[PQ_ACTIVE].pq_pl,
&vmd->vmd_clock[1], plinks.q);
}
/*
* Initialize a physical page in preparation for adding it to the free
* lists.
*/
static void
vm_page_init_page(vm_page_t m, vm_paddr_t pa, int segind)
{
m->object = NULL;
m->ref_count = 0;
m->busy_lock = VPB_FREED;
m->flags = m->a.flags = 0;
m->phys_addr = pa;
m->a.queue = PQ_NONE;
m->psind = 0;
m->segind = segind;
m->order = VM_NFREEORDER;
m->pool = VM_FREEPOOL_DEFAULT;
m->valid = m->dirty = 0;
pmap_page_init(m);
}
#ifndef PMAP_HAS_PAGE_ARRAY
static vm_paddr_t
vm_page_array_alloc(vm_offset_t *vaddr, vm_paddr_t end, vm_paddr_t page_range)
{
vm_paddr_t new_end;
/*
* Reserve an unmapped guard page to trap access to vm_page_array[-1].
* However, because this page is allocated from KVM, out-of-bounds
* accesses using the direct map will not be trapped.
*/
*vaddr += PAGE_SIZE;
/*
* Allocate physical memory for the page structures, and map it.
*/
new_end = trunc_page(end - page_range * sizeof(struct vm_page));
vm_page_array = (vm_page_t)pmap_map(vaddr, new_end, end,
VM_PROT_READ | VM_PROT_WRITE);
vm_page_array_size = page_range;
return (new_end);
}
#endif
/*
* vm_page_startup:
*
* Initializes the resident memory module. Allocates physical memory for
* bootstrapping UMA and some data structures that are used to manage
* physical pages. Initializes these structures, and populates the free
* page queues.
*/
vm_offset_t
vm_page_startup(vm_offset_t vaddr)
{
struct vm_phys_seg *seg;
vm_page_t m;
char *list, *listend;
vm_paddr_t end, high_avail, low_avail, new_end, size;
vm_paddr_t page_range __unused;
vm_paddr_t last_pa, pa;
u_long pagecount;
int biggestone, i, segind;
#ifdef WITNESS
vm_offset_t mapped;
int witness_size;
#endif
#if defined(__i386__) && defined(VM_PHYSSEG_DENSE)
long ii;
#endif
vaddr = round_page(vaddr);
vm_phys_early_startup();
biggestone = vm_phys_avail_largest();
end = phys_avail[biggestone+1];
/*
* Initialize the page and queue locks.
*/
mtx_init(&vm_domainset_lock, "vm domainset lock", NULL, MTX_DEF);
for (i = 0; i < PA_LOCK_COUNT; i++)
mtx_init(&pa_lock[i], "vm page", NULL, MTX_DEF);
for (i = 0; i < vm_ndomains; i++)
vm_page_domain_init(i);
new_end = end;
#ifdef WITNESS
witness_size = round_page(witness_startup_count());
new_end -= witness_size;
mapped = pmap_map(&vaddr, new_end, new_end + witness_size,
VM_PROT_READ | VM_PROT_WRITE);
bzero((void *)mapped, witness_size);
witness_startup((void *)mapped);
#endif
#if defined(__aarch64__) || defined(__amd64__) || defined(__arm__) || \
defined(__i386__) || defined(__mips__) || defined(__riscv) || \
defined(__powerpc64__)
/*
* Allocate a bitmap to indicate that a random physical page
* needs to be included in a minidump.
*
* The amd64 port needs this to indicate which direct map pages
* need to be dumped, via calls to dump_add_page()/dump_drop_page().
*
* However, i386 still needs this workspace internally within the
* minidump code. In theory, they are not needed on i386, but are
* included should the sf_buf code decide to use them.
*/
last_pa = 0;
for (i = 0; dump_avail[i + 1] != 0; i += 2)
if (dump_avail[i + 1] > last_pa)
last_pa = dump_avail[i + 1];
page_range = last_pa / PAGE_SIZE;
vm_page_dump_size = round_page(roundup2(page_range, NBBY) / NBBY);
new_end -= vm_page_dump_size;
vm_page_dump = (void *)(uintptr_t)pmap_map(&vaddr, new_end,
new_end + vm_page_dump_size, VM_PROT_READ | VM_PROT_WRITE);
bzero((void *)vm_page_dump, vm_page_dump_size);
#else
(void)last_pa;
#endif
#if defined(__aarch64__) || defined(__amd64__) || defined(__mips__) || \
defined(__riscv) || defined(__powerpc64__)
/*
* Include the UMA bootstrap pages, witness pages and vm_page_dump
* in a crash dump. When pmap_map() uses the direct map, they are
* not automatically included.
*/
for (pa = new_end; pa < end; pa += PAGE_SIZE)
dump_add_page(pa);
#endif
phys_avail[biggestone + 1] = new_end;
#ifdef __amd64__
/*
* Request that the physical pages underlying the message buffer be
* included in a crash dump. Since the message buffer is accessed
* through the direct map, they are not automatically included.
*/
pa = DMAP_TO_PHYS((vm_offset_t)msgbufp->msg_ptr);
last_pa = pa + round_page(msgbufsize);
while (pa < last_pa) {
dump_add_page(pa);
pa += PAGE_SIZE;
}
#endif
/*
* Compute the number of pages of memory that will be available for
* use, taking into account the overhead of a page structure per page.
* In other words, solve
* "available physical memory" - round_page(page_range *
* sizeof(struct vm_page)) = page_range * PAGE_SIZE
* for page_range.
*/
low_avail = phys_avail[0];
high_avail = phys_avail[1];
for (i = 0; i < vm_phys_nsegs; i++) {
if (vm_phys_segs[i].start < low_avail)
low_avail = vm_phys_segs[i].start;
if (vm_phys_segs[i].end > high_avail)
high_avail = vm_phys_segs[i].end;
}
/* Skip the first chunk. It is already accounted for. */
for (i = 2; phys_avail[i + 1] != 0; i += 2) {
if (phys_avail[i] < low_avail)
low_avail = phys_avail[i];
if (phys_avail[i + 1] > high_avail)
high_avail = phys_avail[i + 1];
}
first_page = low_avail / PAGE_SIZE;
#ifdef VM_PHYSSEG_SPARSE
size = 0;
for (i = 0; i < vm_phys_nsegs; i++)
size += vm_phys_segs[i].end - vm_phys_segs[i].start;
for (i = 0; phys_avail[i + 1] != 0; i += 2)
size += phys_avail[i + 1] - phys_avail[i];
#elif defined(VM_PHYSSEG_DENSE)
size = high_avail - low_avail;
#else
#error "Either VM_PHYSSEG_DENSE or VM_PHYSSEG_SPARSE must be defined."
#endif
#ifdef PMAP_HAS_PAGE_ARRAY
pmap_page_array_startup(size / PAGE_SIZE);
biggestone = vm_phys_avail_largest();
end = new_end = phys_avail[biggestone + 1];
#else
#ifdef VM_PHYSSEG_DENSE
/*
* In the VM_PHYSSEG_DENSE case, the number of pages can account for
* the overhead of a page structure per page only if vm_page_array is
* allocated from the last physical memory chunk. Otherwise, we must
* allocate page structures representing the physical memory
* underlying vm_page_array, even though they will not be used.
*/
if (new_end != high_avail)
page_range = size / PAGE_SIZE;
else
#endif
{
page_range = size / (PAGE_SIZE + sizeof(struct vm_page));
/*
* If the partial bytes remaining are large enough for
* a page (PAGE_SIZE) without a corresponding
* 'struct vm_page', then new_end will contain an
* extra page after subtracting the length of the VM
* page array. Compensate by subtracting an extra
* page from new_end.
*/
if (size % (PAGE_SIZE + sizeof(struct vm_page)) >= PAGE_SIZE) {
if (new_end == high_avail)
high_avail -= PAGE_SIZE;
new_end -= PAGE_SIZE;
}
}
end = new_end;
new_end = vm_page_array_alloc(&vaddr, end, page_range);
#endif
#if VM_NRESERVLEVEL > 0
/*
* Allocate physical memory for the reservation management system's
* data structures, and map it.
*/
new_end = vm_reserv_startup(&vaddr, new_end);
#endif
#if defined(__aarch64__) || defined(__amd64__) || defined(__mips__) || \
defined(__riscv) || defined(__powerpc64__)
/*
* Include vm_page_array and vm_reserv_array in a crash dump.
*/
for (pa = new_end; pa < end; pa += PAGE_SIZE)
dump_add_page(pa);
#endif
phys_avail[biggestone + 1] = new_end;
/*
* Add physical memory segments corresponding to the available
* physical pages.
*/
for (i = 0; phys_avail[i + 1] != 0; i += 2)
if (vm_phys_avail_size(i) != 0)
vm_phys_add_seg(phys_avail[i], phys_avail[i + 1]);
/*
* Initialize the physical memory allocator.
*/
vm_phys_init();
/*
* Initialize the page structures and add every available page to the
* physical memory allocator's free lists.
*/
#if defined(__i386__) && defined(VM_PHYSSEG_DENSE)
for (ii = 0; ii < vm_page_array_size; ii++) {
m = &vm_page_array[ii];
vm_page_init_page(m, (first_page + ii) << PAGE_SHIFT, 0);
m->flags = PG_FICTITIOUS;
}
#endif
vm_cnt.v_page_count = 0;
for (segind = 0; segind < vm_phys_nsegs; segind++) {
seg = &vm_phys_segs[segind];
for (m = seg->first_page, pa = seg->start; pa < seg->end;
m++, pa += PAGE_SIZE)
vm_page_init_page(m, pa, segind);
/*
* Add the segment to the free lists only if it is covered by
* one of the ranges in phys_avail. Because we've added the
* ranges to the vm_phys_segs array, we can assume that each
* segment is either entirely contained in one of the ranges,
* or doesn't overlap any of them.
*/
for (i = 0; phys_avail[i + 1] != 0; i += 2) {
struct vm_domain *vmd;
if (seg->start < phys_avail[i] ||
seg->end > phys_avail[i + 1])
continue;
m = seg->first_page;
pagecount = (u_long)atop(seg->end - seg->start);
vmd = VM_DOMAIN(seg->domain);
vm_domain_free_lock(vmd);
vm_phys_enqueue_contig(m, pagecount);
vm_domain_free_unlock(vmd);
vm_domain_freecnt_inc(vmd, pagecount);
vm_cnt.v_page_count += (u_int)pagecount;
vmd = VM_DOMAIN(seg->domain);
vmd->vmd_page_count += (u_int)pagecount;
vmd->vmd_segs |= 1UL << m->segind;
break;
}
}
/*
* Remove blacklisted pages from the physical memory allocator.
*/
TAILQ_INIT(&blacklist_head);
vm_page_blacklist_load(&list, &listend);
vm_page_blacklist_check(list, listend);
list = kern_getenv("vm.blacklist");
vm_page_blacklist_check(list, NULL);
freeenv(list);
#if VM_NRESERVLEVEL > 0
/*
* Initialize the reservation management system.
*/
vm_reserv_init();
#endif
return (vaddr);
}
void
vm_page_reference(vm_page_t m)
{
vm_page_aflag_set(m, PGA_REFERENCED);
}
/*
* vm_page_trybusy
*
* Helper routine for grab functions to trylock busy.
*
* Returns true on success and false on failure.
*/
static bool
vm_page_trybusy(vm_page_t m, int allocflags)
{
if ((allocflags & (VM_ALLOC_SBUSY | VM_ALLOC_IGN_SBUSY)) != 0)
return (vm_page_trysbusy(m));
else
return (vm_page_tryxbusy(m));
}
/*
* vm_page_tryacquire
*
* Helper routine for grab functions to trylock busy and wire.
*
* Returns true on success and false on failure.
*/
static inline bool
vm_page_tryacquire(vm_page_t m, int allocflags)
{
bool locked;
locked = vm_page_trybusy(m, allocflags);
if (locked && (allocflags & VM_ALLOC_WIRED) != 0)
vm_page_wire(m);
return (locked);
}
/*
* vm_page_busy_acquire:
*
* Acquire the busy lock as described by VM_ALLOC_* flags. Will loop
* and drop the object lock if necessary.
*/
bool
vm_page_busy_acquire(vm_page_t m, int allocflags)
{
vm_object_t obj;
bool locked;
/*
* The page-specific object must be cached because page
* identity can change during the sleep, causing the
* re-lock of a different object.
* It is assumed that a reference to the object is already
* held by the callers.
*/
obj = m->object;
for (;;) {
if (vm_page_tryacquire(m, allocflags))
return (true);
if ((allocflags & VM_ALLOC_NOWAIT) != 0)
return (false);
if (obj != NULL)
locked = VM_OBJECT_WOWNED(obj);
else
locked = false;
MPASS(locked || vm_page_wired(m));
if (_vm_page_busy_sleep(obj, m, m->pindex, "vmpba", allocflags,
locked) && locked)
VM_OBJECT_WLOCK(obj);
if ((allocflags & VM_ALLOC_WAITFAIL) != 0)
return (false);
KASSERT(m->object == obj || m->object == NULL,
("vm_page_busy_acquire: page %p does not belong to %p",
m, obj));
}
}
/*
* vm_page_busy_downgrade:
*
* Downgrade an exclusive busy page into a single shared busy page.
*/
void
vm_page_busy_downgrade(vm_page_t m)
{
u_int x;
vm_page_assert_xbusied(m);
x = m->busy_lock;
for (;;) {
if (atomic_fcmpset_rel_int(&m->busy_lock,
&x, VPB_SHARERS_WORD(1)))
break;
}
if ((x & VPB_BIT_WAITERS) != 0)
wakeup(m);
}
/*
*
* vm_page_busy_tryupgrade:
*
* Attempt to upgrade a single shared busy into an exclusive busy.
*/
int
vm_page_busy_tryupgrade(vm_page_t m)
{
u_int ce, x;
vm_page_assert_sbusied(m);
x = m->busy_lock;
ce = VPB_CURTHREAD_EXCLUSIVE;
for (;;) {
if (VPB_SHARERS(x) > 1)
return (0);
KASSERT((x & ~VPB_BIT_WAITERS) == VPB_SHARERS_WORD(1),
("vm_page_busy_tryupgrade: invalid lock state"));
if (!atomic_fcmpset_acq_int(&m->busy_lock, &x,
ce | (x & VPB_BIT_WAITERS)))
continue;
return (1);
}
}
/*
* vm_page_sbusied:
*
* Return a positive value if the page is shared busied, 0 otherwise.
*/
int
vm_page_sbusied(vm_page_t m)
{
u_int x;
x = m->busy_lock;
return ((x & VPB_BIT_SHARED) != 0 && x != VPB_UNBUSIED);
}
/*
* vm_page_sunbusy:
*
* Shared unbusy a page.
*/
void
vm_page_sunbusy(vm_page_t m)
{
u_int x;
vm_page_assert_sbusied(m);
x = m->busy_lock;
for (;;) {
KASSERT(x != VPB_FREED,
("vm_page_sunbusy: Unlocking freed page."));
if (VPB_SHARERS(x) > 1) {
if (atomic_fcmpset_int(&m->busy_lock, &x,
x - VPB_ONE_SHARER))
break;
continue;
}
KASSERT((x & ~VPB_BIT_WAITERS) == VPB_SHARERS_WORD(1),
("vm_page_sunbusy: invalid lock state"));
if (!atomic_fcmpset_rel_int(&m->busy_lock, &x, VPB_UNBUSIED))
continue;
if ((x & VPB_BIT_WAITERS) == 0)
break;
wakeup(m);
break;
}
}
/*
* vm_page_busy_sleep:
*
* Sleep if the page is busy, using the page pointer as wchan.
* This is used to implement the hard-path of busying mechanism.
*
* If nonshared is true, sleep only if the page is xbusy.
*
* The object lock must be held on entry and will be released on exit.
*/
void
vm_page_busy_sleep(vm_page_t m, const char *wmesg, bool nonshared)
{
vm_object_t obj;
obj = m->object;
VM_OBJECT_ASSERT_LOCKED(obj);
vm_page_lock_assert(m, MA_NOTOWNED);
if (!_vm_page_busy_sleep(obj, m, m->pindex, wmesg,
nonshared ? VM_ALLOC_SBUSY : 0 , true))
VM_OBJECT_DROP(obj);
}
/*
* vm_page_busy_sleep_unlocked:
*
* Sleep if the page is busy, using the page pointer as wchan.
* This is used to implement the hard-path of busying mechanism.
*
* If nonshared is true, sleep only if the page is xbusy.
*
* The object lock must not be held on entry. The operation will
* return if the page changes identity.
*/
void
vm_page_busy_sleep_unlocked(vm_object_t obj, vm_page_t m, vm_pindex_t pindex,
const char *wmesg, bool nonshared)
{
VM_OBJECT_ASSERT_UNLOCKED(obj);
vm_page_lock_assert(m, MA_NOTOWNED);
_vm_page_busy_sleep(obj, m, pindex, wmesg,
nonshared ? VM_ALLOC_SBUSY : 0, false);
}
/*
* _vm_page_busy_sleep:
*
* Internal busy sleep function. Verifies the page identity and
* lockstate against parameters. Returns true if it sleeps and
* false otherwise.
*
* If locked is true the lock will be dropped for any true returns
* and held for any false returns.
*/
static bool
_vm_page_busy_sleep(vm_object_t obj, vm_page_t m, vm_pindex_t pindex,
const char *wmesg, int allocflags, bool locked)
{
bool xsleep;
u_int x;
/*
* If the object is busy we must wait for that to drain to zero
* before trying the page again.
*/
if (obj != NULL && vm_object_busied(obj)) {
if (locked)
VM_OBJECT_DROP(obj);
vm_object_busy_wait(obj, wmesg);
return (true);
}
if (!vm_page_busied(m))
return (false);
xsleep = (allocflags & (VM_ALLOC_SBUSY | VM_ALLOC_IGN_SBUSY)) != 0;
sleepq_lock(m);
x = atomic_load_int(&m->busy_lock);
do {
/*
* If the page changes objects or becomes unlocked we can
* simply return.
*/
if (x == VPB_UNBUSIED ||
(xsleep && (x & VPB_BIT_SHARED) != 0) ||
m->object != obj || m->pindex != pindex) {
sleepq_release(m);
return (false);
}
if ((x & VPB_BIT_WAITERS) != 0)
break;
} while (!atomic_fcmpset_int(&m->busy_lock, &x, x | VPB_BIT_WAITERS));
if (locked)
VM_OBJECT_DROP(obj);
DROP_GIANT();
sleepq_add(m, NULL, wmesg, 0, 0);
sleepq_wait(m, PVM);
PICKUP_GIANT();
return (true);
}
/*
* vm_page_trysbusy:
*
* Try to shared busy a page.
* If the operation succeeds 1 is returned otherwise 0.
* The operation never sleeps.
*/
int
vm_page_trysbusy(vm_page_t m)
{
vm_object_t obj;
u_int x;
obj = m->object;
x = m->busy_lock;
for (;;) {
if ((x & VPB_BIT_SHARED) == 0)
return (0);
/*
* Reduce the window for transient busies that will trigger
* false negatives in vm_page_ps_test().
*/
if (obj != NULL && vm_object_busied(obj))
return (0);
if (atomic_fcmpset_acq_int(&m->busy_lock, &x,
x + VPB_ONE_SHARER))
break;
}
/* Refetch the object now that we're guaranteed that it is stable. */
obj = m->object;
if (obj != NULL && vm_object_busied(obj)) {
vm_page_sunbusy(m);
return (0);
}
return (1);
}
/*
* vm_page_tryxbusy:
*
* Try to exclusive busy a page.
* If the operation succeeds 1 is returned otherwise 0.
* The operation never sleeps.
*/
int
vm_page_tryxbusy(vm_page_t m)
{
vm_object_t obj;
if (atomic_cmpset_acq_int(&(m)->busy_lock, VPB_UNBUSIED,
VPB_CURTHREAD_EXCLUSIVE) == 0)
return (0);
obj = m->object;
if (obj != NULL && vm_object_busied(obj)) {
vm_page_xunbusy(m);
return (0);
}
return (1);
}
static void
vm_page_xunbusy_hard_tail(vm_page_t m)
{
atomic_store_rel_int(&m->busy_lock, VPB_UNBUSIED);
/* Wake the waiter. */
wakeup(m);
}
/*
* vm_page_xunbusy_hard:
*
* Called when unbusy has failed because there is a waiter.
*/
void
vm_page_xunbusy_hard(vm_page_t m)
{
vm_page_assert_xbusied(m);
vm_page_xunbusy_hard_tail(m);
}
void
vm_page_xunbusy_hard_unchecked(vm_page_t m)
{
vm_page_assert_xbusied_unchecked(m);
vm_page_xunbusy_hard_tail(m);
}
static void
vm_page_busy_free(vm_page_t m)
{
u_int x;
atomic_thread_fence_rel();
x = atomic_swap_int(&m->busy_lock, VPB_FREED);
if ((x & VPB_BIT_WAITERS) != 0)
wakeup(m);
}
/*
* vm_page_unhold_pages:
*
* Unhold each of the pages that is referenced by the given array.
*/
void
vm_page_unhold_pages(vm_page_t *ma, int count)
{
for (; count != 0; count--) {
vm_page_unwire(*ma, PQ_ACTIVE);
ma++;
}
}
vm_page_t
PHYS_TO_VM_PAGE(vm_paddr_t pa)
{
vm_page_t m;
#ifdef VM_PHYSSEG_SPARSE
m = vm_phys_paddr_to_vm_page(pa);
if (m == NULL)
m = vm_phys_fictitious_to_vm_page(pa);
return (m);
#elif defined(VM_PHYSSEG_DENSE)
long pi;
pi = atop(pa);
if (pi >= first_page && (pi - first_page) < vm_page_array_size) {
m = &vm_page_array[pi - first_page];
return (m);
}
return (vm_phys_fictitious_to_vm_page(pa));
#else
#error "Either VM_PHYSSEG_DENSE or VM_PHYSSEG_SPARSE must be defined."
#endif
}
/*
* vm_page_getfake:
*
* Create a fictitious page with the specified physical address and
* memory attribute. The memory attribute is the only the machine-
* dependent aspect of a fictitious page that must be initialized.
*/
vm_page_t
vm_page_getfake(vm_paddr_t paddr, vm_memattr_t memattr)
{
vm_page_t m;
m = uma_zalloc(fakepg_zone, M_WAITOK | M_ZERO);
vm_page_initfake(m, paddr, memattr);
return (m);
}
void
vm_page_initfake(vm_page_t m, vm_paddr_t paddr, vm_memattr_t memattr)
{
if ((m->flags & PG_FICTITIOUS) != 0) {
/*
* The page's memattr might have changed since the
* previous initialization. Update the pmap to the
* new memattr.
*/
goto memattr;
}
m->phys_addr = paddr;
m->a.queue = PQ_NONE;
/* Fictitious pages don't use "segind". */
m->flags = PG_FICTITIOUS;
/* Fictitious pages don't use "order" or "pool". */
m->oflags = VPO_UNMANAGED;
m->busy_lock = VPB_CURTHREAD_EXCLUSIVE;
/* Fictitious pages are unevictable. */
m->ref_count = 1;
pmap_page_init(m);
memattr:
pmap_page_set_memattr(m, memattr);
}
/*
* vm_page_putfake:
*
* Release a fictitious page.
*/
void
vm_page_putfake(vm_page_t m)
{
KASSERT((m->oflags & VPO_UNMANAGED) != 0, ("managed %p", m));
KASSERT((m->flags & PG_FICTITIOUS) != 0,
("vm_page_putfake: bad page %p", m));
vm_page_assert_xbusied(m);
vm_page_busy_free(m);
uma_zfree(fakepg_zone, m);
}
/*
* vm_page_updatefake:
*
* Update the given fictitious page to the specified physical address and
* memory attribute.
*/
void
vm_page_updatefake(vm_page_t m, vm_paddr_t paddr, vm_memattr_t memattr)
{
KASSERT((m->flags & PG_FICTITIOUS) != 0,
("vm_page_updatefake: bad page %p", m));
m->phys_addr = paddr;
pmap_page_set_memattr(m, memattr);
}
/*
* vm_page_free:
*
* Free a page.
*/
void
vm_page_free(vm_page_t m)
{
m->flags &= ~PG_ZERO;
vm_page_free_toq(m);
}
/*
* vm_page_free_zero:
*
* Free a page to the zerod-pages queue
*/
void
vm_page_free_zero(vm_page_t m)
{
m->flags |= PG_ZERO;
vm_page_free_toq(m);
}
/*
* Unbusy and handle the page queueing for a page from a getpages request that
* was optionally read ahead or behind.
*/
void
vm_page_readahead_finish(vm_page_t m)
{
/* We shouldn't put invalid pages on queues. */
KASSERT(!vm_page_none_valid(m), ("%s: %p is invalid", __func__, m));
/*
* Since the page is not the actually needed one, whether it should
* be activated or deactivated is not obvious. Empirical results
* have shown that deactivating the page is usually the best choice,
* unless the page is wanted by another thread.
*/
if ((m->busy_lock & VPB_BIT_WAITERS) != 0)
vm_page_activate(m);
else
vm_page_deactivate(m);
vm_page_xunbusy_unchecked(m);
}
/*
* vm_page_sleep_if_busy:
*
* Sleep and release the object lock if the page is busied.
* Returns TRUE if the thread slept.
*
* The given page must be unlocked and object containing it must
* be locked.
*/
int
vm_page_sleep_if_busy(vm_page_t m, const char *wmesg)
{
vm_object_t obj;
vm_page_lock_assert(m, MA_NOTOWNED);
VM_OBJECT_ASSERT_WLOCKED(m->object);
/*
* The page-specific object must be cached because page
* identity can change during the sleep, causing the
* re-lock of a different object.
* It is assumed that a reference to the object is already
* held by the callers.
*/
obj = m->object;
if (_vm_page_busy_sleep(obj, m, m->pindex, wmesg, 0, true)) {
VM_OBJECT_WLOCK(obj);
return (TRUE);
}
return (FALSE);
}
/*
* vm_page_sleep_if_xbusy:
*
* Sleep and release the object lock if the page is xbusied.
* Returns TRUE if the thread slept.
*
* The given page must be unlocked and object containing it must
* be locked.
*/
int
vm_page_sleep_if_xbusy(vm_page_t m, const char *wmesg)
{
vm_object_t obj;
vm_page_lock_assert(m, MA_NOTOWNED);
VM_OBJECT_ASSERT_WLOCKED(m->object);
/*
* The page-specific object must be cached because page
* identity can change during the sleep, causing the
* re-lock of a different object.
* It is assumed that a reference to the object is already
* held by the callers.
*/
obj = m->object;
if (_vm_page_busy_sleep(obj, m, m->pindex, wmesg, VM_ALLOC_SBUSY,
true)) {
VM_OBJECT_WLOCK(obj);
return (TRUE);
}
return (FALSE);
}
/*
* vm_page_dirty_KBI: [ internal use only ]
*
* Set all bits in the page's dirty field.
*
* The object containing the specified page must be locked if the
* call is made from the machine-independent layer.
*
* See vm_page_clear_dirty_mask().
*
* This function should only be called by vm_page_dirty().
*/
void
vm_page_dirty_KBI(vm_page_t m)
{
/* Refer to this operation by its public name. */
KASSERT(vm_page_all_valid(m), ("vm_page_dirty: page is invalid!"));
m->dirty = VM_PAGE_BITS_ALL;
}
/*
* vm_page_insert: [ internal use only ]
*
* Inserts the given mem entry into the object and object list.
*
* The object must be locked.
*/
int
vm_page_insert(vm_page_t m, vm_object_t object, vm_pindex_t pindex)
{
vm_page_t mpred;
VM_OBJECT_ASSERT_WLOCKED(object);
mpred = vm_radix_lookup_le(&object->rtree, pindex);
return (vm_page_insert_after(m, object, pindex, mpred));
}
/*
* vm_page_insert_after:
*
* Inserts the page "m" into the specified object at offset "pindex".
*
* The page "mpred" must immediately precede the offset "pindex" within
* the specified object.
*
* The object must be locked.
*/
static int
vm_page_insert_after(vm_page_t m, vm_object_t object, vm_pindex_t pindex,
vm_page_t mpred)
{
vm_page_t msucc;
VM_OBJECT_ASSERT_WLOCKED(object);
KASSERT(m->object == NULL,
("vm_page_insert_after: page already inserted"));
if (mpred != NULL) {
KASSERT(mpred->object == object,
("vm_page_insert_after: object doesn't contain mpred"));
KASSERT(mpred->pindex < pindex,
("vm_page_insert_after: mpred doesn't precede pindex"));
msucc = TAILQ_NEXT(mpred, listq);
} else
msucc = TAILQ_FIRST(&object->memq);
if (msucc != NULL)
KASSERT(msucc->pindex > pindex,
("vm_page_insert_after: msucc doesn't succeed pindex"));
/*
* Record the object/offset pair in this page.
*/
m->object = object;
m->pindex = pindex;
m->ref_count |= VPRC_OBJREF;
/*
* Now link into the object's ordered list of backed pages.
*/
if (vm_radix_insert(&object->rtree, m)) {
m->object = NULL;
m->pindex = 0;
m->ref_count &= ~VPRC_OBJREF;
return (1);
}
vm_page_insert_radixdone(m, object, mpred);
return (0);
}
/*
* vm_page_insert_radixdone:
*
* Complete page "m" insertion into the specified object after the
* radix trie hooking.
*
* The page "mpred" must precede the offset "m->pindex" within the
* specified object.
*
* The object must be locked.
*/
static void
vm_page_insert_radixdone(vm_page_t m, vm_object_t object, vm_page_t mpred)
{
VM_OBJECT_ASSERT_WLOCKED(object);
KASSERT(object != NULL && m->object == object,
("vm_page_insert_radixdone: page %p has inconsistent object", m));
KASSERT((m->ref_count & VPRC_OBJREF) != 0,
("vm_page_insert_radixdone: page %p is missing object ref", m));
if (mpred != NULL) {
KASSERT(mpred->object == object,
("vm_page_insert_radixdone: object doesn't contain mpred"));
KASSERT(mpred->pindex < m->pindex,
("vm_page_insert_radixdone: mpred doesn't precede pindex"));
}
if (mpred != NULL)
TAILQ_INSERT_AFTER(&object->memq, mpred, m, listq);
else
TAILQ_INSERT_HEAD(&object->memq, m, listq);
/*
* Show that the object has one more resident page.
*/
object->resident_page_count++;
/*
* Hold the vnode until the last page is released.
*/
if (object->resident_page_count == 1 && object->type == OBJT_VNODE)
vhold(object->handle);
/*
* Since we are inserting a new and possibly dirty page,
* update the object's generation count.
*/
if (pmap_page_is_write_mapped(m))
vm_object_set_writeable_dirty(object);
}
/*
* Do the work to remove a page from its object. The caller is responsible for
* updating the page's fields to reflect this removal.
*/
static void
vm_page_object_remove(vm_page_t m)
{
vm_object_t object;
vm_page_t mrem;
vm_page_assert_xbusied(m);
object = m->object;
VM_OBJECT_ASSERT_WLOCKED(object);
KASSERT((m->ref_count & VPRC_OBJREF) != 0,
("page %p is missing its object ref", m));
/* Deferred free of swap space. */
if ((m->a.flags & PGA_SWAP_FREE) != 0)
vm_pager_page_unswapped(m);
m->object = NULL;
mrem = vm_radix_remove(&object->rtree, m->pindex);
KASSERT(mrem == m, ("removed page %p, expected page %p", mrem, m));
/*
* Now remove from the object's list of backed pages.
*/
TAILQ_REMOVE(&object->memq, m, listq);
/*
* And show that the object has one fewer resident page.
*/
object->resident_page_count--;
/*
* The vnode may now be recycled.
*/
if (object->resident_page_count == 0 && object->type == OBJT_VNODE)
vdrop(object->handle);
}
/*
* vm_page_remove:
*
* Removes the specified page from its containing object, but does not
* invalidate any backing storage. Returns true if the object's reference
* was the last reference to the page, and false otherwise.
*
* The object must be locked and the page must be exclusively busied.
* The exclusive busy will be released on return. If this is not the
* final ref and the caller does not hold a wire reference it may not
* continue to access the page.
*/
bool
vm_page_remove(vm_page_t m)
{
bool dropped;
dropped = vm_page_remove_xbusy(m);
vm_page_xunbusy(m);
return (dropped);
}
/*
* vm_page_remove_xbusy
*
* Removes the page but leaves the xbusy held. Returns true if this
* removed the final ref and false otherwise.
*/
bool
vm_page_remove_xbusy(vm_page_t m)
{
vm_page_object_remove(m);
return (vm_page_drop(m, VPRC_OBJREF) == VPRC_OBJREF);
}
/*
* vm_page_lookup:
*
* Returns the page associated with the object/offset
* pair specified; if none is found, NULL is returned.
*
* The object must be locked.
*/
vm_page_t
vm_page_lookup(vm_object_t object, vm_pindex_t pindex)
{
VM_OBJECT_ASSERT_LOCKED(object);
return (vm_radix_lookup(&object->rtree, pindex));
}
/*
* vm_page_relookup:
*
* Returns a page that must already have been busied by
* the caller. Used for bogus page replacement.
*/
vm_page_t
vm_page_relookup(vm_object_t object, vm_pindex_t pindex)
{
vm_page_t m;
m = vm_radix_lookup_unlocked(&object->rtree, pindex);
KASSERT(m != NULL && (vm_page_busied(m) || vm_page_wired(m)) &&
m->object == object && m->pindex == pindex,
("vm_page_relookup: Invalid page %p", m));
return (m);
}
/*
* This should only be used by lockless functions for releasing transient
* incorrect acquires. The page may have been freed after we acquired a
* busy lock. In this case busy_lock == VPB_FREED and we have nothing
* further to do.
*/
static void
vm_page_busy_release(vm_page_t m)
{
u_int x;
x = atomic_load_int(&m->busy_lock);
for (;;) {
if (x == VPB_FREED)
break;
if ((x & VPB_BIT_SHARED) != 0 && VPB_SHARERS(x) > 1) {
if (atomic_fcmpset_int(&m->busy_lock, &x,
x - VPB_ONE_SHARER))
break;
continue;
}
KASSERT((x & VPB_BIT_SHARED) != 0 ||
(x & ~VPB_BIT_WAITERS) == VPB_CURTHREAD_EXCLUSIVE,
("vm_page_busy_release: %p xbusy not owned.", m));
if (!atomic_fcmpset_rel_int(&m->busy_lock, &x, VPB_UNBUSIED))
continue;
if ((x & VPB_BIT_WAITERS) != 0)
wakeup(m);
break;
}
}
/*
* vm_page_find_least:
*
* Returns the page associated with the object with least pindex
* greater than or equal to the parameter pindex, or NULL.
*
* The object must be locked.
*/
vm_page_t
vm_page_find_least(vm_object_t object, vm_pindex_t pindex)
{
vm_page_t m;
VM_OBJECT_ASSERT_LOCKED(object);
if ((m = TAILQ_FIRST(&object->memq)) != NULL && m->pindex < pindex)
m = vm_radix_lookup_ge(&object->rtree, pindex);
return (m);
}
/*
* Returns the given page's successor (by pindex) within the object if it is
* resident; if none is found, NULL is returned.
*
* The object must be locked.
*/
vm_page_t
vm_page_next(vm_page_t m)
{
vm_page_t next;
VM_OBJECT_ASSERT_LOCKED(m->object);
if ((next = TAILQ_NEXT(m, listq)) != NULL) {
MPASS(next->object == m->object);
if (next->pindex != m->pindex + 1)
next = NULL;
}
return (next);
}
/*
* Returns the given page's predecessor (by pindex) within the object if it is
* resident; if none is found, NULL is returned.
*
* The object must be locked.
*/
vm_page_t
vm_page_prev(vm_page_t m)
{
vm_page_t prev;
VM_OBJECT_ASSERT_LOCKED(m->object);
if ((prev = TAILQ_PREV(m, pglist, listq)) != NULL) {
MPASS(prev->object == m->object);
if (prev->pindex != m->pindex - 1)
prev = NULL;
}
return (prev);
}
/*
* Uses the page mnew as a replacement for an existing page at index
* pindex which must be already present in the object.
*
* Both pages must be exclusively busied on enter. The old page is
* unbusied on exit.
*
* A return value of true means mold is now free. If this is not the
* final ref and the caller does not hold a wire reference it may not
* continue to access the page.
*/
static bool
vm_page_replace_hold(vm_page_t mnew, vm_object_t object, vm_pindex_t pindex,
vm_page_t mold)
{
vm_page_t mret;
bool dropped;
VM_OBJECT_ASSERT_WLOCKED(object);
vm_page_assert_xbusied(mold);
KASSERT(mnew->object == NULL && (mnew->ref_count & VPRC_OBJREF) == 0,
("vm_page_replace: page %p already in object", mnew));
/*
* This function mostly follows vm_page_insert() and
* vm_page_remove() without the radix, object count and vnode
* dance. Double check such functions for more comments.
*/
mnew->object = object;
mnew->pindex = pindex;
atomic_set_int(&mnew->ref_count, VPRC_OBJREF);
mret = vm_radix_replace(&object->rtree, mnew);
KASSERT(mret == mold,
("invalid page replacement, mold=%p, mret=%p", mold, mret));
KASSERT((mold->oflags & VPO_UNMANAGED) ==
(mnew->oflags & VPO_UNMANAGED),
("vm_page_replace: mismatched VPO_UNMANAGED"));
/* Keep the resident page list in sorted order. */
TAILQ_INSERT_AFTER(&object->memq, mold, mnew, listq);
TAILQ_REMOVE(&object->memq, mold, listq);
mold->object = NULL;
/*
* The object's resident_page_count does not change because we have
* swapped one page for another, but the generation count should
* change if the page is dirty.
*/
if (pmap_page_is_write_mapped(mnew))
vm_object_set_writeable_dirty(object);
dropped = vm_page_drop(mold, VPRC_OBJREF) == VPRC_OBJREF;
vm_page_xunbusy(mold);
return (dropped);
}
void
vm_page_replace(vm_page_t mnew, vm_object_t object, vm_pindex_t pindex,
vm_page_t mold)
{
vm_page_assert_xbusied(mnew);
if (vm_page_replace_hold(mnew, object, pindex, mold))
vm_page_free(mold);
}
/*
* vm_page_rename:
*
* Move the given memory entry from its
* current object to the specified target object/offset.
*
* Note: swap associated with the page must be invalidated by the move. We
* have to do this for several reasons: (1) we aren't freeing the
* page, (2) we are dirtying the page, (3) the VM system is probably
* moving the page from object A to B, and will then later move
* the backing store from A to B and we can't have a conflict.
*
* Note: we *always* dirty the page. It is necessary both for the
* fact that we moved it, and because we may be invalidating
* swap.
*
* The objects must be locked.
*/
int
vm_page_rename(vm_page_t m, vm_object_t new_object, vm_pindex_t new_pindex)
{
vm_page_t mpred;
vm_pindex_t opidx;
VM_OBJECT_ASSERT_WLOCKED(new_object);
KASSERT(m->ref_count != 0, ("vm_page_rename: page %p has no refs", m));
mpred = vm_radix_lookup_le(&new_object->rtree, new_pindex);
KASSERT(mpred == NULL || mpred->pindex != new_pindex,
("vm_page_rename: pindex already renamed"));
/*
* Create a custom version of vm_page_insert() which does not depend
* by m_prev and can cheat on the implementation aspects of the
* function.
*/
opidx = m->pindex;
m->pindex = new_pindex;
if (vm_radix_insert(&new_object->rtree, m)) {
m->pindex = opidx;
return (1);
}
/*
* The operation cannot fail anymore. The removal must happen before
* the listq iterator is tainted.
*/
m->pindex = opidx;
vm_page_object_remove(m);
/* Return back to the new pindex to complete vm_page_insert(). */
m->pindex = new_pindex;
m->object = new_object;
vm_page_insert_radixdone(m, new_object, mpred);
vm_page_dirty(m);
return (0);
}
/*
* vm_page_alloc:
*
* Allocate and return a page that is associated with the specified
* object and offset pair. By default, this page is exclusive busied.
*
* The caller must always specify an allocation class.
*
* allocation classes:
* VM_ALLOC_NORMAL normal process request
* VM_ALLOC_SYSTEM system *really* needs a page
* VM_ALLOC_INTERRUPT interrupt time request
*
* optional allocation flags:
* VM_ALLOC_COUNT(number) the number of additional pages that the caller
* intends to allocate
* VM_ALLOC_NOBUSY do not exclusive busy the page
* VM_ALLOC_NODUMP do not include the page in a kernel core dump
* VM_ALLOC_NOOBJ page is not associated with an object and
* should not be exclusive busy
* VM_ALLOC_SBUSY shared busy the allocated page
* VM_ALLOC_WIRED wire the allocated page
* VM_ALLOC_ZERO prefer a zeroed page
*/
vm_page_t
vm_page_alloc(vm_object_t object, vm_pindex_t pindex, int req)
{
return (vm_page_alloc_after(object, pindex, req, object != NULL ?
vm_radix_lookup_le(&object->rtree, pindex) : NULL));
}
vm_page_t
vm_page_alloc_domain(vm_object_t object, vm_pindex_t pindex, int domain,
int req)
{
return (vm_page_alloc_domain_after(object, pindex, domain, req,
object != NULL ? vm_radix_lookup_le(&object->rtree, pindex) :
NULL));
}
/*
* Allocate a page in the specified object with the given page index. To
* optimize insertion of the page into the object, the caller must also specifiy
* the resident page in the object with largest index smaller than the given
* page index, or NULL if no such page exists.
*/
vm_page_t
vm_page_alloc_after(vm_object_t object, vm_pindex_t pindex,
int req, vm_page_t mpred)
{
struct vm_domainset_iter di;
vm_page_t m;
int domain;
vm_domainset_iter_page_init(&di, object, pindex, &domain, &req);
do {
m = vm_page_alloc_domain_after(object, pindex, domain, req,
mpred);
if (m != NULL)
break;
} while (vm_domainset_iter_page(&di, object, &domain) == 0);
return (m);
}
/*
* Returns true if the number of free pages exceeds the minimum
* for the request class and false otherwise.
*/
static int
_vm_domain_allocate(struct vm_domain *vmd, int req_class, int npages)
{
u_int limit, old, new;
if (req_class == VM_ALLOC_INTERRUPT)
limit = 0;
else if (req_class == VM_ALLOC_SYSTEM)
limit = vmd->vmd_interrupt_free_min;
else
limit = vmd->vmd_free_reserved;
/*
* Attempt to reserve the pages. Fail if we're below the limit.
*/
limit += npages;
old = vmd->vmd_free_count;
do {
if (old < limit)
return (0);
new = old - npages;
} while (atomic_fcmpset_int(&vmd->vmd_free_count, &old, new) == 0);
/* Wake the page daemon if we've crossed the threshold. */
if (vm_paging_needed(vmd, new) && !vm_paging_needed(vmd, old))
pagedaemon_wakeup(vmd->vmd_domain);
/* Only update bitsets on transitions. */
if ((old >= vmd->vmd_free_min && new < vmd->vmd_free_min) ||
(old >= vmd->vmd_free_severe && new < vmd->vmd_free_severe))
vm_domain_set(vmd);
return (1);
}
int
vm_domain_allocate(struct vm_domain *vmd, int req, int npages)
{
int req_class;
/*
* The page daemon is allowed to dig deeper into the free page list.
*/
req_class = req & VM_ALLOC_CLASS_MASK;
if (curproc == pageproc && req_class != VM_ALLOC_INTERRUPT)
req_class = VM_ALLOC_SYSTEM;
return (_vm_domain_allocate(vmd, req_class, npages));
}
vm_page_t
vm_page_alloc_domain_after(vm_object_t object, vm_pindex_t pindex, int domain,
int req, vm_page_t mpred)
{
struct vm_domain *vmd;
vm_page_t m;
int flags, pool;
KASSERT((object != NULL) == ((req & VM_ALLOC_NOOBJ) == 0) &&
(object != NULL || (req & VM_ALLOC_SBUSY) == 0) &&
((req & (VM_ALLOC_NOBUSY | VM_ALLOC_SBUSY)) !=
(VM_ALLOC_NOBUSY | VM_ALLOC_SBUSY)),
("inconsistent object(%p)/req(%x)", object, req));
KASSERT(object == NULL || (req & VM_ALLOC_WAITOK) == 0,
("Can't sleep and retry object insertion."));
KASSERT(mpred == NULL || mpred->pindex < pindex,
("mpred %p doesn't precede pindex 0x%jx", mpred,
(uintmax_t)pindex));
if (object != NULL)
VM_OBJECT_ASSERT_WLOCKED(object);
flags = 0;
m = NULL;
pool = object != NULL ? VM_FREEPOOL_DEFAULT : VM_FREEPOOL_DIRECT;
again:
#if VM_NRESERVLEVEL > 0
/*
* Can we allocate the page from a reservation?
*/
if (vm_object_reserv(object) &&
(m = vm_reserv_alloc_page(object, pindex, domain, req, mpred)) !=
NULL) {
goto found;
}
#endif
vmd = VM_DOMAIN(domain);
if (vmd->vmd_pgcache[pool].zone != NULL) {
m = uma_zalloc(vmd->vmd_pgcache[pool].zone, M_NOWAIT | M_NOVM);
if (m != NULL) {
flags |= PG_PCPU_CACHE;
goto found;
}
}
if (vm_domain_allocate(vmd, req, 1)) {
/*
* If not, allocate it from the free page queues.
*/
vm_domain_free_lock(vmd);
m = vm_phys_alloc_pages(domain, pool, 0);
vm_domain_free_unlock(vmd);
if (m == NULL) {
vm_domain_freecnt_inc(vmd, 1);
#if VM_NRESERVLEVEL > 0
if (vm_reserv_reclaim_inactive(domain))
goto again;
#endif
}
}
if (m == NULL) {
/*
* Not allocatable, give up.
*/
if (vm_domain_alloc_fail(vmd, object, req))
goto again;
return (NULL);
}
/*
* At this point we had better have found a good page.
*/
found:
vm_page_dequeue(m);
vm_page_alloc_check(m);
/*
* Initialize the page. Only the PG_ZERO flag is inherited.
*/
if ((req & VM_ALLOC_ZERO) != 0)
flags |= (m->flags & PG_ZERO);
if ((req & VM_ALLOC_NODUMP) != 0)
flags |= PG_NODUMP;
m->flags = flags;
m->a.flags = 0;
m->oflags = object == NULL || (object->flags & OBJ_UNMANAGED) != 0 ?
VPO_UNMANAGED : 0;
if ((req & (VM_ALLOC_NOBUSY | VM_ALLOC_NOOBJ | VM_ALLOC_SBUSY)) == 0)
m->busy_lock = VPB_CURTHREAD_EXCLUSIVE;
else if ((req & VM_ALLOC_SBUSY) != 0)
m->busy_lock = VPB_SHARERS_WORD(1);
else
m->busy_lock = VPB_UNBUSIED;
if (req & VM_ALLOC_WIRED) {
vm_wire_add(1);
m->ref_count = 1;
}
m->a.act_count = 0;
if (object != NULL) {
if (vm_page_insert_after(m, object, pindex, mpred)) {
if (req & VM_ALLOC_WIRED) {
vm_wire_sub(1);
m->ref_count = 0;
}
KASSERT(m->object == NULL, ("page %p has object", m));
m->oflags = VPO_UNMANAGED;
m->busy_lock = VPB_UNBUSIED;
/* Don't change PG_ZERO. */
vm_page_free_toq(m);
if (req & VM_ALLOC_WAITFAIL) {
VM_OBJECT_WUNLOCK(object);
vm_radix_wait();
VM_OBJECT_WLOCK(object);
}
return (NULL);
}
/* Ignore device objects; the pager sets "memattr" for them. */
if (object->memattr != VM_MEMATTR_DEFAULT &&
(object->flags & OBJ_FICTITIOUS) == 0)
pmap_page_set_memattr(m, object->memattr);
} else
m->pindex = pindex;
return (m);
}
/*
* vm_page_alloc_contig:
*
* Allocate a contiguous set of physical pages of the given size "npages"
* from the free lists. All of the physical pages must be at or above
* the given physical address "low" and below the given physical address
* "high". The given value "alignment" determines the alignment of the
* first physical page in the set. If the given value "boundary" is
* non-zero, then the set of physical pages cannot cross any physical
* address boundary that is a multiple of that value. Both "alignment"
* and "boundary" must be a power of two.
*
* If the specified memory attribute, "memattr", is VM_MEMATTR_DEFAULT,
* then the memory attribute setting for the physical pages is configured
* to the object's memory attribute setting. Otherwise, the memory
* attribute setting for the physical pages is configured to "memattr",
* overriding the object's memory attribute setting. However, if the
* object's memory attribute setting is not VM_MEMATTR_DEFAULT, then the
* memory attribute setting for the physical pages cannot be configured
* to VM_MEMATTR_DEFAULT.
*
* The specified object may not contain fictitious pages.
*
* The caller must always specify an allocation class.
*
* allocation classes:
* VM_ALLOC_NORMAL normal process request
* VM_ALLOC_SYSTEM system *really* needs a page
* VM_ALLOC_INTERRUPT interrupt time request
*
* optional allocation flags:
* VM_ALLOC_NOBUSY do not exclusive busy the page
* VM_ALLOC_NODUMP do not include the page in a kernel core dump
* VM_ALLOC_NOOBJ page is not associated with an object and
* should not be exclusive busy
* VM_ALLOC_SBUSY shared busy the allocated page
* VM_ALLOC_WIRED wire the allocated page
* VM_ALLOC_ZERO prefer a zeroed page
*/
vm_page_t
vm_page_alloc_contig(vm_object_t object, vm_pindex_t pindex, int req,
u_long npages, vm_paddr_t low, vm_paddr_t high, u_long alignment,
vm_paddr_t boundary, vm_memattr_t memattr)
{
struct vm_domainset_iter di;
vm_page_t m;
int domain;
vm_domainset_iter_page_init(&di, object, pindex, &domain, &req);
do {
m = vm_page_alloc_contig_domain(object, pindex, domain, req,
npages, low, high, alignment, boundary, memattr);
if (m != NULL)
break;
} while (vm_domainset_iter_page(&di, object, &domain) == 0);
return (m);
}
vm_page_t
vm_page_alloc_contig_domain(vm_object_t object, vm_pindex_t pindex, int domain,
int req, u_long npages, vm_paddr_t low, vm_paddr_t high, u_long alignment,
vm_paddr_t boundary, vm_memattr_t memattr)
{
struct vm_domain *vmd;
vm_page_t m, m_ret, mpred;
u_int busy_lock, flags, oflags;
mpred = NULL; /* XXX: pacify gcc */
KASSERT((object != NULL) == ((req & VM_ALLOC_NOOBJ) == 0) &&
(object != NULL || (req & VM_ALLOC_SBUSY) == 0) &&
((req & (VM_ALLOC_NOBUSY | VM_ALLOC_SBUSY)) !=
(VM_ALLOC_NOBUSY | VM_ALLOC_SBUSY)),
("vm_page_alloc_contig: inconsistent object(%p)/req(%x)", object,
req));
KASSERT(object == NULL || (req & VM_ALLOC_WAITOK) == 0,
("Can't sleep and retry object insertion."));
if (object != NULL) {
VM_OBJECT_ASSERT_WLOCKED(object);
KASSERT((object->flags & OBJ_FICTITIOUS) == 0,
("vm_page_alloc_contig: object %p has fictitious pages",
object));
}
KASSERT(npages > 0, ("vm_page_alloc_contig: npages is zero"));
if (object != NULL) {
mpred = vm_radix_lookup_le(&object->rtree, pindex);
KASSERT(mpred == NULL || mpred->pindex != pindex,
("vm_page_alloc_contig: pindex already allocated"));
}
/*
* Can we allocate the pages without the number of free pages falling
* below the lower bound for the allocation class?
*/
m_ret = NULL;
again:
#if VM_NRESERVLEVEL > 0
/*
* Can we allocate the pages from a reservation?
*/
if (vm_object_reserv(object) &&
(m_ret = vm_reserv_alloc_contig(object, pindex, domain, req,
mpred, npages, low, high, alignment, boundary)) != NULL) {
goto found;
}
#endif
vmd = VM_DOMAIN(domain);
if (vm_domain_allocate(vmd, req, npages)) {
/*
* allocate them from the free page queues.
*/
vm_domain_free_lock(vmd);
m_ret = vm_phys_alloc_contig(domain, npages, low, high,
alignment, boundary);
vm_domain_free_unlock(vmd);
if (m_ret == NULL) {
vm_domain_freecnt_inc(vmd, npages);
#if VM_NRESERVLEVEL > 0
if (vm_reserv_reclaim_contig(domain, npages, low,
high, alignment, boundary))
goto again;
#endif
}
}
if (m_ret == NULL) {
if (vm_domain_alloc_fail(vmd, object, req))
goto again;
return (NULL);
}
#if VM_NRESERVLEVEL > 0
found:
#endif
for (m = m_ret; m < &m_ret[npages]; m++) {
vm_page_dequeue(m);
vm_page_alloc_check(m);
}
/*
* Initialize the pages. Only the PG_ZERO flag is inherited.
*/
flags = 0;
if ((req & VM_ALLOC_ZERO) != 0)
flags = PG_ZERO;
if ((req & VM_ALLOC_NODUMP) != 0)
flags |= PG_NODUMP;
oflags = object == NULL || (object->flags & OBJ_UNMANAGED) != 0 ?
VPO_UNMANAGED : 0;
if ((req & (VM_ALLOC_NOBUSY | VM_ALLOC_NOOBJ | VM_ALLOC_SBUSY)) == 0)
busy_lock = VPB_CURTHREAD_EXCLUSIVE;
else if ((req & VM_ALLOC_SBUSY) != 0)
busy_lock = VPB_SHARERS_WORD(1);
else
busy_lock = VPB_UNBUSIED;
if ((req & VM_ALLOC_WIRED) != 0)
vm_wire_add(npages);
if (object != NULL) {
if (object->memattr != VM_MEMATTR_DEFAULT &&
memattr == VM_MEMATTR_DEFAULT)
memattr = object->memattr;
}
for (m = m_ret; m < &m_ret[npages]; m++) {
m->a.flags = 0;
m->flags = (m->flags | PG_NODUMP) & flags;
m->busy_lock = busy_lock;
if ((req & VM_ALLOC_WIRED) != 0)
m->ref_count = 1;
m->a.act_count = 0;
m->oflags = oflags;
if (object != NULL) {
if (vm_page_insert_after(m, object, pindex, mpred)) {
if ((req & VM_ALLOC_WIRED) != 0)
vm_wire_sub(npages);
KASSERT(m->object == NULL,
("page %p has object", m));
mpred = m;
for (m = m_ret; m < &m_ret[npages]; m++) {
if (m <= mpred &&
(req & VM_ALLOC_WIRED) != 0)
m->ref_count = 0;
m->oflags = VPO_UNMANAGED;
m->busy_lock = VPB_UNBUSIED;
/* Don't change PG_ZERO. */
vm_page_free_toq(m);
}
if (req & VM_ALLOC_WAITFAIL) {
VM_OBJECT_WUNLOCK(object);
vm_radix_wait();
VM_OBJECT_WLOCK(object);
}
return (NULL);
}
mpred = m;
} else
m->pindex = pindex;
if (memattr != VM_MEMATTR_DEFAULT)
pmap_page_set_memattr(m, memattr);
pindex++;
}
return (m_ret);
}
/*
* Check a page that has been freshly dequeued from a freelist.
*/
static void
vm_page_alloc_check(vm_page_t m)
{
KASSERT(m->object == NULL, ("page %p has object", m));
KASSERT(m->a.queue == PQ_NONE &&
(m->a.flags & PGA_QUEUE_STATE_MASK) == 0,
("page %p has unexpected queue %d, flags %#x",
m, m->a.queue, (m->a.flags & PGA_QUEUE_STATE_MASK)));
KASSERT(m->ref_count == 0, ("page %p has references", m));
KASSERT(vm_page_busy_freed(m), ("page %p is not freed", m));
KASSERT(m->dirty == 0, ("page %p is dirty", m));
KASSERT(pmap_page_get_memattr(m) == VM_MEMATTR_DEFAULT,
("page %p has unexpected memattr %d",
m, pmap_page_get_memattr(m)));
KASSERT(m->valid == 0, ("free page %p is valid", m));
}
/*
* vm_page_alloc_freelist:
*
* Allocate a physical page from the specified free page list.
*
* The caller must always specify an allocation class.
*
* allocation classes:
* VM_ALLOC_NORMAL normal process request
* VM_ALLOC_SYSTEM system *really* needs a page
* VM_ALLOC_INTERRUPT interrupt time request
*
* optional allocation flags:
* VM_ALLOC_COUNT(number) the number of additional pages that the caller
* intends to allocate
* VM_ALLOC_WIRED wire the allocated page
* VM_ALLOC_ZERO prefer a zeroed page
*/
vm_page_t
vm_page_alloc_freelist(int freelist, int req)
{
struct vm_domainset_iter di;
vm_page_t m;
int domain;
vm_domainset_iter_page_init(&di, NULL, 0, &domain, &req);
do {
m = vm_page_alloc_freelist_domain(domain, freelist, req);
if (m != NULL)
break;
} while (vm_domainset_iter_page(&di, NULL, &domain) == 0);
return (m);
}
vm_page_t
vm_page_alloc_freelist_domain(int domain, int freelist, int req)
{
struct vm_domain *vmd;
vm_page_t m;
u_int flags;
m = NULL;
vmd = VM_DOMAIN(domain);
again:
if (vm_domain_allocate(vmd, req, 1)) {
vm_domain_free_lock(vmd);
m = vm_phys_alloc_freelist_pages(domain, freelist,
VM_FREEPOOL_DIRECT, 0);
vm_domain_free_unlock(vmd);
if (m == NULL)
vm_domain_freecnt_inc(vmd, 1);
}
if (m == NULL) {
if (vm_domain_alloc_fail(vmd, NULL, req))
goto again;
return (NULL);
}
vm_page_dequeue(m);
vm_page_alloc_check(m);
/*
* Initialize the page. Only the PG_ZERO flag is inherited.
*/
m->a.flags = 0;
flags = 0;
if ((req & VM_ALLOC_ZERO) != 0)
flags = PG_ZERO;
m->flags &= flags;
if ((req & VM_ALLOC_WIRED) != 0) {
vm_wire_add(1);
m->ref_count = 1;
}
/* Unmanaged pages don't use "act_count". */
m->oflags = VPO_UNMANAGED;
return (m);
}
static int
vm_page_zone_import(void *arg, void **store, int cnt, int domain, int flags)
{
struct vm_domain *vmd;
struct vm_pgcache *pgcache;
int i;
pgcache = arg;
vmd = VM_DOMAIN(pgcache->domain);
/*
* The page daemon should avoid creating extra memory pressure since its
* main purpose is to replenish the store of free pages.
*/
if (vmd->vmd_severeset || curproc == pageproc ||
!_vm_domain_allocate(vmd, VM_ALLOC_NORMAL, cnt))
return (0);
domain = vmd->vmd_domain;
vm_domain_free_lock(vmd);
i = vm_phys_alloc_npages(domain, pgcache->pool, cnt,
(vm_page_t *)store);
vm_domain_free_unlock(vmd);
if (cnt != i)
vm_domain_freecnt_inc(vmd, cnt - i);
return (i);
}
static void
vm_page_zone_release(void *arg, void **store, int cnt)
{
struct vm_domain *vmd;
struct vm_pgcache *pgcache;
vm_page_t m;
int i;
pgcache = arg;
vmd = VM_DOMAIN(pgcache->domain);
vm_domain_free_lock(vmd);
for (i = 0; i < cnt; i++) {
m = (vm_page_t)store[i];
vm_phys_free_pages(m, 0);
}
vm_domain_free_unlock(vmd);
vm_domain_freecnt_inc(vmd, cnt);
}
#define VPSC_ANY 0 /* No restrictions. */
#define VPSC_NORESERV 1 /* Skip reservations; implies VPSC_NOSUPER. */
#define VPSC_NOSUPER 2 /* Skip superpages. */
/*
* vm_page_scan_contig:
*
* Scan vm_page_array[] between the specified entries "m_start" and
* "m_end" for a run of contiguous physical pages that satisfy the
* specified conditions, and return the lowest page in the run. The
* specified "alignment" determines the alignment of the lowest physical
* page in the run. If the specified "boundary" is non-zero, then the
* run of physical pages cannot span a physical address that is a
* multiple of "boundary".
*
* "m_end" is never dereferenced, so it need not point to a vm_page
* structure within vm_page_array[].
*
* "npages" must be greater than zero. "m_start" and "m_end" must not
* span a hole (or discontiguity) in the physical address space. Both
* "alignment" and "boundary" must be a power of two.
*/
vm_page_t
vm_page_scan_contig(u_long npages, vm_page_t m_start, vm_page_t m_end,
u_long alignment, vm_paddr_t boundary, int options)
{
vm_object_t object;
vm_paddr_t pa;
vm_page_t m, m_run;
#if VM_NRESERVLEVEL > 0
int level;
#endif
int m_inc, order, run_ext, run_len;
KASSERT(npages > 0, ("npages is 0"));
KASSERT(powerof2(alignment), ("alignment is not a power of 2"));
KASSERT(powerof2(boundary), ("boundary is not a power of 2"));
m_run = NULL;
run_len = 0;
for (m = m_start; m < m_end && run_len < npages; m += m_inc) {
KASSERT((m->flags & PG_MARKER) == 0,
("page %p is PG_MARKER", m));
KASSERT((m->flags & PG_FICTITIOUS) == 0 || m->ref_count >= 1,
("fictitious page %p has invalid ref count", m));
/*
* If the current page would be the start of a run, check its
* physical address against the end, alignment, and boundary
* conditions. If it doesn't satisfy these conditions, either
* terminate the scan or advance to the next page that
* satisfies the failed condition.
*/
if (run_len == 0) {
KASSERT(m_run == NULL, ("m_run != NULL"));
if (m + npages > m_end)
break;
pa = VM_PAGE_TO_PHYS(m);
if ((pa & (alignment - 1)) != 0) {
m_inc = atop(roundup2(pa, alignment) - pa);
continue;
}
if (rounddown2(pa ^ (pa + ptoa(npages) - 1),
boundary) != 0) {
m_inc = atop(roundup2(pa, boundary) - pa);
continue;
}
} else
KASSERT(m_run != NULL, ("m_run == NULL"));
retry:
m_inc = 1;
if (vm_page_wired(m))
run_ext = 0;
#if VM_NRESERVLEVEL > 0
else if ((level = vm_reserv_level(m)) >= 0 &&
(options & VPSC_NORESERV) != 0) {
run_ext = 0;
/* Advance to the end of the reservation. */
pa = VM_PAGE_TO_PHYS(m);
m_inc = atop(roundup2(pa + 1, vm_reserv_size(level)) -
pa);
}
#endif
else if ((object = atomic_load_ptr(&m->object)) != NULL) {
/*
* The page is considered eligible for relocation if
* and only if it could be laundered or reclaimed by
* the page daemon.
*/
VM_OBJECT_RLOCK(object);
if (object != m->object) {
VM_OBJECT_RUNLOCK(object);
goto retry;
}
/* Don't care: PG_NODUMP, PG_ZERO. */
if (object->type != OBJT_DEFAULT &&
object->type != OBJT_SWAP &&
object->type != OBJT_VNODE) {
run_ext = 0;
#if VM_NRESERVLEVEL > 0
} else if ((options & VPSC_NOSUPER) != 0 &&
(level = vm_reserv_level_iffullpop(m)) >= 0) {
run_ext = 0;
/* Advance to the end of the superpage. */
pa = VM_PAGE_TO_PHYS(m);
m_inc = atop(roundup2(pa + 1,
vm_reserv_size(level)) - pa);
#endif
} else if (object->memattr == VM_MEMATTR_DEFAULT &&
vm_page_queue(m) != PQ_NONE && !vm_page_busied(m)) {
/*
* The page is allocated but eligible for
* relocation. Extend the current run by one
* page.
*/
KASSERT(pmap_page_get_memattr(m) ==
VM_MEMATTR_DEFAULT,
("page %p has an unexpected memattr", m));
KASSERT((m->oflags & (VPO_SWAPINPROG |
VPO_SWAPSLEEP | VPO_UNMANAGED)) == 0,
("page %p has unexpected oflags", m));
/* Don't care: PGA_NOSYNC. */
run_ext = 1;
} else
run_ext = 0;
VM_OBJECT_RUNLOCK(object);
#if VM_NRESERVLEVEL > 0
} else if (level >= 0) {
/*
* The page is reserved but not yet allocated. In
* other words, it is still free. Extend the current
* run by one page.
*/
run_ext = 1;
#endif
} else if ((order = m->order) < VM_NFREEORDER) {
/*
* The page is enqueued in the physical memory
* allocator's free page queues. Moreover, it is the
* first page in a power-of-two-sized run of
* contiguous free pages. Add these pages to the end
* of the current run, and jump ahead.
*/
run_ext = 1 << order;
m_inc = 1 << order;
} else {
/*
* Skip the page for one of the following reasons: (1)
* It is enqueued in the physical memory allocator's
* free page queues. However, it is not the first
* page in a run of contiguous free pages. (This case
* rarely occurs because the scan is performed in
* ascending order.) (2) It is not reserved, and it is
* transitioning from free to allocated. (Conversely,
* the transition from allocated to free for managed
* pages is blocked by the page lock.) (3) It is
* allocated but not contained by an object and not
* wired, e.g., allocated by Xen's balloon driver.
*/
run_ext = 0;
}
/*
* Extend or reset the current run of pages.
*/
if (run_ext > 0) {
if (run_len == 0)
m_run = m;
run_len += run_ext;
} else {
if (run_len > 0) {
m_run = NULL;
run_len = 0;
}
}
}
if (run_len >= npages)
return (m_run);
return (NULL);
}
/*
* vm_page_reclaim_run:
*
* Try to relocate each of the allocated virtual pages within the
* specified run of physical pages to a new physical address. Free the
* physical pages underlying the relocated virtual pages. A virtual page
* is relocatable if and only if it could be laundered or reclaimed by
* the page daemon. Whenever possible, a virtual page is relocated to a
* physical address above "high".
*
* Returns 0 if every physical page within the run was already free or
* just freed by a successful relocation. Otherwise, returns a non-zero
* value indicating why the last attempt to relocate a virtual page was
* unsuccessful.
*
* "req_class" must be an allocation class.
*/
static int
vm_page_reclaim_run(int req_class, int domain, u_long npages, vm_page_t m_run,
vm_paddr_t high)
{
struct vm_domain *vmd;
struct spglist free;
vm_object_t object;
vm_paddr_t pa;
vm_page_t m, m_end, m_new;
int error, order, req;
KASSERT((req_class & VM_ALLOC_CLASS_MASK) == req_class,
("req_class is not an allocation class"));
SLIST_INIT(&free);
error = 0;
m = m_run;
m_end = m_run + npages;
for (; error == 0 && m < m_end; m++) {
KASSERT((m->flags & (PG_FICTITIOUS | PG_MARKER)) == 0,
("page %p is PG_FICTITIOUS or PG_MARKER", m));
/*
* Racily check for wirings. Races are handled once the object
* lock is held and the page is unmapped.
*/
if (vm_page_wired(m))
error = EBUSY;
else if ((object = atomic_load_ptr(&m->object)) != NULL) {
/*
* The page is relocated if and only if it could be
* laundered or reclaimed by the page daemon.
*/
VM_OBJECT_WLOCK(object);
/* Don't care: PG_NODUMP, PG_ZERO. */
if (m->object != object ||
(object->type != OBJT_DEFAULT &&
object->type != OBJT_SWAP &&
object->type != OBJT_VNODE))
error = EINVAL;
else if (object->memattr != VM_MEMATTR_DEFAULT)
error = EINVAL;
else if (vm_page_queue(m) != PQ_NONE &&
vm_page_tryxbusy(m) != 0) {
if (vm_page_wired(m)) {
vm_page_xunbusy(m);
error = EBUSY;
goto unlock;
}
KASSERT(pmap_page_get_memattr(m) ==
VM_MEMATTR_DEFAULT,
("page %p has an unexpected memattr", m));
KASSERT(m->oflags == 0,
("page %p has unexpected oflags", m));
/* Don't care: PGA_NOSYNC. */
if (!vm_page_none_valid(m)) {
/*
* First, try to allocate a new page
* that is above "high". Failing
* that, try to allocate a new page
* that is below "m_run". Allocate
* the new page between the end of
* "m_run" and "high" only as a last
* resort.
*/
req = req_class | VM_ALLOC_NOOBJ;
if ((m->flags & PG_NODUMP) != 0)
req |= VM_ALLOC_NODUMP;
if (trunc_page(high) !=
~(vm_paddr_t)PAGE_MASK) {
m_new = vm_page_alloc_contig(
NULL, 0, req, 1,
round_page(high),
~(vm_paddr_t)0,
PAGE_SIZE, 0,
VM_MEMATTR_DEFAULT);
} else
m_new = NULL;
if (m_new == NULL) {
pa = VM_PAGE_TO_PHYS(m_run);
m_new = vm_page_alloc_contig(
NULL, 0, req, 1,
0, pa - 1, PAGE_SIZE, 0,
VM_MEMATTR_DEFAULT);
}
if (m_new == NULL) {
pa += ptoa(npages);
m_new = vm_page_alloc_contig(
NULL, 0, req, 1,
pa, high, PAGE_SIZE, 0,
VM_MEMATTR_DEFAULT);
}
if (m_new == NULL) {
vm_page_xunbusy(m);
error = ENOMEM;
goto unlock;
}
/*
* Unmap the page and check for new
* wirings that may have been acquired
* through a pmap lookup.
*/
if (object->ref_count != 0 &&
!vm_page_try_remove_all(m)) {
vm_page_xunbusy(m);
vm_page_free(m_new);
error = EBUSY;
goto unlock;
}
/*
* Replace "m" with the new page. For
* vm_page_replace(), "m" must be busy
* and dequeued. Finally, change "m"
* as if vm_page_free() was called.
*/
m_new->a.flags = m->a.flags &
~PGA_QUEUE_STATE_MASK;
KASSERT(m_new->oflags == VPO_UNMANAGED,
("page %p is managed", m_new));
m_new->oflags = 0;
pmap_copy_page(m, m_new);
m_new->valid = m->valid;
m_new->dirty = m->dirty;
m->flags &= ~PG_ZERO;
vm_page_dequeue(m);
if (vm_page_replace_hold(m_new, object,
m->pindex, m) &&
vm_page_free_prep(m))
SLIST_INSERT_HEAD(&free, m,
plinks.s.ss);
/*
* The new page must be deactivated
* before the object is unlocked.
*/
vm_page_deactivate(m_new);
} else {
m->flags &= ~PG_ZERO;
vm_page_dequeue(m);
if (vm_page_free_prep(m))
SLIST_INSERT_HEAD(&free, m,
plinks.s.ss);
KASSERT(m->dirty == 0,
("page %p is dirty", m));
}
} else
error = EBUSY;
unlock:
VM_OBJECT_WUNLOCK(object);
} else {
MPASS(vm_phys_domain(m) == domain);
vmd = VM_DOMAIN(domain);
vm_domain_free_lock(vmd);
order = m->order;
if (order < VM_NFREEORDER) {
/*
* The page is enqueued in the physical memory
* allocator's free page queues. Moreover, it
* is the first page in a power-of-two-sized
* run of contiguous free pages. Jump ahead
* to the last page within that run, and
* continue from there.
*/
m += (1 << order) - 1;
}
#if VM_NRESERVLEVEL > 0
else if (vm_reserv_is_page_free(m))
order = 0;
#endif
vm_domain_free_unlock(vmd);
if (order == VM_NFREEORDER)
error = EINVAL;
}
}
if ((m = SLIST_FIRST(&free)) != NULL) {
int cnt;
vmd = VM_DOMAIN(domain);
cnt = 0;
vm_domain_free_lock(vmd);
do {
MPASS(vm_phys_domain(m) == domain);
SLIST_REMOVE_HEAD(&free, plinks.s.ss);
vm_phys_free_pages(m, 0);
cnt++;
} while ((m = SLIST_FIRST(&free)) != NULL);
vm_domain_free_unlock(vmd);
vm_domain_freecnt_inc(vmd, cnt);
}
return (error);
}
#define NRUNS 16
CTASSERT(powerof2(NRUNS));
#define RUN_INDEX(count) ((count) & (NRUNS - 1))
#define MIN_RECLAIM 8
/*
* vm_page_reclaim_contig:
*
* Reclaim allocated, contiguous physical memory satisfying the specified
* conditions by relocating the virtual pages using that physical memory.
* Returns true if reclamation is successful and false otherwise. Since
* relocation requires the allocation of physical pages, reclamation may
* fail due to a shortage of free pages. When reclamation fails, callers
* are expected to perform vm_wait() before retrying a failed allocation
* operation, e.g., vm_page_alloc_contig().
*
* The caller must always specify an allocation class through "req".
*
* allocation classes:
* VM_ALLOC_NORMAL normal process request
* VM_ALLOC_SYSTEM system *really* needs a page
* VM_ALLOC_INTERRUPT interrupt time request
*
* The optional allocation flags are ignored.
*
* "npages" must be greater than zero. Both "alignment" and "boundary"
* must be a power of two.
*/
bool
vm_page_reclaim_contig_domain(int domain, int req, u_long npages,
vm_paddr_t low, vm_paddr_t high, u_long alignment, vm_paddr_t boundary)
{
struct vm_domain *vmd;
vm_paddr_t curr_low;
vm_page_t m_run, m_runs[NRUNS];
u_long count, reclaimed;
int error, i, options, req_class;
KASSERT(npages > 0, ("npages is 0"));
KASSERT(powerof2(alignment), ("alignment is not a power of 2"));
KASSERT(powerof2(boundary), ("boundary is not a power of 2"));
req_class = req & VM_ALLOC_CLASS_MASK;
/*
* The page daemon is allowed to dig deeper into the free page list.
*/
if (curproc == pageproc && req_class != VM_ALLOC_INTERRUPT)
req_class = VM_ALLOC_SYSTEM;
/*
* Return if the number of free pages cannot satisfy the requested
* allocation.
*/
vmd = VM_DOMAIN(domain);
count = vmd->vmd_free_count;
if (count < npages + vmd->vmd_free_reserved || (count < npages +
vmd->vmd_interrupt_free_min && req_class == VM_ALLOC_SYSTEM) ||
(count < npages && req_class == VM_ALLOC_INTERRUPT))
return (false);
/*
* Scan up to three times, relaxing the restrictions ("options") on
* the reclamation of reservations and superpages each time.
*/
for (options = VPSC_NORESERV;;) {
/*
* Find the highest runs that satisfy the given constraints
* and restrictions, and record them in "m_runs".
*/
curr_low = low;
count = 0;
for (;;) {
m_run = vm_phys_scan_contig(domain, npages, curr_low,
high, alignment, boundary, options);
if (m_run == NULL)
break;
curr_low = VM_PAGE_TO_PHYS(m_run) + ptoa(npages);
m_runs[RUN_INDEX(count)] = m_run;
count++;
}
/*
* Reclaim the highest runs in LIFO (descending) order until
* the number of reclaimed pages, "reclaimed", is at least
* MIN_RECLAIM. Reset "reclaimed" each time because each
* reclamation is idempotent, and runs will (likely) recur
* from one scan to the next as restrictions are relaxed.
*/
reclaimed = 0;
for (i = 0; count > 0 && i < NRUNS; i++) {
count--;
m_run = m_runs[RUN_INDEX(count)];
error = vm_page_reclaim_run(req_class, domain, npages,
m_run, high);
if (error == 0) {
reclaimed += npages;
if (reclaimed >= MIN_RECLAIM)
return (true);
}
}
/*
* Either relax the restrictions on the next scan or return if
* the last scan had no restrictions.
*/
if (options == VPSC_NORESERV)
options = VPSC_NOSUPER;
else if (options == VPSC_NOSUPER)
options = VPSC_ANY;
else if (options == VPSC_ANY)
return (reclaimed != 0);
}
}
bool
vm_page_reclaim_contig(int req, u_long npages, vm_paddr_t low, vm_paddr_t high,
u_long alignment, vm_paddr_t boundary)
{
struct vm_domainset_iter di;
int domain;
bool ret;
vm_domainset_iter_page_init(&di, NULL, 0, &domain, &req);
do {
ret = vm_page_reclaim_contig_domain(domain, req, npages, low,
high, alignment, boundary);
if (ret)
break;
} while (vm_domainset_iter_page(&di, NULL, &domain) == 0);
return (ret);
}
/*
* Set the domain in the appropriate page level domainset.
*/
void
vm_domain_set(struct vm_domain *vmd)
{
mtx_lock(&vm_domainset_lock);
if (!vmd->vmd_minset && vm_paging_min(vmd)) {
vmd->vmd_minset = 1;
DOMAINSET_SET(vmd->vmd_domain, &vm_min_domains);
}
if (!vmd->vmd_severeset && vm_paging_severe(vmd)) {
vmd->vmd_severeset = 1;
DOMAINSET_SET(vmd->vmd_domain, &vm_severe_domains);
}
mtx_unlock(&vm_domainset_lock);
}
/*
* Clear the domain from the appropriate page level domainset.
*/
void
vm_domain_clear(struct vm_domain *vmd)
{
mtx_lock(&vm_domainset_lock);
if (vmd->vmd_minset && !vm_paging_min(vmd)) {
vmd->vmd_minset = 0;
DOMAINSET_CLR(vmd->vmd_domain, &vm_min_domains);
if (vm_min_waiters != 0) {
vm_min_waiters = 0;
wakeup(&vm_min_domains);
}
}
if (vmd->vmd_severeset && !vm_paging_severe(vmd)) {
vmd->vmd_severeset = 0;
DOMAINSET_CLR(vmd->vmd_domain, &vm_severe_domains);
if (vm_severe_waiters != 0) {
vm_severe_waiters = 0;
wakeup(&vm_severe_domains);
}
}
/*
* If pageout daemon needs pages, then tell it that there are
* some free.
*/
if (vmd->vmd_pageout_pages_needed &&
vmd->vmd_free_count >= vmd->vmd_pageout_free_min) {
wakeup(&vmd->vmd_pageout_pages_needed);
vmd->vmd_pageout_pages_needed = 0;
}
/* See comments in vm_wait_doms(). */
if (vm_pageproc_waiters) {
vm_pageproc_waiters = 0;
wakeup(&vm_pageproc_waiters);
}
mtx_unlock(&vm_domainset_lock);
}
/*
* Wait for free pages to exceed the min threshold globally.
*/
void
vm_wait_min(void)
{
mtx_lock(&vm_domainset_lock);
while (vm_page_count_min()) {
vm_min_waiters++;
msleep(&vm_min_domains, &vm_domainset_lock, PVM, "vmwait", 0);
}
mtx_unlock(&vm_domainset_lock);
}
/*
* Wait for free pages to exceed the severe threshold globally.
*/
void
vm_wait_severe(void)
{
mtx_lock(&vm_domainset_lock);
while (vm_page_count_severe()) {
vm_severe_waiters++;
msleep(&vm_severe_domains, &vm_domainset_lock, PVM,
"vmwait", 0);
}
mtx_unlock(&vm_domainset_lock);
}
u_int
vm_wait_count(void)
{
return (vm_severe_waiters + vm_min_waiters + vm_pageproc_waiters);
}
void
vm_wait_doms(const domainset_t *wdoms)
{
/*
* We use racey wakeup synchronization to avoid expensive global
* locking for the pageproc when sleeping with a non-specific vm_wait.
* To handle this, we only sleep for one tick in this instance. It
* is expected that most allocations for the pageproc will come from
* kmem or vm_page_grab* which will use the more specific and
* race-free vm_wait_domain().
*/
if (curproc == pageproc) {
mtx_lock(&vm_domainset_lock);
vm_pageproc_waiters++;
msleep(&vm_pageproc_waiters, &vm_domainset_lock, PVM | PDROP,
"pageprocwait", 1);
} else {
/*
* XXX Ideally we would wait only until the allocation could
* be satisfied. This condition can cause new allocators to
* consume all freed pages while old allocators wait.
*/
mtx_lock(&vm_domainset_lock);
if (vm_page_count_min_set(wdoms)) {
vm_min_waiters++;
msleep(&vm_min_domains, &vm_domainset_lock,
PVM | PDROP, "vmwait", 0);
} else
mtx_unlock(&vm_domainset_lock);
}
}
/*
* vm_wait_domain:
*
* Sleep until free pages are available for allocation.
* - Called in various places after failed memory allocations.
*/
void
vm_wait_domain(int domain)
{
struct vm_domain *vmd;
domainset_t wdom;
vmd = VM_DOMAIN(domain);
vm_domain_free_assert_unlocked(vmd);
if (curproc == pageproc) {
mtx_lock(&vm_domainset_lock);
if (vmd->vmd_free_count < vmd->vmd_pageout_free_min) {
vmd->vmd_pageout_pages_needed = 1;
msleep(&vmd->vmd_pageout_pages_needed,
&vm_domainset_lock, PDROP | PSWP, "VMWait", 0);
} else
mtx_unlock(&vm_domainset_lock);
} else {
if (pageproc == NULL)
panic("vm_wait in early boot");
DOMAINSET_ZERO(&wdom);
DOMAINSET_SET(vmd->vmd_domain, &wdom);
vm_wait_doms(&wdom);
}
}
/*
* vm_wait:
*
* Sleep until free pages are available for allocation in the
* affinity domains of the obj. If obj is NULL, the domain set
* for the calling thread is used.
* Called in various places after failed memory allocations.
*/
void
vm_wait(vm_object_t obj)
{
struct domainset *d;
d = NULL;
/*
* Carefully fetch pointers only once: the struct domainset
* itself is ummutable but the pointer might change.
*/
if (obj != NULL)
d = obj->domain.dr_policy;
if (d == NULL)
d = curthread->td_domain.dr_policy;
vm_wait_doms(&d->ds_mask);
}
/*
* vm_domain_alloc_fail:
*
* Called when a page allocation function fails. Informs the
* pagedaemon and performs the requested wait. Requires the
* domain_free and object lock on entry. Returns with the
* object lock held and free lock released. Returns an error when
* retry is necessary.
*
*/
static int
vm_domain_alloc_fail(struct vm_domain *vmd, vm_object_t object, int req)
{
vm_domain_free_assert_unlocked(vmd);
atomic_add_int(&vmd->vmd_pageout_deficit,
max((u_int)req >> VM_ALLOC_COUNT_SHIFT, 1));
if (req & (VM_ALLOC_WAITOK | VM_ALLOC_WAITFAIL)) {
if (object != NULL)
VM_OBJECT_WUNLOCK(object);
vm_wait_domain(vmd->vmd_domain);
if (object != NULL)
VM_OBJECT_WLOCK(object);
if (req & VM_ALLOC_WAITOK)
return (EAGAIN);
}
return (0);
}
/*
* vm_waitpfault:
*
* Sleep until free pages are available for allocation.
* - Called only in vm_fault so that processes page faulting
* can be easily tracked.
* - Sleeps at a lower priority than vm_wait() so that vm_wait()ing
* processes will be able to grab memory first. Do not change
* this balance without careful testing first.
*/
void
vm_waitpfault(struct domainset *dset, int timo)
{
/*
* XXX Ideally we would wait only until the allocation could
* be satisfied. This condition can cause new allocators to
* consume all freed pages while old allocators wait.
*/
mtx_lock(&vm_domainset_lock);
if (vm_page_count_min_set(&dset->ds_mask)) {
vm_min_waiters++;
msleep(&vm_min_domains, &vm_domainset_lock, PUSER | PDROP,
"pfault", timo);
} else
mtx_unlock(&vm_domainset_lock);
}
static struct vm_pagequeue *
_vm_page_pagequeue(vm_page_t m, uint8_t queue)
{
return (&vm_pagequeue_domain(m)->vmd_pagequeues[queue]);
}
#ifdef INVARIANTS
static struct vm_pagequeue *
vm_page_pagequeue(vm_page_t m)
{
return (_vm_page_pagequeue(m, vm_page_astate_load(m).queue));
}
#endif
static __always_inline bool
vm_page_pqstate_fcmpset(vm_page_t m, vm_page_astate_t *old, vm_page_astate_t new)
{
vm_page_astate_t tmp;
tmp = *old;
do {
if (__predict_true(vm_page_astate_fcmpset(m, old, new)))
return (true);
counter_u64_add(pqstate_commit_retries, 1);
} while (old->_bits == tmp._bits);
return (false);
}
/*
* Do the work of committing a queue state update that moves the page out of
* its current queue.
*/
static bool
_vm_page_pqstate_commit_dequeue(struct vm_pagequeue *pq, vm_page_t m,
vm_page_astate_t *old, vm_page_astate_t new)
{
vm_page_t next;
vm_pagequeue_assert_locked(pq);
KASSERT(vm_page_pagequeue(m) == pq,
("%s: queue %p does not match page %p", __func__, pq, m));
KASSERT(old->queue != PQ_NONE && new.queue != old->queue,
("%s: invalid queue indices %d %d",
__func__, old->queue, new.queue));
/*
* Once the queue index of the page changes there is nothing
* synchronizing with further updates to the page's physical
* queue state. Therefore we must speculatively remove the page
* from the queue now and be prepared to roll back if the queue
* state update fails. If the page is not physically enqueued then
* we just update its queue index.
*/
if ((old->flags & PGA_ENQUEUED) != 0) {
new.flags &= ~PGA_ENQUEUED;
next = TAILQ_NEXT(m, plinks.q);
TAILQ_REMOVE(&pq->pq_pl, m, plinks.q);
vm_pagequeue_cnt_dec(pq);
if (!vm_page_pqstate_fcmpset(m, old, new)) {
if (next == NULL)
TAILQ_INSERT_TAIL(&pq->pq_pl, m, plinks.q);
else
TAILQ_INSERT_BEFORE(next, m, plinks.q);
vm_pagequeue_cnt_inc(pq);
return (false);
} else {
return (true);
}
} else {
return (vm_page_pqstate_fcmpset(m, old, new));
}
}
static bool
vm_page_pqstate_commit_dequeue(vm_page_t m, vm_page_astate_t *old,
vm_page_astate_t new)
{
struct vm_pagequeue *pq;
vm_page_astate_t as;
bool ret;
pq = _vm_page_pagequeue(m, old->queue);
/*
* The queue field and PGA_ENQUEUED flag are stable only so long as the
* corresponding page queue lock is held.
*/
vm_pagequeue_lock(pq);
as = vm_page_astate_load(m);
if (__predict_false(as._bits != old->_bits)) {
*old = as;
ret = false;
} else {
ret = _vm_page_pqstate_commit_dequeue(pq, m, old, new);
}
vm_pagequeue_unlock(pq);
return (ret);
}
/*
* Commit a queue state update that enqueues or requeues a page.
*/
static bool
_vm_page_pqstate_commit_requeue(struct vm_pagequeue *pq, vm_page_t m,
vm_page_astate_t *old, vm_page_astate_t new)
{
struct vm_domain *vmd;
vm_pagequeue_assert_locked(pq);
KASSERT(old->queue != PQ_NONE && new.queue == old->queue,
("%s: invalid queue indices %d %d",
__func__, old->queue, new.queue));
new.flags |= PGA_ENQUEUED;
if (!vm_page_pqstate_fcmpset(m, old, new))
return (false);
if ((old->flags & PGA_ENQUEUED) != 0)
TAILQ_REMOVE(&pq->pq_pl, m, plinks.q);
else
vm_pagequeue_cnt_inc(pq);
/*
* Give PGA_REQUEUE_HEAD precedence over PGA_REQUEUE. In particular, if
* both flags are set in close succession, only PGA_REQUEUE_HEAD will be
* applied, even if it was set first.
*/
if ((old->flags & PGA_REQUEUE_HEAD) != 0) {
vmd = vm_pagequeue_domain(m);
KASSERT(pq == &vmd->vmd_pagequeues[PQ_INACTIVE],
("%s: invalid page queue for page %p", __func__, m));
TAILQ_INSERT_BEFORE(&vmd->vmd_inacthead, m, plinks.q);
} else {
TAILQ_INSERT_TAIL(&pq->pq_pl, m, plinks.q);
}
return (true);
}
/*
* Commit a queue state update that encodes a request for a deferred queue
* operation.
*/
static bool
vm_page_pqstate_commit_request(vm_page_t m, vm_page_astate_t *old,
vm_page_astate_t new)
{
KASSERT(old->queue == new.queue || new.queue != PQ_NONE,
("%s: invalid state, queue %d flags %x",
__func__, new.queue, new.flags));
if (old->_bits != new._bits &&
!vm_page_pqstate_fcmpset(m, old, new))
return (false);
vm_page_pqbatch_submit(m, new.queue);
return (true);
}
/*
* A generic queue state update function. This handles more cases than the
* specialized functions above.
*/
bool
vm_page_pqstate_commit(vm_page_t m, vm_page_astate_t *old, vm_page_astate_t new)
{
if (old->_bits == new._bits)
return (true);
if (old->queue != PQ_NONE && new.queue != old->queue) {
if (!vm_page_pqstate_commit_dequeue(m, old, new))
return (false);
if (new.queue != PQ_NONE)
vm_page_pqbatch_submit(m, new.queue);
} else {
if (!vm_page_pqstate_fcmpset(m, old, new))
return (false);
if (new.queue != PQ_NONE &&
((new.flags & ~old->flags) & PGA_QUEUE_OP_MASK) != 0)
vm_page_pqbatch_submit(m, new.queue);
}
return (true);
}
/*
* Apply deferred queue state updates to a page.
*/
static inline void
vm_pqbatch_process_page(struct vm_pagequeue *pq, vm_page_t m, uint8_t queue)
{
vm_page_astate_t new, old;
CRITICAL_ASSERT(curthread);
vm_pagequeue_assert_locked(pq);
KASSERT(queue < PQ_COUNT,
("%s: invalid queue index %d", __func__, queue));
KASSERT(pq == _vm_page_pagequeue(m, queue),
("%s: page %p does not belong to queue %p", __func__, m, pq));
for (old = vm_page_astate_load(m);;) {
if (__predict_false(old.queue != queue ||
(old.flags & PGA_QUEUE_OP_MASK) == 0)) {
counter_u64_add(queue_nops, 1);
break;
}
KASSERT(old.queue != PQ_NONE || (old.flags & PGA_QUEUE_STATE_MASK) == 0,
("%s: page %p has unexpected queue state", __func__, m));
new = old;
if ((old.flags & PGA_DEQUEUE) != 0) {
new.flags &= ~PGA_QUEUE_OP_MASK;
new.queue = PQ_NONE;
if (__predict_true(_vm_page_pqstate_commit_dequeue(pq,
m, &old, new))) {
counter_u64_add(queue_ops, 1);
break;
}
} else {
new.flags &= ~(PGA_REQUEUE | PGA_REQUEUE_HEAD);
if (__predict_true(_vm_page_pqstate_commit_requeue(pq,
m, &old, new))) {
counter_u64_add(queue_ops, 1);
break;
}
}
}
}
static void
vm_pqbatch_process(struct vm_pagequeue *pq, struct vm_batchqueue *bq,
uint8_t queue)
{
int i;
for (i = 0; i < bq->bq_cnt; i++)
vm_pqbatch_process_page(pq, bq->bq_pa[i], queue);
vm_batchqueue_init(bq);
}
/*
* vm_page_pqbatch_submit: [ internal use only ]
*
* Enqueue a page in the specified page queue's batched work queue.
* The caller must have encoded the requested operation in the page
* structure's a.flags field.
*/
void
vm_page_pqbatch_submit(vm_page_t m, uint8_t queue)
{
struct vm_batchqueue *bq;
struct vm_pagequeue *pq;
int domain;
KASSERT((m->oflags & VPO_UNMANAGED) == 0,
("page %p is unmanaged", m));
KASSERT(queue < PQ_COUNT, ("invalid queue %d", queue));
domain = vm_phys_domain(m);
pq = &vm_pagequeue_domain(m)->vmd_pagequeues[queue];
critical_enter();
bq = DPCPU_PTR(pqbatch[domain][queue]);
if (vm_batchqueue_insert(bq, m)) {
critical_exit();
return;
}
critical_exit();
vm_pagequeue_lock(pq);
critical_enter();
bq = DPCPU_PTR(pqbatch[domain][queue]);
vm_pqbatch_process(pq, bq, queue);
vm_pqbatch_process_page(pq, m, queue);
vm_pagequeue_unlock(pq);
critical_exit();
}
/*
* vm_page_pqbatch_drain: [ internal use only ]
*
* Force all per-CPU page queue batch queues to be drained. This is
* intended for use in severe memory shortages, to ensure that pages
* do not remain stuck in the batch queues.
*/
void
vm_page_pqbatch_drain(void)
{
struct thread *td;
struct vm_domain *vmd;
struct vm_pagequeue *pq;
int cpu, domain, queue;
td = curthread;
CPU_FOREACH(cpu) {
thread_lock(td);
sched_bind(td, cpu);
thread_unlock(td);
for (domain = 0; domain < vm_ndomains; domain++) {
vmd = VM_DOMAIN(domain);
for (queue = 0; queue < PQ_COUNT; queue++) {
pq = &vmd->vmd_pagequeues[queue];
vm_pagequeue_lock(pq);
critical_enter();
vm_pqbatch_process(pq,
DPCPU_PTR(pqbatch[domain][queue]), queue);
critical_exit();
vm_pagequeue_unlock(pq);
}
}
}
thread_lock(td);
sched_unbind(td);
thread_unlock(td);
}
/*
* vm_page_dequeue_deferred: [ internal use only ]
*
* Request removal of the given page from its current page
* queue. Physical removal from the queue may be deferred
* indefinitely.
*
* The page must be locked.
*/
void
vm_page_dequeue_deferred(vm_page_t m)
{
vm_page_astate_t new, old;
old = vm_page_astate_load(m);
do {
if (old.queue == PQ_NONE) {
KASSERT((old.flags & PGA_QUEUE_STATE_MASK) == 0,
("%s: page %p has unexpected queue state",
__func__, m));
break;
}
new = old;
new.flags |= PGA_DEQUEUE;
} while (!vm_page_pqstate_commit_request(m, &old, new));
}
/*
* vm_page_dequeue:
*
* Remove the page from whichever page queue it's in, if any, before
* returning.
*/
void
vm_page_dequeue(vm_page_t m)
{
vm_page_astate_t new, old;
old = vm_page_astate_load(m);
do {
if (old.queue == PQ_NONE) {
KASSERT((old.flags & PGA_QUEUE_STATE_MASK) == 0,
("%s: page %p has unexpected queue state",
__func__, m));
break;
}
new = old;
new.flags &= ~PGA_QUEUE_OP_MASK;
new.queue = PQ_NONE;
} while (!vm_page_pqstate_commit_dequeue(m, &old, new));
}
/*
* Schedule the given page for insertion into the specified page queue.
* Physical insertion of the page may be deferred indefinitely.
*/
static void
vm_page_enqueue(vm_page_t m, uint8_t queue)
{
KASSERT(m->a.queue == PQ_NONE &&
(m->a.flags & PGA_QUEUE_STATE_MASK) == 0,
("%s: page %p is already enqueued", __func__, m));
KASSERT(m->ref_count > 0,
("%s: page %p does not carry any references", __func__, m));
m->a.queue = queue;
if ((m->a.flags & PGA_REQUEUE) == 0)
vm_page_aflag_set(m, PGA_REQUEUE);
vm_page_pqbatch_submit(m, queue);
}
/*
* vm_page_free_prep:
*
* Prepares the given page to be put on the free list,
* disassociating it from any VM object. The caller may return
* the page to the free list only if this function returns true.
*
* The object, if it exists, must be locked, and then the page must
* be xbusy. Otherwise the page must be not busied. A managed
* page must be unmapped.
*/
static bool
vm_page_free_prep(vm_page_t m)
{
/*
* Synchronize with threads that have dropped a reference to this
* page.
*/
atomic_thread_fence_acq();
#if defined(DIAGNOSTIC) && defined(PHYS_TO_DMAP)
if (PMAP_HAS_DMAP && (m->flags & PG_ZERO) != 0) {
uint64_t *p;
int i;
p = (uint64_t *)PHYS_TO_DMAP(VM_PAGE_TO_PHYS(m));
for (i = 0; i < PAGE_SIZE / sizeof(uint64_t); i++, p++)
KASSERT(*p == 0, ("vm_page_free_prep %p PG_ZERO %d %jx",
m, i, (uintmax_t)*p));
}
#endif
if ((m->oflags & VPO_UNMANAGED) == 0) {
KASSERT(!pmap_page_is_mapped(m),
("vm_page_free_prep: freeing mapped page %p", m));
KASSERT((m->a.flags & (PGA_EXECUTABLE | PGA_WRITEABLE)) == 0,
("vm_page_free_prep: mapping flags set in page %p", m));
} else {
KASSERT(m->a.queue == PQ_NONE,
("vm_page_free_prep: unmanaged page %p is queued", m));
}
VM_CNT_INC(v_tfree);
if (m->object != NULL) {
KASSERT(((m->oflags & VPO_UNMANAGED) != 0) ==
((m->object->flags & OBJ_UNMANAGED) != 0),
("vm_page_free_prep: managed flag mismatch for page %p",
m));
vm_page_assert_xbusied(m);
/*
* The object reference can be released without an atomic
* operation.
*/
KASSERT((m->flags & PG_FICTITIOUS) != 0 ||
m->ref_count == VPRC_OBJREF,
("vm_page_free_prep: page %p has unexpected ref_count %u",
m, m->ref_count));
vm_page_object_remove(m);
m->ref_count -= VPRC_OBJREF;
} else
vm_page_assert_unbusied(m);
vm_page_busy_free(m);
/*
* If fictitious remove object association and
* return.
*/
if ((m->flags & PG_FICTITIOUS) != 0) {
KASSERT(m->ref_count == 1,
("fictitious page %p is referenced", m));
KASSERT(m->a.queue == PQ_NONE,
("fictitious page %p is queued", m));
return (false);
}
/*
* Pages need not be dequeued before they are returned to the physical
* memory allocator, but they must at least be marked for a deferred
* dequeue.
*/
if ((m->oflags & VPO_UNMANAGED) == 0)
vm_page_dequeue_deferred(m);
m->valid = 0;
vm_page_undirty(m);
if (m->ref_count != 0)
panic("vm_page_free_prep: page %p has references", m);
/*
* Restore the default memory attribute to the page.
*/
if (pmap_page_get_memattr(m) != VM_MEMATTR_DEFAULT)
pmap_page_set_memattr(m, VM_MEMATTR_DEFAULT);
#if VM_NRESERVLEVEL > 0
/*
* Determine whether the page belongs to a reservation. If the page was
* allocated from a per-CPU cache, it cannot belong to a reservation, so
* as an optimization, we avoid the check in that case.
*/
if ((m->flags & PG_PCPU_CACHE) == 0 && vm_reserv_free_page(m))
return (false);
#endif
return (true);
}
/*
* vm_page_free_toq:
*
* Returns the given page to the free list, disassociating it
* from any VM object.
*
* The object must be locked. The page must be locked if it is
* managed.
*/
static void
vm_page_free_toq(vm_page_t m)
{
struct vm_domain *vmd;
uma_zone_t zone;
if (!vm_page_free_prep(m))
return;
vmd = vm_pagequeue_domain(m);
zone = vmd->vmd_pgcache[m->pool].zone;
if ((m->flags & PG_PCPU_CACHE) != 0 && zone != NULL) {
uma_zfree(zone, m);
return;
}
vm_domain_free_lock(vmd);
vm_phys_free_pages(m, 0);
vm_domain_free_unlock(vmd);
vm_domain_freecnt_inc(vmd, 1);
}
/*
* vm_page_free_pages_toq:
*
* Returns a list of pages to the free list, disassociating it
* from any VM object. In other words, this is equivalent to
* calling vm_page_free_toq() for each page of a list of VM objects.
*
* The objects must be locked. The pages must be locked if it is
* managed.
*/
void
vm_page_free_pages_toq(struct spglist *free, bool update_wire_count)
{
vm_page_t m;
int count;
if (SLIST_EMPTY(free))
return;
count = 0;
while ((m = SLIST_FIRST(free)) != NULL) {
count++;
SLIST_REMOVE_HEAD(free, plinks.s.ss);
vm_page_free_toq(m);
}
if (update_wire_count)
vm_wire_sub(count);
}
/*
* Mark this page as wired down, preventing reclamation by the page daemon
* or when the containing object is destroyed.
*/
void
vm_page_wire(vm_page_t m)
{
u_int old;
KASSERT(m->object != NULL,
("vm_page_wire: page %p does not belong to an object", m));
if (!vm_page_busied(m) && !vm_object_busied(m->object))
VM_OBJECT_ASSERT_LOCKED(m->object);
KASSERT((m->flags & PG_FICTITIOUS) == 0 ||
VPRC_WIRE_COUNT(m->ref_count) >= 1,
("vm_page_wire: fictitious page %p has zero wirings", m));
old = atomic_fetchadd_int(&m->ref_count, 1);
KASSERT(VPRC_WIRE_COUNT(old) != VPRC_WIRE_COUNT_MAX,
("vm_page_wire: counter overflow for page %p", m));
if (VPRC_WIRE_COUNT(old) == 0) {
if ((m->oflags & VPO_UNMANAGED) == 0)
vm_page_aflag_set(m, PGA_DEQUEUE);
vm_wire_add(1);
}
}
/*
* Attempt to wire a mapped page following a pmap lookup of that page.
* This may fail if a thread is concurrently tearing down mappings of the page.
* The transient failure is acceptable because it translates to the
* failure of the caller pmap_extract_and_hold(), which should be then
* followed by the vm_fault() fallback, see e.g. vm_fault_quick_hold_pages().
*/
bool
vm_page_wire_mapped(vm_page_t m)
{
u_int old;
old = m->ref_count;
do {
KASSERT(old > 0,
("vm_page_wire_mapped: wiring unreferenced page %p", m));
if ((old & VPRC_BLOCKED) != 0)
return (false);
} while (!atomic_fcmpset_int(&m->ref_count, &old, old + 1));
if (VPRC_WIRE_COUNT(old) == 0) {
if ((m->oflags & VPO_UNMANAGED) == 0)
vm_page_aflag_set(m, PGA_DEQUEUE);
vm_wire_add(1);
}
return (true);
}
/*
* Release a wiring reference to a managed page. If the page still belongs to
* an object, update its position in the page queues to reflect the reference.
* If the wiring was the last reference to the page, free the page.
*/
static void
vm_page_unwire_managed(vm_page_t m, uint8_t nqueue, bool noreuse)
{
u_int old;
KASSERT((m->oflags & VPO_UNMANAGED) == 0,
("%s: page %p is unmanaged", __func__, m));
/*
* Update LRU state before releasing the wiring reference.
* Use a release store when updating the reference count to
* synchronize with vm_page_free_prep().
*/
old = m->ref_count;
do {
KASSERT(VPRC_WIRE_COUNT(old) > 0,
("vm_page_unwire: wire count underflow for page %p", m));
if (old > VPRC_OBJREF + 1) {
/*
* The page has at least one other wiring reference. An
* earlier iteration of this loop may have called
* vm_page_release_toq() and cleared PGA_DEQUEUE, so
* re-set it if necessary.
*/
if ((vm_page_astate_load(m).flags & PGA_DEQUEUE) == 0)
vm_page_aflag_set(m, PGA_DEQUEUE);
} else if (old == VPRC_OBJREF + 1) {
/*
* This is the last wiring. Clear PGA_DEQUEUE and
* update the page's queue state to reflect the
* reference. If the page does not belong to an object
* (i.e., the VPRC_OBJREF bit is clear), we only need to
* clear leftover queue state.
*/
vm_page_release_toq(m, nqueue, false);
} else if (old == 1) {
vm_page_aflag_clear(m, PGA_DEQUEUE);
}
} while (!atomic_fcmpset_rel_int(&m->ref_count, &old, old - 1));
if (VPRC_WIRE_COUNT(old) == 1) {
vm_wire_sub(1);
if (old == 1)
vm_page_free(m);
}
}
/*
* Release one wiring of the specified page, potentially allowing it to be
* paged out.
*
* Only managed pages belonging to an object can be paged out. If the number
* of wirings transitions to zero and the page is eligible for page out, then
* the page is added to the specified paging queue. If the released wiring
* represented the last reference to the page, the page is freed.
*
* A managed page must be locked.
*/
void
vm_page_unwire(vm_page_t m, uint8_t nqueue)
{
KASSERT(nqueue < PQ_COUNT,
("vm_page_unwire: invalid queue %u request for page %p",
nqueue, m));
if ((m->oflags & VPO_UNMANAGED) != 0) {
if (vm_page_unwire_noq(m) && m->ref_count == 0)
vm_page_free(m);
return;
}
vm_page_unwire_managed(m, nqueue, false);
}
/*
* Unwire a page without (re-)inserting it into a page queue. It is up
* to the caller to enqueue, requeue, or free the page as appropriate.
* In most cases involving managed pages, vm_page_unwire() should be used
* instead.
*/
bool
vm_page_unwire_noq(vm_page_t m)
{
u_int old;
old = vm_page_drop(m, 1);
KASSERT(VPRC_WIRE_COUNT(old) != 0,
("vm_page_unref: counter underflow for page %p", m));
KASSERT((m->flags & PG_FICTITIOUS) == 0 || VPRC_WIRE_COUNT(old) > 1,
("vm_page_unref: missing ref on fictitious page %p", m));
if (VPRC_WIRE_COUNT(old) > 1)
return (false);
if ((m->oflags & VPO_UNMANAGED) == 0)
vm_page_aflag_clear(m, PGA_DEQUEUE);
vm_wire_sub(1);
return (true);
}
/*
* Ensure that the page ends up in the specified page queue. If the page is
* active or being moved to the active queue, ensure that its act_count is
* at least ACT_INIT but do not otherwise mess with it.
*
* A managed page must be locked.
*/
static __always_inline void
vm_page_mvqueue(vm_page_t m, const uint8_t nqueue, const uint16_t nflag)
{
vm_page_astate_t old, new;
KASSERT(m->ref_count > 0,
("%s: page %p does not carry any references", __func__, m));
KASSERT(nflag == PGA_REQUEUE || nflag == PGA_REQUEUE_HEAD,
("%s: invalid flags %x", __func__, nflag));
if ((m->oflags & VPO_UNMANAGED) != 0 || vm_page_wired(m))
return;
old = vm_page_astate_load(m);
do {
if ((old.flags & PGA_DEQUEUE) != 0)
break;
new = old;
new.flags &= ~PGA_QUEUE_OP_MASK;
if (nqueue == PQ_ACTIVE)
new.act_count = max(old.act_count, ACT_INIT);
if (old.queue == nqueue) {
if (nqueue != PQ_ACTIVE)
new.flags |= nflag;
} else {
new.flags |= nflag;
new.queue = nqueue;
}
} while (!vm_page_pqstate_commit(m, &old, new));
}
/*
* Put the specified page on the active list (if appropriate).
*/
void
vm_page_activate(vm_page_t m)
{
vm_page_mvqueue(m, PQ_ACTIVE, PGA_REQUEUE);
}
/*
* Move the specified page to the tail of the inactive queue, or requeue
* the page if it is already in the inactive queue.
*/
void
vm_page_deactivate(vm_page_t m)
{
vm_page_mvqueue(m, PQ_INACTIVE, PGA_REQUEUE);
}
void
vm_page_deactivate_noreuse(vm_page_t m)
{
vm_page_mvqueue(m, PQ_INACTIVE, PGA_REQUEUE_HEAD);
}
/*
* Put a page in the laundry, or requeue it if it is already there.
*/
void
vm_page_launder(vm_page_t m)
{
vm_page_mvqueue(m, PQ_LAUNDRY, PGA_REQUEUE);
}
/*
* Put a page in the PQ_UNSWAPPABLE holding queue.
*/
void
vm_page_unswappable(vm_page_t m)
{
KASSERT(!vm_page_wired(m) && (m->oflags & VPO_UNMANAGED) == 0,
("page %p already unswappable", m));
vm_page_dequeue(m);
vm_page_enqueue(m, PQ_UNSWAPPABLE);
}
/*
* Release a page back to the page queues in preparation for unwiring.
*/
static void
vm_page_release_toq(vm_page_t m, uint8_t nqueue, const bool noreuse)
{
vm_page_astate_t old, new;
uint16_t nflag;
/*
* Use a check of the valid bits to determine whether we should
* accelerate reclamation of the page. The object lock might not be
* held here, in which case the check is racy. At worst we will either
* accelerate reclamation of a valid page and violate LRU, or
* unnecessarily defer reclamation of an invalid page.
*
* If we were asked to not cache the page, place it near the head of the
* inactive queue so that is reclaimed sooner.
*/
if (noreuse || m->valid == 0) {
nqueue = PQ_INACTIVE;
nflag = PGA_REQUEUE_HEAD;
} else {
nflag = PGA_REQUEUE;
}
old = vm_page_astate_load(m);
do {
new = old;
/*
* If the page is already in the active queue and we are not
* trying to accelerate reclamation, simply mark it as
* referenced and avoid any queue operations.
*/
new.flags &= ~PGA_QUEUE_OP_MASK;
if (nflag != PGA_REQUEUE_HEAD && old.queue == PQ_ACTIVE)
new.flags |= PGA_REFERENCED;
else {
new.flags |= nflag;
new.queue = nqueue;
}
} while (!vm_page_pqstate_commit(m, &old, new));
}
/*
* Unwire a page and either attempt to free it or re-add it to the page queues.
*/
void
vm_page_release(vm_page_t m, int flags)
{
vm_object_t object;
KASSERT((m->oflags & VPO_UNMANAGED) == 0,
("vm_page_release: page %p is unmanaged", m));
if ((flags & VPR_TRYFREE) != 0) {
for (;;) {
object = atomic_load_ptr(&m->object);
if (object == NULL)
break;
/* Depends on type-stability. */
if (vm_page_busied(m) || !VM_OBJECT_TRYWLOCK(object))
break;
if (object == m->object) {
vm_page_release_locked(m, flags);
VM_OBJECT_WUNLOCK(object);
return;
}
VM_OBJECT_WUNLOCK(object);
}
}
vm_page_unwire_managed(m, PQ_INACTIVE, flags != 0);
}
/* See vm_page_release(). */
void
vm_page_release_locked(vm_page_t m, int flags)
{
VM_OBJECT_ASSERT_WLOCKED(m->object);
KASSERT((m->oflags & VPO_UNMANAGED) == 0,
("vm_page_release_locked: page %p is unmanaged", m));
if (vm_page_unwire_noq(m)) {
if ((flags & VPR_TRYFREE) != 0 &&
(m->object->ref_count == 0 || !pmap_page_is_mapped(m)) &&
m->dirty == 0 && vm_page_tryxbusy(m)) {
/*
* An unlocked lookup may have wired the page before the
* busy lock was acquired, in which case the page must
* not be freed.
*/
if (__predict_true(!vm_page_wired(m))) {
vm_page_free(m);
return;
}
vm_page_xunbusy(m);
} else {
vm_page_release_toq(m, PQ_INACTIVE, flags != 0);
}
}
}
static bool
vm_page_try_blocked_op(vm_page_t m, void (*op)(vm_page_t))
{
u_int old;
KASSERT(m->object != NULL && (m->oflags & VPO_UNMANAGED) == 0,
("vm_page_try_blocked_op: page %p has no object", m));
KASSERT(vm_page_busied(m),
("vm_page_try_blocked_op: page %p is not busy", m));
VM_OBJECT_ASSERT_LOCKED(m->object);
old = m->ref_count;
do {
KASSERT(old != 0,
("vm_page_try_blocked_op: page %p has no references", m));
if (VPRC_WIRE_COUNT(old) != 0)
return (false);
} while (!atomic_fcmpset_int(&m->ref_count, &old, old | VPRC_BLOCKED));
(op)(m);
/*
* If the object is read-locked, new wirings may be created via an
* object lookup.
*/
old = vm_page_drop(m, VPRC_BLOCKED);
KASSERT(!VM_OBJECT_WOWNED(m->object) ||
old == (VPRC_BLOCKED | VPRC_OBJREF),
("vm_page_try_blocked_op: unexpected refcount value %u for %p",
old, m));
return (true);
}
/*
* Atomically check for wirings and remove all mappings of the page.
*/
bool
vm_page_try_remove_all(vm_page_t m)
{
return (vm_page_try_blocked_op(m, pmap_remove_all));
}
/*
* Atomically check for wirings and remove all writeable mappings of the page.
*/
bool
vm_page_try_remove_write(vm_page_t m)
{
return (vm_page_try_blocked_op(m, pmap_remove_write));
}
/*
* vm_page_advise
*
* Apply the specified advice to the given page.
*
* The object and page must be locked.
*/
void
vm_page_advise(vm_page_t m, int advice)
{
VM_OBJECT_ASSERT_WLOCKED(m->object);
if (advice == MADV_FREE)
/*
* Mark the page clean. This will allow the page to be freed
* without first paging it out. MADV_FREE pages are often
* quickly reused by malloc(3), so we do not do anything that
* would result in a page fault on a later access.
*/
vm_page_undirty(m);
else if (advice != MADV_DONTNEED) {
if (advice == MADV_WILLNEED)
vm_page_activate(m);
return;
}
if (advice != MADV_FREE && m->dirty == 0 && pmap_is_modified(m))
vm_page_dirty(m);
/*
* Clear any references to the page. Otherwise, the page daemon will
* immediately reactivate the page.
*/
vm_page_aflag_clear(m, PGA_REFERENCED);
/*
* Place clean pages near the head of the inactive queue rather than
* the tail, thus defeating the queue's LRU operation and ensuring that
* the page will be reused quickly. Dirty pages not already in the
* laundry are moved there.
*/
if (m->dirty == 0)
vm_page_deactivate_noreuse(m);
else if (!vm_page_in_laundry(m))
vm_page_launder(m);
}
/*
* vm_page_grab_release
*
* Helper routine for grab functions to release busy on return.
*/
static inline void
vm_page_grab_release(vm_page_t m, int allocflags)
{
if ((allocflags & VM_ALLOC_NOBUSY) != 0) {
if ((allocflags & VM_ALLOC_IGN_SBUSY) != 0)
vm_page_sunbusy(m);
else
vm_page_xunbusy(m);
}
}
/*
* vm_page_grab_sleep
*
* Sleep for busy according to VM_ALLOC_ parameters. Returns true
* if the caller should retry and false otherwise.
*
* If the object is locked on entry the object will be unlocked with
* false returns and still locked but possibly having been dropped
* with true returns.
*/
static bool
vm_page_grab_sleep(vm_object_t object, vm_page_t m, vm_pindex_t pindex,
const char *wmesg, int allocflags, bool locked)
{
if ((allocflags & VM_ALLOC_NOWAIT) != 0)
return (false);
/*
* Reference the page before unlocking and sleeping so that
* the page daemon is less likely to reclaim it.
*/
if (locked && (allocflags & VM_ALLOC_NOCREAT) == 0)
vm_page_reference(m);
if (_vm_page_busy_sleep(object, m, m->pindex, wmesg, allocflags,
locked) && locked)
VM_OBJECT_WLOCK(object);
if ((allocflags & VM_ALLOC_WAITFAIL) != 0)
return (false);
return (true);
}
/*
* Assert that the grab flags are valid.
*/
static inline void
vm_page_grab_check(int allocflags)
{
KASSERT((allocflags & VM_ALLOC_NOBUSY) == 0 ||
(allocflags & VM_ALLOC_WIRED) != 0,
("vm_page_grab*: the pages must be busied or wired"));
KASSERT((allocflags & VM_ALLOC_SBUSY) == 0 ||
(allocflags & VM_ALLOC_IGN_SBUSY) != 0,
("vm_page_grab*: VM_ALLOC_SBUSY/VM_ALLOC_IGN_SBUSY mismatch"));
}
/*
* Calculate the page allocation flags for grab.
*/
static inline int
vm_page_grab_pflags(int allocflags)
{
int pflags;
pflags = allocflags &
~(VM_ALLOC_NOWAIT | VM_ALLOC_WAITOK | VM_ALLOC_WAITFAIL |
VM_ALLOC_NOBUSY);
if ((allocflags & VM_ALLOC_NOWAIT) == 0)
pflags |= VM_ALLOC_WAITFAIL;
if ((allocflags & VM_ALLOC_IGN_SBUSY) != 0)
pflags |= VM_ALLOC_SBUSY;
return (pflags);
}
/*
* Grab a page, waiting until we are waken up due to the page
* changing state. We keep on waiting, if the page continues
* to be in the object. If the page doesn't exist, first allocate it
* and then conditionally zero it.
*
* This routine may sleep.
*
* The object must be locked on entry. The lock will, however, be released
* and reacquired if the routine sleeps.
*/
vm_page_t
vm_page_grab(vm_object_t object, vm_pindex_t pindex, int allocflags)
{
vm_page_t m;
VM_OBJECT_ASSERT_WLOCKED(object);
vm_page_grab_check(allocflags);
retrylookup:
if ((m = vm_page_lookup(object, pindex)) != NULL) {
if (!vm_page_tryacquire(m, allocflags)) {
if (vm_page_grab_sleep(object, m, pindex, "pgrbwt",
allocflags, true))
goto retrylookup;
return (NULL);
}
goto out;
}
if ((allocflags & VM_ALLOC_NOCREAT) != 0)
return (NULL);
m = vm_page_alloc(object, pindex, vm_page_grab_pflags(allocflags));
if (m == NULL) {
if ((allocflags & (VM_ALLOC_NOWAIT | VM_ALLOC_WAITFAIL)) != 0)
return (NULL);
goto retrylookup;
}
if (allocflags & VM_ALLOC_ZERO && (m->flags & PG_ZERO) == 0)
pmap_zero_page(m);
out:
vm_page_grab_release(m, allocflags);
return (m);
}
/*
* Locklessly attempt to acquire a page given a (object, pindex) tuple
* and an optional previous page to avoid the radix lookup. The resulting
* page will be validated against the identity tuple and busied or wired
* as requested. A NULL *mp return guarantees that the page was not in
* radix at the time of the call but callers must perform higher level
* synchronization or retry the operation under a lock if they require
* an atomic answer. This is the only lock free validation routine,
* other routines can depend on the resulting page state.
*
* The return value indicates whether the operation failed due to caller
* flags. The return is tri-state with mp:
*
* (true, *mp != NULL) - The operation was successful.
* (true, *mp == NULL) - The page was not found in tree.
* (false, *mp == NULL) - WAITFAIL or NOWAIT prevented acquisition.
*/
static bool
vm_page_acquire_unlocked(vm_object_t object, vm_pindex_t pindex,
vm_page_t prev, vm_page_t *mp, int allocflags)
{
vm_page_t m;
vm_page_grab_check(allocflags);
MPASS(prev == NULL || vm_page_busied(prev) || vm_page_wired(prev));
*mp = NULL;
for (;;) {
/*
* We may see a false NULL here because the previous page
* has been removed or just inserted and the list is loaded
* without barriers. Switch to radix to verify.
*/
if (prev == NULL || (m = TAILQ_NEXT(prev, listq)) == NULL ||
QMD_IS_TRASHED(m) || m->pindex != pindex ||
atomic_load_ptr(&m->object) != object) {
prev = NULL;
/*
* This guarantees the result is instantaneously
* correct.
*/
m = vm_radix_lookup_unlocked(&object->rtree, pindex);
}
if (m == NULL)
return (true);
if (vm_page_trybusy(m, allocflags)) {
if (m->object == object && m->pindex == pindex)
break;
/* relookup. */
vm_page_busy_release(m);
cpu_spinwait();
continue;
}
if (!vm_page_grab_sleep(object, m, pindex, "pgnslp",
allocflags, false))
return (false);
}
if ((allocflags & VM_ALLOC_WIRED) != 0)
vm_page_wire(m);
vm_page_grab_release(m, allocflags);
*mp = m;
return (true);
}
/*
* Try to locklessly grab a page and fall back to the object lock if NOCREAT
* is not set.
*/
vm_page_t
vm_page_grab_unlocked(vm_object_t object, vm_pindex_t pindex, int allocflags)
{
vm_page_t m;
vm_page_grab_check(allocflags);
if (!vm_page_acquire_unlocked(object, pindex, NULL, &m, allocflags))
return (NULL);
if (m != NULL)
return (m);
/*
* The radix lockless lookup should never return a false negative
* errors. If the user specifies NOCREAT they are guaranteed there
* was no page present at the instant of the call. A NOCREAT caller
* must handle create races gracefully.
*/
if ((allocflags & VM_ALLOC_NOCREAT) != 0)
return (NULL);
VM_OBJECT_WLOCK(object);
m = vm_page_grab(object, pindex, allocflags);
VM_OBJECT_WUNLOCK(object);
return (m);
}
/*
* Grab a page and make it valid, paging in if necessary. Pages missing from
* their pager are zero filled and validated. If a VM_ALLOC_COUNT is supplied
* and the page is not valid as many as VM_INITIAL_PAGEIN pages can be brought
* in simultaneously. Additional pages will be left on a paging queue but
* will neither be wired nor busy regardless of allocflags.
*/
int
vm_page_grab_valid(vm_page_t *mp, vm_object_t object, vm_pindex_t pindex, int allocflags)
{
vm_page_t m;
vm_page_t ma[VM_INITIAL_PAGEIN];
int after, i, pflags, rv;
KASSERT((allocflags & VM_ALLOC_SBUSY) == 0 ||
(allocflags & VM_ALLOC_IGN_SBUSY) != 0,
("vm_page_grab_valid: VM_ALLOC_SBUSY/VM_ALLOC_IGN_SBUSY mismatch"));
KASSERT((allocflags &
(VM_ALLOC_NOWAIT | VM_ALLOC_WAITFAIL | VM_ALLOC_ZERO)) == 0,
("vm_page_grab_valid: Invalid flags 0x%X", allocflags));
VM_OBJECT_ASSERT_WLOCKED(object);
pflags = allocflags & ~(VM_ALLOC_NOBUSY | VM_ALLOC_SBUSY |
VM_ALLOC_WIRED);
pflags |= VM_ALLOC_WAITFAIL;
retrylookup:
if ((m = vm_page_lookup(object, pindex)) != NULL) {
/*
* If the page is fully valid it can only become invalid
* with the object lock held. If it is not valid it can
* become valid with the busy lock held. Therefore, we
* may unnecessarily lock the exclusive busy here if we
* race with I/O completion not using the object lock.
* However, we will not end up with an invalid page and a
* shared lock.
*/
if (!vm_page_trybusy(m,
vm_page_all_valid(m) ? allocflags : 0)) {
(void)vm_page_grab_sleep(object, m, pindex, "pgrbwt",
allocflags, true);
goto retrylookup;
}
if (vm_page_all_valid(m))
goto out;
if ((allocflags & VM_ALLOC_NOCREAT) != 0) {
vm_page_busy_release(m);
*mp = NULL;
return (VM_PAGER_FAIL);
}
} else if ((allocflags & VM_ALLOC_NOCREAT) != 0) {
*mp = NULL;
return (VM_PAGER_FAIL);
} else if ((m = vm_page_alloc(object, pindex, pflags)) == NULL) {
goto retrylookup;
}
vm_page_assert_xbusied(m);
if (vm_pager_has_page(object, pindex, NULL, &after)) {
after = MIN(after, VM_INITIAL_PAGEIN);
after = MIN(after, allocflags >> VM_ALLOC_COUNT_SHIFT);
after = MAX(after, 1);
ma[0] = m;
for (i = 1; i < after; i++) {
if ((ma[i] = vm_page_next(ma[i - 1])) != NULL) {
if (ma[i]->valid || !vm_page_tryxbusy(ma[i]))
break;
} else {
ma[i] = vm_page_alloc(object, m->pindex + i,
VM_ALLOC_NORMAL);
if (ma[i] == NULL)
break;
}
}
after = i;
vm_object_pip_add(object, after);
VM_OBJECT_WUNLOCK(object);
rv = vm_pager_get_pages(object, ma, after, NULL, NULL);
VM_OBJECT_WLOCK(object);
vm_object_pip_wakeupn(object, after);
/* Pager may have replaced a page. */
m = ma[0];
if (rv != VM_PAGER_OK) {
for (i = 0; i < after; i++) {
if (!vm_page_wired(ma[i]))
vm_page_free(ma[i]);
else
vm_page_xunbusy(ma[i]);
}
*mp = NULL;
return (rv);
}
for (i = 1; i < after; i++)
vm_page_readahead_finish(ma[i]);
MPASS(vm_page_all_valid(m));
} else {
vm_page_zero_invalid(m, TRUE);
}
out:
if ((allocflags & VM_ALLOC_WIRED) != 0)
vm_page_wire(m);
if ((allocflags & VM_ALLOC_SBUSY) != 0 && vm_page_xbusied(m))
vm_page_busy_downgrade(m);
else if ((allocflags & VM_ALLOC_NOBUSY) != 0)
vm_page_busy_release(m);
*mp = m;
return (VM_PAGER_OK);
}
/*
* Locklessly grab a valid page. If the page is not valid or not yet
* allocated this will fall back to the object lock method.
*/
int
vm_page_grab_valid_unlocked(vm_page_t *mp, vm_object_t object,
vm_pindex_t pindex, int allocflags)
{
vm_page_t m;
int flags;
int error;
KASSERT((allocflags & VM_ALLOC_SBUSY) == 0 ||
(allocflags & VM_ALLOC_IGN_SBUSY) != 0,
("vm_page_grab_valid_unlocked: VM_ALLOC_SBUSY/VM_ALLOC_IGN_SBUSY "
"mismatch"));
KASSERT((allocflags &
(VM_ALLOC_NOWAIT | VM_ALLOC_WAITFAIL | VM_ALLOC_ZERO)) == 0,
("vm_page_grab_valid_unlocked: Invalid flags 0x%X", allocflags));
/*
* Attempt a lockless lookup and busy. We need at least an sbusy
* before we can inspect the valid field and return a wired page.
*/
flags = allocflags & ~(VM_ALLOC_NOBUSY | VM_ALLOC_WIRED);
if (!vm_page_acquire_unlocked(object, pindex, NULL, mp, flags))
return (VM_PAGER_FAIL);
if ((m = *mp) != NULL) {
if (vm_page_all_valid(m)) {
if ((allocflags & VM_ALLOC_WIRED) != 0)
vm_page_wire(m);
vm_page_grab_release(m, allocflags);
return (VM_PAGER_OK);
}
vm_page_busy_release(m);
}
if ((allocflags & VM_ALLOC_NOCREAT) != 0) {
*mp = NULL;
return (VM_PAGER_FAIL);
}
VM_OBJECT_WLOCK(object);
error = vm_page_grab_valid(mp, object, pindex, allocflags);
VM_OBJECT_WUNLOCK(object);
return (error);
}
/*
* Return the specified range of pages from the given object. For each
* page offset within the range, if a page already exists within the object
* at that offset and it is busy, then wait for it to change state. If,
* instead, the page doesn't exist, then allocate it.
*
* The caller must always specify an allocation class.
*
* allocation classes:
* VM_ALLOC_NORMAL normal process request
* VM_ALLOC_SYSTEM system *really* needs the pages
*
* The caller must always specify that the pages are to be busied and/or
* wired.
*
* optional allocation flags:
* VM_ALLOC_IGN_SBUSY do not sleep on soft busy pages
* VM_ALLOC_NOBUSY do not exclusive busy the page
* VM_ALLOC_NOWAIT do not sleep
* VM_ALLOC_SBUSY set page to sbusy state
* VM_ALLOC_WIRED wire the pages
* VM_ALLOC_ZERO zero and validate any invalid pages
*
* If VM_ALLOC_NOWAIT is not specified, this routine may sleep. Otherwise, it
* may return a partial prefix of the requested range.
*/
int
vm_page_grab_pages(vm_object_t object, vm_pindex_t pindex, int allocflags,
vm_page_t *ma, int count)
{
vm_page_t m, mpred;
int pflags;
int i;
VM_OBJECT_ASSERT_WLOCKED(object);
KASSERT(((u_int)allocflags >> VM_ALLOC_COUNT_SHIFT) == 0,
("vm_page_grap_pages: VM_ALLOC_COUNT() is not allowed"));
vm_page_grab_check(allocflags);
pflags = vm_page_grab_pflags(allocflags);
if (count == 0)
return (0);
i = 0;
retrylookup:
m = vm_radix_lookup_le(&object->rtree, pindex + i);
if (m == NULL || m->pindex != pindex + i) {
mpred = m;
m = NULL;
} else
mpred = TAILQ_PREV(m, pglist, listq);
for (; i < count; i++) {
if (m != NULL) {
if (!vm_page_tryacquire(m, allocflags)) {
if (vm_page_grab_sleep(object, m, pindex,
"grbmaw", allocflags, true))
goto retrylookup;
break;
}
} else {
if ((allocflags & VM_ALLOC_NOCREAT) != 0)
break;
m = vm_page_alloc_after(object, pindex + i,
pflags | VM_ALLOC_COUNT(count - i), mpred);
if (m == NULL) {
if ((allocflags & (VM_ALLOC_NOWAIT |
VM_ALLOC_WAITFAIL)) != 0)
break;
goto retrylookup;
}
}
if (vm_page_none_valid(m) &&
(allocflags & VM_ALLOC_ZERO) != 0) {
if ((m->flags & PG_ZERO) == 0)
pmap_zero_page(m);
vm_page_valid(m);
}
vm_page_grab_release(m, allocflags);
ma[i] = mpred = m;
m = vm_page_next(m);
}
return (i);
}
/*
* Unlocked variant of vm_page_grab_pages(). This accepts the same flags
* and will fall back to the locked variant to handle allocation.
*/
int
vm_page_grab_pages_unlocked(vm_object_t object, vm_pindex_t pindex,
int allocflags, vm_page_t *ma, int count)
{
vm_page_t m, pred;
int flags;
int i;
vm_page_grab_check(allocflags);
/*
* Modify flags for lockless acquire to hold the page until we
* set it valid if necessary.
*/
flags = allocflags & ~VM_ALLOC_NOBUSY;
pred = NULL;
for (i = 0; i < count; i++, pindex++) {
if (!vm_page_acquire_unlocked(object, pindex, pred, &m, flags))
return (i);
if (m == NULL)
break;
if ((flags & VM_ALLOC_ZERO) != 0 && vm_page_none_valid(m)) {
if ((m->flags & PG_ZERO) == 0)
pmap_zero_page(m);
vm_page_valid(m);
}
/* m will still be wired or busy according to flags. */
vm_page_grab_release(m, allocflags);
pred = ma[i] = m;
}
if ((allocflags & VM_ALLOC_NOCREAT) != 0)
return (i);
count -= i;
VM_OBJECT_WLOCK(object);
i += vm_page_grab_pages(object, pindex, allocflags, &ma[i], count);
VM_OBJECT_WUNLOCK(object);
return (i);
}
/*
* Mapping function for valid or dirty bits in a page.
*
* Inputs are required to range within a page.
*/
vm_page_bits_t
vm_page_bits(int base, int size)
{
int first_bit;
int last_bit;
KASSERT(
base + size <= PAGE_SIZE,
("vm_page_bits: illegal base/size %d/%d", base, size)
);
if (size == 0) /* handle degenerate case */
return (0);
first_bit = base >> DEV_BSHIFT;
last_bit = (base + size - 1) >> DEV_BSHIFT;
return (((vm_page_bits_t)2 << last_bit) -
((vm_page_bits_t)1 << first_bit));
}
void
vm_page_bits_set(vm_page_t m, vm_page_bits_t *bits, vm_page_bits_t set)
{
#if PAGE_SIZE == 32768
atomic_set_64((uint64_t *)bits, set);
#elif PAGE_SIZE == 16384
atomic_set_32((uint32_t *)bits, set);
#elif (PAGE_SIZE == 8192) && defined(atomic_set_16)
atomic_set_16((uint16_t *)bits, set);
#elif (PAGE_SIZE == 4096) && defined(atomic_set_8)
atomic_set_8((uint8_t *)bits, set);
#else /* PAGE_SIZE <= 8192 */
uintptr_t addr;
int shift;
addr = (uintptr_t)bits;
/*
* Use a trick to perform a 32-bit atomic on the
* containing aligned word, to not depend on the existence
* of atomic_{set, clear}_{8, 16}.
*/
shift = addr & (sizeof(uint32_t) - 1);
#if BYTE_ORDER == BIG_ENDIAN
shift = (sizeof(uint32_t) - sizeof(vm_page_bits_t) - shift) * NBBY;
#else
shift *= NBBY;
#endif
addr &= ~(sizeof(uint32_t) - 1);
atomic_set_32((uint32_t *)addr, set << shift);
#endif /* PAGE_SIZE */
}
static inline void
vm_page_bits_clear(vm_page_t m, vm_page_bits_t *bits, vm_page_bits_t clear)
{
#if PAGE_SIZE == 32768
atomic_clear_64((uint64_t *)bits, clear);
#elif PAGE_SIZE == 16384
atomic_clear_32((uint32_t *)bits, clear);
#elif (PAGE_SIZE == 8192) && defined(atomic_clear_16)
atomic_clear_16((uint16_t *)bits, clear);
#elif (PAGE_SIZE == 4096) && defined(atomic_clear_8)
atomic_clear_8((uint8_t *)bits, clear);
#else /* PAGE_SIZE <= 8192 */
uintptr_t addr;
int shift;
addr = (uintptr_t)bits;
/*
* Use a trick to perform a 32-bit atomic on the
* containing aligned word, to not depend on the existence
* of atomic_{set, clear}_{8, 16}.
*/
shift = addr & (sizeof(uint32_t) - 1);
#if BYTE_ORDER == BIG_ENDIAN
shift = (sizeof(uint32_t) - sizeof(vm_page_bits_t) - shift) * NBBY;
#else
shift *= NBBY;
#endif
addr &= ~(sizeof(uint32_t) - 1);
atomic_clear_32((uint32_t *)addr, clear << shift);
#endif /* PAGE_SIZE */
}
static inline vm_page_bits_t
vm_page_bits_swap(vm_page_t m, vm_page_bits_t *bits, vm_page_bits_t newbits)
{
#if PAGE_SIZE == 32768
uint64_t old;
old = *bits;
while (atomic_fcmpset_64(bits, &old, newbits) == 0);
return (old);
#elif PAGE_SIZE == 16384
uint32_t old;
old = *bits;
while (atomic_fcmpset_32(bits, &old, newbits) == 0);
return (old);
#elif (PAGE_SIZE == 8192) && defined(atomic_fcmpset_16)
uint16_t old;
old = *bits;
while (atomic_fcmpset_16(bits, &old, newbits) == 0);
return (old);
#elif (PAGE_SIZE == 4096) && defined(atomic_fcmpset_8)
uint8_t old;
old = *bits;
while (atomic_fcmpset_8(bits, &old, newbits) == 0);
return (old);
#else /* PAGE_SIZE <= 4096*/
uintptr_t addr;
uint32_t old, new, mask;
int shift;
addr = (uintptr_t)bits;
/*
* Use a trick to perform a 32-bit atomic on the
* containing aligned word, to not depend on the existence
* of atomic_{set, swap, clear}_{8, 16}.
*/
shift = addr & (sizeof(uint32_t) - 1);
#if BYTE_ORDER == BIG_ENDIAN
shift = (sizeof(uint32_t) - sizeof(vm_page_bits_t) - shift) * NBBY;
#else
shift *= NBBY;
#endif
addr &= ~(sizeof(uint32_t) - 1);
mask = VM_PAGE_BITS_ALL << shift;
old = *bits;
do {
new = old & ~mask;
new |= newbits << shift;
} while (atomic_fcmpset_32((uint32_t *)addr, &old, new) == 0);
return (old >> shift);
#endif /* PAGE_SIZE */
}
/*
* vm_page_set_valid_range:
*
* Sets portions of a page valid. The arguments are expected
* to be DEV_BSIZE aligned but if they aren't the bitmap is inclusive
* of any partial chunks touched by the range. The invalid portion of
* such chunks will be zeroed.
*
* (base + size) must be less then or equal to PAGE_SIZE.
*/
void
vm_page_set_valid_range(vm_page_t m, int base, int size)
{
int endoff, frag;
vm_page_bits_t pagebits;
vm_page_assert_busied(m);
if (size == 0) /* handle degenerate case */
return;
/*
* If the base is not DEV_BSIZE aligned and the valid
* bit is clear, we have to zero out a portion of the
* first block.
*/
if ((frag = rounddown2(base, DEV_BSIZE)) != base &&
(m->valid & (1 << (base >> DEV_BSHIFT))) == 0)
pmap_zero_page_area(m, frag, base - frag);
/*
* If the ending offset is not DEV_BSIZE aligned and the
* valid bit is clear, we have to zero out a portion of
* the last block.
*/
endoff = base + size;
if ((frag = rounddown2(endoff, DEV_BSIZE)) != endoff &&
(m->valid & (1 << (endoff >> DEV_BSHIFT))) == 0)
pmap_zero_page_area(m, endoff,
DEV_BSIZE - (endoff & (DEV_BSIZE - 1)));
/*
* Assert that no previously invalid block that is now being validated
* is already dirty.
*/
KASSERT((~m->valid & vm_page_bits(base, size) & m->dirty) == 0,
("vm_page_set_valid_range: page %p is dirty", m));
/*
* Set valid bits inclusive of any overlap.
*/
pagebits = vm_page_bits(base, size);
if (vm_page_xbusied(m))
m->valid |= pagebits;
else
vm_page_bits_set(m, &m->valid, pagebits);
}
/*
* Set the page dirty bits and free the invalid swap space if
* present. Returns the previous dirty bits.
*/
vm_page_bits_t
vm_page_set_dirty(vm_page_t m)
{
vm_page_bits_t old;
VM_PAGE_OBJECT_BUSY_ASSERT(m);
if (vm_page_xbusied(m) && !pmap_page_is_write_mapped(m)) {
old = m->dirty;
m->dirty = VM_PAGE_BITS_ALL;
} else
old = vm_page_bits_swap(m, &m->dirty, VM_PAGE_BITS_ALL);
if (old == 0 && (m->a.flags & PGA_SWAP_SPACE) != 0)
vm_pager_page_unswapped(m);
return (old);
}
/*
* Clear the given bits from the specified page's dirty field.
*/
static __inline void
vm_page_clear_dirty_mask(vm_page_t m, vm_page_bits_t pagebits)
{
vm_page_assert_busied(m);
/*
* If the page is xbusied and not write mapped we are the
* only thread that can modify dirty bits. Otherwise, The pmap
* layer can call vm_page_dirty() without holding a distinguished
* lock. The combination of page busy and atomic operations
* suffice to guarantee consistency of the page dirty field.
*/
if (vm_page_xbusied(m) && !pmap_page_is_write_mapped(m))
m->dirty &= ~pagebits;
else
vm_page_bits_clear(m, &m->dirty, pagebits);
}
/*
* vm_page_set_validclean:
*
* Sets portions of a page valid and clean. The arguments are expected
* to be DEV_BSIZE aligned but if they aren't the bitmap is inclusive
* of any partial chunks touched by the range. The invalid portion of
* such chunks will be zero'd.
*
* (base + size) must be less then or equal to PAGE_SIZE.
*/
void
vm_page_set_validclean(vm_page_t m, int base, int size)
{
vm_page_bits_t oldvalid, pagebits;
int endoff, frag;
vm_page_assert_busied(m);
if (size == 0) /* handle degenerate case */
return;
/*
* If the base is not DEV_BSIZE aligned and the valid
* bit is clear, we have to zero out a portion of the
* first block.
*/
if ((frag = rounddown2(base, DEV_BSIZE)) != base &&
(m->valid & ((vm_page_bits_t)1 << (base >> DEV_BSHIFT))) == 0)
pmap_zero_page_area(m, frag, base - frag);
/*
* If the ending offset is not DEV_BSIZE aligned and the
* valid bit is clear, we have to zero out a portion of
* the last block.
*/
endoff = base + size;
if ((frag = rounddown2(endoff, DEV_BSIZE)) != endoff &&
(m->valid & ((vm_page_bits_t)1 << (endoff >> DEV_BSHIFT))) == 0)
pmap_zero_page_area(m, endoff,
DEV_BSIZE - (endoff & (DEV_BSIZE - 1)));
/*
* Set valid, clear dirty bits. If validating the entire
* page we can safely clear the pmap modify bit. We also
* use this opportunity to clear the PGA_NOSYNC flag. If a process
* takes a write fault on a MAP_NOSYNC memory area the flag will
* be set again.
*
* We set valid bits inclusive of any overlap, but we can only
* clear dirty bits for DEV_BSIZE chunks that are fully within
* the range.
*/
oldvalid = m->valid;
pagebits = vm_page_bits(base, size);
if (vm_page_xbusied(m))
m->valid |= pagebits;
else
vm_page_bits_set(m, &m->valid, pagebits);
#if 0 /* NOT YET */
if ((frag = base & (DEV_BSIZE - 1)) != 0) {
frag = DEV_BSIZE - frag;
base += frag;
size -= frag;
if (size < 0)
size = 0;
}
pagebits = vm_page_bits(base, size & (DEV_BSIZE - 1));
#endif
if (base == 0 && size == PAGE_SIZE) {
/*
* The page can only be modified within the pmap if it is
* mapped, and it can only be mapped if it was previously
* fully valid.
*/
if (oldvalid == VM_PAGE_BITS_ALL)
/*
* Perform the pmap_clear_modify() first. Otherwise,
* a concurrent pmap operation, such as
* pmap_protect(), could clear a modification in the
* pmap and set the dirty field on the page before
* pmap_clear_modify() had begun and after the dirty
* field was cleared here.
*/
pmap_clear_modify(m);
m->dirty = 0;
vm_page_aflag_clear(m, PGA_NOSYNC);
} else if (oldvalid != VM_PAGE_BITS_ALL && vm_page_xbusied(m))
m->dirty &= ~pagebits;
else
vm_page_clear_dirty_mask(m, pagebits);
}
void
vm_page_clear_dirty(vm_page_t m, int base, int size)
{
vm_page_clear_dirty_mask(m, vm_page_bits(base, size));
}
/*
* vm_page_set_invalid:
*
* Invalidates DEV_BSIZE'd chunks within a page. Both the
* valid and dirty bits for the effected areas are cleared.
*/
void
vm_page_set_invalid(vm_page_t m, int base, int size)
{
vm_page_bits_t bits;
vm_object_t object;
/*
* The object lock is required so that pages can't be mapped
* read-only while we're in the process of invalidating them.
*/
object = m->object;
VM_OBJECT_ASSERT_WLOCKED(object);
vm_page_assert_busied(m);
if (object->type == OBJT_VNODE && base == 0 && IDX_TO_OFF(m->pindex) +
size >= object->un_pager.vnp.vnp_size)
bits = VM_PAGE_BITS_ALL;
else
bits = vm_page_bits(base, size);
if (object->ref_count != 0 && vm_page_all_valid(m) && bits != 0)
pmap_remove_all(m);
KASSERT((bits == 0 && vm_page_all_valid(m)) ||
!pmap_page_is_mapped(m),
("vm_page_set_invalid: page %p is mapped", m));
if (vm_page_xbusied(m)) {
m->valid &= ~bits;
m->dirty &= ~bits;
} else {
vm_page_bits_clear(m, &m->valid, bits);
vm_page_bits_clear(m, &m->dirty, bits);
}
}
/*
* vm_page_invalid:
*
* Invalidates the entire page. The page must be busy, unmapped, and
* the enclosing object must be locked. The object locks protects
* against concurrent read-only pmap enter which is done without
* busy.
*/
void
vm_page_invalid(vm_page_t m)
{
vm_page_assert_busied(m);
VM_OBJECT_ASSERT_LOCKED(m->object);
MPASS(!pmap_page_is_mapped(m));
if (vm_page_xbusied(m))
m->valid = 0;
else
vm_page_bits_clear(m, &m->valid, VM_PAGE_BITS_ALL);
}
/*
* vm_page_zero_invalid()
*
* The kernel assumes that the invalid portions of a page contain
* garbage, but such pages can be mapped into memory by user code.
* When this occurs, we must zero out the non-valid portions of the
* page so user code sees what it expects.
*
* Pages are most often semi-valid when the end of a file is mapped
* into memory and the file's size is not page aligned.
*/
void
vm_page_zero_invalid(vm_page_t m, boolean_t setvalid)
{
int b;
int i;
/*
* Scan the valid bits looking for invalid sections that
* must be zeroed. Invalid sub-DEV_BSIZE'd areas ( where the
* valid bit may be set ) have already been zeroed by
* vm_page_set_validclean().
*/
for (b = i = 0; i <= PAGE_SIZE / DEV_BSIZE; ++i) {
if (i == (PAGE_SIZE / DEV_BSIZE) ||
(m->valid & ((vm_page_bits_t)1 << i))) {
if (i > b) {
pmap_zero_page_area(m,
b << DEV_BSHIFT, (i - b) << DEV_BSHIFT);
}
b = i + 1;
}
}
/*
* setvalid is TRUE when we can safely set the zero'd areas
* as being valid. We can do this if there are no cache consistancy
* issues. e.g. it is ok to do with UFS, but not ok to do with NFS.
*/
if (setvalid)
vm_page_valid(m);
}
/*
* vm_page_is_valid:
*
* Is (partial) page valid? Note that the case where size == 0
* will return FALSE in the degenerate case where the page is
* entirely invalid, and TRUE otherwise.
*
* Some callers envoke this routine without the busy lock held and
* handle races via higher level locks. Typical callers should
* hold a busy lock to prevent invalidation.
*/
int
vm_page_is_valid(vm_page_t m, int base, int size)
{
vm_page_bits_t bits;
bits = vm_page_bits(base, size);
return (m->valid != 0 && (m->valid & bits) == bits);
}
/*
* Returns true if all of the specified predicates are true for the entire
* (super)page and false otherwise.
*/
bool
vm_page_ps_test(vm_page_t m, int flags, vm_page_t skip_m)
{
vm_object_t object;
int i, npages;
object = m->object;
if (skip_m != NULL && skip_m->object != object)
return (false);
VM_OBJECT_ASSERT_LOCKED(object);
npages = atop(pagesizes[m->psind]);
/*
* The physically contiguous pages that make up a superpage, i.e., a
* page with a page size index ("psind") greater than zero, will
* occupy adjacent entries in vm_page_array[].
*/
for (i = 0; i < npages; i++) {
/* Always test object consistency, including "skip_m". */
if (m[i].object != object)
return (false);
if (&m[i] == skip_m)
continue;
if ((flags & PS_NONE_BUSY) != 0 && vm_page_busied(&m[i]))
return (false);
if ((flags & PS_ALL_DIRTY) != 0) {
/*
* Calling vm_page_test_dirty() or pmap_is_modified()
* might stop this case from spuriously returning
* "false". However, that would require a write lock
* on the object containing "m[i]".
*/
if (m[i].dirty != VM_PAGE_BITS_ALL)
return (false);
}
if ((flags & PS_ALL_VALID) != 0 &&
m[i].valid != VM_PAGE_BITS_ALL)
return (false);
}
return (true);
}
/*
* Set the page's dirty bits if the page is modified.
*/
void
vm_page_test_dirty(vm_page_t m)
{
vm_page_assert_busied(m);
if (m->dirty != VM_PAGE_BITS_ALL && pmap_is_modified(m))
vm_page_dirty(m);
}
void
vm_page_valid(vm_page_t m)
{
vm_page_assert_busied(m);
if (vm_page_xbusied(m))
m->valid = VM_PAGE_BITS_ALL;
else
vm_page_bits_set(m, &m->valid, VM_PAGE_BITS_ALL);
}
void
vm_page_lock_KBI(vm_page_t m, const char *file, int line)
{
mtx_lock_flags_(vm_page_lockptr(m), 0, file, line);
}
void
vm_page_unlock_KBI(vm_page_t m, const char *file, int line)
{
mtx_unlock_flags_(vm_page_lockptr(m), 0, file, line);
}
int
vm_page_trylock_KBI(vm_page_t m, const char *file, int line)
{
return (mtx_trylock_flags_(vm_page_lockptr(m), 0, file, line));
}
#if defined(INVARIANTS) || defined(INVARIANT_SUPPORT)
void
vm_page_assert_locked_KBI(vm_page_t m, const char *file, int line)
{
vm_page_lock_assert_KBI(m, MA_OWNED, file, line);
}
void
vm_page_lock_assert_KBI(vm_page_t m, int a, const char *file, int line)
{
mtx_assert_(vm_page_lockptr(m), a, file, line);
}
#endif
#ifdef INVARIANTS
void
vm_page_object_busy_assert(vm_page_t m)
{
/*
* Certain of the page's fields may only be modified by the
* holder of a page or object busy.
*/
if (m->object != NULL && !vm_page_busied(m))
VM_OBJECT_ASSERT_BUSY(m->object);
}
void
vm_page_assert_pga_writeable(vm_page_t m, uint16_t bits)
{
if ((bits & PGA_WRITEABLE) == 0)
return;
/*
* The PGA_WRITEABLE flag can only be set if the page is
* managed, is exclusively busied or the object is locked.
* Currently, this flag is only set by pmap_enter().
*/
KASSERT((m->oflags & VPO_UNMANAGED) == 0,
("PGA_WRITEABLE on unmanaged page"));
if (!vm_page_xbusied(m))
VM_OBJECT_ASSERT_BUSY(m->object);
}
#endif
#include "opt_ddb.h"
#ifdef DDB
#include <sys/kernel.h>
#include <ddb/ddb.h>
DB_SHOW_COMMAND(page, vm_page_print_page_info)
{
db_printf("vm_cnt.v_free_count: %d\n", vm_free_count());
db_printf("vm_cnt.v_inactive_count: %d\n", vm_inactive_count());
db_printf("vm_cnt.v_active_count: %d\n", vm_active_count());
db_printf("vm_cnt.v_laundry_count: %d\n", vm_laundry_count());
db_printf("vm_cnt.v_wire_count: %d\n", vm_wire_count());
db_printf("vm_cnt.v_free_reserved: %d\n", vm_cnt.v_free_reserved);
db_printf("vm_cnt.v_free_min: %d\n", vm_cnt.v_free_min);
db_printf("vm_cnt.v_free_target: %d\n", vm_cnt.v_free_target);
db_printf("vm_cnt.v_inactive_target: %d\n", vm_cnt.v_inactive_target);
}
DB_SHOW_COMMAND(pageq, vm_page_print_pageq_info)
{
int dom;
db_printf("pq_free %d\n", vm_free_count());
for (dom = 0; dom < vm_ndomains; dom++) {
db_printf(
"dom %d page_cnt %d free %d pq_act %d pq_inact %d pq_laund %d pq_unsw %d\n",
dom,
vm_dom[dom].vmd_page_count,
vm_dom[dom].vmd_free_count,
vm_dom[dom].vmd_pagequeues[PQ_ACTIVE].pq_cnt,
vm_dom[dom].vmd_pagequeues[PQ_INACTIVE].pq_cnt,
vm_dom[dom].vmd_pagequeues[PQ_LAUNDRY].pq_cnt,
vm_dom[dom].vmd_pagequeues[PQ_UNSWAPPABLE].pq_cnt);
}
}
DB_SHOW_COMMAND(pginfo, vm_page_print_pginfo)
{
vm_page_t m;
boolean_t phys, virt;
if (!have_addr) {
db_printf("show pginfo addr\n");
return;
}
phys = strchr(modif, 'p') != NULL;
virt = strchr(modif, 'v') != NULL;
if (virt)
m = PHYS_TO_VM_PAGE(pmap_kextract(addr));
else if (phys)
m = PHYS_TO_VM_PAGE(addr);
else
m = (vm_page_t)addr;
db_printf(
"page %p obj %p pidx 0x%jx phys 0x%jx q %d ref 0x%x\n"
" af 0x%x of 0x%x f 0x%x act %d busy %x valid 0x%x dirty 0x%x\n",
m, m->object, (uintmax_t)m->pindex, (uintmax_t)m->phys_addr,
m->a.queue, m->ref_count, m->a.flags, m->oflags,
m->flags, m->a.act_count, m->busy_lock, m->valid, m->dirty);
}
#endif /* DDB */
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