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freebsd-dev/sys/vm/vm_page.c
John Baldwin 4bd7e351f1 Fix an off-by-one error in the VM page array on some systems. 
r31386 changed how the size of the VM page array was calculated to be
less wasteful.  For most systems, the amount of memory is divided by
the overhead required by each page (a page of data plus a struct vm_page)
to determine the maximum number of available pages.  However, if the
remainder for the first non-available page was at least a page of data
(so that the only memory missing was a struct vm_page), this last page
was left in phys_avail[] but was not allocated an entry in the VM page
array.  Handle this case by explicitly excluding the page from
phys_avail[].

Reviewed by:	alc
Sponsored by:	DARPA / AFRL
Differential Revision:	https://reviews.freebsd.org/D11000
2017-06-08 16:18:41 +00:00

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/*-
* 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.
*/
/*
* GENERAL RULES ON VM_PAGE MANIPULATION
*
* - A page queue lock is required when adding or removing a page from a
* page queue regardless of other locks or the busy state of a page.
*
* * In general, no thread besides the page daemon can acquire or
* hold more than one page queue lock at a time.
*
* * The page daemon can acquire and hold any pair of page queue
* locks in any order.
*
* - The object lock is required when inserting or removing
* pages from an object (vm_page_insert() or vm_page_remove()).
*
*/
/*
* Resident memory management module.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_vm.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/lock.h>
#include <sys/kernel.h>
#include <sys/limits.h>
#include <sys/linker.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/sbuf.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_kern.h>
#include <vm/vm_object.h>
#include <vm/vm_page.h>
#include <vm/vm_pageout.h>
#include <vm/vm_pager.h>
#include <vm/vm_phys.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>
/*
* Associated with page of user-allocatable memory is a
* page structure.
*/
struct vm_domain vm_dom[MAXMEMDOM];
struct mtx_padalign vm_page_queue_free_mtx;
struct mtx_padalign pa_lock[PA_LOCK_COUNT];
/*
* 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 int boot_pages = UMA_BOOT_PAGES;
SYSCTL_INT(_vm, OID_AUTO, boot_pages, CTLFLAG_RDTUN | CTLFLAG_NOFETCH,
&boot_pages, 0,
"number of pages allocated for bootstrapping the VM system");
static int pa_tryrelock_restart;
SYSCTL_INT(_vm, OID_AUTO, tryrelock_restart, CTLFLAG_RD,
&pa_tryrelock_restart, 0, "Number of tryrelock restarts");
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");
/* Is the page daemon waiting for free pages? */
static int vm_pageout_pages_needed;
static uma_zone_t fakepg_zone;
static void vm_page_alloc_check(vm_page_t m);
static void vm_page_clear_dirty_mask(vm_page_t m, vm_page_bits_t pagebits);
static void vm_page_enqueue(uint8_t queue, vm_page_t m);
static void vm_page_free_wakeup(void);
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 int vm_page_reclaim_run(int req_class, u_long npages, vm_page_t m_run,
vm_paddr_t high);
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 | UMA_ZONE_VM);
bogus_page = vm_page_alloc(NULL, 0, VM_ALLOC_NOOBJ |
VM_ALLOC_NORMAL | VM_ALLOC_WIRED);
}
/* 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
/*
* Try to acquire a physical address lock while a pmap is locked. If we
* fail to trylock we unlock and lock the pmap directly and cache the
* locked pa in *locked. The caller should then restart their loop in case
* the virtual to physical mapping has changed.
*/
int
vm_page_pa_tryrelock(pmap_t pmap, vm_paddr_t pa, vm_paddr_t *locked)
{
vm_paddr_t lockpa;
lockpa = *locked;
*locked = pa;
if (lockpa) {
PA_LOCK_ASSERT(lockpa, MA_OWNED);
if (PA_LOCKPTR(pa) == PA_LOCKPTR(lockpa))
return (0);
PA_UNLOCK(lockpa);
}
if (PA_TRYLOCK(pa))
return (0);
PMAP_UNLOCK(pmap);
atomic_add_int(&pa_tryrelock_restart, 1);
PA_LOCK(pa);
PMAP_LOCK(pmap);
return (EAGAIN);
}
/*
* 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);
}
/*
* 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;
vm_page_t m;
char *next;
int ret;
next = list;
while (next != NULL) {
if ((pa = vm_page_blacklist_next(&next, end)) == 0)
continue;
m = vm_phys_paddr_to_vm_page(pa);
if (m == NULL)
continue;
mtx_lock(&vm_page_queue_free_mtx);
ret = vm_phys_unfree_page(m);
mtx_unlock(&vm_page_queue_free_mtx);
if (ret == TRUE) {
TAILQ_INSERT_TAIL(&blacklist_head, m, listq);
if (bootverbose)
printf("Skipping page with pa 0x%jx\n",
(uintmax_t)pa);
}
}
}
/*
* 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);
}
static void
vm_page_domain_init(struct vm_domain *vmd)
{
struct vm_pagequeue *pq;
int i;
*__DECONST(char **, &vmd->vmd_pagequeues[PQ_INACTIVE].pq_name) =
"vm inactive pagequeue";
*__DECONST(u_int **, &vmd->vmd_pagequeues[PQ_INACTIVE].pq_vcnt) =
&vm_cnt.v_inactive_count;
*__DECONST(char **, &vmd->vmd_pagequeues[PQ_ACTIVE].pq_name) =
"vm active pagequeue";
*__DECONST(u_int **, &vmd->vmd_pagequeues[PQ_ACTIVE].pq_vcnt) =
&vm_cnt.v_active_count;
*__DECONST(char **, &vmd->vmd_pagequeues[PQ_LAUNDRY].pq_name) =
"vm laundry pagequeue";
*__DECONST(int **, &vmd->vmd_pagequeues[PQ_LAUNDRY].pq_vcnt) =
&vm_cnt.v_laundry_count;
*__DECONST(char **, &vmd->vmd_pagequeues[PQ_UNSWAPPABLE].pq_name) =
"vm unswappable pagequeue";
/* Unswappable dirty pages are counted as being in the laundry. */
*__DECONST(int **, &vmd->vmd_pagequeues[PQ_UNSWAPPABLE].pq_vcnt) =
&vm_cnt.v_laundry_count;
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);
}
}
/*
* 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)
{
vm_offset_t mapped;
vm_paddr_t high_avail, low_avail, page_range, size;
vm_paddr_t new_end;
int i;
vm_paddr_t pa;
vm_paddr_t last_pa;
char *list, *listend;
vm_paddr_t end;
vm_paddr_t biggestsize;
int biggestone;
int pages_per_zone;
biggestsize = 0;
biggestone = 0;
vaddr = round_page(vaddr);
for (i = 0; phys_avail[i + 1]; i += 2) {
phys_avail[i] = round_page(phys_avail[i]);
phys_avail[i + 1] = trunc_page(phys_avail[i + 1]);
}
for (i = 0; phys_avail[i + 1]; i += 2) {
size = phys_avail[i + 1] - phys_avail[i];
if (size > biggestsize) {
biggestone = i;
biggestsize = size;
}
}
end = phys_avail[biggestone+1];
/*
* Initialize the page and queue locks.
*/
mtx_init(&vm_page_queue_free_mtx, "vm page free queue", 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(&vm_dom[i]);
/*
* Almost all of the pages needed for bootstrapping UMA are used
* for zone structures, so if the number of CPUs results in those
* structures taking more than one page each, we set aside more pages
* in proportion to the zone structure size.
*/
pages_per_zone = howmany(sizeof(struct uma_zone) +
sizeof(struct uma_cache) * (mp_maxid + 1), UMA_SLAB_SIZE);
if (pages_per_zone > 1) {
/* Reserve more pages so that we don't run out. */
boot_pages = UMA_BOOT_PAGES_ZONES * pages_per_zone;
}
/*
* Allocate memory for use when boot strapping the kernel memory
* allocator.
*
* CTFLAG_RDTUN doesn't work during the early boot process, so we must
* manually fetch the value.
*/
TUNABLE_INT_FETCH("vm.boot_pages", &boot_pages);
new_end = end - (boot_pages * UMA_SLAB_SIZE);
new_end = trunc_page(new_end);
mapped = pmap_map(&vaddr, new_end, end,
VM_PROT_READ | VM_PROT_WRITE);
bzero((void *)mapped, end - new_end);
uma_startup((void *)mapped, boot_pages);
#if defined(__aarch64__) || defined(__amd64__) || defined(__arm__) || \
defined(__i386__) || defined(__mips__)
/*
* 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);
#endif
#if defined(__aarch64__) || defined(__amd64__) || defined(__mips__)
/*
* Include the UMA bootstrap 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 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;
/*
* 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));
mapped = pmap_map(&vaddr, new_end, end,
VM_PROT_READ | VM_PROT_WRITE);
vm_page_array = (vm_page_t) mapped;
#if VM_NRESERVLEVEL > 0
/*
* Allocate physical memory for the reservation management system's
* data structures, and map it.
*/
if (high_avail == end)
high_avail = new_end;
new_end = vm_reserv_startup(&vaddr, new_end, high_avail);
#endif
#if defined(__aarch64__) || defined(__amd64__) || defined(__mips__)
/*
* 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)
vm_phys_add_seg(phys_avail[i], phys_avail[i + 1]);
/*
* Clear all of the page structures
*/
bzero((caddr_t) vm_page_array, page_range * sizeof(struct vm_page));
for (i = 0; i < page_range; i++)
vm_page_array[i].order = VM_NFREEORDER;
vm_page_array_size = page_range;
/*
* Initialize the physical memory allocator.
*/
vm_phys_init();
/*
* Add every available physical page that is not blacklisted to
* the free lists.
*/
vm_cnt.v_page_count = 0;
vm_cnt.v_free_count = 0;
for (i = 0; phys_avail[i + 1] != 0; i += 2) {
pa = phys_avail[i];
last_pa = phys_avail[i + 1];
while (pa < last_pa) {
vm_phys_add_page(pa);
pa += PAGE_SIZE;
}
}
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_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;
bool locked;
vm_page_assert_xbusied(m);
locked = mtx_owned(vm_page_lockptr(m));
for (;;) {
x = m->busy_lock;
x &= VPB_BIT_WAITERS;
if (x != 0 && !locked)
vm_page_lock(m);
if (atomic_cmpset_rel_int(&m->busy_lock,
VPB_SINGLE_EXCLUSIVER | x, VPB_SHARERS_WORD(1)))
break;
if (x != 0 && !locked)
vm_page_unlock(m);
}
if (x != 0) {
wakeup(m);
if (!locked)
vm_page_unlock(m);
}
}
/*
* 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);
for (;;) {
x = m->busy_lock;
if (VPB_SHARERS(x) > 1) {
if (atomic_cmpset_int(&m->busy_lock, x,
x - VPB_ONE_SHARER))
break;
continue;
}
if ((x & VPB_BIT_WAITERS) == 0) {
KASSERT(x == VPB_SHARERS_WORD(1),
("vm_page_sunbusy: invalid lock state"));
if (atomic_cmpset_int(&m->busy_lock,
VPB_SHARERS_WORD(1), VPB_UNBUSIED))
break;
continue;
}
KASSERT(x == (VPB_SHARERS_WORD(1) | VPB_BIT_WAITERS),
("vm_page_sunbusy: invalid lock state for waiters"));
vm_page_lock(m);
if (!atomic_cmpset_int(&m->busy_lock, x, VPB_UNBUSIED)) {
vm_page_unlock(m);
continue;
}
wakeup(m);
vm_page_unlock(m);
break;
}
}
/*
* vm_page_busy_sleep:
*
* Sleep and release the page lock, using the page pointer as wchan.
* This is used to implement the hard-path of busying mechanism.
*
* The given page must be locked.
*
* If nonshared is true, sleep only if the page is xbusy.
*/
void
vm_page_busy_sleep(vm_page_t m, const char *wmesg, bool nonshared)
{
u_int x;
vm_page_assert_locked(m);
x = m->busy_lock;
if (x == VPB_UNBUSIED || (nonshared && (x & VPB_BIT_SHARED) != 0) ||
((x & VPB_BIT_WAITERS) == 0 &&
!atomic_cmpset_int(&m->busy_lock, x, x | VPB_BIT_WAITERS))) {
vm_page_unlock(m);
return;
}
msleep(m, vm_page_lockptr(m), PVM | PDROP, wmesg, 0);
}
/*
* 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)
{
u_int x;
for (;;) {
x = m->busy_lock;
if ((x & VPB_BIT_SHARED) == 0)
return (0);
if (atomic_cmpset_acq_int(&m->busy_lock, x, x + VPB_ONE_SHARER))
return (1);
}
}
static void
vm_page_xunbusy_locked(vm_page_t m)
{
vm_page_assert_xbusied(m);
vm_page_assert_locked(m);
atomic_store_rel_int(&m->busy_lock, VPB_UNBUSIED);
/* There is a waiter, do wakeup() instead of vm_page_flash(). */
wakeup(m);
}
void
vm_page_xunbusy_maybelocked(vm_page_t m)
{
bool lockacq;
vm_page_assert_xbusied(m);
/*
* Fast path for unbusy. If it succeeds, we know that there
* are no waiters, so we do not need a wakeup.
*/
if (atomic_cmpset_rel_int(&m->busy_lock, VPB_SINGLE_EXCLUSIVER,
VPB_UNBUSIED))
return;
lockacq = !mtx_owned(vm_page_lockptr(m));
if (lockacq)
vm_page_lock(m);
vm_page_xunbusy_locked(m);
if (lockacq)
vm_page_unlock(m);
}
/*
* vm_page_xunbusy_hard:
*
* Called after the first try the exclusive unbusy of a page failed.
* It is assumed that the waiters bit is on.
*/
void
vm_page_xunbusy_hard(vm_page_t m)
{
vm_page_assert_xbusied(m);
vm_page_lock(m);
vm_page_xunbusy_locked(m);
vm_page_unlock(m);
}
/*
* vm_page_flash:
*
* Wakeup anyone waiting for the page.
* The ownership bits do not change.
*
* The given page must be locked.
*/
void
vm_page_flash(vm_page_t m)
{
u_int x;
vm_page_lock_assert(m, MA_OWNED);
for (;;) {
x = m->busy_lock;
if ((x & VPB_BIT_WAITERS) == 0)
return;
if (atomic_cmpset_int(&m->busy_lock, x,
x & (~VPB_BIT_WAITERS)))
break;
}
wakeup(m);
}
/*
* Keep page from being freed by the page daemon
* much of the same effect as wiring, except much lower
* overhead and should be used only for *very* temporary
* holding ("wiring").
*/
void
vm_page_hold(vm_page_t mem)
{
vm_page_lock_assert(mem, MA_OWNED);
mem->hold_count++;
}
void
vm_page_unhold(vm_page_t mem)
{
vm_page_lock_assert(mem, MA_OWNED);
KASSERT(mem->hold_count >= 1, ("vm_page_unhold: hold count < 0!!!"));
--mem->hold_count;
if (mem->hold_count == 0 && (mem->flags & PG_UNHOLDFREE) != 0)
vm_page_free_toq(mem);
}
/*
* 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)
{
struct mtx *mtx, *new_mtx;
mtx = NULL;
for (; count != 0; count--) {
/*
* Avoid releasing and reacquiring the same page lock.
*/
new_mtx = vm_page_lockptr(*ma);
if (mtx != new_mtx) {
if (mtx != NULL)
mtx_unlock(mtx);
mtx = new_mtx;
mtx_lock(mtx);
}
vm_page_unhold(*ma);
ma++;
}
if (mtx != NULL)
mtx_unlock(mtx);
}
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->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_SINGLE_EXCLUSIVER;
m->wire_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));
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(m->valid != 0, ("%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.
*/
vm_page_lock(m);
if ((m->busy_lock & VPB_BIT_WAITERS) != 0)
vm_page_activate(m);
else
vm_page_deactivate(m);
vm_page_unlock(m);
vm_page_xunbusy(m);
}
/*
* vm_page_sleep_if_busy:
*
* Sleep and release the page queues 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 *msg)
{
vm_object_t obj;
vm_page_lock_assert(m, MA_NOTOWNED);
VM_OBJECT_ASSERT_WLOCKED(m->object);
if (vm_page_busied(m)) {
/*
* 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;
vm_page_lock(m);
VM_OBJECT_WUNLOCK(obj);
vm_page_busy_sleep(m, msg, false);
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(m->valid == VM_PAGE_BITS_ALL,
("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;
/*
* Now link into the object's ordered list of backed pages.
*/
if (vm_radix_insert(&object->rtree, m)) {
m->object = NULL;
m->pindex = 0;
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));
if (mpred != NULL) {
KASSERT(mpred->object == object,
("vm_page_insert_after: object doesn't contain mpred"));
KASSERT(mpred->pindex < m->pindex,
("vm_page_insert_after: 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 OBJ_MIGHTBEDIRTY flag.
*/
if (pmap_page_is_write_mapped(m))
vm_object_set_writeable_dirty(object);
}
/*
* vm_page_remove:
*
* Removes the specified page from its containing object, but does not
* invalidate any backing storage.
*
* The object must be locked. The page must be locked if it is managed.
*/
void
vm_page_remove(vm_page_t m)
{
vm_object_t object;
vm_page_t mrem;
if ((m->oflags & VPO_UNMANAGED) == 0)
vm_page_assert_locked(m);
if ((object = m->object) == NULL)
return;
VM_OBJECT_ASSERT_WLOCKED(object);
if (vm_page_xbusied(m))
vm_page_xunbusy_maybelocked(m);
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);
m->object = NULL;
}
/*
* 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_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.
*
* The existing page must not be on a paging queue.
*/
vm_page_t
vm_page_replace(vm_page_t mnew, vm_object_t object, vm_pindex_t pindex)
{
vm_page_t mold;
VM_OBJECT_ASSERT_WLOCKED(object);
KASSERT(mnew->object == NULL,
("vm_page_replace: page already in object"));
/*
* 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;
mold = vm_radix_replace(&object->rtree, mnew);
KASSERT(mold->queue == PQ_NONE,
("vm_page_replace: mold is on a paging queue"));
/* 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;
vm_page_xunbusy_maybelocked(mold);
/*
* The object's resident_page_count does not change because we have
* swapped one page for another, but OBJ_MIGHTBEDIRTY.
*/
if (pmap_page_is_write_mapped(mnew))
vm_object_set_writeable_dirty(object);
return (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);
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_lock(m);
vm_page_remove(m);
/* Return back to the new pindex to complete vm_page_insert(). */
m->pindex = new_pindex;
m->object = new_object;
vm_page_unlock(m);
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
*
* This routine may not sleep.
*/
vm_page_t
vm_page_alloc(vm_object_t object, vm_pindex_t pindex, int req)
{
vm_page_t m, mpred;
int flags, req_class;
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: inconsistent object(%p)/req(%x)", object, req));
if (object != NULL)
VM_OBJECT_ASSERT_WLOCKED(object);
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;
if (object != NULL) {
mpred = vm_radix_lookup_le(&object->rtree, pindex);
KASSERT(mpred == NULL || mpred->pindex != pindex,
("vm_page_alloc: pindex already allocated"));
}
/*
* Allocate a page if the number of free pages exceeds the minimum
* for the request class.
*/
mtx_lock(&vm_page_queue_free_mtx);
if (vm_cnt.v_free_count > vm_cnt.v_free_reserved ||
(req_class == VM_ALLOC_SYSTEM &&
vm_cnt.v_free_count > vm_cnt.v_interrupt_free_min) ||
(req_class == VM_ALLOC_INTERRUPT &&
vm_cnt.v_free_count > 0)) {
/*
* Can we allocate the page from a reservation?
*/
#if VM_NRESERVLEVEL > 0
if (object == NULL || (object->flags & (OBJ_COLORED |
OBJ_FICTITIOUS)) != OBJ_COLORED || (m =
vm_reserv_alloc_page(object, pindex, mpred)) == NULL)
#endif
{
/*
* If not, allocate it from the free page queues.
*/
m = vm_phys_alloc_pages(object != NULL ?
VM_FREEPOOL_DEFAULT : VM_FREEPOOL_DIRECT, 0);
#if VM_NRESERVLEVEL > 0
if (m == NULL && vm_reserv_reclaim_inactive()) {
m = vm_phys_alloc_pages(object != NULL ?
VM_FREEPOOL_DEFAULT : VM_FREEPOOL_DIRECT,
0);
}
#endif
}
} else {
/*
* Not allocatable, give up.
*/
mtx_unlock(&vm_page_queue_free_mtx);
atomic_add_int(&vm_pageout_deficit,
max((u_int)req >> VM_ALLOC_COUNT_SHIFT, 1));
pagedaemon_wakeup();
return (NULL);
}
/*
* At this point we had better have found a good page.
*/
KASSERT(m != NULL, ("vm_page_alloc: missing page"));
vm_phys_freecnt_adj(m, -1);
mtx_unlock(&vm_page_queue_free_mtx);
vm_page_alloc_check(m);
/*
* Initialize the page. Only the PG_ZERO flag is inherited.
*/
flags = 0;
if ((req & VM_ALLOC_ZERO) != 0)
flags = PG_ZERO;
flags &= m->flags;
if ((req & VM_ALLOC_NODUMP) != 0)
flags |= PG_NODUMP;
m->flags = flags;
m->aflags = 0;
m->oflags = object == NULL || (object->flags & OBJ_UNMANAGED) != 0 ?
VPO_UNMANAGED : 0;
m->busy_lock = VPB_UNBUSIED;
if ((req & (VM_ALLOC_NOBUSY | VM_ALLOC_NOOBJ | VM_ALLOC_SBUSY)) == 0)
m->busy_lock = VPB_SINGLE_EXCLUSIVER;
if ((req & VM_ALLOC_SBUSY) != 0)
m->busy_lock = VPB_SHARERS_WORD(1);
if (req & VM_ALLOC_WIRED) {
/*
* The page lock is not required for wiring a page until that
* page is inserted into the object.
*/
atomic_add_int(&vm_cnt.v_wire_count, 1);
m->wire_count = 1;
}
m->act_count = 0;
if (object != NULL) {
if (vm_page_insert_after(m, object, pindex, mpred)) {
pagedaemon_wakeup();
if (req & VM_ALLOC_WIRED) {
atomic_subtract_int(&vm_cnt.v_wire_count, 1);
m->wire_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);
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;
/*
* Don't wakeup too often - wakeup the pageout daemon when
* we would be nearly out of memory.
*/
if (vm_paging_needed())
pagedaemon_wakeup();
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
*
* This routine may not sleep.
*/
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)
{
vm_page_t m, m_ret, mpred;
u_int busy_lock, flags, oflags;
int req_class;
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));
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"));
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;
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?
*/
mtx_lock(&vm_page_queue_free_mtx);
if (vm_cnt.v_free_count >= npages + vm_cnt.v_free_reserved ||
(req_class == VM_ALLOC_SYSTEM &&
vm_cnt.v_free_count >= npages + vm_cnt.v_interrupt_free_min) ||
(req_class == VM_ALLOC_INTERRUPT &&
vm_cnt.v_free_count >= npages)) {
/*
* Can we allocate the pages from a reservation?
*/
#if VM_NRESERVLEVEL > 0
retry:
if (object == NULL || (object->flags & OBJ_COLORED) == 0 ||
(m_ret = vm_reserv_alloc_contig(object, pindex, npages,
low, high, alignment, boundary, mpred)) == NULL)
#endif
/*
* If not, allocate them from the free page queues.
*/
m_ret = vm_phys_alloc_contig(npages, low, high,
alignment, boundary);
} else {
mtx_unlock(&vm_page_queue_free_mtx);
atomic_add_int(&vm_pageout_deficit, npages);
pagedaemon_wakeup();
return (NULL);
}
if (m_ret != NULL)
vm_phys_freecnt_adj(m_ret, -npages);
else {
#if VM_NRESERVLEVEL > 0
if (vm_reserv_reclaim_contig(npages, low, high, alignment,
boundary))
goto retry;
#endif
}
mtx_unlock(&vm_page_queue_free_mtx);
if (m_ret == NULL)
return (NULL);
for (m = m_ret; m < &m_ret[npages]; 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;
busy_lock = VPB_UNBUSIED;
if ((req & (VM_ALLOC_NOBUSY | VM_ALLOC_NOOBJ | VM_ALLOC_SBUSY)) == 0)
busy_lock = VPB_SINGLE_EXCLUSIVER;
if ((req & VM_ALLOC_SBUSY) != 0)
busy_lock = VPB_SHARERS_WORD(1);
if ((req & VM_ALLOC_WIRED) != 0)
atomic_add_int(&vm_cnt.v_wire_count, 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->aflags = 0;
m->flags = (m->flags | PG_NODUMP) & flags;
m->busy_lock = busy_lock;
if ((req & VM_ALLOC_WIRED) != 0)
m->wire_count = 1;
m->act_count = 0;
m->oflags = oflags;
if (object != NULL) {
if (vm_page_insert_after(m, object, pindex, mpred)) {
pagedaemon_wakeup();
if ((req & VM_ALLOC_WIRED) != 0)
atomic_subtract_int(
&vm_cnt.v_wire_count, 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->wire_count = 0;
m->oflags = VPO_UNMANAGED;
m->busy_lock = VPB_UNBUSIED;
/* Don't change PG_ZERO. */
vm_page_free_toq(m);
}
return (NULL);
}
mpred = m;
} else
m->pindex = pindex;
if (memattr != VM_MEMATTR_DEFAULT)
pmap_page_set_memattr(m, memattr);
pindex++;
}
if (vm_paging_needed())
pagedaemon_wakeup();
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->queue == PQ_NONE,
("page %p has unexpected queue %d", m, m->queue));
KASSERT(m->wire_count == 0, ("page %p is wired", m));
KASSERT(m->hold_count == 0, ("page %p is held", m));
KASSERT(!vm_page_busied(m), ("page %p is busy", 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
*
* This routine may not sleep.
*/
vm_page_t
vm_page_alloc_freelist(int flind, int req)
{
vm_page_t m;
u_int flags;
int req_class;
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;
/*
* Do not allocate reserved pages unless the req has asked for it.
*/
mtx_lock(&vm_page_queue_free_mtx);
if (vm_cnt.v_free_count > vm_cnt.v_free_reserved ||
(req_class == VM_ALLOC_SYSTEM &&
vm_cnt.v_free_count > vm_cnt.v_interrupt_free_min) ||
(req_class == VM_ALLOC_INTERRUPT &&
vm_cnt.v_free_count > 0))
m = vm_phys_alloc_freelist_pages(flind, VM_FREEPOOL_DIRECT, 0);
else {
mtx_unlock(&vm_page_queue_free_mtx);
atomic_add_int(&vm_pageout_deficit,
max((u_int)req >> VM_ALLOC_COUNT_SHIFT, 1));
pagedaemon_wakeup();
return (NULL);
}
if (m == NULL) {
mtx_unlock(&vm_page_queue_free_mtx);
return (NULL);
}
vm_phys_freecnt_adj(m, -1);
mtx_unlock(&vm_page_queue_free_mtx);
vm_page_alloc_check(m);
/*
* Initialize the page. Only the PG_ZERO flag is inherited.
*/
m->aflags = 0;
flags = 0;
if ((req & VM_ALLOC_ZERO) != 0)
flags = PG_ZERO;
m->flags &= flags;
if ((req & VM_ALLOC_WIRED) != 0) {
/*
* The page lock is not required for wiring a page that does
* not belong to an object.
*/
atomic_add_int(&vm_cnt.v_wire_count, 1);
m->wire_count = 1;
}
/* Unmanaged pages don't use "act_count". */
m->oflags = VPO_UNMANAGED;
if (vm_paging_needed())
pagedaemon_wakeup();
return (m);
}
#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)
{
struct mtx *m_mtx, *new_mtx;
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;
m_mtx = NULL;
for (m = m_start; m < m_end && run_len < npages; m += m_inc) {
KASSERT((m->flags & (PG_FICTITIOUS | PG_MARKER)) == 0,
("page %p is PG_FICTITIOUS or PG_MARKER", 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"));
/*
* Avoid releasing and reacquiring the same page lock.
*/
new_mtx = vm_page_lockptr(m);
if (m_mtx != new_mtx) {
if (m_mtx != NULL)
mtx_unlock(m_mtx);
m_mtx = new_mtx;
mtx_lock(m_mtx);
}
m_inc = 1;
retry:
if (m->wire_count != 0 || m->hold_count != 0)
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 = m->object) != NULL) {
/*
* The page is considered eligible for relocation if
* and only if it could be laundered or reclaimed by
* the page daemon.
*/
if (!VM_OBJECT_TRYRLOCK(object)) {
mtx_unlock(m_mtx);
VM_OBJECT_RLOCK(object);
mtx_lock(m_mtx);
if (m->object != object) {
/*
* The page may have been freed.
*/
VM_OBJECT_RUNLOCK(object);
goto retry;
} else if (m->wire_count != 0 ||
m->hold_count != 0) {
run_ext = 0;
goto unlock;
}
}
KASSERT((m->flags & PG_UNHOLDFREE) == 0,
("page %p is PG_UNHOLDFREE", m));
/* 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 &&
m->queue != 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: VPO_NOSYNC. */
run_ext = 1;
} else
run_ext = 0;
unlock:
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 (m_mtx != NULL)
mtx_unlock(m_mtx);
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, u_long npages, vm_page_t m_run,
vm_paddr_t high)
{
struct mtx *m_mtx, *new_mtx;
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;
m_mtx = NULL;
for (; error == 0 && m < m_end; m++) {
KASSERT((m->flags & (PG_FICTITIOUS | PG_MARKER)) == 0,
("page %p is PG_FICTITIOUS or PG_MARKER", m));
/*
* Avoid releasing and reacquiring the same page lock.
*/
new_mtx = vm_page_lockptr(m);
if (m_mtx != new_mtx) {
if (m_mtx != NULL)
mtx_unlock(m_mtx);
m_mtx = new_mtx;
mtx_lock(m_mtx);
}
retry:
if (m->wire_count != 0 || m->hold_count != 0)
error = EBUSY;
else if ((object = m->object) != NULL) {
/*
* The page is relocated if and only if it could be
* laundered or reclaimed by the page daemon.
*/
if (!VM_OBJECT_TRYWLOCK(object)) {
mtx_unlock(m_mtx);
VM_OBJECT_WLOCK(object);
mtx_lock(m_mtx);
if (m->object != object) {
/*
* The page may have been freed.
*/
VM_OBJECT_WUNLOCK(object);
goto retry;
} else if (m->wire_count != 0 ||
m->hold_count != 0) {
error = EBUSY;
goto unlock;
}
}
KASSERT((m->flags & PG_UNHOLDFREE) == 0,
("page %p is PG_UNHOLDFREE", m));
/* Don't care: PG_NODUMP, PG_ZERO. */
if (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 (m->queue != PQ_NONE && !vm_page_busied(m)) {
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: VPO_NOSYNC. */
if (m->valid != 0) {
/*
* 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) {
error = ENOMEM;
goto unlock;
}
KASSERT(m_new->wire_count == 0,
("page %p is wired", m));
/*
* 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.
*/
if (object->ref_count != 0)
pmap_remove_all(m);
m_new->aflags = m->aflags;
KASSERT(m_new->oflags == VPO_UNMANAGED,
("page %p is managed", m));
m_new->oflags = m->oflags & VPO_NOSYNC;
pmap_copy_page(m, m_new);
m_new->valid = m->valid;
m_new->dirty = m->dirty;
m->flags &= ~PG_ZERO;
vm_page_xbusy(m);
vm_page_remque(m);
vm_page_replace_checked(m_new, object,
m->pindex, m);
m->valid = 0;
vm_page_undirty(m);
/*
* The new page must be deactivated
* before the object is unlocked.
*/
new_mtx = vm_page_lockptr(m_new);
if (m_mtx != new_mtx) {
mtx_unlock(m_mtx);
m_mtx = new_mtx;
mtx_lock(m_mtx);
}
vm_page_deactivate(m_new);
} else {
m->flags &= ~PG_ZERO;
vm_page_remque(m);
vm_page_remove(m);
KASSERT(m->dirty == 0,
("page %p is dirty", m));
}
SLIST_INSERT_HEAD(&free, m, plinks.s.ss);
} else
error = EBUSY;
unlock:
VM_OBJECT_WUNLOCK(object);
} else {
mtx_lock(&vm_page_queue_free_mtx);
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
mtx_unlock(&vm_page_queue_free_mtx);
if (order == VM_NFREEORDER)
error = EINVAL;
}
}
if (m_mtx != NULL)
mtx_unlock(m_mtx);
if ((m = SLIST_FIRST(&free)) != NULL) {
mtx_lock(&vm_page_queue_free_mtx);
do {
SLIST_REMOVE_HEAD(&free, plinks.s.ss);
vm_phys_freecnt_adj(m, 1);
#if VM_NRESERVLEVEL > 0
if (!vm_reserv_free_page(m))
#else
if (true)
#endif
vm_phys_free_pages(m, 0);
} while ((m = SLIST_FIRST(&free)) != NULL);
vm_page_free_wakeup();
mtx_unlock(&vm_page_queue_free_mtx);
}
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(int req, u_long npages, vm_paddr_t low, vm_paddr_t high,
u_long alignment, vm_paddr_t boundary)
{
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.
*/
count = vm_cnt.v_free_count;
if (count < npages + vm_cnt.v_free_reserved || (count < npages +
vm_cnt.v_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(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, 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);
}
}
/*
* vm_wait: (also see VM_WAIT macro)
*
* Sleep until free pages are available for allocation.
* - Called in various places before memory allocations.
*/
void
vm_wait(void)
{
mtx_lock(&vm_page_queue_free_mtx);
if (curproc == pageproc) {
vm_pageout_pages_needed = 1;
msleep(&vm_pageout_pages_needed, &vm_page_queue_free_mtx,
PDROP | PSWP, "VMWait", 0);
} else {
if (__predict_false(pageproc == NULL))
panic("vm_wait in early boot");
if (!vm_pageout_wanted) {
vm_pageout_wanted = true;
wakeup(&vm_pageout_wanted);
}
vm_pages_needed = true;
msleep(&vm_cnt.v_free_count, &vm_page_queue_free_mtx, PDROP | PVM,
"vmwait", 0);
}
}
/*
* vm_waitpfault: (also see VM_WAITPFAULT macro)
*
* 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(void)
{
mtx_lock(&vm_page_queue_free_mtx);
if (!vm_pageout_wanted) {
vm_pageout_wanted = true;
wakeup(&vm_pageout_wanted);
}
vm_pages_needed = true;
msleep(&vm_cnt.v_free_count, &vm_page_queue_free_mtx, PDROP | PUSER,
"pfault", 0);
}
struct vm_pagequeue *
vm_page_pagequeue(vm_page_t m)
{
if (vm_page_in_laundry(m))
return (&vm_dom[0].vmd_pagequeues[m->queue]);
else
return (&vm_phys_domain(m)->vmd_pagequeues[m->queue]);
}
/*
* vm_page_dequeue:
*
* Remove the given page from its current page queue.
*
* The page must be locked.
*/
void
vm_page_dequeue(vm_page_t m)
{
struct vm_pagequeue *pq;
vm_page_assert_locked(m);
KASSERT(m->queue < PQ_COUNT, ("vm_page_dequeue: page %p is not queued",
m));
pq = vm_page_pagequeue(m);
vm_pagequeue_lock(pq);
m->queue = PQ_NONE;
TAILQ_REMOVE(&pq->pq_pl, m, plinks.q);
vm_pagequeue_cnt_dec(pq);
vm_pagequeue_unlock(pq);
}
/*
* vm_page_dequeue_locked:
*
* Remove the given page from its current page queue.
*
* The page and page queue must be locked.
*/
void
vm_page_dequeue_locked(vm_page_t m)
{
struct vm_pagequeue *pq;
vm_page_lock_assert(m, MA_OWNED);
pq = vm_page_pagequeue(m);
vm_pagequeue_assert_locked(pq);
m->queue = PQ_NONE;
TAILQ_REMOVE(&pq->pq_pl, m, plinks.q);
vm_pagequeue_cnt_dec(pq);
}
/*
* vm_page_enqueue:
*
* Add the given page to the specified page queue.
*
* The page must be locked.
*/
static void
vm_page_enqueue(uint8_t queue, vm_page_t m)
{
struct vm_pagequeue *pq;
vm_page_lock_assert(m, MA_OWNED);
KASSERT(queue < PQ_COUNT,
("vm_page_enqueue: invalid queue %u request for page %p",
queue, m));
if (queue == PQ_LAUNDRY || queue == PQ_UNSWAPPABLE)
pq = &vm_dom[0].vmd_pagequeues[queue];
else
pq = &vm_phys_domain(m)->vmd_pagequeues[queue];
vm_pagequeue_lock(pq);
m->queue = queue;
TAILQ_INSERT_TAIL(&pq->pq_pl, m, plinks.q);
vm_pagequeue_cnt_inc(pq);
vm_pagequeue_unlock(pq);
}
/*
* vm_page_requeue:
*
* Move the given page to the tail of its current page queue.
*
* The page must be locked.
*/
void
vm_page_requeue(vm_page_t m)
{
struct vm_pagequeue *pq;
vm_page_lock_assert(m, MA_OWNED);
KASSERT(m->queue != PQ_NONE,
("vm_page_requeue: page %p is not queued", m));
pq = vm_page_pagequeue(m);
vm_pagequeue_lock(pq);
TAILQ_REMOVE(&pq->pq_pl, m, plinks.q);
TAILQ_INSERT_TAIL(&pq->pq_pl, m, plinks.q);
vm_pagequeue_unlock(pq);
}
/*
* vm_page_requeue_locked:
*
* Move the given page to the tail of its current page queue.
*
* The page queue must be locked.
*/
void
vm_page_requeue_locked(vm_page_t m)
{
struct vm_pagequeue *pq;
KASSERT(m->queue != PQ_NONE,
("vm_page_requeue_locked: page %p is not queued", m));
pq = vm_page_pagequeue(m);
vm_pagequeue_assert_locked(pq);
TAILQ_REMOVE(&pq->pq_pl, m, plinks.q);
TAILQ_INSERT_TAIL(&pq->pq_pl, m, plinks.q);
}
/*
* vm_page_activate:
*
* Put the specified page on the active list (if appropriate).
* Ensure that act_count is at least ACT_INIT but do not otherwise
* mess with it.
*
* The page must be locked.
*/
void
vm_page_activate(vm_page_t m)
{
int queue;
vm_page_lock_assert(m, MA_OWNED);
if ((queue = m->queue) != PQ_ACTIVE) {
if (m->wire_count == 0 && (m->oflags & VPO_UNMANAGED) == 0) {
if (m->act_count < ACT_INIT)
m->act_count = ACT_INIT;
if (queue != PQ_NONE)
vm_page_dequeue(m);
vm_page_enqueue(PQ_ACTIVE, m);
} else
KASSERT(queue == PQ_NONE,
("vm_page_activate: wired page %p is queued", m));
} else {
if (m->act_count < ACT_INIT)
m->act_count = ACT_INIT;
}
}
/*
* vm_page_free_wakeup:
*
* Helper routine for vm_page_free_toq(). This routine is called
* when a page is added to the free queues.
*
* The page queues must be locked.
*/
static inline void
vm_page_free_wakeup(void)
{
mtx_assert(&vm_page_queue_free_mtx, MA_OWNED);
/*
* if pageout daemon needs pages, then tell it that there are
* some free.
*/
if (vm_pageout_pages_needed &&
vm_cnt.v_free_count >= vm_cnt.v_pageout_free_min) {
wakeup(&vm_pageout_pages_needed);
vm_pageout_pages_needed = 0;
}
/*
* wakeup processes that are waiting on memory if we hit a
* high water mark. And wakeup scheduler process if we have
* lots of memory. this process will swapin processes.
*/
if (vm_pages_needed && !vm_page_count_min()) {
vm_pages_needed = false;
wakeup(&vm_cnt.v_free_count);
}
}
/*
* vm_page_free_toq:
*
* Returns the given page to the free list,
* disassociating it with any VM object.
*
* The object must be locked. The page must be locked if it is managed.
*/
void
vm_page_free_toq(vm_page_t m)
{
if ((m->oflags & VPO_UNMANAGED) == 0) {
vm_page_lock_assert(m, MA_OWNED);
KASSERT(!pmap_page_is_mapped(m),
("vm_page_free_toq: freeing mapped page %p", m));
} else
KASSERT(m->queue == PQ_NONE,
("vm_page_free_toq: unmanaged page %p is queued", m));
VM_CNT_INC(v_tfree);
if (vm_page_sbusied(m))
panic("vm_page_free: freeing busy page %p", m);
/*
* Unqueue, then remove page. Note that we cannot destroy
* the page here because we do not want to call the pager's
* callback routine until after we've put the page on the
* appropriate free queue.
*/
vm_page_remque(m);
vm_page_remove(m);
/*
* If fictitious remove object association and
* return, otherwise delay object association removal.
*/
if ((m->flags & PG_FICTITIOUS) != 0) {
return;
}
m->valid = 0;
vm_page_undirty(m);
if (m->wire_count != 0)
panic("vm_page_free: freeing wired page %p", m);
if (m->hold_count != 0) {
m->flags &= ~PG_ZERO;
KASSERT((m->flags & PG_UNHOLDFREE) == 0,
("vm_page_free: freeing PG_UNHOLDFREE page %p", m));
m->flags |= PG_UNHOLDFREE;
} else {
/*
* 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);
/*
* Insert the page into the physical memory allocator's free
* page queues.
*/
mtx_lock(&vm_page_queue_free_mtx);
vm_phys_freecnt_adj(m, 1);
#if VM_NRESERVLEVEL > 0
if (!vm_reserv_free_page(m))
#else
if (TRUE)
#endif
vm_phys_free_pages(m, 0);
vm_page_free_wakeup();
mtx_unlock(&vm_page_queue_free_mtx);
}
}
/*
* vm_page_wire:
*
* Mark this page as wired down by yet
* another map, removing it from paging queues
* as necessary.
*
* If the page is fictitious, then its wire count must remain one.
*
* The page must be locked.
*/
void
vm_page_wire(vm_page_t m)
{
/*
* Only bump the wire statistics if the page is not already wired,
* and only unqueue the page if it is on some queue (if it is unmanaged
* it is already off the queues).
*/
vm_page_lock_assert(m, MA_OWNED);
if ((m->flags & PG_FICTITIOUS) != 0) {
KASSERT(m->wire_count == 1,
("vm_page_wire: fictitious page %p's wire count isn't one",
m));
return;
}
if (m->wire_count == 0) {
KASSERT((m->oflags & VPO_UNMANAGED) == 0 ||
m->queue == PQ_NONE,
("vm_page_wire: unmanaged page %p is queued", m));
vm_page_remque(m);
atomic_add_int(&vm_cnt.v_wire_count, 1);
}
m->wire_count++;
KASSERT(m->wire_count != 0, ("vm_page_wire: wire_count overflow m=%p", m));
}
/*
* vm_page_unwire:
*
* Release one wiring of the specified page, potentially allowing it to be
* paged out. Returns TRUE if the number of wirings transitions to zero and
* FALSE otherwise.
*
* 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 (unless PQ_NONE is
* specified).
*
* If a page is fictitious, then its wire count must always be one.
*
* A managed page must be locked.
*/
boolean_t
vm_page_unwire(vm_page_t m, uint8_t queue)
{
KASSERT(queue < PQ_COUNT || queue == PQ_NONE,
("vm_page_unwire: invalid queue %u request for page %p",
queue, m));
if ((m->oflags & VPO_UNMANAGED) == 0)
vm_page_assert_locked(m);
if ((m->flags & PG_FICTITIOUS) != 0) {
KASSERT(m->wire_count == 1,
("vm_page_unwire: fictitious page %p's wire count isn't one", m));
return (FALSE);
}
if (m->wire_count > 0) {
m->wire_count--;
if (m->wire_count == 0) {
atomic_subtract_int(&vm_cnt.v_wire_count, 1);
if ((m->oflags & VPO_UNMANAGED) == 0 &&
m->object != NULL && queue != PQ_NONE)
vm_page_enqueue(queue, m);
return (TRUE);
} else
return (FALSE);
} else
panic("vm_page_unwire: page %p's wire count is zero", m);
}
/*
* Move the specified page to the inactive queue.
*
* Normally, "noreuse" is FALSE, resulting in LRU ordering of the inactive
* queue. However, setting "noreuse" to TRUE will accelerate the specified
* page's reclamation, but it will not unmap the page from any address space.
* This is implemented by inserting the page near the head of the inactive
* queue, using a marker page to guide FIFO insertion ordering.
*
* The page must be locked.
*/
static inline void
_vm_page_deactivate(vm_page_t m, boolean_t noreuse)
{
struct vm_pagequeue *pq;
int queue;
vm_page_assert_locked(m);
/*
* Ignore if the page is already inactive, unless it is unlikely to be
* reactivated.
*/
if ((queue = m->queue) == PQ_INACTIVE && !noreuse)
return;
if (m->wire_count == 0 && (m->oflags & VPO_UNMANAGED) == 0) {
pq = &vm_phys_domain(m)->vmd_pagequeues[PQ_INACTIVE];
/* Avoid multiple acquisitions of the inactive queue lock. */
if (queue == PQ_INACTIVE) {
vm_pagequeue_lock(pq);
vm_page_dequeue_locked(m);
} else {
if (queue != PQ_NONE)
vm_page_dequeue(m);
vm_pagequeue_lock(pq);
}
m->queue = PQ_INACTIVE;
if (noreuse)
TAILQ_INSERT_BEFORE(&vm_phys_domain(m)->vmd_inacthead,
m, plinks.q);
else
TAILQ_INSERT_TAIL(&pq->pq_pl, m, plinks.q);
vm_pagequeue_cnt_inc(pq);
vm_pagequeue_unlock(pq);
}
}
/*
* Move the specified page to the inactive queue.
*
* The page must be locked.
*/
void
vm_page_deactivate(vm_page_t m)
{
_vm_page_deactivate(m, FALSE);
}
/*
* Move the specified page to the inactive queue with the expectation
* that it is unlikely to be reused.
*
* The page must be locked.
*/
void
vm_page_deactivate_noreuse(vm_page_t m)
{
_vm_page_deactivate(m, TRUE);
}
/*
* vm_page_launder
*
* Put a page in the laundry.
*/
void
vm_page_launder(vm_page_t m)
{
int queue;
vm_page_assert_locked(m);
if ((queue = m->queue) != PQ_LAUNDRY) {
if (m->wire_count == 0 && (m->oflags & VPO_UNMANAGED) == 0) {
if (queue != PQ_NONE)
vm_page_dequeue(m);
vm_page_enqueue(PQ_LAUNDRY, m);
} else
KASSERT(queue == PQ_NONE,
("wired page %p is queued", m));
}
}
/*
* vm_page_unswappable
*
* Put a page in the PQ_UNSWAPPABLE holding queue.
*/
void
vm_page_unswappable(vm_page_t m)
{
vm_page_assert_locked(m);
KASSERT(m->wire_count == 0 && (m->oflags & VPO_UNMANAGED) == 0,
("page %p already unswappable", m));
if (m->queue != PQ_NONE)
vm_page_dequeue(m);
vm_page_enqueue(PQ_UNSWAPPABLE, m);
}
/*
* vm_page_try_to_free()
*
* Attempt to free the page. If we cannot free it, we do nothing.
* 1 is returned on success, 0 on failure.
*/
int
vm_page_try_to_free(vm_page_t m)
{
vm_page_lock_assert(m, MA_OWNED);
if (m->object != NULL)
VM_OBJECT_ASSERT_WLOCKED(m->object);
if (m->dirty || m->hold_count || m->wire_count ||
(m->oflags & VPO_UNMANAGED) != 0 || vm_page_busied(m))
return (0);
pmap_remove_all(m);
if (m->dirty)
return (0);
vm_page_free(m);
return (1);
}
/*
* 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_page_assert_locked(m);
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;
}
/*
* Clear any references to the page. Otherwise, the page daemon will
* immediately reactivate the page.
*/
vm_page_aflag_clear(m, PGA_REFERENCED);
if (advice != MADV_FREE && m->dirty == 0 && pmap_is_modified(m))
vm_page_dirty(m);
/*
* 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
vm_page_launder(m);
}
/*
* 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;
int sleep;
VM_OBJECT_ASSERT_WLOCKED(object);
KASSERT((allocflags & VM_ALLOC_SBUSY) == 0 ||
(allocflags & VM_ALLOC_IGN_SBUSY) != 0,
("vm_page_grab: VM_ALLOC_SBUSY/VM_ALLOC_IGN_SBUSY mismatch"));
retrylookup:
if ((m = vm_page_lookup(object, pindex)) != NULL) {
sleep = (allocflags & VM_ALLOC_IGN_SBUSY) != 0 ?
vm_page_xbusied(m) : vm_page_busied(m);
if (sleep) {
if ((allocflags & VM_ALLOC_NOWAIT) != 0)
return (NULL);
/*
* Reference the page before unlocking and
* sleeping so that the page daemon is less
* likely to reclaim it.
*/
vm_page_aflag_set(m, PGA_REFERENCED);
vm_page_lock(m);
VM_OBJECT_WUNLOCK(object);
vm_page_busy_sleep(m, "pgrbwt", (allocflags &
VM_ALLOC_IGN_SBUSY) != 0);
VM_OBJECT_WLOCK(object);
goto retrylookup;
} else {
if ((allocflags & VM_ALLOC_WIRED) != 0) {
vm_page_lock(m);
vm_page_wire(m);
vm_page_unlock(m);
}
if ((allocflags &
(VM_ALLOC_NOBUSY | VM_ALLOC_SBUSY)) == 0)
vm_page_xbusy(m);
if ((allocflags & VM_ALLOC_SBUSY) != 0)
vm_page_sbusy(m);
return (m);
}
}
m = vm_page_alloc(object, pindex, allocflags);
if (m == NULL) {
if ((allocflags & VM_ALLOC_NOWAIT) != 0)
return (NULL);
VM_OBJECT_WUNLOCK(object);
VM_WAIT;
VM_OBJECT_WLOCK(object);
goto retrylookup;
}
if (allocflags & VM_ALLOC_ZERO && (m->flags & PG_ZERO) == 0)
pmap_zero_page(m);
return (m);
}
/*
* 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));
}
/*
* 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_OBJECT_ASSERT_WLOCKED(m->object);
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.
*/
m->valid |= vm_page_bits(base, size);
}
/*
* 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)
{
uintptr_t addr;
#if PAGE_SIZE < 16384
int shift;
#endif
/*
* If the object is locked and the page is neither exclusive busy nor
* write mapped, then the page's dirty field cannot possibly be
* set by a concurrent pmap operation.
*/
VM_OBJECT_ASSERT_WLOCKED(m->object);
if (!vm_page_xbusied(m) && !pmap_page_is_write_mapped(m))
m->dirty &= ~pagebits;
else {
/*
* The pmap layer can call vm_page_dirty() without
* holding a distinguished lock. The combination of
* the object's lock and an atomic operation suffice
* to guarantee consistency of the page dirty field.
*
* For PAGE_SIZE == 32768 case, compiler already
* properly aligns the dirty field, so no forcible
* alignment is needed. Only require existence of
* atomic_clear_64 when page size is 32768.
*/
addr = (uintptr_t)&m->dirty;
#if PAGE_SIZE == 32768
atomic_clear_64((uint64_t *)addr, pagebits);
#elif PAGE_SIZE == 16384
atomic_clear_32((uint32_t *)addr, pagebits);
#else /* PAGE_SIZE <= 8192 */
/*
* Use a trick to perform a 32-bit atomic on the
* containing aligned word, to not depend on the existence
* of atomic_clear_{8, 16}.
*/
shift = addr & (sizeof(uint32_t) - 1);
#if BYTE_ORDER == BIG_ENDIAN
shift = (sizeof(uint32_t) - sizeof(m->dirty) - shift) * NBBY;
#else
shift *= NBBY;
#endif
addr &= ~(sizeof(uint32_t) - 1);
atomic_clear_32((uint32_t *)addr, pagebits << shift);
#endif /* PAGE_SIZE */
}
}
/*
* 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_OBJECT_ASSERT_WLOCKED(m->object);
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 VPO_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);
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;
m->oflags &= ~VPO_NOSYNC;
} else if (oldvalid != VM_PAGE_BITS_ALL)
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;
object = m->object;
VM_OBJECT_ASSERT_WLOCKED(object);
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 && m->valid == VM_PAGE_BITS_ALL &&
bits != 0)
pmap_remove_all(m);
KASSERT((bits == 0 && m->valid == VM_PAGE_BITS_ALL) ||
!pmap_page_is_mapped(m),
("vm_page_set_invalid: page %p is mapped", m));
m->valid &= ~bits;
m->dirty &= ~bits;
}
/*
* 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;
VM_OBJECT_ASSERT_WLOCKED(m->object);
/*
* 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)
m->valid = VM_PAGE_BITS_ALL;
}
/*
* 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.
*/
int
vm_page_is_valid(vm_page_t m, int base, int size)
{
vm_page_bits_t bits;
VM_OBJECT_ASSERT_LOCKED(m->object);
bits = vm_page_bits(base, size);
return (m->valid != 0 && (m->valid & bits) == bits);
}
/*
* vm_page_ps_is_valid:
*
* Returns TRUE if the entire (super)page is valid and FALSE otherwise.
*/
boolean_t
vm_page_ps_is_valid(vm_page_t m)
{
int i, npages;
VM_OBJECT_ASSERT_LOCKED(m->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++) {
if (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_OBJECT_ASSERT_WLOCKED(m->object);
if (m->dirty != VM_PAGE_BITS_ALL && pmap_is_modified(m))
vm_page_dirty(m);
}
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_lock_assert(vm_page_t m)
{
/*
* Certain of the page's fields may only be modified by the
* holder of the containing object's lock or the exclusive busy.
* holder. Unfortunately, the holder of the write busy is
* not recorded, and thus cannot be checked here.
*/
if (m->object != NULL && !vm_page_xbusied(m))
VM_OBJECT_ASSERT_WLOCKED(m->object);
}
void
vm_page_assert_pga_writeable(vm_page_t m, uint8_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_LOCKED(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_cnt.v_free_count);
db_printf("vm_cnt.v_inactive_count: %d\n", vm_cnt.v_inactive_count);
db_printf("vm_cnt.v_active_count: %d\n", vm_cnt.v_active_count);
db_printf("vm_cnt.v_laundry_count: %d\n", vm_cnt.v_laundry_count);
db_printf("vm_cnt.v_wire_count: %d\n", vm_cnt.v_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_cnt.v_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;
if (!have_addr) {
db_printf("show pginfo addr\n");
return;
}
phys = strchr(modif, 'p') != NULL;
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 hold %d wire %d\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->queue, m->hold_count, m->wire_count, m->aflags, m->oflags,
m->flags, m->act_count, m->busy_lock, m->valid, m->dirty);
}
#endif /* DDB */
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