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Add the superpage reservation system. This is "part 2 of 2" of the

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machine-independent support for superpages.  (The earlier part was
the rewrite of the physical memory allocator.)  The remainder of the
code required for superpages support is machine-dependent and will
be added to the various pmap implementations at a later date.

Initially, I am only supporting one large page size per architecture.
Moreover, I am only enabling the reservation system on amd64.  (In
an emergency, it can be disabled by setting VM_NRESERVLEVELS to 0
in amd64/include/vmparam.h or your kernel configuration file.)
This commit is contained in:
Alan Cox 2007-12-29 19:53:04 +00:00
parent 098ff746f8
commit f8a47341fe
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=174982
7 changed files with 842 additions and 4 deletions
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1
sys/conf/files
View File

@ -2108,6 +2108,7 @@ vm/vm_pageout.c standard
vm/vm_pageq.c standard
vm/vm_pager.c standard
vm/vm_phys.c standard
vm/vm_reserv.c standard
vm/vm_unix.c standard
vm/vm_zeroidle.c standard
vm/vnode_pager.c standard

7
sys/kern/kern_exec.c
View File

@ -30,6 +30,7 @@ __FBSDID("$FreeBSD$");
#include "opt_hwpmc_hooks.h"
#include "opt_ktrace.h"
#include "opt_mac.h"
#include "opt_vm.h"
#include <sys/param.h>
#include <sys/systm.h>
@ -820,6 +821,12 @@ exec_map_first_page(imgp)
if (object == NULL)
return (EACCES);
VM_OBJECT_LOCK(object);
#if VM_NRESERVLEVEL > 0
if ((object->flags & OBJ_COLORED) == 0) {
object->flags |= OBJ_COLORED;
object->pg_color = 0;
}
#endif
ma[0] = vm_page_grab(object, 0, VM_ALLOC_NORMAL | VM_ALLOC_RETRY);
if ((ma[0]->valid & VM_PAGE_BITS_ALL) != VM_PAGE_BITS_ALL) {
initial_pagein = VM_INITIAL_PAGEIN;

13
sys/vm/vm_fault.c
View File

@ -74,6 +74,8 @@
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_vm.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
@ -429,6 +431,13 @@ RetryFault:;
*/
fs.m = NULL;
if (!vm_page_count_severe()) {
#if VM_NRESERVLEVEL > 0
if ((fs.object->flags & OBJ_COLORED) == 0) {
fs.object->flags |= OBJ_COLORED;
fs.object->pg_color = atop(vaddr) -
fs.pindex;
}
#endif
fs.m = vm_page_alloc(fs.object, fs.pindex,
(fs.vp || fs.object->backing_object)? VM_ALLOC_NORMAL: VM_ALLOC_ZERO);
}
@ -1107,6 +1116,10 @@ vm_fault_copy_entry(dst_map, src_map, dst_entry, src_entry)
*/
dst_object = vm_object_allocate(OBJT_DEFAULT,
OFF_TO_IDX(dst_entry->end - dst_entry->start));
#if VM_NRESERVLEVEL > 0
dst_object->flags |= OBJ_COLORED;
dst_object->pg_color = atop(dst_entry->start);
#endif
VM_OBJECT_LOCK(dst_object);
dst_entry->object.vm_object = dst_object;

45
sys/vm/vm_object.c
View File

@ -65,6 +65,8 @@
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_vm.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/lock.h>
@ -90,6 +92,7 @@ __FBSDID("$FreeBSD$");
#include <vm/swap_pager.h>
#include <vm/vm_kern.h>
#include <vm/vm_extern.h>
#include <vm/vm_reserv.h>
#include <vm/uma.h>
#define EASY_SCAN_FACTOR 8
@ -170,6 +173,11 @@ vm_object_zdtor(void *mem, int size, void *arg)
KASSERT(TAILQ_EMPTY(&object->memq),
("object %p has resident pages",
object));
#if VM_NRESERVLEVEL > 0
KASSERT(LIST_EMPTY(&object->rvq),
("object %p has reservations",
object));
#endif
KASSERT(object->cache == NULL,
("object %p has cached pages",
object));
@ -220,6 +228,9 @@ _vm_object_allocate(objtype_t type, vm_pindex_t size, vm_object_t object)
object->handle = NULL;
object->backing_object = NULL;
object->backing_object_offset = (vm_ooffset_t) 0;
#if VM_NRESERVLEVEL > 0
LIST_INIT(&object->rvq);
#endif
object->cache = NULL;
mtx_lock(&vm_object_list_mtx);
@ -241,10 +252,18 @@ vm_object_init(void)
VM_OBJECT_LOCK_INIT(&kernel_object_store, "kernel object");
_vm_object_allocate(OBJT_PHYS, OFF_TO_IDX(VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS),
kernel_object);
#if VM_NRESERVLEVEL > 0
kernel_object->flags |= OBJ_COLORED;
kernel_object->pg_color = (u_short)atop(VM_MIN_KERNEL_ADDRESS);
#endif
VM_OBJECT_LOCK_INIT(&kmem_object_store, "kmem object");
_vm_object_allocate(OBJT_PHYS, OFF_TO_IDX(VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS),
kmem_object);
#if VM_NRESERVLEVEL > 0
kmem_object->flags |= OBJ_COLORED;
kmem_object->pg_color = (u_short)atop(VM_MIN_KERNEL_ADDRESS);
#endif
/*
* The lock portion of struct vm_object must be type stable due
@ -652,6 +671,10 @@ vm_object_terminate(vm_object_t object)
}
vm_page_unlock_queues();
#if VM_NRESERVLEVEL > 0
if (__predict_false(!LIST_EMPTY(&object->rvq)))
vm_reserv_break_all(object);
#endif
if (__predict_false(object->cache != NULL))
vm_page_cache_free(object, 0, 0);
@ -1248,7 +1271,13 @@ vm_object_shadow(
LIST_INSERT_HEAD(&source->shadow_head, result, shadow_list);
source->shadow_count++;
source->generation++;
#if VM_NRESERVLEVEL > 0
result->flags |= source->flags & (OBJ_NEEDGIANT | OBJ_COLORED);
result->pg_color = (source->pg_color + OFF_TO_IDX(*offset)) &
((1 << (VM_NFREEORDER - 1)) - 1);
#else
result->flags |= source->flags & OBJ_NEEDGIANT;
#endif
VM_OBJECT_UNLOCK(source);
}
@ -1560,6 +1589,14 @@ vm_object_backing_scan(vm_object_t object, int op)
continue;
}
#if VM_NRESERVLEVEL > 0
/*
* Rename the reservation.
*/
vm_reserv_rename(p, object, backing_object,
backing_offset_index);
#endif
/*
* Page does not exist in parent, rename the
* page from the backing object to the main object.
@ -1662,6 +1699,14 @@ vm_object_collapse(vm_object_t object)
*/
vm_object_backing_scan(object, OBSC_COLLAPSE_WAIT);
#if VM_NRESERVLEVEL > 0
/*
* Break any reservations from backing_object.
*/
if (__predict_false(!LIST_EMPTY(&backing_object->rvq)))
vm_reserv_break_all(backing_object);
#endif
/*
* Move the pager from backing_object to object.
*/

53
sys/vm/vm_page.c
View File

@ -99,6 +99,8 @@
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_vm.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/lock.h>
@ -118,6 +120,7 @@ __FBSDID("$FreeBSD$");
#include <vm/vm_pageout.h>
#include <vm/vm_pager.h>
#include <vm/vm_phys.h>
#include <vm/vm_reserv.h>
#include <vm/vm_extern.h>
#include <vm/uma.h>
#include <vm/uma_int.h>
@ -318,6 +321,13 @@ vm_page_startup(vm_offset_t vaddr)
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 memory for the reservation management system's data
* structures.
*/
new_end = vm_reserv_startup(&vaddr, new_end, high_water);
#endif
#ifdef __amd64__
/*
* pmap_map on amd64 comes out of the direct-map, not kvm like i386,
@ -363,6 +373,12 @@ vm_page_startup(vm_offset_t vaddr)
}
}
freeenv(list);
#if VM_NRESERVLEVEL > 0
/*
* Initialize the reservation management system.
*/
vm_reserv_init();
#endif
return (vaddr);
}
@ -1028,15 +1044,33 @@ vm_page_alloc(vm_object_t object, vm_pindex_t pindex, int req)
}
if (vm_phys_unfree_page(m))
vm_phys_set_pool(VM_FREEPOOL_DEFAULT, m, 0);
#if VM_NRESERVLEVEL > 0
else if (!vm_reserv_reactivate_page(m))
#else
else
#endif
panic("vm_page_alloc: cache page %p is missing"
" from the free queue", m);
} else if ((req & VM_ALLOC_IFCACHED) != 0) {
mtx_unlock(&vm_page_queue_free_mtx);
return (NULL);
} else
#if VM_NRESERVLEVEL > 0
} else if (object == NULL ||
(object->flags & OBJ_COLORED) == 0 ||
(m = vm_reserv_alloc_page(object, pindex)) == NULL) {
#else
} else {
#endif
m = vm_phys_alloc_pages(object != NULL ?
VM_FREEPOOL_DEFAULT : VM_FREEPOOL_DIRECT, 0);
#if VM_NRESERVLEVEL > 0
if (m == NULL && vm_reserv_reclaim()) {
m = vm_phys_alloc_pages(object != NULL ?
VM_FREEPOOL_DEFAULT : VM_FREEPOOL_DIRECT,
0);
}
#endif
}
} else {
/*
* Not allocatable, give up.
@ -1301,7 +1335,12 @@ vm_page_free_toq(vm_page_t m)
m->flags |= PG_FREE;
mtx_lock(&vm_page_queue_free_mtx);
cnt.v_free_count++;
vm_phys_free_pages(m, 0);
#if VM_NRESERVLEVEL > 0
if (!vm_reserv_free_page(m))
#else
if (TRUE)
#endif
vm_phys_free_pages(m, 0);
if ((m->flags & PG_ZERO) != 0)
++vm_page_zero_count;
else
@ -1548,7 +1587,6 @@ vm_page_cache(vm_page_t m)
vm_page_flag_set(m, PG_CACHED);
vm_page_flag_clear(m, PG_ZERO);
mtx_lock(&vm_page_queue_free_mtx);
vm_phys_set_pool(VM_FREEPOOL_CACHE, m, 0);
cnt.v_cache_count++;
root = object->cache;
if (root == NULL) {
@ -1569,7 +1607,14 @@ vm_page_cache(vm_page_t m)
}
}
object->cache = m;
vm_phys_free_pages(m, 0);
#if VM_NRESERVLEVEL > 0
if (!vm_reserv_free_page(m)) {
#else
if (TRUE) {
#endif
vm_phys_set_pool(VM_FREEPOOL_CACHE, m, 0);
vm_phys_free_pages(m, 0);
}
vm_page_free_wakeup();
mtx_unlock(&vm_page_queue_free_mtx);

668
sys/vm/vm_reserv.c Normal file
View File

@ -0,0 +1,668 @@
/*-
* Copyright (c) 2002-2006 Rice University
* Copyright (c) 2007 Alan L. Cox <alc@cs.rice.edu>
* All rights reserved.
*
* This software was developed for the FreeBSD Project by Alan L. Cox,
* Olivier Crameri, Peter Druschel, Sitaram Iyer, and Juan Navarro.
*
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 COPYRIGHT
* HOLDERS 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.
*/
/*
* Superpage reservation management module
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_vm.h"
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mutex.h>
#include <sys/queue.h>
#include <sys/sbuf.h>
#include <sys/sysctl.h>
#include <sys/systm.h>
#include <vm/vm.h>
#include <vm/vm_param.h>
#include <vm/vm_object.h>
#include <vm/vm_page.h>
#include <vm/vm_phys.h>
#include <vm/vm_reserv.h>
/*
* The reservation system supports the speculative allocation of large physical
* pages ("superpages"). Speculative allocation enables the fully-automatic
* utilization of superpages by the virtual memory system. In other words, no
* programmatic directives are required to use superpages.
*/
#if VM_NRESERVLEVEL > 0
/*
* The number of small pages that are contained in a level 0 reservation
*/
#define VM_LEVEL_0_NPAGES (1 << VM_LEVEL_0_ORDER)
/*
* The number of bits by which a physical address is shifted to obtain the
* reservation number
*/
#define VM_LEVEL_0_SHIFT (VM_LEVEL_0_ORDER + PAGE_SHIFT)
/*
* The size of a level 0 reservation in bytes
*/
#define VM_LEVEL_0_SIZE (1 << VM_LEVEL_0_SHIFT)
/*
* Computes the index of the small page underlying the given (object, pindex)
* within the reservation's array of small pages.
*/
#define VM_RESERV_INDEX(object, pindex) \
(((object)->pg_color + (pindex)) & (VM_LEVEL_0_NPAGES - 1))
/*
* The reservation structure
*
* A reservation structure is constructed whenever a large physical page is
* speculatively allocated to an object. The reservation provides the small
* physical pages for the range [pindex, pindex + VM_LEVEL_0_NPAGES) of offsets
* within that object. The reservation's "popcnt" tracks the number of these
* small physical pages that are in use at any given time. When and if the
* reservation is not fully utilized, it appears in the queue of partially-
* populated reservations. The reservation always appears on the containing
* object's list of reservations.
*
* A partially-populated reservation can be broken and reclaimed at any time.
*/
struct vm_reserv {
TAILQ_ENTRY(vm_reserv) partpopq;
LIST_ENTRY(vm_reserv) objq;
vm_object_t object; /* containing object */
vm_pindex_t pindex; /* offset within object */
vm_page_t pages; /* first page of a superpage */
int popcnt; /* # of pages in use */
char inpartpopq;
};
/*
* The reservation array
*
* This array is analoguous in function to vm_page_array. It differs in the
* respect that it may contain a greater number of useful reservation
* structures than there are (physical) superpages. These "invalid"
* reservation structures exist to trade-off space for time in the
* implementation of vm_reserv_from_page(). Invalid reservation structures are
* distinguishable from "valid" reservation structures by inspecting the
* reservation's "pages" field. Invalid reservation structures have a NULL
* "pages" field.
*
* vm_reserv_from_page() maps a small (physical) page to an element of this
* array by computing a physical reservation number from the page's physical
* address. The physical reservation number is used as the array index.
*
* An "active" reservation is a valid reservation structure that has a non-NULL
* "object" field and a non-zero "popcnt" field. In other words, every active
* reservation belongs to a particular object. Moreover, every active
* reservation has an entry in the containing object's list of reservations.
*/
static vm_reserv_t vm_reserv_array;
/*
* The partially-populated reservation queue
*
* This queue enables the fast recovery of an unused cached or free small page
* from a partially-populated reservation. The head of this queue is either
* the least-recently-populated or most-recently-depopulated reservation.
*
* Access to this queue is synchronized by the free page queue lock.
*/
static TAILQ_HEAD(, vm_reserv) vm_rvq_partpop =
TAILQ_HEAD_INITIALIZER(vm_rvq_partpop);
static SYSCTL_NODE(_vm, OID_AUTO, reserv, CTLFLAG_RD, 0, "Reservation Info");
static long vm_reserv_broken;
SYSCTL_LONG(_vm_reserv, OID_AUTO, broken, CTLFLAG_RD,
&vm_reserv_broken, 0, "Cumulative number of broken reservations");
static long vm_reserv_freed;
SYSCTL_LONG(_vm_reserv, OID_AUTO, freed, CTLFLAG_RD,
&vm_reserv_freed, 0, "Cumulative number of freed reservations");
static int sysctl_vm_reserv_partpopq(SYSCTL_HANDLER_ARGS);
SYSCTL_OID(_vm_reserv, OID_AUTO, partpopq, CTLTYPE_STRING | CTLFLAG_RD, NULL, 0,
sysctl_vm_reserv_partpopq, "A", "Partially-populated reservation queues");
static long vm_reserv_reclaimed;
SYSCTL_LONG(_vm_reserv, OID_AUTO, reclaimed, CTLFLAG_RD,
&vm_reserv_reclaimed, 0, "Cumulative number of reclaimed reservations");
static void vm_reserv_depopulate(vm_reserv_t rv);
static vm_reserv_t vm_reserv_from_page(vm_page_t m);
static boolean_t vm_reserv_has_pindex(vm_reserv_t rv,
vm_pindex_t pindex);
static void vm_reserv_populate(vm_reserv_t rv);
/*
* Describes the current state of the partially-populated reservation queue.
*/
static int
sysctl_vm_reserv_partpopq(SYSCTL_HANDLER_ARGS)
{
struct sbuf sbuf;
vm_reserv_t rv;
char *cbuf;
const int cbufsize = (VM_NRESERVLEVEL + 1) * 81;
int counter, error, level, unused_pages;
cbuf = malloc(cbufsize, M_TEMP, M_WAITOK | M_ZERO);
sbuf_new(&sbuf, cbuf, cbufsize, SBUF_FIXEDLEN);
sbuf_printf(&sbuf, "\nLEVEL SIZE NUMBER\n\n");
for (level = -1; level <= VM_NRESERVLEVEL - 2; level++) {
counter = 0;
unused_pages = 0;
mtx_lock(&vm_page_queue_free_mtx);
TAILQ_FOREACH(rv, &vm_rvq_partpop/*[level]*/, partpopq) {
counter++;
unused_pages += VM_LEVEL_0_NPAGES - rv->popcnt;
}
mtx_unlock(&vm_page_queue_free_mtx);
sbuf_printf(&sbuf, "%5.5d: %6.6dK, %6.6d\n", level,
unused_pages * (PAGE_SIZE / 1024), counter);
}
sbuf_finish(&sbuf);
error = SYSCTL_OUT(req, sbuf_data(&sbuf), sbuf_len(&sbuf));
sbuf_delete(&sbuf);
free(cbuf, M_TEMP);
return (error);
}
/*
* Reduces the given reservation's population count. If the population count
* becomes zero, the reservation is destroyed. Additionally, moves the
* reservation to the head of the partially-populated reservations queue if the
* population count is non-zero.
*
* The free page queue lock must be held.
*/
static void
vm_reserv_depopulate(vm_reserv_t rv)
{
mtx_assert(&vm_page_queue_free_mtx, MA_OWNED);
KASSERT(rv->object != NULL,
("vm_reserv_depopulate: reserv %p is free", rv));
KASSERT(rv->popcnt > 0,
("vm_reserv_depopulate: reserv %p's popcnt is corrupted", rv));
if (rv->inpartpopq) {
TAILQ_REMOVE(&vm_rvq_partpop, rv, partpopq);
rv->inpartpopq = FALSE;
}
rv->popcnt--;
if (rv->popcnt == 0) {
LIST_REMOVE(rv, objq);
rv->object = NULL;
vm_phys_free_pages(rv->pages, VM_LEVEL_0_ORDER);
vm_reserv_freed++;
} else {
rv->inpartpopq = TRUE;
TAILQ_INSERT_HEAD(&vm_rvq_partpop, rv, partpopq);
}
}
/*
* Returns the reservation to which the given page might belong.
*/
static __inline vm_reserv_t
vm_reserv_from_page(vm_page_t m)
{
return (&vm_reserv_array[VM_PAGE_TO_PHYS(m) >> VM_LEVEL_0_SHIFT]);
}
/*
* Returns TRUE if the given reservation contains the given page index and
* FALSE otherwise.
*/
static __inline boolean_t
vm_reserv_has_pindex(vm_reserv_t rv, vm_pindex_t pindex)
{
return (((pindex - rv->pindex) & ~(VM_LEVEL_0_NPAGES - 1)) == 0);
}
/*
* Increases the given reservation's population count. Moves the reservation
* to the tail of the partially-populated reservation queue.
*
* The free page queue must be locked.
*/
static void
vm_reserv_populate(vm_reserv_t rv)
{
mtx_assert(&vm_page_queue_free_mtx, MA_OWNED);
KASSERT(rv->object != NULL,
("vm_reserv_populate: reserv %p is free", rv));
KASSERT(rv->popcnt < VM_LEVEL_0_NPAGES,
("vm_reserv_populate: reserv %p is already full", rv));
if (rv->inpartpopq) {
TAILQ_REMOVE(&vm_rvq_partpop, rv, partpopq);
rv->inpartpopq = FALSE;
}
rv->popcnt++;
if (rv->popcnt < VM_LEVEL_0_NPAGES) {
rv->inpartpopq = TRUE;
TAILQ_INSERT_TAIL(&vm_rvq_partpop, rv, partpopq);
}
}
/*
* Allocates a page from an existing or newly-created reservation.
*
* The object and free page queue must be locked.
*/
vm_page_t
vm_reserv_alloc_page(vm_object_t object, vm_pindex_t pindex)
{
vm_page_t m, mpred, msucc;
vm_pindex_t first, leftcap, rightcap;
vm_reserv_t rv;
mtx_assert(&vm_page_queue_free_mtx, MA_OWNED);
/*
* Is a reservation fundamentally not possible?
*/
VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
if (pindex < VM_RESERV_INDEX(object, pindex) ||
pindex >= object->size)
return (NULL);
/*
* Look for an existing reservation.
*/
msucc = NULL;
mpred = object->root;
while (mpred != NULL) {
KASSERT(mpred->pindex != pindex,
("vm_reserv_alloc_page: pindex already allocated"));
rv = vm_reserv_from_page(mpred);
if (rv->object == object && vm_reserv_has_pindex(rv, pindex)) {
m = &rv->pages[VM_RESERV_INDEX(object, pindex)];
/* Handle vm_page_rename(m, new_object, ...). */
if ((m->flags & (PG_CACHED | PG_FREE)) == 0)
return (NULL);
vm_reserv_populate(rv);
return (m);
} else if (mpred->pindex < pindex) {
if (msucc != NULL ||
(msucc = TAILQ_NEXT(mpred, listq)) == NULL)
break;
KASSERT(msucc->pindex != pindex,
("vm_reserv_alloc_page: pindex already allocated"));
rv = vm_reserv_from_page(msucc);
if (rv->object == object &&
vm_reserv_has_pindex(rv, pindex)) {
m = &rv->pages[VM_RESERV_INDEX(object, pindex)];
/* Handle vm_page_rename(m, new_object, ...). */
if ((m->flags & (PG_CACHED | PG_FREE)) == 0)
return (NULL);
vm_reserv_populate(rv);
return (m);
} else if (pindex < msucc->pindex)
break;
} else if (msucc == NULL) {
msucc = mpred;
mpred = TAILQ_PREV(msucc, pglist, listq);
continue;
}
msucc = NULL;
mpred = object->root = vm_page_splay(pindex, object->root);
}
/*
* Determine the first index to the left that can be used.
*/
if (mpred == NULL)
leftcap = 0;
else if ((rv = vm_reserv_from_page(mpred))->object != object)
leftcap = mpred->pindex + 1;
else
leftcap = rv->pindex + VM_LEVEL_0_NPAGES;
/*
* Determine the first index to the right that cannot be used.
*/
if (msucc == NULL)
rightcap = pindex + VM_LEVEL_0_NPAGES;
else if ((rv = vm_reserv_from_page(msucc))->object != object)
rightcap = msucc->pindex;
else
rightcap = rv->pindex;
/*
* Determine if a reservation fits between the first index to
* the left that can be used and the first index to the right
* that cannot be used.
*/
first = pindex - VM_RESERV_INDEX(object, pindex);
if (first < leftcap || first + VM_LEVEL_0_NPAGES > rightcap)
return (NULL);
/*
* Would a new reservation extend past the end of the given object?
*/
if (object->size < first + VM_LEVEL_0_NPAGES) {
/*
* Don't allocate a new reservation if the object is a vnode or
* backed by another object that is a vnode.
*/
if (object->type == OBJT_VNODE ||
(object->backing_object != NULL &&
object->backing_object->type == OBJT_VNODE))
return (NULL);
/* Speculate that the object may grow. */
}
/*
* Allocate a new reservation.
*/
m = vm_phys_alloc_pages(VM_FREEPOOL_DEFAULT, VM_LEVEL_0_ORDER);
if (m != NULL) {
rv = vm_reserv_from_page(m);
KASSERT(rv->pages == m,
("vm_reserv_alloc_page: reserv %p's pages is corrupted",
rv));
KASSERT(rv->object == NULL,
("vm_reserv_alloc_page: reserv %p isn't free", rv));
LIST_INSERT_HEAD(&object->rvq, rv, objq);
rv->object = object;
rv->pindex = first;
KASSERT(rv->popcnt == 0,
("vm_reserv_alloc_page: reserv %p's popcnt is corrupted",
rv));
KASSERT(!rv->inpartpopq,
("vm_reserv_alloc_page: reserv %p's inpartpopq is TRUE",
rv));
vm_reserv_populate(rv);
m = &rv->pages[VM_RESERV_INDEX(object, pindex)];
}
return (m);
}
/*
* Breaks all reservations belonging to the given object.
*/
void
vm_reserv_break_all(vm_object_t object)
{
vm_reserv_t rv;
int i;
mtx_lock(&vm_page_queue_free_mtx);
while ((rv = LIST_FIRST(&object->rvq)) != NULL) {
KASSERT(rv->object == object,
("vm_reserv_break_all: reserv %p is corrupted", rv));
if (rv->inpartpopq) {
TAILQ_REMOVE(&vm_rvq_partpop, rv, partpopq);
rv->inpartpopq = FALSE;
}
LIST_REMOVE(rv, objq);
rv->object = NULL;
for (i = 0; i < VM_LEVEL_0_NPAGES; i++) {
if ((rv->pages[i].flags & (PG_CACHED | PG_FREE)) != 0)
vm_phys_free_pages(&rv->pages[i], 0);
else
rv->popcnt--;
}
KASSERT(rv->popcnt == 0,
("vm_reserv_break_all: reserv %p's popcnt is corrupted",
rv));
vm_reserv_broken++;
}
mtx_unlock(&vm_page_queue_free_mtx);
}
/*
* Frees the given page if it belongs to a reservation. Returns TRUE if the
* page is freed and FALSE otherwise.
*
* The free page queue lock must be held.
*/
boolean_t
vm_reserv_free_page(vm_page_t m)
{
vm_reserv_t rv;
mtx_assert(&vm_page_queue_free_mtx, MA_OWNED);
rv = vm_reserv_from_page(m);
if (rv->object != NULL) {
vm_reserv_depopulate(rv);
return (TRUE);
}
return (FALSE);
}
/*
* Initializes the reservation management system. Specifically, initializes
* the reservation array.
*
* Requires that vm_page_array and first_page are initialized!
*/
void
vm_reserv_init(void)
{
vm_paddr_t paddr;
int i;
/*
* Initialize the reservation array. Specifically, initialize the
* "pages" field for every element that has an underlying superpage.
*/
for (i = 0; phys_avail[i + 1] != 0; i += 2) {
paddr = roundup2(phys_avail[i], VM_LEVEL_0_SIZE);
while (paddr + VM_LEVEL_0_SIZE <= phys_avail[i + 1]) {
vm_reserv_array[paddr >> VM_LEVEL_0_SHIFT].pages =
PHYS_TO_VM_PAGE(paddr);
paddr += VM_LEVEL_0_SIZE;
}
}
}
/*
* Returns a reservation level if the given page belongs to a fully-populated
* reservation and -1 otherwise.
*/
int
vm_reserv_level_iffullpop(vm_page_t m)
{
vm_reserv_t rv;
rv = vm_reserv_from_page(m);
return (rv->popcnt == VM_LEVEL_0_NPAGES ? 0 : -1);
}
/*
* Prepare for the reactivation of a cached page.
*
* First, suppose that the given page "m" was allocated individually, i.e., not
* as part of a reservation, and cached. Then, suppose a reservation
* containing "m" is allocated by the same object. Although "m" and the
* reservation belong to the same object, "m"'s pindex may not match the
* reservation's.
*
* The free page queue must be locked.
*/
boolean_t
vm_reserv_reactivate_page(vm_page_t m)
{
vm_reserv_t rv;
int i, m_index;
mtx_assert(&vm_page_queue_free_mtx, MA_OWNED);
rv = vm_reserv_from_page(m);
if (rv->object == NULL)
return (FALSE);
KASSERT((m->flags & PG_CACHED) != 0,
("vm_reserv_uncache_page: page %p is not cached", m));
if (m->object == rv->object &&
m->pindex - rv->pindex == VM_RESERV_INDEX(m->object, m->pindex))
vm_reserv_populate(rv);
else {
KASSERT(rv->inpartpopq,
("vm_reserv_uncache_page: reserv %p's inpartpopq is FALSE",
rv));
TAILQ_REMOVE(&vm_rvq_partpop, rv, partpopq);
rv->inpartpopq = FALSE;
LIST_REMOVE(rv, objq);
rv->object = NULL;
/* Don't vm_phys_free_pages(m, 0). */
m_index = m - rv->pages;
for (i = 0; i < m_index; i++) {
if ((rv->pages[i].flags & (PG_CACHED | PG_FREE)) != 0)
vm_phys_free_pages(&rv->pages[i], 0);
else
rv->popcnt--;
}
for (i++; i < VM_LEVEL_0_NPAGES; i++) {
if ((rv->pages[i].flags & (PG_CACHED | PG_FREE)) != 0)
vm_phys_free_pages(&rv->pages[i], 0);
else
rv->popcnt--;
}
KASSERT(rv->popcnt == 0,
("vm_reserv_uncache_page: reserv %p's popcnt is corrupted",
rv));
vm_reserv_broken++;
}
return (TRUE);
}
/*
* Breaks the reservation at the head of the partially-populated reservation
* queue, releasing its cached and free pages to the physical memory
* allocator. Returns TRUE if a reservation is broken and FALSE otherwise.
*
* The free page queue lock must be held.
*/
boolean_t
vm_reserv_reclaim(void)
{
vm_reserv_t rv;
int i;
mtx_assert(&vm_page_queue_free_mtx, MA_OWNED);
if ((rv = TAILQ_FIRST(&vm_rvq_partpop)) != NULL) {
KASSERT(rv->inpartpopq,
("vm_reserv_reclaim: reserv %p's inpartpopq is corrupted",
rv));
TAILQ_REMOVE(&vm_rvq_partpop, rv, partpopq);
rv->inpartpopq = FALSE;
KASSERT(rv->object != NULL,
("vm_reserv_reclaim: reserv %p is free", rv));
LIST_REMOVE(rv, objq);
rv->object = NULL;
for (i = 0; i < VM_LEVEL_0_NPAGES; i++) {
if ((rv->pages[i].flags & (PG_CACHED | PG_FREE)) != 0)
vm_phys_free_pages(&rv->pages[i], 0);
else
rv->popcnt--;
}
KASSERT(rv->popcnt == 0,
("vm_reserv_reclaim: reserv %p's popcnt is corrupted",
rv));
vm_reserv_reclaimed++;
return (TRUE);
}
return (FALSE);
}
/*
* Transfers the reservation underlying the given page to a new object.
*
* The object must be locked.
*/
void
vm_reserv_rename(vm_page_t m, vm_object_t new_object, vm_object_t old_object,
vm_pindex_t old_object_offset)
{
vm_reserv_t rv;
VM_OBJECT_LOCK_ASSERT(new_object, MA_OWNED);
rv = vm_reserv_from_page(m);
if (rv->object == old_object) {
mtx_lock(&vm_page_queue_free_mtx);
if (rv->object == old_object) {
LIST_REMOVE(rv, objq);
LIST_INSERT_HEAD(&new_object->rvq, rv, objq);
rv->object = new_object;
rv->pindex -= old_object_offset;
}
mtx_unlock(&vm_page_queue_free_mtx);
}
}
/*
* Allocates the virtual and physical memory required by the reservation
* management system's data structures, in particular, the reservation array.
*/
vm_paddr_t
vm_reserv_startup(vm_offset_t *vaddr, vm_paddr_t end, vm_paddr_t high_water)
{
vm_paddr_t new_end;
size_t size;
/*
* Calculate the size (in bytes) of the reservation array. Round up
* from "high_water" because every small page is mapped to an element
* in the reservation array based on its physical address. Thus, the
* number of elements in the reservation array can be greater than the
* number of superpages.
*/
size = howmany(high_water, VM_LEVEL_0_SIZE) * sizeof(struct vm_reserv);
/*
* Allocate and map the physical memory for the reservation array. The
* next available virtual address is returned by reference.
*/
new_end = end - round_page(size);
vm_reserv_array = (void *)(uintptr_t)pmap_map(vaddr, new_end, end,
VM_PROT_READ | VM_PROT_WRITE);
bzero(vm_reserv_array, size);
/*
* Return the next available physical address.
*/
return (new_end);
}
#endif /* VM_NRESERVLEVEL > 0 */

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sys/vm/vm_reserv.h Normal file
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@ -0,0 +1,59 @@
/*-
* Copyright (c) 2002-2006 Rice University
* Copyright (c) 2007 Alan L. Cox <alc@cs.rice.edu>
* All rights reserved.
*
* This software was developed for the FreeBSD Project by Alan L. Cox,
* Olivier Crameri, Peter Druschel, Sitaram Iyer, and Juan Navarro.
*
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 COPYRIGHT
* HOLDERS 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.
*
* $FreeBSD$
*/
/*
* Superpage reservation management definitions
*/
#ifndef _VM_RESERV_H_
#define _VM_RESERV_H_
#ifdef _KERNEL
#if VM_NRESERVLEVEL > 0
vm_page_t vm_reserv_alloc_page(vm_object_t object, vm_pindex_t pindex);
void vm_reserv_break_all(vm_object_t object);
boolean_t vm_reserv_free_page(vm_page_t m);
void vm_reserv_init(void);
int vm_reserv_level_iffullpop(vm_page_t m);
boolean_t vm_reserv_reactivate_page(vm_page_t m);
boolean_t vm_reserv_reclaim(void);
void vm_reserv_rename(vm_page_t m, vm_object_t new_object,
vm_object_t old_object, vm_pindex_t old_object_offset);
vm_paddr_t vm_reserv_startup(vm_offset_t *vaddr, vm_paddr_t end,
vm_paddr_t high_water);
#endif /* VM_NRESERVLEVEL > 0 */
#endif /* _KERNEL */
#endif /* !_VM_RESERV_H_ */