63e9755548
This is the first in a series of patches that promotes the page busy field to a first class lock that no longer requires the object lock for consistency. Reviewed by: kib, markj Tested by: pho Sponsored by: Netflix, Intel Differential Revision: https://reviews.freebsd.org/D21548
254 lines
6.7 KiB
C
254 lines
6.7 KiB
C
/*-
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* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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*
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* Copyright (c) 2000 Peter Wemm
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/conf.h>
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#include <sys/kernel.h>
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#include <sys/lock.h>
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#include <sys/proc.h>
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#include <sys/mutex.h>
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#include <sys/mman.h>
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#include <sys/rwlock.h>
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#include <sys/sysctl.h>
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#include <vm/vm.h>
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#include <vm/vm_param.h>
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#include <vm/vm_object.h>
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#include <vm/vm_page.h>
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#include <vm/vm_pageout.h>
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#include <vm/vm_pager.h>
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/* list of phys pager objects */
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static struct pagerlst phys_pager_object_list;
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/* protect access to phys_pager_object_list */
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static struct mtx phys_pager_mtx;
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static void
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phys_pager_init(void)
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{
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TAILQ_INIT(&phys_pager_object_list);
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mtx_init(&phys_pager_mtx, "phys_pager list", NULL, MTX_DEF);
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}
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static vm_object_t
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phys_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot,
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vm_ooffset_t foff, struct ucred *cred)
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{
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vm_object_t object, object1;
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vm_pindex_t pindex;
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/*
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* Offset should be page aligned.
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*/
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if (foff & PAGE_MASK)
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return (NULL);
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pindex = OFF_TO_IDX(foff + PAGE_MASK + size);
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if (handle != NULL) {
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mtx_lock(&phys_pager_mtx);
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/*
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* Look up pager, creating as necessary.
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*/
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object1 = NULL;
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object = vm_pager_object_lookup(&phys_pager_object_list, handle);
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if (object == NULL) {
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/*
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* Allocate object and associate it with the pager.
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*/
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mtx_unlock(&phys_pager_mtx);
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object1 = vm_object_allocate(OBJT_PHYS, pindex);
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mtx_lock(&phys_pager_mtx);
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object = vm_pager_object_lookup(&phys_pager_object_list,
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handle);
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if (object != NULL) {
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/*
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* We raced with other thread while
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* allocating object.
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*/
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if (pindex > object->size)
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object->size = pindex;
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} else {
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object = object1;
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object1 = NULL;
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object->handle = handle;
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vm_object_set_flag(object, OBJ_POPULATE);
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TAILQ_INSERT_TAIL(&phys_pager_object_list,
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object, pager_object_list);
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}
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} else {
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if (pindex > object->size)
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object->size = pindex;
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}
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mtx_unlock(&phys_pager_mtx);
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vm_object_deallocate(object1);
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} else {
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object = vm_object_allocate(OBJT_PHYS, pindex);
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vm_object_set_flag(object, OBJ_POPULATE);
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}
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return (object);
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}
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static void
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phys_pager_dealloc(vm_object_t object)
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{
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if (object->handle != NULL) {
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VM_OBJECT_WUNLOCK(object);
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mtx_lock(&phys_pager_mtx);
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TAILQ_REMOVE(&phys_pager_object_list, object, pager_object_list);
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mtx_unlock(&phys_pager_mtx);
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VM_OBJECT_WLOCK(object);
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}
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object->handle = NULL;
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object->type = OBJT_DEAD;
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}
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/*
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* Fill as many pages as vm_fault has allocated for us.
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*/
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static int
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phys_pager_getpages(vm_object_t object, vm_page_t *m, int count, int *rbehind,
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int *rahead)
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{
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int i;
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VM_OBJECT_ASSERT_WLOCKED(object);
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for (i = 0; i < count; i++) {
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if (m[i]->valid == 0) {
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if ((m[i]->flags & PG_ZERO) == 0)
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pmap_zero_page(m[i]);
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m[i]->valid = VM_PAGE_BITS_ALL;
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}
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KASSERT(m[i]->valid == VM_PAGE_BITS_ALL,
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("phys_pager_getpages: partially valid page %p", m[i]));
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KASSERT(m[i]->dirty == 0,
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("phys_pager_getpages: dirty page %p", m[i]));
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}
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if (rbehind)
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*rbehind = 0;
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if (rahead)
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*rahead = 0;
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return (VM_PAGER_OK);
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}
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/*
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* Implement a pretty aggressive clustered getpages strategy. Hint that
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* everything in an entire 4MB window should be prefaulted at once.
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*
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* 4MB (1024 slots per page table page) is convenient for x86,
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* but may not be for other arches.
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*/
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#ifndef PHYSCLUSTER
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#define PHYSCLUSTER 1024
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#endif
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static int phys_pager_cluster = PHYSCLUSTER;
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SYSCTL_INT(_vm, OID_AUTO, phys_pager_cluster, CTLFLAG_RWTUN,
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&phys_pager_cluster, 0,
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"prefault window size for phys pager");
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/*
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* Max hint to vm_page_alloc() about the further allocation needs
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* inside the phys_pager_populate() loop. The number of bits used to
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* implement VM_ALLOC_COUNT() determines the hard limit on this value.
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* That limit is currently 65535.
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*/
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#define PHYSALLOC 16
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static int
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phys_pager_populate(vm_object_t object, vm_pindex_t pidx,
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int fault_type __unused, vm_prot_t max_prot __unused, vm_pindex_t *first,
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vm_pindex_t *last)
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{
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vm_page_t m;
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vm_pindex_t base, end, i;
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int ahead;
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base = rounddown(pidx, phys_pager_cluster);
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end = base + phys_pager_cluster - 1;
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if (end >= object->size)
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end = object->size - 1;
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if (*first > base)
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base = *first;
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if (end > *last)
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end = *last;
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*first = base;
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*last = end;
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for (i = base; i <= end; i++) {
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ahead = MIN(end - i, PHYSALLOC);
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m = vm_page_grab(object, i,
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VM_ALLOC_NORMAL | VM_ALLOC_COUNT(ahead));
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if (m->valid != VM_PAGE_BITS_ALL) {
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vm_page_zero_invalid(m, TRUE);
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m->valid = VM_PAGE_BITS_ALL;
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}
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KASSERT(m->dirty == 0,
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("phys_pager_populate: dirty page %p", m));
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}
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return (VM_PAGER_OK);
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}
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static void
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phys_pager_putpages(vm_object_t object, vm_page_t *m, int count, boolean_t sync,
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int *rtvals)
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{
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panic("phys_pager_putpage called");
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}
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static boolean_t
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phys_pager_haspage(vm_object_t object, vm_pindex_t pindex, int *before,
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int *after)
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{
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vm_pindex_t base, end;
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base = rounddown(pindex, phys_pager_cluster);
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end = base + phys_pager_cluster - 1;
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if (before != NULL)
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*before = pindex - base;
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if (after != NULL)
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*after = end - pindex;
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return (TRUE);
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}
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struct pagerops physpagerops = {
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.pgo_init = phys_pager_init,
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.pgo_alloc = phys_pager_alloc,
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.pgo_dealloc = phys_pager_dealloc,
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.pgo_getpages = phys_pager_getpages,
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.pgo_putpages = phys_pager_putpages,
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.pgo_haspage = phys_pager_haspage,
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.pgo_populate = phys_pager_populate,
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};
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