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(1/6) Replace busy checks with acquires where it is trival to do so.

Browse Source 
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
This commit is contained in:
Jeff Roberson 2019-10-15 03:35:11 +00:00
parent f44e743679
commit 63e9755548
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=353535
15 changed files with 211 additions and 127 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
sys/dev/xen/gntdev/gntdev.c
View File

@ -835,9 +835,9 @@ gntdev_gmap_pg_fault(vm_object_t object, vm_ooffset_t offset, int prot,
*mres = NULL;
}
vm_page_busy_acquire(page, 0);
vm_page_insert(page, object, pidx);
page->valid = VM_PAGE_BITS_ALL;
vm_page_xbusy(page);
*mres = page;
return (VM_PAGER_OK);
}

2
sys/dev/xen/privcmd/privcmd.c
View File

@ -178,9 +178,9 @@ privcmd_pg_fault(vm_object_t object, vm_ooffset_t offset,
*mres = NULL;
}
vm_page_busy_acquire(page, 0);
vm_page_insert(page, object, pidx);
page->valid = VM_PAGE_BITS_ALL;
vm_page_xbusy(page);
*mres = page;
return (VM_PAGER_OK);
}

6
sys/fs/tmpfs/tmpfs_subr.c
View File

@ -1406,10 +1406,8 @@ tmpfs_reg_resize(struct vnode *vp, off_t newsize, boolean_t ignerr)
if (base != 0) {
idx = OFF_TO_IDX(newsize);
retry:
m = vm_page_lookup(uobj, idx);
m = vm_page_grab(uobj, idx, VM_ALLOC_NOCREAT);
if (m != NULL) {
if (vm_page_sleep_if_busy(m, "tmfssz"))
goto retry;
MPASS(m->valid == VM_PAGE_BITS_ALL);
} else if (vm_pager_has_page(uobj, idx, NULL, NULL)) {
m = vm_page_alloc(uobj, idx, VM_ALLOC_NORMAL |
@ -1430,7 +1428,6 @@ tmpfs_reg_resize(struct vnode *vp, off_t newsize, boolean_t ignerr)
vm_page_lock(m);
vm_page_launder(m);
vm_page_unlock(m);
vm_page_xunbusy(m);
} else {
vm_page_free(m);
if (ignerr)
@ -1444,6 +1441,7 @@ tmpfs_reg_resize(struct vnode *vp, off_t newsize, boolean_t ignerr)
if (m != NULL) {
pmap_zero_page_area(m, base, PAGE_SIZE - base);
vm_page_dirty(m);
vm_page_xunbusy(m);
vm_pager_page_unswapped(m);
}
}

6
sys/kern/kern_exec.c
View File

@ -976,10 +976,14 @@ exec_map_first_page(struct image_params *imgp)
#if VM_NRESERVLEVEL > 0
vm_object_color(object, 0);
#endif
retry:
ma[0] = vm_page_grab(object, 0, VM_ALLOC_NORMAL | VM_ALLOC_NOBUSY |
VM_ALLOC_WIRED);
if (ma[0]->valid != VM_PAGE_BITS_ALL) {
vm_page_xbusy(ma[0]);
if (vm_page_busy_acquire(ma[0], VM_ALLOC_WAITFAIL) == 0) {
vm_page_unwire_noq(ma[0]);
goto retry;
}
if (!vm_pager_has_page(object, 0, NULL, &after)) {
if (vm_page_unwire_noq(ma[0]))
vm_page_free(ma[0]);

7
sys/kern/uipc_shm.c
View File

@ -457,10 +457,9 @@ shm_dotruncate_locked(struct shmfd *shmfd, off_t length, void *rl_cookie)
if (base != 0) {
idx = OFF_TO_IDX(length);
retry:
m = vm_page_lookup(object, idx);
m = vm_page_grab(object, idx, VM_ALLOC_NOCREAT);
if (m != NULL) {
if (vm_page_sleep_if_busy(m, "shmtrc"))
goto retry;
MPASS(m->valid == VM_PAGE_BITS_ALL);
} else if (vm_pager_has_page(object, idx, NULL, NULL)) {
m = vm_page_alloc(object, idx,
VM_ALLOC_NORMAL | VM_ALLOC_WAITFAIL);
@ -478,7 +477,6 @@ shm_dotruncate_locked(struct shmfd *shmfd, off_t length, void *rl_cookie)
* as an access.
*/
vm_page_launder(m);
vm_page_xunbusy(m);
} else {
vm_page_free(m);
VM_OBJECT_WUNLOCK(object);
@ -490,6 +488,7 @@ shm_dotruncate_locked(struct shmfd *shmfd, off_t length, void *rl_cookie)
KASSERT(m->valid == VM_PAGE_BITS_ALL,
("shm_dotruncate: page %p is invalid", m));
vm_page_dirty(m);
vm_page_xunbusy(m);
vm_pager_page_unswapped(m);
}
}

48
sys/kern/vfs_bio.c
View File

@ -2945,10 +2945,10 @@ vfs_vmio_invalidate(struct buf *bp)
presid = resid > (PAGE_SIZE - poffset) ?
(PAGE_SIZE - poffset) : resid;
KASSERT(presid >= 0, ("brelse: extra page"));
while (vm_page_xbusied(m))
vm_page_sleep_if_xbusy(m, "mbncsh");
vm_page_busy_acquire(m, VM_ALLOC_SBUSY);
if (pmap_page_wired_mappings(m) == 0)
vm_page_set_invalid(m, poffset, presid);
vm_page_sunbusy(m);
vm_page_release_locked(m, flags);
resid -= presid;
poffset = 0;
@ -3651,7 +3651,7 @@ vfs_clean_pages_dirty_buf(struct buf *bp)
("vfs_clean_pages_dirty_buf: no buffer offset"));
VM_OBJECT_WLOCK(bp->b_bufobj->bo_object);
vfs_drain_busy_pages(bp);
vfs_busy_pages_acquire(bp);
vfs_setdirty_locked_object(bp);
for (i = 0; i < bp->b_npages; i++) {
noff = (foff + PAGE_SIZE) & ~(off_t)PAGE_MASK;
@ -3663,6 +3663,7 @@ vfs_clean_pages_dirty_buf(struct buf *bp)
/* vm_page_clear_dirty(m, foff & PAGE_MASK, eoff - foff); */
foff = noff;
}
vfs_busy_pages_release(bp);
VM_OBJECT_WUNLOCK(bp->b_bufobj->bo_object);
}
@ -4559,28 +4560,25 @@ vfs_page_set_validclean(struct buf *bp, vm_ooffset_t off, vm_page_t m)
}
/*
* Ensure that all buffer pages are not exclusive busied. If any page is
* exclusive busy, drain it.
* Acquire a shared busy on all pages in the buf.
*/
void
vfs_drain_busy_pages(struct buf *bp)
vfs_busy_pages_acquire(struct buf *bp)
{
vm_page_t m;
int i, last_busied;
int i;
VM_OBJECT_ASSERT_WLOCKED(bp->b_bufobj->bo_object);
last_busied = 0;
for (i = 0; i < bp->b_npages; i++) {
m = bp->b_pages[i];
if (vm_page_xbusied(m)) {
for (; last_busied < i; last_busied++)
vm_page_sbusy(bp->b_pages[last_busied]);
while (vm_page_xbusied(m)) {
vm_page_sleep_if_xbusy(m, "vbpage");
}
}
}
for (i = 0; i < last_busied; i++)
for (i = 0; i < bp->b_npages; i++)
vm_page_busy_acquire(bp->b_pages[i], VM_ALLOC_SBUSY);
}
void
vfs_busy_pages_release(struct buf *bp)
{
int i;
VM_OBJECT_ASSERT_WLOCKED(bp->b_bufobj->bo_object);
for (i = 0; i < bp->b_npages; i++)
vm_page_sunbusy(bp->b_pages[i]);
}
@ -4613,17 +4611,17 @@ vfs_busy_pages(struct buf *bp, int clear_modify)
KASSERT(bp->b_offset != NOOFFSET,
("vfs_busy_pages: no buffer offset"));
VM_OBJECT_WLOCK(obj);
vfs_drain_busy_pages(bp);
if ((bp->b_flags & B_CLUSTER) == 0) {
vm_object_pip_add(obj, bp->b_npages);
vfs_busy_pages_acquire(bp);
}
if (bp->b_bufsize != 0)
vfs_setdirty_locked_object(bp);
bogus = false;
for (i = 0; i < bp->b_npages; i++) {
m = bp->b_pages[i];
vm_page_assert_sbusied(m);
if ((bp->b_flags & B_CLUSTER) == 0) {
vm_object_pip_add(obj, 1);
vm_page_sbusy(m);
}
/*
* When readying a buffer for a read ( i.e
* clear_modify == 0 ), it is important to do

18
sys/kern/vfs_cluster.c
View File

@ -418,11 +418,9 @@ cluster_rbuild(struct vnode *vp, u_quad_t filesize, daddr_t lbn,
for (bn = blkno, i = 0; i < run; ++i, bn += inc) {
if (i == 0) {
VM_OBJECT_WLOCK(tbp->b_bufobj->bo_object);
vfs_drain_busy_pages(tbp);
vm_object_pip_add(tbp->b_bufobj->bo_object,
tbp->b_npages);
for (k = 0; k < tbp->b_npages; k++)
vm_page_sbusy(tbp->b_pages[k]);
vfs_busy_pages_acquire(tbp);
VM_OBJECT_WUNLOCK(tbp->b_bufobj->bo_object);
} else {
if ((bp->b_npages * PAGE_SIZE) +
@ -470,10 +468,9 @@ cluster_rbuild(struct vnode *vp, u_quad_t filesize, daddr_t lbn,
if ((tbp->b_pages[j]->valid &
vm_page_bits(toff, tinc)) != 0)
break;
if (vm_page_xbusied(tbp->b_pages[j]))
if (vm_page_trysbusy(tbp->b_pages[j]) == 0)
break;
vm_object_pip_add(tbp->b_bufobj->bo_object, 1);
vm_page_sbusy(tbp->b_pages[j]);
off += tinc;
tsize -= tinc;
}
@ -991,11 +988,14 @@ cluster_wbuild(struct vnode *vp, long size, daddr_t start_lbn, int len,
VM_OBJECT_WLOCK(tbp->b_bufobj->bo_object);
if (i == 0) {
vfs_drain_busy_pages(tbp);
vfs_busy_pages_acquire(tbp);
} else { /* if not first buffer */
for (j = 0; j < tbp->b_npages; j += 1) {
m = tbp->b_pages[j];
if (vm_page_xbusied(m)) {
if (vm_page_trysbusy(m) == 0) {
for (j--; j >= 0; j--)
vm_page_sunbusy(
tbp->b_pages[j]);
VM_OBJECT_WUNLOCK(
tbp->b_object);
bqrelse(tbp);
@ -1003,10 +1003,10 @@ cluster_wbuild(struct vnode *vp, long size, daddr_t start_lbn, int len,
}
}
}
vm_object_pip_add(tbp->b_bufobj->bo_object,
tbp->b_npages);
for (j = 0; j < tbp->b_npages; j += 1) {
m = tbp->b_pages[j];
vm_page_sbusy(m);
vm_object_pip_add(m->object, 1);
if ((bp->b_npages == 0) ||
(bp->b_pages[bp->b_npages - 1] != m)) {
bp->b_pages[bp->b_npages] = m;

3
sys/sys/buf.h
View File

@ -539,7 +539,8 @@ void bufstrategy(struct bufobj *, struct buf *);
void brelse(struct buf *);
void bqrelse(struct buf *);
int vfs_bio_awrite(struct buf *);
void vfs_drain_busy_pages(struct buf *bp);
void vfs_busy_pages_acquire(struct buf *bp);
void vfs_busy_pages_release(struct buf *bp);
struct buf *incore(struct bufobj *, daddr_t);
struct buf *gbincore(struct bufobj *, daddr_t);
struct buf *getblk(struct vnode *, daddr_t, int, int, int, int);

26
sys/vm/phys_pager.c
View File

@ -206,29 +206,13 @@ phys_pager_populate(vm_object_t object, vm_pindex_t pidx,
*last = end;
for (i = base; i <= end; i++) {
retry:
m = vm_page_lookup(object, i);
if (m == NULL) {
ahead = MIN(end - i, PHYSALLOC);
m = vm_page_alloc(object, i, VM_ALLOC_NORMAL |
VM_ALLOC_ZERO | VM_ALLOC_WAITFAIL |
VM_ALLOC_COUNT(ahead));
if (m == NULL)
goto retry;
if ((m->flags & PG_ZERO) == 0)
pmap_zero_page(m);
ahead = MIN(end - i, PHYSALLOC);
m = vm_page_grab(object, i,
VM_ALLOC_NORMAL | VM_ALLOC_COUNT(ahead));
if (m->valid != VM_PAGE_BITS_ALL) {
vm_page_zero_invalid(m, TRUE);
m->valid = VM_PAGE_BITS_ALL;
} else if (vm_page_xbusied(m)) {
vm_page_sleep_if_xbusy(m, "physb");
goto retry;
} else {
vm_page_xbusy(m);
if (m->valid != VM_PAGE_BITS_ALL)
vm_page_zero_invalid(m, TRUE);
}
KASSERT(m->valid == VM_PAGE_BITS_ALL,
("phys_pager_populate: partially valid page %p", m));
KASSERT(m->dirty == 0,
("phys_pager_populate: dirty page %p", m));
}

12
sys/vm/vm_fault.c
View File

@ -787,7 +787,7 @@ vm_fault(vm_map_t map, vm_offset_t vaddr, vm_prot_t fault_type,
* around with a shared busied page except, perhaps,
* to pmap it.
*/
if (vm_page_busied(fs.m)) {
if (vm_page_tryxbusy(fs.m) == 0) {
/*
* Reference the page before unlocking and
* sleeping so that the page daemon is less
@ -819,12 +819,11 @@ vm_fault(vm_map_t map, vm_offset_t vaddr, vm_prot_t fault_type,
}
/*
* Mark page busy for other processes, and the
* The page is marked busy for other processes and the
* pagedaemon. If it still isn't completely valid
* (readable), jump to readrest, else break-out ( we
* found the page ).
*/
vm_page_xbusy(fs.m);
if (fs.m->valid != VM_PAGE_BITS_ALL)
goto readrest;
break; /* break to PAGE HAS BEEN FOUND */
@ -1826,16 +1825,17 @@ vm_fault_copy_entry(vm_map_t dst_map, vm_map_t src_map,
dst_m->dirty = dst_m->valid = src_m->valid;
} else {
dst_m = src_m;
if (vm_page_sleep_if_busy(dst_m, "fltupg"))
if (vm_page_busy_acquire(dst_m, VM_ALLOC_WAITFAIL) == 0)
goto again;
if (dst_m->pindex >= dst_object->size)
if (dst_m->pindex >= dst_object->size) {
/*
* We are upgrading. Index can occur
* out of bounds if the object type is
* vnode and the file was truncated.
*/
vm_page_xunbusy(dst_m);
break;
vm_page_xbusy(dst_m);
}
}
VM_OBJECT_WUNLOCK(dst_object);

49
sys/vm/vm_object.c
View File

@ -838,7 +838,7 @@ vm_object_page_clean(vm_object_t object, vm_ooffset_t start, vm_ooffset_t end,
np = TAILQ_NEXT(p, listq);
if (p->valid == 0)
continue;
if (vm_page_sleep_if_busy(p, "vpcwai")) {
if (vm_page_busy_acquire(p, VM_ALLOC_WAITFAIL) == 0) {
if (object->generation != curgeneration) {
if ((flags & OBJPC_SYNC) != 0)
goto rescan;
@ -848,8 +848,10 @@ vm_object_page_clean(vm_object_t object, vm_ooffset_t start, vm_ooffset_t end,
np = vm_page_find_least(object, pi);
continue;
}
if (!vm_object_page_remove_write(p, flags, &clearobjflags))
if (!vm_object_page_remove_write(p, flags, &clearobjflags)) {
vm_page_xunbusy(p);
continue;
}
n = vm_object_page_collect_flush(object, p, pagerflags,
flags, &clearobjflags, &eio);
@ -899,6 +901,7 @@ vm_object_page_collect_flush(vm_object_t object, vm_page_t p, int pagerflags,
int count, i, mreq, runlen;
vm_page_lock_assert(p, MA_NOTOWNED);
vm_page_assert_xbusied(p);
VM_OBJECT_ASSERT_WLOCKED(object);
count = 1;
@ -906,18 +909,22 @@ vm_object_page_collect_flush(vm_object_t object, vm_page_t p, int pagerflags,
for (tp = p; count < vm_pageout_page_count; count++) {
tp = vm_page_next(tp);
if (tp == NULL || vm_page_busied(tp))
if (tp == NULL || vm_page_tryxbusy(tp) == 0)
break;
if (!vm_object_page_remove_write(tp, flags, clearobjflags))
if (!vm_object_page_remove_write(tp, flags, clearobjflags)) {
vm_page_xunbusy(tp);
break;
}
}
for (p_first = p; count < vm_pageout_page_count; count++) {
tp = vm_page_prev(p_first);
if (tp == NULL || vm_page_busied(tp))
if (tp == NULL || vm_page_tryxbusy(tp) == 0)
break;
if (!vm_object_page_remove_write(tp, flags, clearobjflags))
if (!vm_object_page_remove_write(tp, flags, clearobjflags)) {
vm_page_xunbusy(tp);
break;
}
p_first = tp;
mreq++;
}
@ -1158,7 +1165,7 @@ vm_object_madvise(vm_object_t object, vm_pindex_t pindex, vm_pindex_t end,
("vm_object_madvise: page %p is fictitious", tm));
KASSERT((tm->oflags & VPO_UNMANAGED) == 0,
("vm_object_madvise: page %p is not managed", tm));
if (vm_page_busied(tm)) {
if (vm_page_tryxbusy(tm) == 0) {
if (object != tobject)
VM_OBJECT_WUNLOCK(object);
if (advice == MADV_WILLNEED) {
@ -1175,6 +1182,7 @@ vm_object_madvise(vm_object_t object, vm_pindex_t pindex, vm_pindex_t end,
vm_page_lock(tm);
vm_page_advise(tm, advice);
vm_page_unlock(tm);
vm_page_xunbusy(tm);
vm_object_madvise_freespace(tobject, advice, tm->pindex, 1);
next_pindex:
if (tobject != object)
@ -1341,7 +1349,7 @@ vm_object_split(vm_map_entry_t entry)
* We do not have to VM_PROT_NONE the page as mappings should
* not be changed by this operation.
*/
if (vm_page_busied(m)) {
if (vm_page_tryxbusy(m) == 0) {
VM_OBJECT_WUNLOCK(new_object);
vm_page_sleep_if_busy(m, "spltwt");
VM_OBJECT_WLOCK(new_object);
@ -1350,6 +1358,7 @@ vm_object_split(vm_map_entry_t entry)
/* vm_page_rename() will dirty the page. */
if (vm_page_rename(m, new_object, idx)) {
vm_page_xunbusy(m);
VM_OBJECT_WUNLOCK(new_object);
VM_OBJECT_WUNLOCK(orig_object);
vm_radix_wait();
@ -1357,6 +1366,8 @@ vm_object_split(vm_map_entry_t entry)
VM_OBJECT_WLOCK(new_object);
goto retry;
}
/* Rename released the xbusy lock. */
#if VM_NRESERVLEVEL > 0
/*
* If some of the reservation's allocated pages remain with
@ -1405,7 +1416,6 @@ vm_object_collapse_scan_wait(vm_object_t object, vm_page_t p, vm_page_t next,
backing_object = object->backing_object;
VM_OBJECT_ASSERT_WLOCKED(backing_object);
KASSERT(p == NULL || vm_page_busied(p), ("unbusy page %p", p));
KASSERT(p == NULL || p->object == object || p->object == backing_object,
("invalid ownership %p %p %p", p, object, backing_object));
if ((op & OBSC_COLLAPSE_NOWAIT) != 0)
@ -1510,7 +1520,7 @@ vm_object_collapse_scan(vm_object_t object, int op)
/*
* Check for busy page
*/
if (vm_page_busied(p)) {
if (vm_page_tryxbusy(p) == 0) {
next = vm_object_collapse_scan_wait(object, p, next, op);
continue;
}
@ -1532,7 +1542,8 @@ vm_object_collapse_scan(vm_object_t object, int op)
}
pp = vm_page_lookup(object, new_pindex);
if (pp != NULL && vm_page_busied(pp)) {
if (pp != NULL && vm_page_tryxbusy(pp) == 0) {
vm_page_xunbusy(p);
/*
* The page in the parent is busy and possibly not
* (yet) valid. Until its state is finalized by the
@ -1568,6 +1579,8 @@ vm_object_collapse_scan(vm_object_t object, int op)
("freeing mapped page %p", p));
if (vm_page_remove(p))
vm_page_free(p);
if (pp != NULL)
vm_page_xunbusy(pp);
continue;
}
@ -1579,10 +1592,14 @@ vm_object_collapse_scan(vm_object_t object, int op)
* through the rename. vm_page_rename() will dirty the page.
*/
if (vm_page_rename(p, object, new_pindex)) {
vm_page_xunbusy(p);
if (pp != NULL)
vm_page_xunbusy(pp);
next = vm_object_collapse_scan_wait(object, NULL, next,
op);
continue;
}
/* Rename released the xbusy lock. */
/* Use the old pindex to free the right page. */
if (backing_object->type == OBJT_SWAP)
@ -1859,7 +1876,7 @@ vm_object_page_remove(vm_object_t object, vm_pindex_t start, vm_pindex_t end,
* however, be invalidated if the option OBJPR_CLEANONLY is
* not specified.
*/
if (vm_page_busied(p)) {
if (vm_page_tryxbusy(p) == 0) {
vm_page_sleep_if_busy(p, "vmopar");
goto again;
}
@ -1872,6 +1889,7 @@ vm_object_page_remove(vm_object_t object, vm_pindex_t start, vm_pindex_t end,
p->valid = 0;
vm_page_undirty(p);
}
vm_page_xunbusy(p);
continue;
}
KASSERT((p->flags & PG_FICTITIOUS) == 0,
@ -1881,8 +1899,10 @@ vm_object_page_remove(vm_object_t object, vm_pindex_t start, vm_pindex_t end,
object->ref_count != 0 &&
!vm_page_try_remove_write(p))
goto wired;
if (p->dirty != 0)
if (p->dirty != 0) {
vm_page_xunbusy(p);
continue;
}
}
if ((options & OBJPR_NOTMAPPED) == 0 &&
object->ref_count != 0 && !vm_page_try_remove_all(p))
@ -2168,7 +2188,7 @@ vm_object_unwire(vm_object_t object, vm_ooffset_t offset, vm_size_t length,
tm = m;
m = TAILQ_NEXT(m, listq);
}
if (vm_page_xbusied(tm)) {
if (vm_page_trysbusy(tm) == 0) {
for (tobject = object; locked_depth >= 1;
locked_depth--) {
t1object = tobject->backing_object;
@ -2180,6 +2200,7 @@ vm_object_unwire(vm_object_t object, vm_ooffset_t offset, vm_size_t length,
goto again;
}
vm_page_unwire(tm, queue);
vm_page_sunbusy(tm);
next_page:
pindex++;
}

90
sys/vm/vm_page.c
View File

@ -971,6 +971,32 @@ vm_page_busy_downgrade(vm_page_t m)
wakeup(m);
}
/*
*
* vm_page_busy_tryupgrade:
*
* Attempt to upgrade a single shared busy into an exclusive busy.
*/
int
vm_page_busy_tryupgrade(vm_page_t m)
{
u_int x;
vm_page_assert_sbusied(m);
x = m->busy_lock;
for (;;) {
if (VPB_SHARERS(x) > 1)
return (0);
KASSERT((x & ~VPB_BIT_WAITERS) == VPB_SHARERS_WORD(1),
("vm_page_busy_tryupgrade: invalid lock state"));
if (!atomic_fcmpset_acq_int(&m->busy_lock, &x,
VPB_SINGLE_EXCLUSIVER | (x & VPB_BIT_WAITERS)))
continue;
return (1);
}
}
/*
* vm_page_sbusied:
*
@ -2570,7 +2596,12 @@ vm_page_reclaim_run(int req_class, int domain, u_long npages, vm_page_t m_run,
else if (object->memattr != VM_MEMATTR_DEFAULT)
error = EINVAL;
else if (vm_page_queue(m) != PQ_NONE &&
!vm_page_busied(m) && !vm_page_wired(m)) {
vm_page_tryxbusy(m) != 0) {
if (vm_page_wired(m)) {
vm_page_xunbusy(m);
error = EBUSY;
goto unlock;
}
KASSERT(pmap_page_get_memattr(m) ==
VM_MEMATTR_DEFAULT,
("page %p has an unexpected memattr", m));
@ -2616,6 +2647,7 @@ vm_page_reclaim_run(int req_class, int domain, u_long npages, vm_page_t m_run,
VM_MEMATTR_DEFAULT);
}
if (m_new == NULL) {
vm_page_xunbusy(m);
error = ENOMEM;
goto unlock;
}
@ -2647,7 +2679,6 @@ vm_page_reclaim_run(int req_class, int domain, u_long npages, vm_page_t m_run,
m_new->valid = m->valid;
m_new->dirty = m->dirty;
m->flags &= ~PG_ZERO;
vm_page_xbusy(m);
vm_page_dequeue(m);
vm_page_replace_checked(m_new, object,
m->pindex, m);
@ -4046,8 +4077,8 @@ vm_page_try_blocked_op(vm_page_t m, void (*op)(vm_page_t))
KASSERT(m->object != NULL && (m->oflags & VPO_UNMANAGED) == 0,
("vm_page_try_blocked_op: page %p has no object", m));
KASSERT(!vm_page_busied(m),
("vm_page_try_blocked_op: page %p is busy", m));
KASSERT(vm_page_busied(m),
("vm_page_try_blocked_op: page %p is not busy", m));
VM_OBJECT_ASSERT_LOCKED(m->object);
old = m->ref_count;
@ -4163,13 +4194,18 @@ vm_page_grab(vm_object_t object, vm_pindex_t pindex, int allocflags)
(allocflags & VM_ALLOC_IGN_SBUSY) != 0,
("vm_page_grab: VM_ALLOC_SBUSY/VM_ALLOC_IGN_SBUSY mismatch"));
pflags = allocflags &
~(VM_ALLOC_NOWAIT | VM_ALLOC_WAITOK | VM_ALLOC_WAITFAIL);
~(VM_ALLOC_NOWAIT | VM_ALLOC_WAITOK | VM_ALLOC_WAITFAIL |
VM_ALLOC_NOBUSY);
if ((allocflags & VM_ALLOC_NOWAIT) == 0)
pflags |= VM_ALLOC_WAITFAIL;
if ((allocflags & VM_ALLOC_IGN_SBUSY) != 0)
pflags |= VM_ALLOC_SBUSY;
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 ((allocflags & (VM_ALLOC_IGN_SBUSY | VM_ALLOC_SBUSY)) != 0)
sleep = !vm_page_trysbusy(m);
else
sleep = !vm_page_tryxbusy(m);
if (sleep) {
if ((allocflags & VM_ALLOC_NOWAIT) != 0)
return (NULL);
@ -4189,12 +4225,7 @@ vm_page_grab(vm_object_t object, vm_pindex_t pindex, int allocflags)
} else {
if ((allocflags & VM_ALLOC_WIRED) != 0)
vm_page_wire(m);
if ((allocflags &
(VM_ALLOC_NOBUSY | VM_ALLOC_SBUSY)) == 0)
vm_page_xbusy(m);
else if ((allocflags & VM_ALLOC_SBUSY) != 0)
vm_page_sbusy(m);
return (m);
goto out;
}
}
if ((allocflags & VM_ALLOC_NOCREAT) != 0)
@ -4207,6 +4238,14 @@ vm_page_grab(vm_object_t object, vm_pindex_t pindex, int allocflags)
}
if (allocflags & VM_ALLOC_ZERO && (m->flags & PG_ZERO) == 0)
pmap_zero_page(m);
out:
if ((allocflags & VM_ALLOC_NOBUSY) != 0) {
if ((allocflags & VM_ALLOC_IGN_SBUSY) != 0)
vm_page_sunbusy(m);
else
vm_page_xunbusy(m);
}
return (m);
}
@ -4359,10 +4398,13 @@ vm_page_grab_pages(vm_object_t object, vm_pindex_t pindex, int allocflags,
("vm_page_grab_pages: VM_ALLOC_SBUSY/IGN_SBUSY mismatch"));
if (count == 0)
return (0);
pflags = allocflags & ~(VM_ALLOC_NOWAIT | VM_ALLOC_WAITOK |
VM_ALLOC_WAITFAIL | VM_ALLOC_IGN_SBUSY);
pflags = allocflags &
~(VM_ALLOC_NOWAIT | VM_ALLOC_WAITOK | VM_ALLOC_WAITFAIL |
VM_ALLOC_NOBUSY);
if ((allocflags & VM_ALLOC_NOWAIT) == 0)
pflags |= VM_ALLOC_WAITFAIL;
if ((allocflags & VM_ALLOC_IGN_SBUSY) != 0)
pflags |= VM_ALLOC_SBUSY;
i = 0;
retrylookup:
m = vm_radix_lookup_le(&object->rtree, pindex + i);
@ -4373,8 +4415,11 @@ vm_page_grab_pages(vm_object_t object, vm_pindex_t pindex, int allocflags,
mpred = TAILQ_PREV(m, pglist, listq);
for (; i < count; i++) {
if (m != NULL) {
sleep = (allocflags & VM_ALLOC_IGN_SBUSY) != 0 ?
vm_page_xbusied(m) : vm_page_busied(m);
if ((allocflags &
(VM_ALLOC_SBUSY | VM_ALLOC_IGN_SBUSY)) != 0)
sleep = !vm_page_trysbusy(m);
else
sleep = !vm_page_tryxbusy(m);
if (sleep) {
if ((allocflags & VM_ALLOC_NOWAIT) != 0)
break;
@ -4392,11 +4437,6 @@ vm_page_grab_pages(vm_object_t object, vm_pindex_t pindex, int allocflags,
}
if ((allocflags & VM_ALLOC_WIRED) != 0)
vm_page_wire(m);
if ((allocflags & (VM_ALLOC_NOBUSY |
VM_ALLOC_SBUSY)) == 0)
vm_page_xbusy(m);
if ((allocflags & VM_ALLOC_SBUSY) != 0)
vm_page_sbusy(m);
} else {
if ((allocflags & VM_ALLOC_NOCREAT) != 0)
break;
@ -4413,6 +4453,12 @@ vm_page_grab_pages(vm_object_t object, vm_pindex_t pindex, int allocflags,
pmap_zero_page(m);
m->valid = VM_PAGE_BITS_ALL;
}
if ((allocflags & VM_ALLOC_NOBUSY) != 0) {
if ((allocflags & VM_ALLOC_IGN_SBUSY) != 0)
vm_page_sunbusy(m);
else
vm_page_xunbusy(m);
}
ma[i] = mpred = m;
m = vm_page_next(m);
}

1
sys/vm/vm_page.h
View File

@ -542,6 +542,7 @@ malloc2vm_flags(int malloc_flags)
int vm_page_busy_acquire(vm_page_t m, int allocflags);
void vm_page_busy_downgrade(vm_page_t m);
int vm_page_busy_tryupgrade(vm_page_t m);
void vm_page_busy_sleep(vm_page_t m, const char *msg, bool nonshared);
void vm_page_free(vm_page_t m);
void vm_page_free_zero(vm_page_t m);

57
sys/vm/vm_pageout.c
View File

@ -334,7 +334,7 @@ vm_pageout_cluster(vm_page_t m)
VM_OBJECT_ASSERT_WLOCKED(object);
pindex = m->pindex;
vm_page_assert_unbusied(m);
vm_page_assert_xbusied(m);
mc[vm_pageout_page_count] = pb = ps = m;
pageout_count = 1;
@ -360,19 +360,26 @@ vm_pageout_cluster(vm_page_t m)
ib = 0;
break;
}
if ((p = vm_page_prev(pb)) == NULL || vm_page_busied(p) ||
vm_page_wired(p)) {
if ((p = vm_page_prev(pb)) == NULL ||
vm_page_tryxbusy(p) == 0) {
ib = 0;
break;
}
if (vm_page_wired(p)) {
ib = 0;
vm_page_xunbusy(p);
break;
}
vm_page_test_dirty(p);
if (p->dirty == 0) {
ib = 0;
vm_page_xunbusy(p);
break;
}
vm_page_lock(p);
if (!vm_page_in_laundry(p) || !vm_page_try_remove_write(p)) {
vm_page_unlock(p);
vm_page_xunbusy(p);
ib = 0;
break;
}
@ -390,15 +397,22 @@ vm_pageout_cluster(vm_page_t m)
}
while (pageout_count < vm_pageout_page_count &&
pindex + is < object->size) {
if ((p = vm_page_next(ps)) == NULL || vm_page_busied(p) ||
vm_page_wired(p))
if ((p = vm_page_next(ps)) == NULL ||
vm_page_tryxbusy(p) == 0)
break;
if (vm_page_wired(p)) {
vm_page_xunbusy(p);
break;
}
vm_page_test_dirty(p);
if (p->dirty == 0)
if (p->dirty == 0) {
vm_page_xunbusy(p);
break;
}
vm_page_lock(p);
if (!vm_page_in_laundry(p) || !vm_page_try_remove_write(p)) {
vm_page_unlock(p);
vm_page_xunbusy(p);
break;
}
vm_page_unlock(p);
@ -445,8 +459,8 @@ vm_pageout_flush(vm_page_t *mc, int count, int flags, int mreq, int *prunlen,
VM_OBJECT_ASSERT_WLOCKED(object);
/*
* Initiate I/O. Mark the pages busy and verify that they're valid
* and read-only.
* Initiate I/O. Mark the pages shared busy and verify that they're
* valid and read-only.
*
* We do not have to fixup the clean/dirty bits here... we can
* allow the pager to do it after the I/O completes.
@ -460,7 +474,7 @@ vm_pageout_flush(vm_page_t *mc, int count, int flags, int mreq, int *prunlen,
mc[i], i, count));
KASSERT((mc[i]->aflags & PGA_WRITEABLE) == 0,
("vm_pageout_flush: writeable page %p", mc[i]));
vm_page_sbusy(mc[i]);
vm_page_busy_downgrade(mc[i]);
}
vm_object_pip_add(object, count);
@ -598,6 +612,7 @@ vm_pageout_clean(vm_page_t m, int *numpagedout)
*/
if (object->type == OBJT_VNODE) {
vm_page_unlock(m);
vm_page_xunbusy(m);
vp = object->handle;
if (vp->v_type == VREG &&
vn_start_write(vp, &mp, V_NOWAIT) != 0) {
@ -648,7 +663,7 @@ vm_pageout_clean(vm_page_t m, int *numpagedout)
* The page may have been busied while the object and page
* locks were released.
*/
if (vm_page_busied(m)) {
if (vm_page_tryxbusy(m) == 0) {
vm_page_unlock(m);
error = EBUSY;
goto unlock_all;
@ -659,6 +674,7 @@ vm_pageout_clean(vm_page_t m, int *numpagedout)
* Remove all writeable mappings, failing if the page is wired.
*/
if (!vm_page_try_remove_write(m)) {
vm_page_xunbusy(m);
vm_page_unlock(m);
error = EBUSY;
goto unlock_all;
@ -792,7 +808,7 @@ vm_pageout_launder(struct vm_domain *vmd, int launder, bool in_shortfall)
KASSERT(m->object == object, ("page %p does not belong to %p",
m, object));
if (vm_page_busied(m))
if (vm_page_tryxbusy(m) == 0)
continue;
/*
@ -804,6 +820,7 @@ vm_pageout_launder(struct vm_domain *vmd, int launder, bool in_shortfall)
* wire count is guaranteed not to increase.
*/
if (__predict_false(vm_page_wired(m))) {
vm_page_xunbusy(m);
vm_page_dequeue_deferred(m);
continue;
}
@ -837,6 +854,7 @@ vm_pageout_launder(struct vm_domain *vmd, int launder, bool in_shortfall)
}
if (act_delta != 0) {
if (object->ref_count != 0) {
vm_page_xunbusy(m);
VM_CNT_INC(v_reactivated);
vm_page_activate(m);
@ -861,6 +879,7 @@ vm_pageout_launder(struct vm_domain *vmd, int launder, bool in_shortfall)
launder--;
continue;
} else if ((object->flags & OBJ_DEAD) == 0) {
vm_page_xunbusy(m);
vm_page_requeue(m);
continue;
}
@ -876,6 +895,7 @@ vm_pageout_launder(struct vm_domain *vmd, int launder, bool in_shortfall)
if (object->ref_count != 0) {
vm_page_test_dirty(m);
if (m->dirty == 0 && !vm_page_try_remove_all(m)) {
vm_page_xunbusy(m);
vm_page_dequeue_deferred(m);
continue;
}
@ -900,6 +920,7 @@ vm_pageout_launder(struct vm_domain *vmd, int launder, bool in_shortfall)
else
pageout_ok = true;
if (!pageout_ok) {
vm_page_xunbusy(m);
vm_page_requeue(m);
continue;
}
@ -927,7 +948,8 @@ vm_pageout_launder(struct vm_domain *vmd, int launder, bool in_shortfall)
}
mtx = NULL;
object = NULL;
}
} else
vm_page_xunbusy(m);
}
if (mtx != NULL) {
mtx_unlock(mtx);
@ -1507,7 +1529,7 @@ vm_pageout_scan_inactive(struct vm_domain *vmd, int shortage,
KASSERT(m->object == object, ("page %p does not belong to %p",
m, object));
if (vm_page_busied(m)) {
if (vm_page_tryxbusy(m) == 0) {
/*
* Don't mess with busy pages. Leave them at
* the front of the queue. Most likely, they
@ -1529,6 +1551,7 @@ vm_pageout_scan_inactive(struct vm_domain *vmd, int shortage,
* wire count is guaranteed not to increase.
*/
if (__predict_false(vm_page_wired(m))) {
vm_page_xunbusy(m);
vm_page_dequeue_deferred(m);
continue;
}
@ -1562,6 +1585,7 @@ vm_pageout_scan_inactive(struct vm_domain *vmd, int shortage,
}
if (act_delta != 0) {
if (object->ref_count != 0) {
vm_page_xunbusy(m);
VM_CNT_INC(v_reactivated);
vm_page_activate(m);
@ -1575,6 +1599,7 @@ vm_pageout_scan_inactive(struct vm_domain *vmd, int shortage,
m->act_count += act_delta + ACT_ADVANCE;
continue;
} else if ((object->flags & OBJ_DEAD) == 0) {
vm_page_xunbusy(m);
vm_page_aflag_set(m, PGA_REQUEUE);
goto reinsert;
}
@ -1590,6 +1615,7 @@ vm_pageout_scan_inactive(struct vm_domain *vmd, int shortage,
if (object->ref_count != 0) {
vm_page_test_dirty(m);
if (m->dirty == 0 && !vm_page_try_remove_all(m)) {
vm_page_xunbusy(m);
vm_page_dequeue_deferred(m);
continue;
}
@ -1615,7 +1641,10 @@ vm_pageout_scan_inactive(struct vm_domain *vmd, int shortage,
m->queue = PQ_NONE;
vm_page_free(m);
page_shortage--;
} else if ((object->flags & OBJ_DEAD) == 0)
continue;
}
vm_page_xunbusy(m);
if ((object->flags & OBJ_DEAD) == 0)
vm_page_launder(m);
continue;
reinsert:

11
sys/vm/vm_swapout.c
View File

@ -208,6 +208,9 @@ vm_swapout_object_deactivate_pages(pmap_t pmap, vm_object_t first_object,
goto unlock_return;
if (should_yield())
goto unlock_return;
if (vm_page_tryxbusy(p) == 0)
continue;
VM_CNT_INC(v_pdpages);
/*
* The page may acquire a wiring after this check.
@ -215,11 +218,10 @@ vm_swapout_object_deactivate_pages(pmap_t pmap, vm_object_t first_object,
* no harm done if a wiring appears while we are
* attempting to deactivate the page.
*/
if (vm_page_busied(p) || vm_page_wired(p))
continue;
VM_CNT_INC(v_pdpages);
if (!pmap_page_exists_quick(pmap, p))
if (vm_page_wired(p) || !pmap_page_exists_quick(pmap, p)) {
vm_page_xunbusy(p);
continue;
}
act_delta = pmap_ts_referenced(p);
vm_page_lock(p);
if ((p->aflags & PGA_REFERENCED) != 0) {
@ -251,6 +253,7 @@ vm_swapout_object_deactivate_pages(pmap_t pmap, vm_object_t first_object,
} else if (vm_page_inactive(p))
(void)vm_page_try_remove_all(p);
vm_page_unlock(p);
vm_page_xunbusy(p);
}
if ((backing_object = object->backing_object) == NULL)
goto unlock_return;