diff options
author | alc <alc@FreeBSD.org> | 2010-05-02 17:33:46 +0000 |
---|---|---|
committer | alc <alc@FreeBSD.org> | 2010-05-02 17:33:46 +0000 |
commit | f35e97166b133de28351ffee3f6de3407d0272b7 (patch) | |
tree | 800dba3ed92fa905f4e1acbc91746a06e2e47bc9 /sys | |
parent | 1b4eb78965d8d551d4997edd6125fd401a212f5b (diff) | |
download | FreeBSD-src-f35e97166b133de28351ffee3f6de3407d0272b7.zip FreeBSD-src-f35e97166b133de28351ffee3f6de3407d0272b7.tar.gz |
It makes no sense for vm_page_sleep_if_busy()'s helper, vm_page_sleep(),
to unconditionally set PG_REFERENCED on a page before sleeping. In many
cases, it's perfectly ok for the page to disappear, i.e., be reclaimed by
the page daemon, before the caller to vm_page_sleep() is reawakened.
Instead, we now explicitly set PG_REFERENCED in those cases where having
the page persist until the caller is awakened is clearly desirable. Note,
however, that setting PG_REFERENCED on the page is still only a hint,
and not a guarantee that the page should persist.
Diffstat (limited to 'sys')
-rw-r--r-- | sys/fs/tmpfs/tmpfs_vnops.c | 30 | ||||
-rw-r--r-- | sys/kern/vfs_bio.c | 11 | ||||
-rw-r--r-- | sys/vm/vm_fault.c | 6 | ||||
-rw-r--r-- | sys/vm/vm_page.c | 25 |
4 files changed, 59 insertions, 13 deletions
diff --git a/sys/fs/tmpfs/tmpfs_vnops.c b/sys/fs/tmpfs/tmpfs_vnops.c index c17efff..3d3755d 100644 --- a/sys/fs/tmpfs/tmpfs_vnops.c +++ b/sys/fs/tmpfs/tmpfs_vnops.c @@ -516,8 +516,16 @@ tmpfs_mappedread(vm_object_t vobj, vm_object_t tobj, size_t len, struct uio *uio lookupvpg: if (((m = vm_page_lookup(vobj, idx)) != NULL) && vm_page_is_valid(m, offset, tlen)) { - if (vm_page_sleep_if_busy(m, FALSE, "tmfsmr")) + if ((m->oflags & VPO_BUSY) != 0) { + /* + * Reference the page before unlocking and sleeping so + * that the page daemon is less likely to reclaim it. + */ + vm_page_lock_queues(); + vm_page_flag_set(m, PG_REFERENCED); + vm_page_sleep(m, "tmfsmr"); goto lookupvpg; + } vm_page_busy(m); VM_OBJECT_UNLOCK(vobj); error = uiomove_fromphys(&m, offset, tlen, uio); @@ -526,8 +534,16 @@ lookupvpg: VM_OBJECT_UNLOCK(vobj); return (error); } else if (m != NULL && uio->uio_segflg == UIO_NOCOPY) { - if (vm_page_sleep_if_busy(m, FALSE, "tmfsmr")) + if ((m->oflags & VPO_BUSY) != 0) { + /* + * Reference the page before unlocking and sleeping so + * that the page daemon is less likely to reclaim it. + */ + vm_page_lock_queues(); + vm_page_flag_set(m, PG_REFERENCED); + vm_page_sleep(m, "tmfsmr"); goto lookupvpg; + } vm_page_busy(m); VM_OBJECT_UNLOCK(vobj); sched_pin(); @@ -627,8 +643,16 @@ tmpfs_mappedwrite(vm_object_t vobj, vm_object_t tobj, size_t len, struct uio *ui lookupvpg: if (((vpg = vm_page_lookup(vobj, idx)) != NULL) && vm_page_is_valid(vpg, offset, tlen)) { - if (vm_page_sleep_if_busy(vpg, FALSE, "tmfsmw")) + if ((vpg->oflags & VPO_BUSY) != 0) { + /* + * Reference the page before unlocking and sleeping so + * that the page daemon is less likely to reclaim it. + */ + vm_page_lock_queues(); + vm_page_flag_set(vpg, PG_REFERENCED); + vm_page_sleep(vpg, "tmfsmw"); goto lookupvpg; + } vm_page_busy(vpg); vm_page_lock_queues(); vm_page_undirty(vpg); diff --git a/sys/kern/vfs_bio.c b/sys/kern/vfs_bio.c index ea846a5..dbcd6e8 100644 --- a/sys/kern/vfs_bio.c +++ b/sys/kern/vfs_bio.c @@ -3024,8 +3024,17 @@ allocbuf(struct buf *bp, int size) * vm_fault->getpages->cluster_read->allocbuf * */ - if (vm_page_sleep_if_busy(m, FALSE, "pgtblk")) + if ((m->oflags & VPO_BUSY) != 0) { + /* + * Reference the page before unlocking + * and sleeping so that the page daemon + * is less likely to reclaim it. + */ + vm_page_lock_queues(); + vm_page_flag_set(m, PG_REFERENCED); + vm_page_sleep(m, "pgtblk"); continue; + } /* * We have a good page. diff --git a/sys/vm/vm_fault.c b/sys/vm/vm_fault.c index d9cf63e..5ee4ab4 100644 --- a/sys/vm/vm_fault.c +++ b/sys/vm/vm_fault.c @@ -338,6 +338,12 @@ RetryFault:; * to pmap it. */ if ((fs.m->oflags & VPO_BUSY) || fs.m->busy) { + /* + * Reference the page before unlocking and + * sleeping so that the page daemon is less + * likely to reclaim it. + */ + vm_page_flag_set(fs.m, PG_REFERENCED); vm_page_unlock_queues(); vm_page_unlock(fs.m); VM_OBJECT_UNLOCK(fs.object); diff --git a/sys/vm/vm_page.c b/sys/vm/vm_page.c index fb0950e..e73586a 100644 --- a/sys/vm/vm_page.c +++ b/sys/vm/vm_page.c @@ -599,7 +599,7 @@ vm_page_free_zero(vm_page_t m) /* * vm_page_sleep: * - * Sleep and release the page queues lock. + * Sleep and release the page and page queues locks. * * The object containing the given page must be locked. */ @@ -608,13 +608,10 @@ vm_page_sleep(vm_page_t m, const char *msg) { VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); - if (!mtx_owned(vm_page_lockptr(m))) - vm_page_lock(m); - if (!mtx_owned(&vm_page_queue_mtx)) - vm_page_lock_queues(); - vm_page_flag_set(m, PG_REFERENCED); - vm_page_unlock_queues(); - vm_page_unlock(m); + if (mtx_owned(&vm_page_queue_mtx)) + vm_page_unlock_queues(); + if (mtx_owned(vm_page_lockptr(m))) + vm_page_unlock(m); /* * It's possible that while we sleep, the page will get @@ -1896,7 +1893,17 @@ vm_page_grab(vm_object_t object, vm_pindex_t pindex, int allocflags) VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); retrylookup: if ((m = vm_page_lookup(object, pindex)) != NULL) { - if (vm_page_sleep_if_busy(m, TRUE, "pgrbwt")) { + if ((m->oflags & VPO_BUSY) != 0 || m->busy != 0) { + if ((allocflags & VM_ALLOC_RETRY) != 0) { + /* + * Reference the page before unlocking and + * sleeping so that the page daemon is less + * likely to reclaim it. + */ + vm_page_lock_queues(); + vm_page_flag_set(m, PG_REFERENCED); + } + vm_page_sleep(m, "pgrbwt"); if ((allocflags & VM_ALLOC_RETRY) == 0) return (NULL); goto retrylookup; |