diff options
author | alc <alc@FreeBSD.org> | 2004-11-03 20:17:31 +0000 |
---|---|---|
committer | alc <alc@FreeBSD.org> | 2004-11-03 20:17:31 +0000 |
commit | 25b80a64b9fc30297401a041a69a8229872b01c4 (patch) | |
tree | 424cbe6b795ce744b46e7a81db98175896cc5a16 /sys/vm/vm_pageout.c | |
parent | d083dba3a2fbaeb254502ed1ca0893eb4a5aae14 (diff) | |
download | FreeBSD-src-25b80a64b9fc30297401a041a69a8229872b01c4.zip FreeBSD-src-25b80a64b9fc30297401a041a69a8229872b01c4.tar.gz |
The synchronization provided by vm object locking has eliminated the
need for most calls to vm_page_busy(). Specifically, most calls to
vm_page_busy() occur immediately prior to a call to vm_page_remove().
In such cases, the containing vm object is locked across both calls.
Consequently, the setting of the vm page's PG_BUSY flag is not even
visible to other threads that are following the synchronization
protocol.
This change (1) eliminates the calls to vm_page_busy() that
immediately precede a call to vm_page_remove() or functions, such as
vm_page_free() and vm_page_rename(), that call it and (2) relaxes the
requirement in vm_page_remove() that the vm page's PG_BUSY flag is
set. Now, the vm page's PG_BUSY flag is set only when the vm object
lock is released while the vm page is still in transition. Typically,
this is when it is undergoing I/O.
Diffstat (limited to 'sys/vm/vm_pageout.c')
-rw-r--r-- | sys/vm/vm_pageout.c | 2 |
1 files changed, 0 insertions, 2 deletions
diff --git a/sys/vm/vm_pageout.c b/sys/vm/vm_pageout.c index 3d21c1f..cfb9eab 100644 --- a/sys/vm/vm_pageout.c +++ b/sys/vm/vm_pageout.c @@ -823,7 +823,6 @@ rescan0: /* * Invalid pages can be easily freed */ - vm_page_busy(m); pmap_remove_all(m); vm_page_free(m); cnt.v_dfree++; @@ -1107,7 +1106,6 @@ unlock_and_continue: cache_rover = (m->pc + PQ_PRIME2) & PQ_L2_MASK; object = m->object; VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); - vm_page_busy(m); vm_page_free(m); VM_OBJECT_UNLOCK(object); cnt.v_dfree++; |