cvs commit: src/sys/sys buf.h src/sys/kern vfs_bio.c
src/sys/nfsclient nfs_bio.c src/sys/ufs/ffs ffs_vnops.c
jeff at FreeBSD.org
Thu Nov 18 08:44:10 GMT 2004
jeff 2004-11-18 08:44:09 UTC
FreeBSD src repository
- Eliminate the acquisition and release of the bqlock in bremfree() by
setting the B_REMFREE flag in the buf. This is done to prevent lock order
reversals with code that must call bremfree() with a local lock held.
This also reduces overhead by removing two lock operations per buf for
fsync() and similar.
- Check for the B_REMFREE flag in brelse() and bqrelse() after the bqlock
has been acquired so that we may remove ourself from the free-list.
- Provide a bremfreef() function to immediately remove a buf from a
free-list for use only by NFS. This is done because the nfsclient code
overloads the b_freelist queue for its own async. io queue.
- Simplify the numfreebuffers accounting by removing a switch statement
that executed the same code in every possible case.
- getnewbuf() can encounter locked bufs on free-lists once Giant is removed.
Remove a panic associated with this condition and delay asserts that
inspect the buf until after it is locked.
Reviewed by: phk
Sponsored by: Isilon Systems, Inc.
Revision Changes Path
1.469 +66 -38 src/sys/kern/vfs_bio.c
1.140 +2 -0 src/sys/nfsclient/nfs_bio.c
1.181 +2 -1 src/sys/sys/buf.h
1.142 +2 -1 src/sys/ufs/ffs/ffs_vnops.c
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