diff options
| author |   gluk <gluk@openbsd.org> | 2001-04-06 19:10:49 +0000 |
|---|---|---|
| committer | gluk <gluk@openbsd.org> | 2001-04-06 19:10:49 +0000 |
| commit | b0132761a3f4b304ae3461d2e519590dcbc3b3df (patch) | |
| tree | 9e6bfb6f76ec2570e295d253843a11a0c84458d7 | |
| parent | Change softdep_count_dependencies interface so that it may be called (diff) | |
| download | wireguard-openbsd-b0132761a3f4b304ae3461d2e519590dcbc3b3df.tar.xz wireguard-openbsd-b0132761a3f4b304ae3461d2e519590dcbc3b3df.zip | |
Avoid a livelock problem where the buffer cache code would be
recycling B_AGE buffers with dependencies.
>From NetBSD. costa@ ok.
| -rw-r--r-- | sys/kern/vfs_bio.c | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/sys/kern/vfs_bio.c b/sys/kern/vfs_bio.c index 5ba80311513..7749cef7a09 100644 --- a/sys/kern/vfs_bio.c +++ b/sys/kern/vfs_bio.c @@ -1,4 +1,4 @@ -/* $OpenBSD: vfs_bio.c,v 1.36 2001/03/30 10:30:26 art Exp $ */ +/* $OpenBSD: vfs_bio.c,v 1.37 2001/04/06 19:10:49 gluk Exp $ */ /* $NetBSD: vfs_bio.c,v 1.44 1996/06/11 11:15:36 pk Exp $ */ /*- @@ -588,6 +588,10 @@ brelse(bp) /* * It has valid data. Put it on the end of the appropriate * queue, so that it'll stick around for as long as possible. + * If buf is AGE, but has dependencies, must put it on last + * bufqueue to be scanned, ie LRU. This protects against the + * livelock where BQ_AGE only has buffers with dependencies, + * and we thus never get to the dependent buffers in BQ_LRU. */ if (ISSET(bp->b_flags, B_LOCKED)) /* locked in core */ @@ -598,7 +602,8 @@ brelse(bp) numcleanbufs++; if (ISSET(bp->b_flags, B_AGE)) /* stale but valid data */ - bufq = &bufqueues[BQ_AGE]; + bufq = buf_countdeps(bp, 0, 1) ? + &bufqueues[BQ_LRU] : &bufqueues[BQ_AGE]; else /* valid data */ bufq = &bufqueues[BQ_LRU]; |