Date: Fri, 26 Feb 1999 16:19:11 -0800 (PST) From: Matthew Dillon <dillon@apollo.backplane.com> To: Matthew Jacob <mjacob@feral.com>, freebsd-hackers@FreeBSD.ORG Subject: Re: Panic in FFS/4.0 as of yesterday - update Message-ID: <199902270019.QAA20214@apollo.backplane.com> References: <Pine.LNX.4.04.9902260950020.985-100000@feral-gw>
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:: Pop the patch at 1:00 p.m. today. By then I should have an update.
:: The one I have now is very close - just a couple of missing wakeups.
:
: This patch seems to fix buildworld. I ran Matt Jacob's STEST and managed
: to lock it up -- looks like flushdirtybuffers() needs to allow the syncer
: to get in whether or not some other process is flushing dirty buffers
: at the same time.
:
: I'll have another update to vfs_bio on my site at around 4:00 p.m.
: -Matt
Ugh. inode lock now - if a process has a lock on an inode and then blocks
in getnewbuf(), the syncer can still allocate buffers but can deadlock
trying to lock the inode.
I'll bet the inode lockup reported a few days ago under heavy test loads
is due to this problem too.
I think the solution may be to have the syncer reschedule a vnode which
it finds locked rather then block getting the lock as it does now.
( excerpt from kern/vfs_subr.c, sched_sync() )
splx(s);
while ((vp = LIST_FIRST(slp)) != NULL) {
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p);
(void) VOP_FSYNC(vp, p->p_ucred, MNT_LAZY, p);
VOP_UNLOCK(vp, 0, p);
s = splbio();
if (LIST_FIRST(slp) == vp) {
...
-Matt
Matthew Dillon
<dillon@backplane.com>
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