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    SubjectRe: [patch] voluntary-preempt-2.6.8.1-P9
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    On Sat, 2004-08-28 at 03:37, Ingo Molnar wrote:
    > * Lee Revell <rlrevell@joe-job.com> wrote:
    >
    > > I am seeing large latencies (600-2000 usec) latencies in
    > > dcache_readdir. This started when the machine became a Samba server
    > > and the dcache presumably got large. Traces are at the above url (8
    > > and 9 I believe). I think this patch fixes it.
    > >
    > > --- fs/libfs.c~ 2004-08-14 06:54:47.000000000 -0400
    > > +++ fs/libfs.c 2004-08-27 00:44:17.000000000 -0400
    > > @@ -140,6 +140,7 @@
    > > }
    > > for (p=q->next; p != &dentry->d_subdirs; p=p->next) {
    > > struct dentry *next;
    > > + voluntary_resched_lock(&dcache_lock);
    > > next = list_entry(p, struct dentry, d_child);
    > > if (d_unhashed(next) || !next->d_inode)
    > > continue;
    >
    > In this loop we are iterating over the child-directories of this
    > directory. In the next line (not shown in this patch) we drop the
    > dcache_lock - so the issue is the 'continue' - where we skip already
    > deleted entries. Are you positive this fixes the latencies you are
    > seeing? The 'deleted entries' situation ought to be relatively rare.

    No, I am not sure this fixes the problem. This is a pretty rare one, I
    only saw it twice. I have not seen it since making the above change,
    but this doesn't mean anything.

    Lee

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