Re: [patch] voluntary-preempt-2.6.8.1-P9

Lee Revell
2004-08-27T16:54:36Z

On Thu, 2004-08-26 at 17:39, Lee Revell wrote:
> On Tue, 2004-08-24 at 02:14, Ingo Molnar wrote:
>
> > http://redhat.com/~mingo/voluntary-preempt/voluntary-preempt-2.6.8.1-P9
> >
>
> Hmm, it seems that those strange ~1ms latencies are back. This was
> triggered by mounting an NTFS volume:
>
> http://krustophenia.net/testresults.php?dataset=2.6.8.1-P9#/var/www/2.6.8.1-P9/trace5.txt
>

I think vger was messed up yesterday, as this did not get through the
first time I sent it, and I did not get any messages from the list for
4-5 hours last night.

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;

Lee