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Re: [patch] Re: stalled 'sync' on ext3+quota over drbd



Hi,

On Mon, 2004-04-19 at 19:27, Eugene Crosser wrote:

> > From the first impression, it did not help.
> 
> Luckily, I was wrong.  At least on the test environment I get the
> results below.  This is 2.6.5 kernel with euivalent of Stephen's patch. 
> 'setquota' sets user and group quota for 40,000 userids and 40,000
> groupids.  'mktree' writes one byte into 40,000 files and sets their
> owner and group to 40,000 unique values.
> 
> 			unpatched		patched
> sync			7m50			0m0.8

OK, that's a win. :-)

> On my 'big' system sync still runs unexpectedly long (40sec - 4min) but
> it is by far better than it was before the patch...

That's quote possibly just the raw cost of writing out a million
dquots.  The overhead of the list traversal should be under control now,
though.  A profile would help determine what the remaining cost is: is
that time spent in the CPU, or in IO wait?

Jan, mind if I push the patch to 2.4?  Your locking concern seems to be
2.6-only; on 2.4, BKL should be sufficient protection even on SMP.

Cheers,
 Stephen



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