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

Stephen C. Tweedie sct at redhat.com
Fri Apr 23 17:06:17 UTC 2004


On Wed, 2004-04-21 at 11:29, Jan Kara wrote:

> > That's only part of the problem: a million dquots on a single sb will
> > still show this performance degradation currently.  Rotating the list
> > head after each progress will make sure that even if we are processing
> > unnecessary dquots, we at least do so only once per sync (which is way
> > better than 0.5*N^2 times!)

>   If I have dirty dquot list for sb+type (which is what I actually have)
> then I just always get first entry from the list, sync it, delete it and
> continue.. This way I will have the same asymptotic performance as with
> moving on inuse_list (ie. O(N)), no? And I will get some constant bonus
> for smaller list... Or do I miss something?

Never mind me, I was reading your email as suggesting per-sb quota
lists, not per-sb *dirty* quota lists.  With new lists specifically for
dirty dquots the problem clearly goes away, yes.


> 								Honza
Stephen C. Tweedie <sct at redhat.com>

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