Date: Tue, 29 Jul 2003 22:19:28 +0000 From: Bosko Milekic <bmilekic@technokratis.com> To: Tor.Egge@cvsup.no.freebsd.org Cc: current@freebsd.org Subject: Re: HEADSUP: UMA not reentrant / possible memory leak Message-ID: <20030729221928.GA54757@technokratis.com> In-Reply-To: <20030730012321I.tegge@cvsup.no.freebsd.org> References: <88569.1059513090@critter.freebsd.dk> <20030730012321I.tegge@cvsup.no.freebsd.org>
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On Wed, Jul 30, 2003 at 01:23:21AM +0000, Tor.Egge@cvsup.no.freebsd.org wrote: > > The indication of this is that the g_bio zone does not return to > > zero USED as it should. > > It looks like z->uz_cachefree is slightly out of date (updated in > zone_timout() every 20th second) and often too low (not taking the > z->uz_full_bucket list into account). > > The enclosed patch recalculates the number of free elements on the > buckets instead of using z->uz_cachefree. > > - Tor Egge > We took this into account when we did the comparison. We know that uz_cachefree is only a snapshot count; but Poul-Henning`s patch clearly illustrates a frequent fluctuation in the free zone value but where the actual number of allocated g_bio zone elements stays stable at 0, for example. The fact that the problem is solved when buckets are disabled also is indicative that there is a clear reentrancy problems somewhere. There may also be some bucket leakage (although I have not yet confirmed this) as well. -- Bosko Milekic * bmilekic@technokratis.com * bmilekic@FreeBSD.org TECHNOkRATIS Consulting Services * http://www.technokratis.com/
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