Date: Fri, 13 Apr 2001 02:58:07 -0700 From: Alfred Perlstein <bright@wintelcom.net> To: Seigo Tanimura <tanimura@r.dl.itc.u-tokyo.ac.jp> Cc: phk@critter.freebsd.dk, dillon@earth.backplane.com, riel@conectiva.com.br, bsddiy@21cn.com, Tor.Egge@fast.no, freebsd-hackers@FreeBSD.ORG Subject: Re: vm balance Message-ID: <20010413025806.A976@fw.wintelcom.net> In-Reply-To: <200104130939.f3D9d7Z37169@rina.r.dl.itc.u-tokyo.ac.jp>; from tanimura@r.dl.itc.u-tokyo.ac.jp on Fri, Apr 13, 2001 at 06:39:07PM %2B0900 References: <200104121757.f3CHvJd20639@earth.backplane.com> <59188.987108650@critter> <200104130939.f3D9d7Z37169@rina.r.dl.itc.u-tokyo.ac.jp>
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* Seigo Tanimura <tanimura@r.dl.itc.u-tokyo.ac.jp> [010413 02:39] wrote: > On Thu, 12 Apr 2001 22:50:50 +0200, > Poul-Henning Kamp <phk@critter.freebsd.dk> said: > > Poul-Henning> We keep namecache entries around as long as we can use them, and that > Poul-Henning> generally means that recreating them is a rather expensive operation, > Poul-Henning> involving creation of vnode and very likely a vm object again. > > Holding a namecache entry forever until its vnode is reused results in > disaster when a huge number of files are accessed concurrently, causing > active vnodes to eat up all of memory. This beast killed a box of mine > with 3GB of memory and 200GB of a RAID0 disk array serving about > 300,000 files by cvsupd and making the world a few months ago, when > the number of the vnodes reached around 400,000 to make all of the > processes wait for a free vnode. > > With a help by tegge, the box is now reclaiming directory vnodes when > few free vnodes are available. Only directory vnodes holding no child > directory vnodes held in v_cache_src are recycled, so that directory > vnodes near the root of the filesystem hierarchy remain in namecache > and directory vnodes are not reclaimed in cascade. The number of > vnodes in the box is now about 135,000, staying quite steadily. > > Name'cache' is the place to hold vnodes for future use which may *not* > come, hence vnodes held in namecache should be reclaimed in case of > critical vnode shortage. Are these changes planned for integration? -- -Alfred Perlstein - [bright@wintelcom.net|alfred@freebsd.org] To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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