Date: Thu, 12 Apr 2001 22:50:50 +0200 From: Poul-Henning Kamp <phk@critter.freebsd.dk> To: Matt Dillon <dillon@earth.backplane.com> Cc: Rik van Riel <riel@conectiva.com.br>, David Xu <bsddiy@21cn.com>, freebsd-hackers@FreeBSD.ORG Subject: Re: vm balance Message-ID: <59188.987108650@critter> In-Reply-To: Your message of "Thu, 12 Apr 2001 10:57:19 PDT." <200104121757.f3CHvJd20639@earth.backplane.com>
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In message <200104121757.f3CHvJd20639@earth.backplane.com>, Matt Dillon writes: > Again, keep in mind that the namei cache is strictly throw-away, but > entries can often be reconstituted later by the filesystem without I/O > due to the VM Page cache (and/or buffer cache depending on > vfs.vmiodirenable). So as with the buffer cache and inode cache, > the number of entries can be limited without killing performance or > scaleability. Uhm, that is actually not true. We keep namecache entries around as long as we can use them, and that generally means that recreating them is a rather expensive operation, involving creation of vnode and very likely a vm object again. We can safely say that you cannot profitably _increase_ the size of the namecache, except for the negative entries where raw statistics will have to be the judge of the profitability of the idea. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk@FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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