Date: Wed, 25 Oct 2000 12:31:54 +0200 From: Anton Berezin <tobez@tobez.org> To: Matt Dillon <dillon@earth.backplane.com> Cc: Alfred Perlstein <bright@wintelcom.net>, ps@FreeBSD.ORG, hackers@FreeBSD.ORG Subject: Re: vm_pageout_scan badness Message-ID: <20001025123154.A56298@heechee.tobez.org> In-Reply-To: <200010242010.e9OKAJK19739@earth.backplane.com>; from dillon@earth.backplane.com on Tue, Oct 24, 2000 at 01:10:19PM -0700 References: <20001024112708.E28123@fw.wintelcom.net> <200010242010.e9OKAJK19739@earth.backplane.com>
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On Tue, Oct 24, 2000 at 01:10:19PM -0700, Matt Dillon wrote: > Ouch. The original VM code assumed that pages would not often be > ripped out from under the pageadaemon, so it felt free to restart > whenever. I think you are absolutely correct in regards to the > clustering code causing nearby-page ripouts. > > I don't have much time available, but let me take a crack at the > problem tonight. While you are at it, would you care and have a look at PR19672. It seems to be at least remotely relevant. ;-) > I don't think we want to add another workaround to code that > already has too many of them. The solution may be to create a > dummy placemarker vm_page_t and to insert it into the pagelist > just after the current page after we've locked it and decided we > have to do something significant to it. We would then be able to > pick the scan up where we left off using the placemarker. > > This would allow us to get rid of the restart code entirely, or at > least devolve it back into its original design (i.e. something > that would not happen very often). Since we already have cache > locality of reference for the list node, the placemarker idea > ought to be quite fast. > > I'll take a crack at implementing the openbsd (or was it netbsd?) > partial fsync() code as well, to prevent the update daemon from > locking up large files that have lots of dirty pages for long > periods of time. Cheers, %Anton. -- <img align="lawful"> and <img align="chaotic"> would be a nice addition to HTML specification. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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