Date: Fri, 21 May 1999 09:16:34 -0700 From: Mike Smith <mike@smith.net.au> To: Mark Newton <newton@internode.com.au> Cc: pasha@sim.net.ua (Pavel Narozhniy), freebsd-hackers@FreeBSD.ORG Subject: Re: Source code of SGI XFS Message-ID: <199905211616.JAA00959@dingo.cdrom.com> In-Reply-To: Your message of "Sat, 22 May 1999 00:21:54 %2B0930." <199905211451.AAA74303@gizmo.internode.com.au>
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> Pavel Narozhniy wrote: > > > Does anybody heard about SGI releasing XFS source code? > > Yup, they're doing it. > > I would guess that FreeBSD would need a fairly thorough revamp of its > handling of kernel memory allocation before XFS would be fully usable, > though: XFS buffer management is pretty full-on. Read "Irix has shitty block I/O support so XFS has to do it all itself". > The filesystem maintains its own pool of kernel buffers separate from > the VM page cache which it uses for aggregating I/O transfers (so that > if, say, you make 5 separate out-of-order I/Os which just happen to > blanket a contiguous region of a disk object, XFS will collapse them > into a single I/O; We do this too; it's called I/O clustering, but it's done below the filesystem so that anyone and everyone can benefit from it. > it'll also take small contiguous regions (extents) > and remap them into the next-power-of-two extent size as they grow. Whatever that means. 8) > I know I could probably see by looking at the source, but does FreeBSD > still impose a 64k limit on physical I/O operations? That'll have > to go too... Nominally. We ought to be able to support fragmentation as required to support the underlying device, but it's not complete yet. The fixes are relatively trivial. -- \\ The mind's the standard \\ Mike Smith \\ of the man. \\ msmith@freebsd.org \\ -- Joseph Merrick \\ msmith@cdrom.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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