Date: Tue, 11 May 2010 08:44:07 -0700 From: Artem Belevich <fbsdlist@src.cx> To: Pawel Jakub Dawidek <pjd@freebsd.org> Cc: freebsd-fs@freebsd.org, "Alexander V. Ribchansky" <shurik@zk.informjust.ua> Subject: Re: Freebsd 8.0 kmem map too small Message-ID: <AANLkTikQ3aLp1k85fweZ7TcAhooTDgzh9PylCu3Wbost@mail.gmail.com> In-Reply-To: <20100511152948.GC1667@garage.freebsd.pl> References: <4BE95F1F.5090009@zk.informjust.ua> <20100511152948.GC1667@garage.freebsd.pl>
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> Thanks for confirmation, I also suspected that. I'll turn using UMA for > zio allocations off. Perhaps on i386 only? memory fragmentation is only of concern if you don't have enough VM space. on amd64 it's easily solved by bumping vm.kmem_size up -- something that one's typically advised to do anyways. If I understand it correctly, without ZIO_USE_UMA, ZFS ARC allocations would normally be served from power-of-two zones. For relatively random allocations it would result in fair amount of waste for smaller sized allocations. The increase in apparent amount of wired memory is a bit of red herring. If ARC size is limited to below wired max and there's enough physical memory, then UMA caches may keep a lot of memory hanging on caches' free lists. That memory will be given up as soon as pagedaemon bothers to wake up. --Artem On Tue, May 11, 2010 at 8:29 AM, Pawel Jakub Dawidek <pjd@freebsd.org> wrot= e: > On Tue, May 11, 2010 at 04:43:59PM +0300, Alexander V. Ribchansky wrote: >> As Artem advised, I comment out >> >> CFLAGS+=3D-DZIO_USE_UMA in sys/modules/zfs/Makefile >> >> and things like to be "back in USSR :)" if seriously - all become as goo= d >> as before 18.04.2010 mega ZFS-MFC. >> While with UMA, Wired memory constantly grow up to kmem_max limit and th= an >> PANIC! :(, without it, Wired is approx 380 - 450M on typical 8-STABLE KD= E3 >> desktop with plain ZFS. >> So or there is something wrong with my (and many many other's people's) >> hands or UMA broke ZFS at all. >> >> Thank you, Artem for hint! I already start to think, that revert to >> pre-18.04.2010 8-STABLE is the only solution. > > Thanks for confirmation, I also suspected that. I'll turn using UMA for > zio allocations off. > > -- > Pawel Jakub Dawidek =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 http://ww= w.wheelsystems.com > pjd@FreeBSD.org =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 http:= //www.FreeBSD.org > FreeBSD committer =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 Am I Ev= il? Yes, I Am! >
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