Date: Mon, 10 May 2010 13:53:46 -0700 From: Artem Belevich <fbsdlist@src.cx> To: Mike Andrews <mandrews@bit0.com> Cc: freebsd-stable@freebsd.org, Steve Polyack <korvus@comcast.net> Subject: Re: Freebsd 8.0 kmem map too small Message-ID: <x2ved91d4a81005101353u4320ede5p82d4669e6c04ea57@mail.gmail.com> In-Reply-To: <alpine.BSF.2.00.1005101643490.30993@beast.int.bit0.com> References: <4BDEA86E.3050109@zirakzigil.org> <20100503110100.GA93137@icarus.home.lan> <4BDEC106.3040807@zirakzigil.org> <4BE110E3.8040902@zirakzigil.org> <q2vb269bc571005050819nde819098vfd3306170639a9c9@mail.gmail.com> <4BE82C5D.1080806@bit0.com> <4BE83B9B.5030209@comcast.net> <alpine.BSF.2.00.1005101643490.30993@beast.int.bit0.com>
next in thread | previous in thread | raw e-mail | index | archive | help
vm.kmem_size limitation has been this way for a pretty long time. What's changed recently is that ZFS ARC now uses UMA for its memory allocations. If I understand it correctly, this would make ARC's memory use more efficient as allocated chunks will end up in a zone tuned for allocations of particular size. Increased fragmentation could be the side effect of this change, but I'm guessing here. --Artem On Mon, May 10, 2010 at 1:45 PM, Mike Andrews <mandrews@bit0.com> wrote: > On Mon, 10 May 2010, Steve Polyack wrote: > >> On 05/10/10 11:55, Mike Andrews wrote: >>> >>> On 5/5/10 11:19 AM, Freddie Cash wrote: >>>> >>>> On Tue, May 4, 2010 at 11:32 PM, Giulio Ferro<auryn@zirakzigil.org> >>>> wrote: >>>> >>>>> Giulio Ferro wrote: >>>>> >>>>>> Thanks, I'll try these settings. >>>>>> >>>>>> I'll keep you posted. >>>>>> >>>>> >>>>> Nope, it's happened again... Now I've tried to rise vm.kmem_size to >>>>> 6G... >>>>> I'm really astounded at how unstable zfs is, it's causing me a lot of >>>>> problem. >>>>> Why isn't it stated in the handbook that zfs isn't up to production >>>>> yet? >>>>> >>>> >>>> As with everything related to computers, it all depends on your uses. >>> >>> Sorry to semi-hijack this, but... =A0I'm also running into frequent >>> "kmem_map too small" panics on 8-STABLE, such as: >>> >>> panic: kmem_malloc(131072): kmem_map too small: 2023780352 total >>> allocated >>> panic: kmem_malloc(131072): kmem_map too small: 2011525120 total >>> allocated >>> panic: kmem_malloc(114688): kmem_map too small: 1849356288 total >>> allocated >>> panic: kmem_malloc(114688): kmem_map too small: 1849356288 total >>> allocated >>> panic: kmem_malloc(114688): kmem_map too small: 1849356288 total >>> allocated >>> panic: kmem_malloc(131072): kmem_map too small: 2020409344 total >>> allocated >>> panic: kmem_malloc(536576): kmem_map too small: 2022957056 total >>> allocated >>> >>> (those are over the course of 3-4 days) >>> >>> On this specific system, it has 32 GB physical memory and has >>> vfs.zfs.arc_max=3D"2G" and vm.kmem_size=3D"64G" in /boot/loader.conf. = =A0The >>> latter was added per earlier suggestions on this list, but appears to b= e >>> ignored as "sysctl vm.kmem_size" returns about 2 GB (2172452864) anyway= . >>> >>> >> As Artem stated in another reply, you will need to set vm.kmem_size >> slightly under 2x the physical memory. =A0The kernel will default to 2GB= if >> you pass this limit. =A01.5x physical memory size should be sufficient, = so try >> "48G" and verify that it gets set correctly on the next boot. > > > OK, I've got vm.kmem_size set a bit lower and it now accepts it. =A0It's = still > not clear why this just recently (April?) became necessary to do at all := ) > > Meanwhile, I'll see if things get more stable now... > _______________________________________________ > freebsd-stable@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-stable > To unsubscribe, send any mail to "freebsd-stable-unsubscribe@freebsd.org" >
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?x2ved91d4a81005101353u4320ede5p82d4669e6c04ea57>