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[66.91.135.210]) by mx.google.com with ESMTPSA id re16sm12773029pac.16.2013.06.22.19.35.16 for (version=TLSv1 cipher=RC4-SHA bits=128/128); Sat, 22 Jun 2013 19:35:17 -0700 (PDT) Date: Sat, 22 Jun 2013 16:37:24 -1000 (HST) From: Jeff Roberson X-X-Sender: jroberson@desktop To: Zbyszek Bodek Subject: Re: Kernel build fails on ARM: Cannot fork: Cannot allocate memory In-Reply-To: <51C4A067.7010203@semihalf.com> Message-ID: References: <51C1F53B.2080502@semihalf.com> <51C4A067.7010203@semihalf.com> User-Agent: Alpine 2.00 (BSF 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed X-Gm-Message-State: ALoCoQl8EJ8TRvhROyWNOf2CyMgiPYv8q4fFA7GDkU4GDpQ+6iRofd60kTO6rkRHCp4+ZZAYkS4Z Cc: freebsd-arm@FreeBSD.org, freebsd-current@freebsd.org X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 23 Jun 2013 02:35:18 -0000 On Fri, 21 Jun 2013, Zbyszek Bodek wrote: > On 21.06.2013 01:56, Jeff Roberson wrote: >> On Thu, 20 Jun 2013, Jeff Roberson wrote: >> >>> On Wed, 19 Jun 2013, Zbyszek Bodek wrote: >>> >>>> Hello, >>>> >>>> I've been trying to compile the kernel on my ARMv7 platform using the >>>> sources from the current FreeBSD HEAD. >>>> >>>> make buildkernel <.....> -j5 >>>> >>>> 1/2 builds fails in the way described below: >>>> -------------------------------------------------------------------------- >>>> >>>> ing-include-dirs -fdiagnostics-show-option -nostdinc -I. >>>> -I/root/src/freebsd-arm-superpages/sys >>>> -I/root/src/freebsd-arm-superpages/sys/contrib/altq >>>> -I/root/src/freebsd-arm-superpages/sys/contrib/libfdt -D_KERNEL >>>> -DHAVE_KERNEL_OPTION_HEADERS -include opt_global.h -fno-common >>>> -finline-limit=8000 --param inline-unit-growth=100 --param >>>> large-function-growth=1000 -mno-thumb-interwork -ffreestanding -Werror >>>> /root/src/freebsd-arm-superpages/sys/ufs/ffs/ffs_snapshot.c >>>> Cannot fork: Cannot allocate memory >>>> *** [ffs_snapshot.o] Error code 2 >>>> 1 error >>>> *** [buildkernel] Error code 2 >>>> 1 error >>>> *** [buildkernel] Error code 2 >>>> 1 error >>>> 5487.888u 481.569s 7:35.65 1310.0% 1443+167k 1741+5388io 221pf+0w >>>> -------------------------------------------------------------------------- >>>> >>>> >>>> The warning from std err is: >>>> -------------------------------------------------------------------------- >>>> >>>> vm_thread_new: kstack allocation failed >>>> vm_thread_new: kstack allocation failed >>>> -------------------------------------------------------------------------- >>>> >>>> >>>> I was trying to find out which commit is causing this (because I was >>>> previously working on some older revision) and using bisect I got to: >>>> >>>> -------------------------------------------------------------------------- >>>> >>>> Author: jeff >>>> Date: Tue Jun 18 04:50:20 2013 +0000 >>>> >>>> Refine UMA bucket allocation to reduce space consumption and improve >>>> performance. >>>> >>>> - Always free to the alloc bucket if there is space. This gives >>>> LIFO >>>> allocation order to improve hot-cache performance. This also >>>> allows >>>> for zones with a single bucket per-cpu rather than a pair if the >>>> entire >>>> working set fits in one bucket. >>>> - Enable per-cpu caches of buckets. To prevent recursive bucket >>>> allocation one bucket zone still has per-cpu caches disabled. >>>> - Pick the initial bucket size based on a table driven maximum size >>>> per-bucket rather than the number of items per-page. This gives >>>> more sane initial sizes. >>>> - Only grow the bucket size when we face contention on the zone >>>> lock, this >>>> causes bucket sizes to grow more slowly. >>>> - Adjust the number of items per-bucket to account for the header >>>> space. >>>> This packs the buckets more efficiently per-page while making them >>>> not quite powers of two. >>>> - Eliminate the per-zone free bucket list. Always return buckets >>>> back >>>> to the bucket zone. This ensures that as zones grow into larger >>>> bucket sizes they eventually discard the smaller sizes. It >>>> persists >>>> fewer buckets in the system. The locking is slightly trickier. >>>> - Only switch buckets in zalloc, not zfree, this eliminates >>>> pathological >>>> cases where we ping-pong between two buckets. >>>> - Ensure that the thread that fills a new bucket gets to allocate >>>> from >>>> it to give a better upper bound on allocation time. >>>> >>>> Sponsored by: EMC / Isilon Storage Division >>>> -------------------------------------------------------------------------- >>>> >>>> >>>> I checked this several times and this commits seems to be causing this. >>> >>> Can you tell me how many cores and how much memory you have? And >>> paste the output of vmstat -z when you see this error. >>> >>> You can try changing bucket_select() at line 339 in uma_core.c to read: >>> >>> static int >>> bucket_select(int size) >>> { >>> return (MAX(PAGE_SIZE / size, 1)); >>> } >>> >>> This will approximate the old bucket sizing behavior. >> >> Just to add some more information; On my machine with 16GB of ram the >> handful of recent UMA commits save about 20MB of kmem on boot. There >> are 30% fewer buckets allocated. And all of the malloc zones have >> similar amounts of cached space. Actually the page size malloc bucket >> is taking up much less space. >> >> I don't know if the problem is unique to arm but I have tested x86 >> limited to 512MB of ram without trouble. I will need the stats I >> mentioned before to understand what has happened. >> > > Hello Jeff, > > Thank you for your interest in my problem. > > My system is a quad-core ARMv7 with 2048 MB of RAM on board. > Please see attachment for the output from vmstat -z when the error occurs. > > Changing bucket_select() to > > static int > bucket_select(int size) > { > return (MAX(PAGE_SIZE / size, 1)); > } > > as you suggested helps for the problem. I've performed numerous attempts > to build the kernel and none of them failed. > I don't really see a lot of wasted memory in the zones. There is certainly some. Can you give me sysctl vm from both a working and non-working kernel after the build is done or fails? Thanks, Jeff > Best regards > Zbyszek Bodek >