Kernel build fails on ARM: Cannot fork: Cannot allocate memory

Zbyszek Bodek zbb at
Wed Jun 19 18:15:34 UTC 2013


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/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
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 <jeff at>
Date:   Tue Jun 18 04:50:20 2013 +0000

    Refine UMA bucket allocation to reduce space consumption and improve

     - 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
       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
       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
       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.

Does anyone observe similar behavior or have a solution?

Best regards
Zbyszek Bodek

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