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authorShaohua Li <shli@kernel.org>2013-12-31 11:38:27 +0800
committerJens Axboe <axboe@kernel.dk>2014-01-30 12:57:25 -0700
commitd835502f3dacad1638d516ab156d66f0ba377cf5 (patch)
tree1a82543b7c14120251a4bceaa08f5cc9f86ecf43 /lib/syscall.c
parent53d8ab29f8f6d67e37857b68189b38fa3d87dd8e (diff)
percpu_ida: fix a live lock
steal_tags only happens when free tags is more than half of the total tags. This is too strict and can cause live lock. I found that if one cpu has free tags, but other cpu can't steal (thread is bound to specific cpus), threads which want to allocate tags are always sleeping. I found this when I run next patch, but this could happen without it I think. I did performance test too with null_blk. Two cases (each cpu has enough percpu tags, or total tags are limited), no performance changes were observed. Signed-off-by: Shaohua Li <shli@fusionio.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'lib/syscall.c')
0 files changed, 0 insertions, 0 deletions