]> git.baikalelectronics.ru Git - kernel.git/commit
blkcg, cfq-iosched: use GFP_NOWAIT instead of GFP_ATOMIC for non-critical allocations
authorTejun Heo <tj@kernel.org>
Tue, 18 Aug 2015 21:55:01 +0000 (14:55 -0700)
committerJens Axboe <axboe@fb.com>
Tue, 18 Aug 2015 22:49:16 +0000 (15:49 -0700)
commit9a2c768487a51356531081dee63dfa0413bcffe4
treeb555a4ea359e72e0138590c72c11ece42c83eecb
parentce4fcf31e673245910d7aed728c6098c42722bc8
blkcg, cfq-iosched: use GFP_NOWAIT instead of GFP_ATOMIC for non-critical allocations

blkcg performs several allocations to track IOs per cgroup and enforce
resource control.  Most of these allocations are performed lazily on
demand in the IO path and thus can't involve reclaim path.  Currently,
these allocations use GFP_ATOMIC; however, blkcg can gracefully deal
with occassional failures of these allocations by punting IOs to the
root cgroup and there's no reason to reach into the emergency reserve.

This patch replaces GFP_ATOMIC with GFP_NOWAIT for the following
allocations.

* bdi_writeback_congested and blkcg_gq allocations in blkg_create().

* radix tree node allocations for blkcg->blkg_tree.

* cfq_queue allocation on ioprio changes.

Signed-off-by: Tejun Heo <tj@kernel.org>
Suggested-and-Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Suggested-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
block/blk-cgroup.c
block/cfq-iosched.c