[PATCHSET] blkcg: fix percpu stat allocation and remove stats_lock, take#2

[Tejun Heo <tj@kernel.org>]

Hello, guys.

This patchset is another retry at fixing percpu stat allocation and
removing stats_lock.  From the last try[L], percpu mempool stuff is
replaced with in-blkcg delayed allocation using work item.  Other than
that, the rest of the patchset remain the same.

Vivek, I made some minor adjustments to your percpu alloc patch.
Also, your patch fixes the suspicious RCU deref warning, which was
caused by blkg_alloc() needing sleepable context from the first place.
I added a note for that in the commit message.

  0001-blkcg-alloc-per-cpu-stats-from-worker-thread-in-a-de.patch
  0002-blkcg-don-t-use-percpu-for-merged-stats.patch
  0003-blkcg-simplify-stat-reset.patch
  0004-blkcg-restructure-blkio_get_stat.patch
  0005-blkcg-remove-blkio_group-stats_lock.patch

0001 fix blkcg per cpu stat allocation by implementing delayed
allocation in blkcg proper using a work item.

0002-0005 replace blkg->stats_lock with u64_stats_sync.

This patchset is on top of the current block/for-3.4/core - 671058fb2a
"block: make blk-throttle preserve the issuing task on delayed bios".

and available in the following git branch.

 git://git.kernel.org/pub/scm/linux/kernel/git/tj/misc.git blkcg-stats

Thanks.

 block/blk-cgroup.c |  466 ++++++++++++++++++++++++++---------------------------
 block/blk-cgroup.h |   31 ++-
 2 files changed, 257 insertions(+), 240 deletions(-)

--
tejun

[L] http://thread.gmane.org/gmane.linux.kernel/1257428