path: root/include/scsi/osd_ore.h
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authorTejun Heo <tj@kernel.org>2015-09-16 11:51:12 -0400
committerTejun Heo <tj@kernel.org>2015-09-16 11:51:12 -0400
commit0c986253b939cc14c69d4adbe2b4121bdf4aa220 (patch)
tree78c28e9ff07b67baf4c06f72f92bbaa586452c9a /include/scsi/osd_ore.h
parentf9f9e7b776142fb1c0782cade004cc8e0147a199 (diff)
Revert "sched, cgroup: replace signal_struct->group_rwsem with a global percpu_rwsem"
This reverts commit d59cfc09c32a2ae31f1c3bc2983a0cd79afb3f14. d59cfc09c32a ("sched, cgroup: replace signal_struct->group_rwsem with a global percpu_rwsem") and b5ba75b5fc0e ("cgroup: simplify threadgroup locking") changed how cgroup synchronizes against task fork and exits so that it uses global percpu_rwsem instead of per-process rwsem; unfortunately, the write [un]lock paths of percpu_rwsem always involve synchronize_rcu_expedited() which turned out to be too expensive. Improvements for percpu_rwsem are scheduled to be merged in the coming v4.4-rc1 merge window which alleviates this issue. For now, revert the two commits to restore per-process rwsem. They will be re-applied for the v4.4-rc1 merge window. Signed-off-by: Tejun Heo <tj@kernel.org> Link: http://lkml.kernel.org/g/55F8097A.7000206@de.ibm.com Reported-by: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: stable@vger.kernel.org # v4.2+
Diffstat (limited to 'include/scsi/osd_ore.h')
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