2017-11-29-16-58 merged

Nadav Amit (1):
      fs/hugetlbfs/inode.c: change put_page/unlock_page order in hugetlbfs_fallocate()

Waiman Long (1):
      mm/list_lru.c: prefetch neighboring list entries before acquiring lock
mm/list_lru.c: prefetch neighboring list entries before acquiring lock

list_lru_del() removes the given item from the LRU list.  The operation
looks simple, but it involves writing into the cachelines of the two
neighboring list entries in order to get the deletion done.  That can take
a while if the cachelines aren't there yet, thus prolonging the lock hold
time.

To reduce the lock hold time, the cachelines of the two neighboring list
entries are now prefetched before acquiring the list_lru_node's lock.

Using a multi-threaded test program that created a large number of
dentries and then killed them, the execution time was reduced from 38.5s
to 36.6s after applying the patch on a 2-socket 36-core 72-thread x86-64
system.

Link: http://lkml.kernel.org/r/1511965054-6328-1-git-send-email-longman@redhat.com
Signed-off-by: Waiman Long <longman@redhat.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Dave Chinner <david@fromorbit.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
1 file changed