diff options
| author | Davidlohr Bueso <davidlohr@hp.com> | 2014-04-23 08:27:08 +1000 |
|---|---|---|
| committer | Stephen Rothwell <sfr@canb.auug.org.au> | 2014-04-23 08:27:08 +1000 |
| commit | d2615d1817179d3ad9b45b20b50fa8a917f616cc (patch) | |
| tree | 50641ded60cc86b4f16900ee1d805f849caae3d0 /mm | |
| parent | 88b54d7c5a57d4c113979abb08910fbd24fffe05 (diff) | |
mm,vmacache: optimize overflow system-wide flushing
For single threaded workloads, we can avoid flushing and iterating through
the entire list of tasks, making the whole function a lot faster,
requiring only a single atomic read for the mm_users.
Signed-off-by: Davidlohr Bueso <davidlohr@hp.com>
Suggested-by: Oleg Nesterov <oleg@redhat.com>
Cc: Aswin Chandramouleeswaran <aswin@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/vmacache.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/mm/vmacache.c b/mm/vmacache.c index e167da29ea58..61c38ae9f54b 100644 --- a/mm/vmacache.c +++ b/mm/vmacache.c @@ -17,6 +17,16 @@ void vmacache_flush_all(struct mm_struct *mm) { struct task_struct *g, *p; + /* + * Single threaded tasks need not iterate the entire + * list of process. We can avoid the flushing as well + * since the mm's seqnum was increased and don't have + * to worry about other threads' seqnum. Current's + * flush will occur upon the next lookup. + */ + if (atomic_read(&mm->mm_users) == 1) + return; + rcu_read_lock(); for_each_process_thread(g, p) { /* |