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| author | Davidlohr Bueso <davidlohr@hp.com> | 2014-06-04 16:06:47 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2014-06-04 16:53:57 -0700 |
| commit | 6b4ebc3a9078c5b7b8c4cf495a0b1d2d0e0bfe7a (patch) | |
| tree | b72fad03149fb8e21284558b636bb2a8faa88cb6 /mm/vmacache.c | |
| parent | 4f115147ff802267d0aa41e361c5aa5bd933d896 (diff) | |
| download | lwn-6b4ebc3a9078c5b7b8c4cf495a0b1d2d0e0bfe7a.tar.gz lwn-6b4ebc3a9078c5b7b8c4cf495a0b1d2d0e0bfe7a.zip | |
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>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/vmacache.c')
| -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 658ed3b3e38d..9f25af825dec 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) { /* |