diff options
| author | Peter Collingbourne <pcc@google.com> | 2022-03-22 14:43:08 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2022-03-22 15:57:05 -0700 |
| commit | abe8b2ae64a31146748239a1525ffb275c4f360f (patch) | |
| tree | 31ddaf821a71ee2a11a4dbb0caa40a58e5e3fd5e /mm/mmzone.c | |
| parent | 1dd214b8f21ca46d5431be9b2db8513c59e07a26 (diff) | |
mm/mmzone.c: use try_cmpxchg() in page_cpupid_xchg_last()
This will let us avoid an additional read from page->flags when retrying
the compare-exchange on some architectures.
Link: https://lkml.kernel.org/r/20220120011200.1322836-1-pcc@google.com
Link: https://linux-review.googlesource.com/id/I2e1f5b5b080ac9c4e0eb7f98768dba6fd7821693
Signed-off-by: Peter Collingbourne <pcc@google.com>
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Mel Gorman <mgorman@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/mmzone.c')
| -rw-r--r-- | mm/mmzone.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/mm/mmzone.c b/mm/mmzone.c index eb89d6e018e2..d8a9b0e1b526 100644 --- a/mm/mmzone.c +++ b/mm/mmzone.c @@ -89,13 +89,14 @@ int page_cpupid_xchg_last(struct page *page, int cpupid) unsigned long old_flags, flags; int last_cpupid; + old_flags = READ_ONCE(page->flags); do { - old_flags = flags = page->flags; - last_cpupid = page_cpupid_last(page); + flags = old_flags; + last_cpupid = (flags >> LAST_CPUPID_PGSHIFT) & LAST_CPUPID_MASK; flags &= ~(LAST_CPUPID_MASK << LAST_CPUPID_PGSHIFT); flags |= (cpupid & LAST_CPUPID_MASK) << LAST_CPUPID_PGSHIFT; - } while (unlikely(cmpxchg(&page->flags, old_flags, flags) != old_flags)); + } while (unlikely(!try_cmpxchg(&page->flags, &old_flags, flags))); return last_cpupid; } |