diff options
author | Andrea Arcangeli <aarcange@redhat.com> | 2014-01-21 15:48:52 -0800 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2014-01-21 16:19:43 -0800 |
commit | ca641514f4056deee1fb2eb356e2c99b98718ade (patch) | |
tree | c702724c845aa8510c9f658a18d66a3447f86ba4 /include/linux/kcore.h | |
parent | ebf360f9bb957f68e19e88f5067c015997dc26a6 (diff) |
mm: thp: optimize compound_trans_huge
Currently we don't clobber page_tail->first_page during split_huge_page,
so compound_trans_head can be set to compound_head without adverse
effects, and this mostly optimizes away a smp_rmb.
It looks worthwhile to keep around the implementation that doesn't relay
on page_tail->first_page not to be clobbered, because it would be
necessary if we'll decide to enforce page->private to zero at all times
whenever PG_private is not set, also for anonymous pages. For anonymous
pages enforcing such an invariant doesn't matter as anonymous pages
don't use page->private so we can get away with this microoptimization.
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Cc: Khalid Aziz <khalid.aziz@oracle.com>
Cc: Pravin Shelar <pshelar@nicira.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Ben Hutchings <bhutchings@solarflare.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Johannes Weiner <jweiner@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/kcore.h')
0 files changed, 0 insertions, 0 deletions