Files
ubports_kernel_google_msm/include/linux
Nick Piggin e286781d5f mm: speculative page references
If we can be sure that elevating the page_count on a pagecache page will
pin it, we can speculatively run this operation, and subsequently check to
see if we hit the right page rather than relying on holding a lock or
otherwise pinning a reference to the page.

This can be done if get_page/put_page behaves consistently throughout the
whole tree (ie.  if we "get" the page after it has been used for something
else, we must be able to free it with a put_page).

Actually, there is a period where the count behaves differently: when the
page is free or if it is a constituent page of a compound page.  We need
an atomic_inc_not_zero operation to ensure we don't try to grab the page
in either case.

This patch introduces the core locking protocol to the pagecache (ie.
adds page_cache_get_speculative, and tweaks some update-side code to make
it work).

Thanks to Hugh for pointing out an improvement to the algorithm setting
page_count to zero when we have control of all references, in order to
hold off speculative getters.

[kamezawa.hiroyu@jp.fujitsu.com: fix migration_entry_wait()]
[hugh@veritas.com: fix add_to_page_cache]
[akpm@linux-foundation.org: repair a comment]
Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Jeff Garzik <jeff@garzik.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: "Paul E. McKenney" <paulmck@us.ibm.com>
Reviewed-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Acked-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-26 12:00:06 -07:00
..
2008-07-25 10:53:30 -07:00
2008-07-24 13:32:56 +03:00
2008-07-01 11:28:06 +10:00
2008-07-24 10:47:24 -07:00
2008-07-24 10:47:33 -07:00
2008-07-24 10:47:33 -07:00
2008-07-03 13:21:14 +02:00
2008-07-04 10:40:05 -07:00
2008-07-25 10:53:33 -07:00
2008-07-20 17:12:38 -07:00
2008-07-22 17:30:57 -07:00
2008-07-11 10:46:50 +02:00
2008-07-21 12:00:37 +01:00
2008-07-21 12:00:37 +01:00
2008-07-24 10:47:29 -07:00
2008-07-24 10:47:41 -07:00
2008-07-08 17:55:41 +02:00
2008-07-16 23:27:03 +02:00
2008-07-11 15:49:21 +02:00
2008-07-25 10:53:48 -07:00
2008-07-20 17:12:36 -07:00
2008-07-25 10:53:30 -07:00
2008-07-20 17:12:36 -07:00
2008-07-23 15:25:21 +02:00
2008-07-25 10:53:42 -07:00
2008-07-18 18:05:19 -07:00
2008-07-14 22:49:06 -07:00
2008-07-03 17:51:57 +09:00
2008-07-25 10:53:39 -07:00
2008-07-16 23:27:07 +02:00
2008-07-20 17:12:37 -07:00
2008-07-25 10:53:29 -07:00
2008-07-25 10:53:29 -07:00
2008-07-26 12:00:04 -07:00
2008-07-24 10:47:17 -07:00
2008-07-04 10:40:05 -07:00
2008-07-20 12:42:32 +03:00
2008-07-23 09:49:56 +01:00
2008-07-24 10:47:41 -07:00
2008-07-25 10:53:40 -07:00
2008-07-26 12:00:05 -07:00
2008-07-24 10:47:24 -07:00
2008-07-25 10:53:34 -07:00
2008-07-25 10:53:29 -07:00
2008-07-26 12:00:06 -07:00
2008-07-26 12:00:03 -07:00
2008-07-24 11:50:15 -07:00
2008-07-25 10:53:48 -07:00
2008-07-07 16:26:50 -07:00
2008-07-25 10:53:44 -07:00
2008-07-25 10:53:29 -07:00
2008-07-04 10:40:07 -07:00
2008-07-25 10:53:29 -07:00
2008-07-24 10:47:33 -07:00
2008-07-24 10:47:22 -07:00
2008-07-25 10:53:42 -07:00
2008-07-24 08:31:21 -04:00
2008-07-24 10:47:24 -07:00
2008-07-14 22:49:06 -07:00
2008-07-24 10:47:21 -07:00
2008-07-04 10:40:04 -07:00
2008-07-25 10:53:30 -07:00
2008-07-20 17:12:37 -07:00
2008-07-22 13:03:28 -07:00
2008-07-20 17:12:34 -07:00
2008-07-22 13:03:27 -07:00
2008-07-21 15:15:55 -07:00
2008-07-24 10:47:14 -07:00
2008-07-25 10:53:40 -07:00