linux-stable.git/mm/memory_hotplug.c, branch linux-2.6.37.y

memory hotplug: one more lock on memory hotplug

2011-02-17T23:14:50+00:00

commit 925268a06dc2b1ff7bfcc37419a6827a0e739639 upstream.

Now, memory_hotplug_(un)lock() is used for add/remove/offline pages
for avoiding races with hibernation. But this should be held in
online_pages(), too. It seems asymmetric.

There are cases where one has to avoid a race with memory hotplug
notifier and his own local code, and hotplug v.s. hotplug.
This will add a generic solution for avoiding races. In other view,
having lock here has no big impacts. online pages is tend to be
done by udev script at el against each memory section one by one.

Then, it's better to have lock here, too.

Reviewed-by: Christoph Lameter 
Acked-by: David Rientjes 
Signed-off-by: KAMEZAWA Hiroyuki 
Signed-off-by: Pekka Enberg 
Signed-off-by: Greg Kroah-Hartman

mem-hotplug: introduce {un}lock_memory_hotplug()

2010-12-02T22:51:15+00:00

Presently hwpoison is using lock_system_sleep() to prevent a race with
memory hotplug.  However lock_system_sleep() is a no-op if
CONFIG_HIBERNATION=n.  Therefore we need a new lock.

Signed-off-by: KOSAKI Motohiro 
Cc: Andi Kleen 
Cc: Kamezawa Hiroyuki 
Suggested-by: Hugh Dickins 
Acked-by: Hugh Dickins 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: do_migrate_range: reduce list_empty() check

2010-10-26T23:52:11+00:00

Simple code for reducing list_empty(&source) check.

Signed-off-by: Bob Liu 
Acked-by: KAMEZAWA Hiroyuki 
Acked-by: Wu Fengguang 
Cc: KOSAKI Motohiro 
Cc: Mel Gorman 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: do_migrate_range: exit loop if not_managed is true

2010-10-26T23:52:11+00:00

If not_managed is true all pages will be putback to lru, so break the loop
earlier to skip other pages isolate.

Signed-off-by: Bob Liu 
Acked-by: KAMEZAWA Hiroyuki 
Acked-by: Wu Fengguang 
Cc: KOSAKI Motohiro 
Cc: Mel Gorman 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/memory_hotplug.c: make scan_lru_pages() static

2010-10-26T23:52:10+00:00

Reported-by: KOSAKI Motohiro 
Cc: KAMEZAWA Hiroyuki 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

memory hotplug: unify is_removable and offline detection code

2010-10-26T23:52:06+00:00

Now, sysfs interface of memory hotplug shows whether the section is
removable or not.  But it checks only migrateype of pages and doesn't
check details of cluster of pages.

Next, memory hotplug's set_migratetype_isolate() has the same kind of
check, too.

This patch adds the function __count_unmovable_pages() and makes above 2
checks to use the same logic.  Then, is_removable and hotremove code uses
the same logic.  No changes in the hotremove logic itself.

TODO: need to find a way to check RECLAMABLE. But, considering bit,
      calling shrink_slab() against a range before starting memory hotremove
      sounds better. If so, this patch's logic doesn't need to be changed.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: KAMEZAWA Hiroyuki 
Reported-by: Michal Hocko 
Cc: Wu Fengguang 
Cc: Mel Gorman 
Cc: KAMEZAWA Hiroyuki 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: compaction: fix COMPACTPAGEFAILED counting

2010-10-26T23:52:06+00:00

Presently update_nr_listpages() doesn't have a role.  That's because lists
passed is always empty just after calling migrate_pages.  The
migrate_pages cleans up page list which have failed to migrate before
returning by aaa994b3.

 [PATCH] page migration: handle freeing of pages in migrate_pages()

 Do not leave pages on the lists passed to migrate_pages().  Seems that we will
 not need any postprocessing of pages.  This will simplify the handling of
 pages by the callers of migrate_pages().

At that time, we thought we don't need any postprocessing of pages.  But
the situation is changed.  The compaction need to know the number of
failed to migrate for COMPACTPAGEFAILED stat

This patch makes new rule for caller of migrate_pages to call
putback_lru_pages.  So caller need to clean up the lists so it has a
chance to postprocess the pages.  [suggested by Christoph Lameter]

Signed-off-by: Minchan Kim 
Cc: Hugh Dickins 
Cc: Andi Kleen 
Reviewed-by: Mel Gorman 
Reviewed-by: Wu Fengguang 
Acked-by: Christoph Lameter 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: fix return value of scan_lru_pages in memory unplug

2010-10-26T23:52:03+00:00

scan_lru_pages returns pfn. So, it's type should be "unsigned long"
not "int".

Note: I guess this has been work until now because memory hotplug tester's
      machine has not very big memory....
      physical address < 32bit << PAGE_SHIFT.

Reported-by: KOSAKI Motohiro 
Signed-off-by: KAMEZAWA Hiroyuki 
Reviewed-by: KOSAKI Motohiro 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

memory_hotplug: drop spurious calls to flush_scheduled_work()

2010-10-19T09:08:41+00:00

lru_add_drain_all() uses schedule_on_each_cpu() which is synchronous.
There is no reason to call flush_scheduled_work() after
lru_add_drain_all().  Drop the spurious calls.

This is to prepare for the deprecation and removal of
flush_scheduled_work().

Signed-off-by: Tejun Heo 
Acked-by: KAMEZAWA Hiroyuki 
Reviewed-by: Minchan Kim 
Acked-by: Mel Gorman

memory hotplug: fix next block calculation in is_removable

2010-09-10T01:57:24+00:00

next_active_pageblock() is for finding next _used_ freeblock.  It skips
several blocks when it finds there are a chunk of free pages lager than
pageblock.  But it has 2 bugs.

  1. We have no lock. page_order(page) - pageblock_order can be minus.
  2. pageblocks_stride += is wrong. it should skip page_order(p) of pages.

Signed-off-by: KAMEZAWA Hiroyuki 
Cc: Michal Hocko 
Cc: Wu Fengguang 
Cc: Mel Gorman 
Cc: KAMEZAWA Hiroyuki 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds