korg/linux
0
0
Fork 0
mirror of https://mirrors.bfsu.edu.cn/git/linux.git synced 2024-12-05 10:04:12 +08:00
Code Issues Packages Projects Releases Wiki Activity

mm: page_alloc: only check the zone id check if pages are buddies

Browse Source 
A node/zone index is used to check if pages are compatible for merging
but this happens unconditionally even if the buddy page is not free. Defer
the calculation as long as possible. Ideally we would check the zone boundary
but nodes can overlap.

Signed-off-by: Mel Gorman <mgorman@suse.de>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Jan Kara <jack@suse.cz>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Hugh Dickins <hughd@google.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Mel Gorman 2014-06-04 16:10:10 -07:00 committed by Linus Torvalds
parent 664eeddeef
commit d34c5fa06f
1 changed files with 13 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

16
mm/page_alloc.c
View File

@ -509,16 +509,26 @@ static inline int page_is_buddy(struct page *page, struct page *buddy,
if (!pfn_valid_within(page_to_pfn(buddy)))
return 0;
if (page_zone_id(page) != page_zone_id(buddy))
return 0;
if (page_is_guard(buddy) && page_order(buddy) == order) {
VM_BUG_ON_PAGE(page_count(buddy) != 0, buddy);
if (page_zone_id(page) != page_zone_id(buddy))
return 0;
return 1;
}
if (PageBuddy(buddy) && page_order(buddy) == order) {
VM_BUG_ON_PAGE(page_count(buddy) != 0, buddy);
/*
* zone check is done late to avoid uselessly
* calculating zone/node ids for pages that could
* never merge.
*/
if (page_zone_id(page) != page_zone_id(buddy))
return 0;
return 1;
}
return 0;