lkml.org 
[lkml]   [2011]   [Nov]   [5]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Subject[PATCH] mm: migrate: One less atomic operation
From
Date
From 3754c8617ef4377ce2ca2e3b28bdc28f8de1aa0d Mon Sep 17 00:00:00 2001
From: Jacobo Giralt <jacobo.giralt@gmail.com>
Date: Sat, 5 Nov 2011 13:12:50 +0100
Subject: [PATCH] mm: migrate: One less atomic operation

migrate_page_move_mapping drops a reference from the
old page after unfreezing its counter. Both operations
can be merged into a single atomic operation by
directly unfreezing to one less reference.

The same applies to migrate_huge_page_move_mapping.

Signed-off-by: Jacobo Giralt <jacobo.giralt@gmail.com>
---
mm/migrate.c | 10 ++++------
1 files changed, 4 insertions(+), 6 deletions(-)
diff --git a/mm/migrate.c b/mm/migrate.c
index 33358f8..46d04a0 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -269,12 +269,12 @@ static int migrate_page_move_mapping(struct address_space *mapping,

radix_tree_replace_slot(pslot, newpage);

- page_unfreeze_refs(page, expected_count);
/*
- * Drop cache reference from old page.
+ * Drop cache reference from old page by unfreezing
+ * to one less reference.
* We know this isn't the last reference.
*/
- __put_page(page);
+ page_unfreeze_refs(page, expected_count - 1);

/*
* If moved to a different zone then also account
@@ -334,9 +334,7 @@ int migrate_huge_page_move_mapping(struct address_space *mapping,

radix_tree_replace_slot(pslot, newpage);

- page_unfreeze_refs(page, expected_count);
-
- __put_page(page);
+ page_unfreeze_refs(page, expected_count - 1);

spin_unlock_irq(&mapping->tree_lock);
return 0;
--
1.7.5.4




\
 
 \ /
  Last update: 2011-11-05 15:41    [from the cache]
©2003-2011 Jasper Spaans