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authorNick Piggin <npiggin@suse.de>2008-07-25 19:45:32 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-07-26 12:00:06 -0700
commit19fd6231279be3c3bdd02ed99f9b0eb195978064 (patch)
treeee09121054262d73c551b57114acd855b82a7a82 /mm/migrate.c
parenta60637c85893e7191faaafa6a72e197c24386727 (diff)
downloadlwn-19fd6231279be3c3bdd02ed99f9b0eb195978064.tar.gz
lwn-19fd6231279be3c3bdd02ed99f9b0eb195978064.zip
mm: spinlock tree_lock
mapping->tree_lock has no read lockers. convert the lock from an rwlock to a spinlock. Signed-off-by: Nick Piggin <npiggin@suse.de> 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: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/migrate.c')
-rw-r--r--mm/migrate.c11
1 files changed, 5 insertions, 6 deletions
diff --git a/mm/migrate.c b/mm/migrate.c
index 3ca6392e82cc..153572fb60b8 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -323,7 +323,7 @@ static int migrate_page_move_mapping(struct address_space *mapping,
return 0;
}
- write_lock_irq(&mapping->tree_lock);
+ spin_lock_irq(&mapping->tree_lock);
pslot = radix_tree_lookup_slot(&mapping->page_tree,
page_index(page));
@@ -331,12 +331,12 @@ static int migrate_page_move_mapping(struct address_space *mapping,
expected_count = 2 + !!PagePrivate(page);
if (page_count(page) != expected_count ||
(struct page *)radix_tree_deref_slot(pslot) != page) {
- write_unlock_irq(&mapping->tree_lock);
+ spin_unlock_irq(&mapping->tree_lock);
return -EAGAIN;
}
if (!page_freeze_refs(page, expected_count)) {
- write_unlock_irq(&mapping->tree_lock);
+ spin_unlock_irq(&mapping->tree_lock);
return -EAGAIN;
}
@@ -373,10 +373,9 @@ static int migrate_page_move_mapping(struct address_space *mapping,
__dec_zone_page_state(page, NR_FILE_PAGES);
__inc_zone_page_state(newpage, NR_FILE_PAGES);
- write_unlock_irq(&mapping->tree_lock);
- if (!PageSwapCache(newpage)) {
+ spin_unlock_irq(&mapping->tree_lock);
+ if (!PageSwapCache(newpage))
mem_cgroup_uncharge_cache_page(page);
- }
return 0;
}