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authorHugh Dickins <hugh@veritas.com>2005-10-29 18:16:41 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2005-10-29 21:40:42 -0700
commitf412ac08c9861b4791af0145934c22f1458686da (patch)
tree5e515efa116f3968c2caa75bc691a197199313a8 /mm/memory.c
parent4c21e2f2441dc5fbb957b030333f5a3f2d02dea7 (diff)
downloadlwn-f412ac08c9861b4791af0145934c22f1458686da.tar.gz
lwn-f412ac08c9861b4791af0145934c22f1458686da.zip
[PATCH] mm: fix rss and mmlist locking
A couple of oddities were guarded by page_table_lock, no longer properly guarded when that is split. The mm_counters of file_rss and anon_rss: make those an atomic_t, or an atomic64_t if the architecture supports it, in such a case. Definitions by courtesy of Christoph Lameter: who spent considerable effort on more scalable ways of counting, but found insufficient benefit in practice. And adding an mm with swap to the mmlist for swapoff: the list is well- guarded by its own lock, but the list_empty check now has to be repeated inside it. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'mm/memory.c')
-rw-r--r--mm/memory.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/mm/memory.c b/mm/memory.c
index e9ef599498b5..d68421dd64ef 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -372,7 +372,9 @@ copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm,
/* make sure dst_mm is on swapoff's mmlist. */
if (unlikely(list_empty(&dst_mm->mmlist))) {
spin_lock(&mmlist_lock);
- list_add(&dst_mm->mmlist, &src_mm->mmlist);
+ if (list_empty(&dst_mm->mmlist))
+ list_add(&dst_mm->mmlist,
+ &src_mm->mmlist);
spin_unlock(&mmlist_lock);
}
}