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authorHugh Dickins <hugh.dickins@tiscali.co.uk>2009-12-15 04:58:47 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2009-12-15 19:53:16 +0300
commitaaa468653b4a0d11c603c48d716f765177a5a9e4 (patch)
tree3cb8c9232dd405001fa38d5519937c5e6c6f32ab /mm/shmem.c
parent570a335b8e22579e2a51a68136d2b1f907a20eec (diff)
downloadlinux-aaa468653b4a0d11c603c48d716f765177a5a9e4.tar.xz
swap_info: note SWAP_MAP_SHMEM
While we're fiddling with the swap_map values, let's assign a particular value to shmem/tmpfs swap pages: their swap counts are never incremented, and it helps swapoff's try_to_unuse() a little if it can immediately distinguish those pages from process pages. Since we've no use for SWAP_MAP_BAD | COUNT_CONTINUED, we might as well use that 0xbf value for SWAP_MAP_SHMEM. Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/shmem.c')
-rw-r--r--mm/shmem.c11
1 files changed, 9 insertions, 2 deletions
diff --git a/mm/shmem.c b/mm/shmem.c
index 356dd99566ec..4fb41c83daca 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -1017,7 +1017,14 @@ int shmem_unuse(swp_entry_t entry, struct page *page)
goto out;
}
mutex_unlock(&shmem_swaplist_mutex);
-out: return found; /* 0 or 1 or -ENOMEM */
+ /*
+ * Can some race bring us here? We've been holding page lock,
+ * so I think not; but would rather try again later than BUG()
+ */
+ unlock_page(page);
+ page_cache_release(page);
+out:
+ return (found < 0) ? found : 0;
}
/*
@@ -1080,7 +1087,7 @@ static int shmem_writepage(struct page *page, struct writeback_control *wbc)
else
inode = NULL;
spin_unlock(&info->lock);
- swap_duplicate(swap);
+ swap_shmem_alloc(swap);
BUG_ON(page_mapped(page));
page_cache_release(page); /* pagecache ref */
swap_writepage(page, wbc);