[PATCH] truncate: clear page dirtiness before running try_to_free_buffers()
truncate presently invalidates the dirty page's buffer_heads then shoots down
the page. But try_to_free_buffers() will now bale out because the page is
dirty.
Net effect: the LRU gets filled with dirty pages which have invalidated
buffer_heads attached. They have no ->mapping and hence cannot be cleaned.
The machine leaks memory at an enormous rate.
Fix this by cleaning the page before running try_to_free_buffers(), so
try_to_free_buffers() can do its work.
Also, remember to do dirty-page-acoounting in cancel_dirty_page() so the
machine won't wedge up trying to write non-existent dirty pages.
Probably still wrong, but now less so.
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/mm/truncate.c b/mm/truncate.c
index bf9e296..89a5c35 100644
--- a/mm/truncate.c
+++ b/mm/truncate.c
@@ -60,11 +60,12 @@
WARN_ON(++warncount < 5);
}
- if (TestClearPageDirty(page) && account_size)
+ if (TestClearPageDirty(page) && account_size) {
+ dec_zone_page_state(page, NR_FILE_DIRTY);
task_io_account_cancelled_write(account_size);
+ }
}
-
/*
* If truncate cannot remove the fs-private metadata from the page, the page
* becomes anonymous. It will be left on the LRU and may even be mapped into
@@ -81,11 +82,11 @@
if (page->mapping != mapping)
return;
+ cancel_dirty_page(page, PAGE_CACHE_SIZE);
+
if (PagePrivate(page))
do_invalidatepage(page, 0);
- cancel_dirty_page(page, PAGE_CACHE_SIZE);
-
ClearPageUptodate(page);
ClearPageMappedToDisk(page);
remove_from_page_cache(page);