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authorHugh Dickins <hughd@google.com>2012-01-12 17:19:56 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2012-01-12 20:13:10 -0800
commit2bcf887963812c075f80a14e1fad8ec7e1c67acf (patch)
tree132f11eefe904653307a05b77d16f4c41866e486 /include/linux
parent90b3feaec8ffb167abd8903bf111605c2f035aa8 (diff)
mm: take pagevecs off reclaim stack
Replace pagevecs in putback_lru_pages() and move_active_pages_to_lru() by lists of pages_to_free: then apply Konstantin Khlebnikov's free_hot_cold_page_list() to them instead of pagevec_release(). Which simplifies the flow (no need to drop and retake lock whenever pagevec fills up) and reduces stale addresses in stack backtraces (which often showed through the pagevecs); but more importantly, removes another 120 bytes from the deepest stacks in page reclaim. Although I've not recently seen an actual stack overflow here with a vanilla kernel, move_active_pages_to_lru() has often featured in deep backtraces. However, free_hot_cold_page_list() does not handle compound pages (nor need it: a Transparent HugePage would have been split by the time it reaches the call in shrink_page_list()), but it is possible for putback_lru_pages() or move_active_pages_to_lru() to be left holding the last reference on a THP, so must exclude the unlikely compound case before putting on pages_to_free. Remove pagevec_strip(), its work now done in move_active_pages_to_lru(). The pagevec in scan_mapping_unevictable_pages() remains in mm/vmscan.c, but that is never on the reclaim path, and cannot be replaced by a list. Signed-off-by: Hugh Dickins <hughd@google.com> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Reviewed-by: Konstantin Khlebnikov <khlebnikov@openvz.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux')
-rw-r--r--include/linux/pagevec.h2
1 files changed, 0 insertions, 2 deletions
diff --git a/include/linux/pagevec.h b/include/linux/pagevec.h
index ed17024d2ebe..9def9121f8a2 100644
--- a/include/linux/pagevec.h
+++ b/include/linux/pagevec.h
@@ -22,7 +22,6 @@ struct pagevec {
void __pagevec_release(struct pagevec *pvec);
void ____pagevec_lru_add(struct pagevec *pvec, enum lru_list lru);
-void pagevec_strip(struct pagevec *pvec);
unsigned pagevec_lookup(struct pagevec *pvec, struct address_space *mapping,
pgoff_t start, unsigned nr_pages);
unsigned pagevec_lookup_tag(struct pagevec *pvec,
@@ -59,7 +58,6 @@ static inline unsigned pagevec_add(struct pagevec *pvec, struct page *page)
return pagevec_space(pvec);
}
-
static inline void pagevec_release(struct pagevec *pvec)
{
if (pagevec_count(pvec))