vmscan: set up pagevec as late as possible in shrink_page_list()
shrink_page_list() sets up a pagevec to release pages as according as they
are free. It uses significant amounts of stack on the pagevec. This
patch adds pages to be freed via pagevec to a linked list which is then
freed en-masse at the end. This avoids using stack in the main path that
potentially calls writepage().
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Michael Rubin <mrubin@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 12b6921..512f463 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -622,6 +622,24 @@
return PAGEREF_RECLAIM;
}
+static noinline_for_stack void free_page_list(struct list_head *free_pages)
+{
+ struct pagevec freed_pvec;
+ struct page *page, *tmp;
+
+ pagevec_init(&freed_pvec, 1);
+
+ list_for_each_entry_safe(page, tmp, free_pages, lru) {
+ list_del(&page->lru);
+ if (!pagevec_add(&freed_pvec, page)) {
+ __pagevec_free(&freed_pvec);
+ pagevec_reinit(&freed_pvec);
+ }
+ }
+
+ pagevec_free(&freed_pvec);
+}
+
/*
* shrink_page_list() returns the number of reclaimed pages
*/
@@ -630,13 +648,12 @@
enum pageout_io sync_writeback)
{
LIST_HEAD(ret_pages);
- struct pagevec freed_pvec;
+ LIST_HEAD(free_pages);
int pgactivate = 0;
unsigned long nr_reclaimed = 0;
cond_resched();
- pagevec_init(&freed_pvec, 1);
while (!list_empty(page_list)) {
enum page_references references;
struct address_space *mapping;
@@ -811,10 +828,12 @@
__clear_page_locked(page);
free_it:
nr_reclaimed++;
- if (!pagevec_add(&freed_pvec, page)) {
- __pagevec_free(&freed_pvec);
- pagevec_reinit(&freed_pvec);
- }
+
+ /*
+ * Is there need to periodically free_page_list? It would
+ * appear not as the counts should be low
+ */
+ list_add(&page->lru, &free_pages);
continue;
cull_mlocked:
@@ -837,9 +856,10 @@
list_add(&page->lru, &ret_pages);
VM_BUG_ON(PageLRU(page) || PageUnevictable(page));
}
+
+ free_page_list(&free_pages);
+
list_splice(&ret_pages, page_list);
- if (pagevec_count(&freed_pvec))
- __pagevec_free(&freed_pvec);
count_vm_events(PGACTIVATE, pgactivate);
return nr_reclaimed;
}