The patch titled
Subject: mm: vmscan: move dirty pages out of the way until they're flushed fix
has been removed from the -mm tree. Its filename was
mm-vmscan-move-dirty-pages-out-of-the-way-until-theyre-flushed-fix.patch
This patch was dropped because it was folded into mm-vmscan-move-dirty-pages-out-of-the-way-until-theyre-flushed.patch
------------------------------------------------------
From: Johannes Weiner <hannes@xxxxxxxxxxx>
Subject: mm: vmscan: move dirty pages out of the way until they're flushed fix
Mention the trade-off between waiting for writeback and potentially
causing hot cache refaults in the code where we make this decisions
and activate writeback pages.
Link: http://lkml.kernel.org/r/20170202191957.22872-8-hannes@xxxxxxxxxxx
Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/vmscan.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff -puN mm/vmscan.c~mm-vmscan-move-dirty-pages-out-of-the-way-until-theyre-flushed-fix mm/vmscan.c
--- a/mm/vmscan.c~mm-vmscan-move-dirty-pages-out-of-the-way-until-theyre-flushed-fix
+++ a/mm/vmscan.c
@@ -1056,6 +1056,15 @@ static unsigned long shrink_page_list(st
* throttling so we could easily OOM just because too many
* pages are in writeback and there is nothing else to
* reclaim. Wait for the writeback to complete.
+ *
+ * In cases 1) and 2) we activate the pages to get them out of
+ * the way while we continue scanning for clean pages on the
+ * inactive list and refilling from the active list. The
+ * observation here is that waiting for disk writes is more
+ * expensive than potentially causing reloads down the line.
+ * Since they're marked for immediate reclaim, they won't put
+ * memory pressure on the cache working set any longer than it
+ * takes to write them to disk.
*/
if (PageWriteback(page)) {
/* Case 1 above */
_
Patches currently in -mm which might be from hannes@xxxxxxxxxxx are
mm-vmscan-scan-dirty-pages-even-in-laptop-mode.patch
mm-vmscan-kick-flushers-when-we-encounter-dirty-pages-on-the-lru.patch
mm-vmscan-remove-old-flusher-wakeup-from-direct-reclaim-path.patch
mm-vmscan-only-write-dirty-pages-that-the-scanner-has-seen-twice.patch
mm-vmscan-move-dirty-pages-out-of-the-way-until-theyre-flushed.patch
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