The patch titled
Subject: mm, vmscan: account for skipped pages as a partial scan
has been removed from the -mm tree. Its filename was
mm-vmscan-account-for-skipped-pages-as-a-partial-scan.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Subject: mm, vmscan: account for skipped pages as a partial scan
Page reclaim determines whether a pgdat is unreclaimable by examining how
many pages have been scanned since a page was freed and comparing that to
the LRU sizes. Skipped pages are not reclaim candidates but contribute to
scanned. This can prematurely mark a pgdat as unreclaimable and trigger
an OOM kill.
This patch accounts for skipped pages as a partial scan so that an
unreclaimable pgdat will still be marked as such but by scaling the cost
of a skip, it'll avoid the pgdat being marked prematurely.
Link: http://lkml.kernel.org/r/1469110261-7365-6-git-send-email-mgorman@xxxxxxxxxxxxxxxxxxx
Signed-off-by: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/vmscan.c | 20 ++++++++++++++++++--
1 file changed, 18 insertions(+), 2 deletions(-)
diff -puN mm/vmscan.c~mm-vmscan-account-for-skipped-pages-as-a-partial-scan mm/vmscan.c
--- a/mm/vmscan.c~mm-vmscan-account-for-skipped-pages-as-a-partial-scan
+++ a/mm/vmscan.c
@@ -1424,7 +1424,7 @@ static unsigned long isolate_lru_pages(u
LIST_HEAD(pages_skipped);
for (scan = 0; scan < nr_to_scan && nr_taken < nr_to_scan &&
- !list_empty(src); scan++) {
+ !list_empty(src);) {
struct page *page;
page = lru_to_page(src);
@@ -1438,6 +1438,12 @@ static unsigned long isolate_lru_pages(u
continue;
}
+ /*
+ * Account for scanned and skipped separetly to avoid the pgdat
+ * being prematurely marked unreclaimable by pgdat_reclaimable.
+ */
+ scan++;
+
switch (__isolate_lru_page(page, mode)) {
case 0:
nr_pages = hpage_nr_pages(page);
@@ -1465,14 +1471,24 @@ static unsigned long isolate_lru_pages(u
*/
if (!list_empty(&pages_skipped)) {
int zid;
+ unsigned long total_skipped = 0;
- list_splice(&pages_skipped, src);
for (zid = 0; zid < MAX_NR_ZONES; zid++) {
if (!nr_skipped[zid])
continue;
__count_zid_vm_events(PGSCAN_SKIP, zid, nr_skipped[zid]);
+ total_skipped += nr_skipped[zid];
}
+
+ /*
+ * Account skipped pages as a partial scan as the pgdat may be
+ * close to unreclaimable. If the LRU list is empty, account
+ * skipped pages as a full scan.
+ */
+ scan += list_empty(src) ? total_skipped : total_skipped >> 2;
+
+ list_splice(&pages_skipped, src);
}
*nr_scanned = scan;
trace_mm_vmscan_lru_isolate(sc->reclaim_idx, sc->order, nr_to_scan, scan,
_
Patches currently in -mm which might be from mgorman@xxxxxxxxxxxxxxxxxxx are
--
To unsubscribe from this list: send the line "unsubscribe mm-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
