The patch titled
mm: revert "vmscan: get_scan_ratio() cleanup"
has been added to the -mm tree. Its filename is
mm-revert-vmscan-get_scan_ratio-cleanup.patch
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------------------------------------------------------
Subject: mm: revert "vmscan: get_scan_ratio() cleanup"
From: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
Shaohua Li reported his tmpfs streaming I/O test can lead to make oom.
The test uses a 6G tmpfs in a system with 3G memory. In the tmpfs, there
are 6 copies of kernel source and the test does kbuild for each copy. His
investigation shows the test has a lot of rotated anon pages and quite few
file pages, so get_scan_ratio calculates percent[0] (i.e. scanning
percent for anon) to be zero. Actually the percent[0] shoule be a big
value, but our calculation round it to zero.
Although before commit 84b18490 ("vmscan: get_scan_ratio() cleanup") , we
have the same problem too. But the old logic can rescue percent[0]==0
case only when priority==0. It had hided the real issue. I didn't think
merely streaming io can makes percent[0]==0 && priority==0 situation. but
I was wrong.
So, definitely we have to fix such tmpfs streaming io issue. but anyway I
revert the regression commit at first.
This reverts commit 84b18490d1f1bc7ed5095c929f78bc002eb70f26.
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
Reported-by: Shaohua Li <shaohua.li@xxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxx>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Cc: Minchan Kim <minchan.kim@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/vmscan.c | 23 +++++++++--------------
1 file changed, 9 insertions(+), 14 deletions(-)
diff -puN mm/vmscan.c~mm-revert-vmscan-get_scan_ratio-cleanup mm/vmscan.c
--- a/mm/vmscan.c~mm-revert-vmscan-get_scan_ratio-cleanup
+++ a/mm/vmscan.c
@@ -1535,13 +1535,6 @@ static void get_scan_ratio(struct zone *
unsigned long ap, fp;
struct zone_reclaim_stat *reclaim_stat = get_reclaim_stat(zone, sc);
- /* If we have no swap space, do not bother scanning anon pages. */
- if (!sc->may_swap || (nr_swap_pages <= 0)) {
- percent[0] = 0;
- percent[1] = 100;
- return;
- }
-
anon = zone_nr_lru_pages(zone, sc, LRU_ACTIVE_ANON) +
zone_nr_lru_pages(zone, sc, LRU_INACTIVE_ANON);
file = zone_nr_lru_pages(zone, sc, LRU_ACTIVE_FILE) +
@@ -1639,20 +1632,22 @@ static void shrink_zone(int priority, st
unsigned long nr_reclaimed = sc->nr_reclaimed;
unsigned long nr_to_reclaim = sc->nr_to_reclaim;
struct zone_reclaim_stat *reclaim_stat = get_reclaim_stat(zone, sc);
+ int noswap = 0;
- get_scan_ratio(zone, sc, percent);
+ /* If we have no swap space, do not bother scanning anon pages. */
+ if (!sc->may_swap || (nr_swap_pages <= 0)) {
+ noswap = 1;
+ percent[0] = 0;
+ percent[1] = 100;
+ } else
+ get_scan_ratio(zone, sc, percent);
for_each_evictable_lru(l) {
int file = is_file_lru(l);
unsigned long scan;
- if (percent[file] == 0) {
- nr[l] = 0;
- continue;
- }
-
scan = zone_nr_lru_pages(zone, sc, l);
- if (priority) {
+ if (priority || noswap) {
scan >>= priority;
scan = (scan * percent[file]) / 100;
}
_
Patches currently in -mm which might be from kosaki.motohiro@xxxxxxxxxxxxxx are
mm-revert-vmscan-get_scan_ratio-cleanup.patch
page-allocator-reduce-fragmentation-in-buddy-allocator-by-adding-buddies-that-are-merging-to-the-tail-of-the-free-lists.patch
mm-remove-return-value-of-putback_lru_pages.patch
mempolicy-remove-redundant-code.patch
oom-filter-tasks-not-sharing-the-same-cpuset.patch
oom-sacrifice-child-with-highest-badness-score-for-parent.patch
oom-select-task-from-tasklist-for-mempolicy-ooms.patch
oom-remove-special-handling-for-pagefault-ooms.patch
oom-badness-heuristic-rewrite.patch
oom-deprecate-oom_adj-tunable.patch
oom-replace-sysctls-with-quick-mode.patch
oom-avoid-oom-killer-for-lowmem-allocations.patch
oom-remove-unnecessary-code-and-cleanup.patch
oom-default-to-killing-current-for-pagefault-ooms.patch
oom-avoid-race-for-oom-killed-tasks-detaching-mm-prior-to-exit.patch
oom-hold-tasklist_lock-when-dumping-tasks.patch
oom-give-current-access-to-memory-reserves-if-it-has-been-killed.patch
oom-avoid-sending-exiting-tasks-a-sigkill.patch
oom-clean-up-oom_kill_task.patch
oom-clean-up-oom_badness.patch
mempolicy-dont-call-mpol_set_nodemask-when-no_context.patch
mempolicy-lose-unnecessary-loop-variable-in-mpol_parse_str.patch
mempolicy-rename-policy_types-and-cleanup-initialization.patch
mempolicy-factor-mpol_shared_policy_init-return-paths.patch
mempolicy-document-cpuset-interaction-with-tmpfs-mpol-mount-option.patch
proc-cleanup-remove-unused-assignments.patch
reiser4.patch
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