The patch titled
Subject: mm-vmscan-try-to-reclaim-swapcache-pages-if-no-swap-space-v6
has been added to the -mm mm-unstable branch. Its filename is
mm-vmscan-try-to-reclaim-swapcache-pages-if-no-swap-space-v6.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-vmscan-try-to-reclaim-swapcache-pages-if-no-swap-space-v6.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Liu Shixin <liushixin2@xxxxxxxxxx>
Subject: mm-vmscan-try-to-reclaim-swapcache-pages-if-no-swap-space-v6
Date: Fri, 15 Sep 2023 16:34:17 +0800
fix NULL pointing derefence and hung task problem reported by Sachin
Link: https://lkml.kernel.org/r/20230915083417.3190512-1-liushixin2@xxxxxxxxxx
Signed-off-by: Liu Shixin <liushixin2@xxxxxxxxxx>
Tested-by: Yosry Ahmed <yosryahmed@xxxxxxxxxx>
Reviewed-by: "Huang, Ying" <ying.huang@xxxxxxxxx>
Reviewed-by: Yosry Ahmed <yosryahmed@xxxxxxxxxx>
Cc: "Huang, Ying" <ying.huang@xxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Sachin Sant <sachinp@xxxxxxxxxxxxx>
Cc: Yosry Ahmed <yosryahmed@xxxxxxxxxx>
Cc: Muchun Song <muchun.song@xxxxxxxxx>
Cc: Roman Gushchin <roman.gushchin@xxxxxxxxx>
Cc: Shakeel Butt <shakeelb@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/vmscan.c | 31 +++++++++++++++----------------
1 file changed, 15 insertions(+), 16 deletions(-)
--- a/mm/vmscan.c~mm-vmscan-try-to-reclaim-swapcache-pages-if-no-swap-space-v6
+++ a/mm/vmscan.c
@@ -618,7 +618,8 @@ static inline bool can_reclaim_anon_page
return true;
/* Is there any swapcache pages to reclaim? */
if (total_swapcache_pages() > 0) {
- sc->swapcache_only = 1;
+ if (sc)
+ sc->swapcache_only = 1;
return true;
}
} else {
@@ -627,7 +628,8 @@ static inline bool can_reclaim_anon_page
return true;
/* Is there any swapcache pages in memcg to reclaim? */
if (mem_cgroup_get_nr_swapcache_pages(memcg) > 0) {
- sc->swapcache_only = 1;
+ if (sc)
+ sc->swapcache_only = 1;
return true;
}
}
@@ -2293,19 +2295,6 @@ static bool skip_cma(struct folio *folio
}
#endif
-static bool skip_isolate(struct folio *folio, struct scan_control *sc,
- enum lru_list lru)
-{
- if (folio_zonenum(folio) > sc->reclaim_idx)
- return true;
- if (skip_cma(folio, sc))
- return true;
- if (unlikely(sc->swapcache_only && !is_file_lru(lru) &&
- !folio_test_swapcache(folio)))
- return true;
- return false;
-}
-
/*
* Isolating page from the lruvec to fill in @dst list by nr_to_scan times.
*
@@ -2352,7 +2341,8 @@ static unsigned long isolate_lru_folios(
nr_pages = folio_nr_pages(folio);
total_scan += nr_pages;
- if (skip_isolate(folio, sc, lru)) {
+ if (folio_zonenum(folio) > sc->reclaim_idx ||
+ skip_cma(folio, sc)) {
nr_skipped[folio_zonenum(folio)] += nr_pages;
move_to = &folios_skipped;
goto move;
@@ -2367,6 +2357,15 @@ static unsigned long isolate_lru_folios(
*/
scan += nr_pages;
+ /*
+ * Count non-swapcache too because the swapcache pages may
+ * be rare and it takes too much times here if not count
+ * the non-swapcache pages.
+ */
+ if (unlikely(sc->swapcache_only && !is_file_lru(lru) &&
+ !folio_test_swapcache(folio)))
+ goto move;
+
if (!folio_test_lru(folio))
goto move;
if (!sc->may_unmap && folio_mapped(folio))
_
Patches currently in -mm which might be from liushixin2@xxxxxxxxxx are
mm-vmscan-try-to-reclaim-swapcache-pages-if-no-swap-space.patch
mm-vmscan-try-to-reclaim-swapcache-pages-if-no-swap-space-v6.patch
