The patch titled
mm: fix for infinite churning of mlocked pages
has been added to the -mm tree. Its filename is
mm-fix-for-infinite-churning-of-mlocked-pages.patch
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------------------------------------------------------
Subject: mm: fix for infinite churning of mlocked pages
From: Minchan Kim <minchan.kim@xxxxxxxxx>
An mlocked page might lose the isolatation race. This causes the page to
clear PG_mlocked while it remains in a VM_LOCKED vma. This means it can
be put onto the [in]active list. We can rescue it by using try_to_unmap()
in shrink_page_list().
But now, As Wu Fengguang pointed out, vmscan has a bug. If the page has
PG_referenced, it can't reach try_to_unmap() in shrink_page_list() but is
put into the active list. If the page is referenced repeatedly, it can
remain on the [in]active list without being moving to the unevictable
list.
This patch fixes it.
Reported-by: Wu Fengguang <fengguang.wu@xxxxxxxxx>
Signed-off-by: Minchan Kim <minchan.kim@xxxxxxxxx>
Cc: KOSAKI Motohiro <<kosaki.motohiro@xxxxxxxxxxxxxx>
Cc: Lee Schermerhorn <lee.schermerhorn@xxxxxx>
Acked-by: Rik van Riel <riel@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/rmap.c | 1 +
mm/vmscan.c | 9 +++++++--
2 files changed, 8 insertions(+), 2 deletions(-)
diff -puN mm/rmap.c~mm-fix-for-infinite-churning-of-mlocked-pages mm/rmap.c
--- a/mm/rmap.c~mm-fix-for-infinite-churning-of-mlocked-pages
+++ a/mm/rmap.c
@@ -363,6 +363,7 @@ static int page_referenced_one(struct pa
*/
if (vma->vm_flags & VM_LOCKED) {
*mapcount = 1; /* break early from loop */
+ *vm_flags |= VM_LOCKED;
goto out_unmap;
}
diff -puN mm/vmscan.c~mm-fix-for-infinite-churning-of-mlocked-pages mm/vmscan.c
--- a/mm/vmscan.c~mm-fix-for-infinite-churning-of-mlocked-pages
+++ a/mm/vmscan.c
@@ -630,9 +630,14 @@ static unsigned long shrink_page_list(st
referenced = page_referenced(page, 1,
sc->mem_cgroup, &vm_flags);
- /* In active use or really unfreeable? Activate it. */
+ /*
+ * In active use or really unfreeable? Activate it.
+ * If page which have PG_mlocked lost isoltation race,
+ * try_to_unmap moves it to unevictable list
+ */
if (sc->order <= PAGE_ALLOC_COSTLY_ORDER &&
- referenced && page_mapping_inuse(page))
+ referenced && page_mapping_inuse(page)
+ && !(vm_flags & VM_LOCKED))
goto activate_locked;
/*
_
Patches currently in -mm which might be from minchan.kim@xxxxxxxxx are
linux-next.patch
mm-fix-for-infinite-churning-of-mlocked-pages.patch
mm-show_free_areas-display-slab-pages-in-two-separate-fields.patch
mm-oom-analysis-add-per-zone-statistics-to-show_free_areas.patch
mm-oom-analysis-show-kernel-stack-usage-in-proc-meminfo-and-oom-log-output.patch
mm-rename-pgmoved-variable-in-shrink_active_list.patch
mm-shrink_inactive_list-nr_scan-accounting-fix-fix.patch
mm-vmstat-add-isolate-pages.patch
mm-vmstat-add-isolate-pages-fix.patch
mm-remove-__addsub_zone_page_state.patch
mm-count-only-reclaimable-lru-pages-v2.patch
vmscan-dont-attempt-to-reclaim-anon-page-in-lumpy-reclaim-when-no-swap-space-is-avilable.patch
vmscan-move-clearpageactive-from-move_active_pages-to-shrink_active_list.patch
vmscan-kill-unnecessary-page-flag-test.patch
vmscan-kill-unnecessary-prefetch.patch
mm-introduce-page_lru_base_type.patch
memory-hotplug-fix-updating-of-num_physpages-for-hot-plugged-memory.patch
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