The patch titled
Subject: mm/vmscan.c: add warn on inadvertently reclaiming mapped page
has been added to the -mm tree. Its filename is
mm-vmscan-add-warn-on-inadvertently-reclaiming-mapped-page.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-vmscan-add-warn-on-inadvertently-reclaiming-mapped-page.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-vmscan-add-warn-on-inadvertently-reclaiming-mapped-page.patch
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------------------------------------------------------
From: Hillf Danton <hdanton@xxxxxxxx>
Subject: mm/vmscan.c: add warn on inadvertently reclaiming mapped page
In isolate_lru_pages(), we check scan_control::may_unmap and set isolation
mode accordingly in order to not isolate from the lru list any page that
does not match the isolation mode. For example, we should skip all sill
mapped pages if isolation mode is set to be ISOLATE_UNMAPPED.
So complain, while scanning the isolated pages, about the very unlikely
event that we hit a mapped page that we should never have isolated. Note
no change is added in the current scanning behavior without VM debug
configured.
And cut off one line of comment that goes stale.
Link: http://lkml.kernel.org/r/20190526062353.14684-1-hdanton@xxxxxxxx
Signed-off-by: Hillf Danton <hdanton@xxxxxxxx>
Reviewed-by: Yang Shi <yang.shi@xxxxxxxxxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/vmscan.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
--- a/mm/vmscan.c~mm-vmscan-add-warn-on-inadvertently-reclaiming-mapped-page
+++ a/mm/vmscan.c
@@ -1138,8 +1138,10 @@ static unsigned long shrink_page_list(st
if (unlikely(!page_evictable(page)))
goto activate_locked;
- if (!sc->may_unmap && page_mapped(page))
+ if (!sc->may_unmap && page_mapped(page)) {
+ VM_WARN_ON(true);
goto keep_locked;
+ }
may_enter_fs = (sc->gfp_mask & __GFP_FS) ||
(PageSwapCache(page) && (sc->gfp_mask & __GFP_IO));
@@ -1657,7 +1659,6 @@ static __always_inline void update_lru_s
* @dst: The temp list to put pages on to.
* @nr_scanned: The number of pages that were scanned.
* @sc: The scan_control struct for this reclaim session
- * @mode: One of the LRU isolation modes
* @lru: LRU list id for isolating
*
* returns how many pages were moved onto *@dst.
_
Patches currently in -mm which might be from hdanton@xxxxxxxx are
mm-vmscan-add-warn-on-inadvertently-reclaiming-mapped-page.patch
