The patch titled
Subject: mm/vmscan: filter empty page_list at the beginning
has been added to the -mm mm-unstable branch. Its filename is
mm-vmscan-filter-empty-page_list-at-the-beginning.patch
This patch should soon appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Wei Yang <richard.weiyang@xxxxxxxxx>
Subject: mm/vmscan: filter empty page_list at the beginning
node_page_list would always be !empty on finishing the loop, except
page_list is empty.
Let's handle empty page_list before doing any real work including touching
PF_MEMALLOC flag.
Link: https://lkml.kernel.org/r/20220429014426.29223-1-richard.weiyang@xxxxxxxxx
Signed-off-by: Wei Yang <richard.weiyang@xxxxxxxxx>
Reviewed-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/vmscan.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
--- a/mm/vmscan.c~mm-vmscan-filter-empty-page_list-at-the-beginning
+++ a/mm/vmscan.c
@@ -2568,9 +2568,12 @@ unsigned long reclaim_pages(struct list_
struct page *page;
unsigned int noreclaim_flag;
+ if (list_empty(page_list))
+ return nr_reclaimed;
+
noreclaim_flag = memalloc_noreclaim_save();
- while (!list_empty(page_list)) {
+ do {
page = lru_to_page(page_list);
if (nid == NUMA_NO_NODE)
nid = page_to_nid(page);
@@ -2583,10 +2586,9 @@ unsigned long reclaim_pages(struct list_
nr_reclaimed += reclaim_page_list(&node_page_list, NODE_DATA(nid));
nid = NUMA_NO_NODE;
- }
+ } while (!list_empty(page_list));
- if (!list_empty(&node_page_list))
- nr_reclaimed += reclaim_page_list(&node_page_list, NODE_DATA(nid));
+ nr_reclaimed += reclaim_page_list(&node_page_list, NODE_DATA(nid));
memalloc_noreclaim_restore(noreclaim_flag);
_
Patches currently in -mm which might be from richard.weiyang@xxxxxxxxx are
mm-vmscan-not-necessary-to-re-init-the-list-for-each-iteration.patch
mm-vmscan-filter-empty-page_list-at-the-beginning.patch
mm-vmscan-not-use-numa_no_node-as-indicator-of-page-on-different-node.patch
