+ mm-vmscan-sc-reclaim_idx-must-be-a-valid-zone-index.patch added to -mm tree

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: mm/vmscan: sc->reclaim_idx must be a valid zone index
has been added to the -mm tree.  Its filename is
     mm-vmscan-sc-reclaim_idx-must-be-a-valid-zone-index.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/mm-vmscan-sc-reclaim_idx-must-be-a-valid-zone-index.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/mm-vmscan-sc-reclaim_idx-must-be-a-valid-zone-index.patch

Before you just go and hit "reply", please:
   a) Consider who else should be cc'ed
   b) Prefer to cc a suitable mailing list as well
   c) Ideally: find the original patch on the mailing list and do a
      reply-to-all to that, adding suitable additional cc's

*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***

The -mm tree is included into linux-next and is updated
there every 3-4 working days

------------------------------------------------------
From: Wei Yang <richard.weiyang@gmail.com>
Subject: mm/vmscan: sc->reclaim_idx must be a valid zone index

lruvec_lru_size() is only used in get_scan_count(), so the only possible
zone_idx is sc->reclaim_idx.  Since sc->reclaim_idx is ensured to be a
valid zone idex, we can remove the extra check for zone iteration.

Link: https://lkml.kernel.org/r/20220317234624.23358-1-richard.weiyang@gmail.com
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/vmscan.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/mm/vmscan.c~mm-vmscan-sc-reclaim_idx-must-be-a-valid-zone-index
+++ a/mm/vmscan.c
@@ -587,7 +587,7 @@ unsigned long zone_reclaimable_pages(str
  * lruvec_lru_size -  Returns the number of pages on the given LRU list.
  * @lruvec: lru vector
  * @lru: lru to use
- * @zone_idx: zones to consider (use MAX_NR_ZONES for the whole LRU list)
+ * @zone_idx: zones to consider (use MAX_NR_ZONES - 1 for the whole LRU list)
  */
 static unsigned long lruvec_lru_size(struct lruvec *lruvec, enum lru_list lru,
 				     int zone_idx)
@@ -595,7 +595,7 @@ static unsigned long lruvec_lru_size(str
 	unsigned long size = 0;
 	int zid;
 
-	for (zid = 0; zid <= zone_idx && zid < MAX_NR_ZONES; zid++) {
+	for (zid = 0; zid <= zone_idx; zid++) {
 		struct zone *zone = &lruvec_pgdat(lruvec)->node_zones[zid];
 
 		if (!managed_zone(zone))
_

Patches currently in -mm which might be from richard.weiyang@gmail.com are

mm-page_alloc-add-same-penalty-is-enough-to-get-round-robin-order.patch
mm-vmscan-reclaim-only-affects-managed_zones.patch
mm-vmscan-make-sure-wakeup_kswapd-with-managed-zone.patch
mm-vmscan-sc-reclaim_idx-must-be-a-valid-zone-index.patch