+ mm-page_alloc-avoid-overcounting-bulk-alloc-in-watermark-check.patch added to mm-new branch

+ mm-page_alloc-avoid-overcounting-bulk-alloc-in-watermark-check.patch added to mm-new branch

[Andrew Morton]

The patch titled
     Subject: mm/page_alloc: avoid overcounting bulk alloc in watermark check
has been added to the -mm mm-new branch.  Its filename is
     mm-page_alloc-avoid-overcounting-bulk-alloc-in-watermark-check.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-page_alloc-avoid-overcounting-bulk-alloc-in-watermark-check.patch

This patch will later appear in the mm-new branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Note, mm-new is a provisional staging ground for work-in-progress
patches, and acceptance into mm-new is a notification for others take
notice and to finish up reviews.  Please do not hesitate to respond to
review feedback and post updated versions to replace or incrementally
fixup patches in mm-new.

The mm-new branch of mm.git is not included in linux-next

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------------------------------------------------------
From: Shengming Hu <hu.shengming@zte.com.cn>
Subject: mm/page_alloc: avoid overcounting bulk alloc in watermark check
Date: Thu, 29 Jan 2026 22:38:14 +0800

alloc_pages_bulk_noprof() only fills NULL slots and already tracks how
many entries are pre-populated via nr_populated.

The fast watermark check was adding nr_pages unconditionally, which can
overestimate the demand.  Use (nr_pages - nr_populated) instead, as an
upper bound on the remaining pages this call can still allocate without
scanning the whole array.

Link: https://lkml.kernel.org/r/tencent_F36C5B5FB4DED98C79D9BDEE1210CD338C06@qq.com
Signed-off-by: Shengming Hu <hu.shengming@zte.com.cn>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/page_alloc.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/mm/page_alloc.c~mm-page_alloc-avoid-overcounting-bulk-alloc-in-watermark-check
+++ a/mm/page_alloc.c
@@ -5125,7 +5125,7 @@ unsigned long alloc_pages_bulk_noprof(gf
 
 		cond_accept_memory(zone, 0, alloc_flags);
 retry_this_zone:
-		mark = wmark_pages(zone, alloc_flags & ALLOC_WMARK_MASK) + nr_pages;
+		mark = wmark_pages(zone, alloc_flags & ALLOC_WMARK_MASK) + nr_pages - nr_populated;
 		if (zone_watermark_fast(zone, 0,  mark,
 				zonelist_zone_idx(ac.preferred_zoneref),
 				alloc_flags, gfp)) {
_

Patches currently in -mm which might be from hu.shengming@zte.com.cn are

mm-page_alloc-avoid-overcounting-bulk-alloc-in-watermark-check.patch
watchdog-softlockup-fix-sample-ring-index-wrap-in-need_counting_irqs.patch