The patch titled
Subject: mm/page_alloc: fix memory accept before watermarks gets initialized
has been added to the -mm mm-hotfixes-unstable branch. Its filename is
mm-page_alloc-fix-memory-accept-before-watermarks-gets-initialized.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-fix-memory-accept-before-watermarks-gets-initialized.patch
This patch will later appear in the mm-hotfixes-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
Subject: mm/page_alloc: fix memory accept before watermarks gets initialized
Date: Mon, 10 Mar 2025 10:28:55 +0200
Watermarks are initialized during the postcore initcall. Until then, all
watermarks are set to zero. This causes cond_accept_memory() to
incorrectly skip memory acceptance because a watermark of 0 is always met.
This can lead to a premature OOM on boot.
To ensure progress, accept one MAX_ORDER page if the watermark is zero.
Link: https://lkml.kernel.org/r/20250310082855.2587122-1-kirill.shutemov@xxxxxxxxxxxxxxx
Fixes: dcdfdd40fa82 ("mm: Add support for unaccepted memory")
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Tested-by: Farrah Chen <farrah.chen@xxxxxxxxx>
Reported-by: Farrah Chen <farrah.chen@xxxxxxxxx>
Cc: Ashish Kalra <ashish.kalra@xxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: "Edgecombe, Rick P" <rick.p.edgecombe@xxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Cc: "Mike Rapoport (IBM)" <rppt@xxxxxxxxxx>
Cc: Thomas Lendacky <thomas.lendacky@xxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> [6.5+]
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/page_alloc.c | 14 ++++++++++++--
1 file changed, 12 insertions(+), 2 deletions(-)
--- a/mm/page_alloc.c~mm-page_alloc-fix-memory-accept-before-watermarks-gets-initialized
+++ a/mm/page_alloc.c
@@ -7004,7 +7004,7 @@ static inline bool has_unaccepted_memory
static bool cond_accept_memory(struct zone *zone, unsigned int order)
{
- long to_accept;
+ long to_accept, wmark;
bool ret = false;
if (!has_unaccepted_memory())
@@ -7013,8 +7013,18 @@ static bool cond_accept_memory(struct zo
if (list_empty(&zone->unaccepted_pages))
return false;
+ wmark = promo_wmark_pages(zone);
+
+ /*
+ * Watermarks have not been initialized yet.
+ *
+ * Accepting one MAX_ORDER page to ensure progress.
+ */
+ if (!wmark)
+ return try_to_accept_memory_one(zone);
+
/* How much to accept to get to promo watermark? */
- to_accept = promo_wmark_pages(zone) -
+ to_accept = wmark -
(zone_page_state(zone, NR_FREE_PAGES) -
__zone_watermark_unusable_free(zone, order, 0) -
zone_page_state(zone, NR_UNACCEPTED));
_
Patches currently in -mm which might be from kirill.shutemov@xxxxxxxxxxxxxxx are
mm-page_alloc-fix-memory-accept-before-watermarks-gets-initialized.patch
