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mm/page_alloc: fix memory accept before watermarks gets initialized

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commit 800f1059c99e2b39899bdc67a7593a7bea6375d8 upstream.

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@linux.intel.com
Fixes: dcdfdd40fa ("mm: Add support for unaccepted memory")
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Tested-by: Farrah Chen <farrah.chen@intel.com>
Reported-by: Farrah Chen <farrah.chen@intel.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Pankaj Gupta <pankaj.gupta@amd.com>
Cc: Ashish Kalra <ashish.kalra@amd.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Edgecombe, Rick P" <rick.p.edgecombe@intel.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: "Mike Rapoport (IBM)" <rppt@kernel.org>
Cc: Thomas Lendacky <thomas.lendacky@amd.com>
Cc: <stable@vger.kernel.org>	[6.5+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Kirill A. Shutemov
2025-03-10 10:28:55 +02:00
committed by Greg Kroah-Hartman
parent 404d85a71d
commit 790d30578f
1 changed files with 12 additions and 2 deletions
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14
mm/page_alloc.c
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@@ -6653,7 +6653,7 @@ static bool try_to_accept_memory_one(struct zone *zone)
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())
@@ -6662,8 +6662,18 @@ static bool cond_accept_memory(struct zone *zone, unsigned int order)
if (list_empty(&zone->unaccepted_pages))
return false;
wmark = high_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 high watermark? */
to_accept = high_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));