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...
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@linux.intel.com 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@linux.int... Fixes: dcdfdd40fa82 ("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 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: Vlastimil Babka vbabka@suse.cz Cc: stable@vger.kernel.org [6.5+] Signed-off-by: Andrew Morton akpm@linux-foundation.org ---
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@linux.intel.com are
mm-page_alloc-fix-memory-accept-before-watermarks-gets-initialized.patch