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Shutemov" To: stable@vger.kernel.org Cc: "Kirill A. Shutemov" , Farrah Chen , Vlastimil Babka , Pankaj Gupta , Ashish Kalra , David Hildenbrand , "Edgecombe, Rick P" , Mel Gorman , "Mike Rapoport (IBM)" , Thomas Lendacky , Andrew Morton Subject: [PATCH 6.6.y] mm/page_alloc: fix memory accept before watermarks gets initialized Date: Tue, 25 Mar 2025 14:16:21 +0200 Message-ID: <20250325121621.2011574-1-kirill.shutemov@linux.intel.com> X-Mailer: git-send-email 2.47.2 In-Reply-To: <2025032417-prior-uncooked-bf1f@gregkh> References: <2025032417-prior-uncooked-bf1f@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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: dcdfdd40fa82 ("mm: Add support for unaccepted memory") Signed-off-by: Kirill A. Shutemov Tested-by: Farrah Chen Reported-by: Farrah Chen Acked-by: Vlastimil Babka Reviewed-by: Pankaj Gupta Cc: Ashish Kalra Cc: David Hildenbrand Cc: "Edgecombe, Rick P" Cc: Mel Gorman Cc: "Mike Rapoport (IBM)" Cc: Thomas Lendacky Cc: [6.5+] Signed-off-by: Andrew Morton (cherry picked from commit 800f1059c99e2b39899bdc67a7593a7bea6375d8) Signed-off-by: Kirill A. Shutemov --- mm/page_alloc.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 191f0f95d3ed..bc62bb2a3b13 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -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)); -- 2.47.2