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[80.230.25.21]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-48a5aa3ae83sm884845e9.12.2026.04.21.15.02.11 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 21 Apr 2026 15:02:13 -0700 (PDT) Date: Tue, 21 Apr 2026 18:02:11 -0400 From: "Michael S. Tsirkin" To: linux-kernel@vger.kernel.org Cc: Andrew Morton , David Hildenbrand , Vlastimil Babka , Brendan Jackman , Michal Hocko , Suren Baghdasaryan , Jason Wang , Andrea Arcangeli , Gregory Price , linux-mm@kvack.org, virtualization@lists.linux.dev, Johannes Weiner , Zi Yan Subject: [PATCH RFC v3 18/19] mm: page_alloc: preserve PG_zeroed in page_del_and_expand Message-ID: <23f51ec61026f598a30a2a031fcf88100afc1f98.1776808210.git.mst@redhat.com> References: MIME-Version: 1.0 In-Reply-To: X-Mailer: git-send-email 2.27.0.106.g8ac3dc51b1 X-Mutt-Fcc: =sent X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: ZB_Tx27WxhznCoe-ddbVcvnYRhffJrbW6ADMbhKg5SA_1776808935 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-Rspamd-Server: rspam10 X-Stat-Signature: o5kr841at1pi9fczbswqg6rtgbhk6wei X-Rspam-User: X-Rspamd-Queue-Id: B3FE78000F X-HE-Tag: 1776808937-796657 X-HE-Meta: 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 fX2A8HyU 16AX/KSnH+7fyJs2fZUJmwScDshOkyxbtl7pNKf6wfDE82JNF4zsLnIXDcoHZ6HfnLwyKk9vOILcRMfUDt+4GnCyx+LiR/IsE2ywgf+MulJPRSRR+6awxpvcwGripaYAGo58WxY56777VKgOFraa7X0Yu/5K2Shr0VfiLvOKHpMFnQg1/gdYTBbTKzx0Ev9gxz/fznh/pCe25BJu65naTmI3Oy5gslvfSkR8VO08WyRKNSxlcVbZBlnED/qUhaOZDL+7RSVlNZzjGJ+mFjNcln8qtJr5hyJHhP9FyKLiT0d8DEwNiAbQWEyt+gCA4BhbKca6F0ej+17uF0xioAVwsSo91hpedl9+4moavwqBYf+FGRl6YZvTOFtuuhg== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Don't unconditionally clear PG_zeroed for non-reported pages in page_del_and_expand(). Pages freed via free_frozen_pages_zeroed (balloon deflate) already have the flag set and should keep it through buddy allocation, not just PCP reuse. Signed-off-by: Michael S. Tsirkin Assisted-by: Claude:claude-opus-4-6 Assisted-by: cursor-agent:GPT-5.4-xhigh --- mm/page_alloc.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 122b49a6d435..3f5ed022cb9c 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1751,7 +1751,8 @@ struct page *__pageblock_pfn_to_page(unsigned long start_pfn, * -- nyc */ static inline unsigned int expand(struct zone *zone, struct page *page, int low, - int high, int migratetype, bool reported) + int high, int migratetype, bool reported, + bool zeroed) { unsigned int size = 1 << high; unsigned int nr_added = 0; @@ -1782,6 +1783,8 @@ static inline unsigned int expand(struct zone *zone, struct page *page, int low, */ if (reported) __SetPageReported(&page[size]); + if (zeroed) + __SetPageZeroed(&page[size]); } return nr_added; @@ -1793,10 +1796,12 @@ static __always_inline void page_del_and_expand(struct zone *zone, { int nr_pages = 1 << high; bool was_reported = page_reported(page); + bool was_zeroed = PageZeroed(page); __del_page_from_free_list(page, zone, high, migratetype); - nr_pages -= expand(zone, page, low, high, migratetype, was_reported); + nr_pages -= expand(zone, page, low, high, migratetype, was_reported, + was_zeroed); account_freepages(zone, -nr_pages, migratetype); } @@ -2373,11 +2378,13 @@ try_to_claim_block(struct zone *zone, struct page *page, /* Take ownership for orders >= pageblock_order */ if (current_order >= pageblock_order) { unsigned int nr_added; + bool was_reported = page_reported(page); + bool was_zeroed = PageZeroed(page); del_page_from_free_list(page, zone, current_order, block_type); change_pageblock_range(page, current_order, start_type); nr_added = expand(zone, page, order, current_order, start_type, - false); + was_reported, was_zeroed); account_freepages(zone, nr_added, start_type); return page; } -- MST