From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3A6C13C5535 for ; Wed, 20 May 2026 22:23:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779315794; cv=none; b=XkHhHKUHT3xLsXFd2wlkn4IprmD7fqzGPnXr62Z+YIqJpGcqGKHbAi6mrooL3D6o+4WP8qbVLNW5mMgdy4rQ/pdIh9lBWV1T9C6NSsky53sbhVvivqWu/TMcHdFTxlaE04DIsAndGT7RDMYquD7CNjZ4YUec+xoHWUiD30w7Gvk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779315794; c=relaxed/simple; bh=gX3aTYbHX/GyGonutM5PlW3FkeXMFkBsDPOEXbSa+qI=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Ahi8PIQ5w0Ha6Pu47gqU1zM356VJTedLWwsGVFvSKCDOVnAVWtkG286OzcwX66ESsKwF5fwJwK+ZYvX2bhzkEybK8PHWl66MpcCd/54+L/xF38lgEpH0aa2xkrre0tx5RY6D9ERoyWmxcHJZqZ4oE8kECfP1/g2Om8FBBQydYKk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=inAXTcAr; dkim=pass (2048-bit key) header.d=redhat.com header.i=@redhat.com header.b=db9VyuCX; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="inAXTcAr"; dkim=pass (2048-bit key) header.d=redhat.com header.i=@redhat.com header.b="db9VyuCX" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1779315792; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=yuucL8pRyKGlavgC043yPLfH9MArN/0/T/V0zfd6qpo=; b=inAXTcArsJ/GPlS5MvDbgaWhy/O89WUY8UXFKM1c+yrh4HA1JO/NoB+RmwaAKw6ALQYHXd rgN0eY5DFbPhr4TzJHRctzt2oABDBgqiWGwRNfqU8YvB2aRxP0rWWFKIXfM1y+uYPulqwP DMDJ8EB+qh3lU7/5xRSwlXHEWzt7oSQ= Received: from mail-wr1-f70.google.com (mail-wr1-f70.google.com [209.85.221.70]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-166-ZPlarE5bPkOGHuepFS9QVA-1; Wed, 20 May 2026 18:23:09 -0400 X-MC-Unique: ZPlarE5bPkOGHuepFS9QVA-1 X-Mimecast-MFC-AGG-ID: ZPlarE5bPkOGHuepFS9QVA_1779315789 Received: by mail-wr1-f70.google.com with SMTP id ffacd0b85a97d-45e2f74da10so5973311f8f.2 for ; Wed, 20 May 2026 15:23:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=google; t=1779315788; x=1779920588; darn=vger.kernel.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=yuucL8pRyKGlavgC043yPLfH9MArN/0/T/V0zfd6qpo=; b=db9VyuCXbgqIG29bWhl6vjwCrzXuVd9nVOkOX+mf11usIbY35uE098XK1YA/v//FoA 702u5n/jJwB+r7nCJPEiUc0RjeapSu355SeFOeDaFYrp3gqVpF6yZrF+kZuWiGStuAf2 25L8dMqxoqLE+VXc4Phmh2szAaWGeup0V9Ox2rVgeyB06AMABtNQoCldTNX4bGgjwQ/t Fu1GhElldtPYVL+dUH6gb9FaOLMDDuA3OMs8s0DntALzg9TxyN+kkS8YHa6w990fimU5 qdfuKyzNhp/gEJ+n7D/aryMMPL15ZO3Q/izGuriNPFpAcuFv9ro2x3O79Q2uYhufqeQ2 2f0g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1779315788; x=1779920588; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-gg:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=yuucL8pRyKGlavgC043yPLfH9MArN/0/T/V0zfd6qpo=; b=O3uebXIFznFSLV0LFdvI594engsOHi+dGwLRNrA8zphb0rwwHBJpKU5WDQVRJxgCv0 hFwkrLMfImq0VpAniss1nosOJLWHaOjXsWMa5ObBiUfXsOEmRiaSG9aOerwZDcVfdIXr m4dYGQ8fTHIWjq5+VF9+KdxUVe+/gdYCThyzOUtTaXh473xO0aQs2UHbi4aF28wKt+bZ znskbOle+Ow38IS8t8u8W7jnZvxSdyXeEVurWAo6+IVL5NO5WrKdOtG3qXVyOmugowxL fw7XHmczWFGqGI9sILNqjGaVOFHrRzTT1CnCgM96YlGjwVuPNZhn0eZUoX0MfZMI2a/N 7+xA== X-Gm-Message-State: AOJu0YzPLsVlmn56e5BerLZLc155ENjOOYDVhsbZJFIIFco9tW6s6W3m UGLIFlCKezYaTAFRUIeE8TyFoe5KfHRNRhikLP6mxFsiZuYhuKdNjvdRkSMWnrNZCWtKpro4+j7 1eREZFIXmWivjeD2tNXTSuQ4kNeEkjeFYiTZS/LX4V4DVEi60dYBoGRzqvjy9GRyCI3tfcr2tov Bde32MovorRo3Heo4IifAjqNswIJDjPKqmSHzgzayE8nQ= X-Gm-Gg: Acq92OGDVDTAhZKjM9hcZsMrU0o6BCtVWSCqZN0FTWRgX96r0qjtjWgcdjPpDSkTL6E s7gzgEkz/HdgFX4Qq35gDmuNKGS8QZ7NR3NPCt7sFrLLB5xAeuOfMnakbfFjnIwSCkPOdrL+q5F CNQKkqs6h64QnJaDNzZYMP8LAdKiORVg3kGEoh0gVzc26obou0CItreex/pUIggDxKyIsELD7Xs nnb7ywDKP5QozaEzo/IKzsc6QkSvaBsgow1ncqCwGYo1A4RmIl6FVcuiMUCXReIBNG1AsdqJIxH zXTt5Bnb8tSjuZAsDC4N9Znm+NeoPCKi88wcadx3z98hYCLGbplq4wMRwGtZ1+ZWd7bmgcfHjin O+iz95dg9DsazWFg48vPab2/zhMYZgPXqMtbvg8AXvsY= X-Received: by 2002:a5d:5c81:0:b0:43c:f3ef:ee36 with SMTP id ffacd0b85a97d-45ea3ff957amr218759f8f.33.1779315788444; Wed, 20 May 2026 15:23:08 -0700 (PDT) X-Received: by 2002:a5d:5c81:0:b0:43c:f3ef:ee36 with SMTP id ffacd0b85a97d-45ea3ff957amr218690f8f.33.1779315787876; Wed, 20 May 2026 15:23:07 -0700 (PDT) Received: from redhat.com (IGLD-80-230-25-45.inter.net.il. [80.230.25.45]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-45da0fe1a41sm61756873f8f.31.2026.05.20.15.23.03 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 20 May 2026 15:23:07 -0700 (PDT) Date: Wed, 20 May 2026 18:23:02 -0400 From: "Michael S. Tsirkin" To: linux-kernel@vger.kernel.org Cc: "David Hildenbrand (Arm)" , Jason Wang , Xuan Zhuo , Eugenio =?utf-8?B?UMOpcmV6?= , Muchun Song , Oscar Salvador , Andrew Morton , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Brendan Jackman , Johannes Weiner , Zi Yan , Baolin Wang , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , Hugh Dickins , Matthew Brost , Joshua Hahn , Rakie Kim , Byungchul Park , Gregory Price , Ying Huang , Alistair Popple , Christoph Lameter , David Rientjes , Roman Gushchin , Harry Yoo , Axel Rasmussen , Yuanchu Xie , Wei Xu , Chris Li , Kairui Song , Kemeng Shi , Nhat Pham , Baoquan He , virtualization@lists.linux.dev, linux-mm@kvack.org, Andrea Arcangeli Subject: [PATCH v8 30/37] mm: page_alloc: propagate PG_zeroed in split_large_buddy Message-ID: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Mailer: git-send-email 2.27.0.106.g8ac3dc51b1 X-Mutt-Fcc: =sent When splitting a large buddy page, propagate the PG_zeroed flag to each sub-page before freeing it. __free_pages_prepare clears all flags (including PG_zeroed), so the flag must be re-set on each fragment after the split. This ensures that the buddy merge logic can see PG_zeroed on pages that were part of a larger zeroed block. Signed-off-by: Michael S. Tsirkin Reviewed-by: Gregory Price Assisted-by: Claude:claude-opus-4-6 Assisted-by: cursor-agent:GPT-5.4-xhigh --- mm/page_alloc.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 72e52f049cf0..702fa2ced1e1 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1524,6 +1524,7 @@ static void split_large_buddy(struct zone *zone, struct page *page, { unsigned long end = pfn + (1 << order); bool reported = PageReported(page); + bool zeroed = PageZeroed(page); VM_WARN_ON_ONCE(!IS_ALIGNED(pfn, 1 << order)); /* Caller removed page from freelist, buddy info cleared! */ @@ -1537,6 +1538,8 @@ static void split_large_buddy(struct zone *zone, struct page *page, if (reported) __SetPageReported(page); + if (zeroed) + __SetPageZeroed(page); __free_one_page(page, pfn, zone, order, mt, fpi); pfn += 1 << order; if (pfn == end) -- MST