From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 A67423A784F; Wed, 30 Sep 2026 17:18:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790788689; cv=none; b=XQn2G0H1IAcR3uH5n6+mUcJBfU2povueb4tJwBimoE7tfdJDv/PaN3Pz0CMrJ/AIL9EumZpqHh3Rbmm8IUi/OjXNo/+vnq9vXjwka6TNvVobPc+wzv1WQEkxR+14RbZoxJWgd7wqGL2zm3Q5z373k8NohkJgAPqBRd9lnfmlSYU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790788689; c=relaxed/simple; bh=OBMsysFdhYgCTCDLfxoEf+RHGA7NFS5435qQEs/B+Dc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Aprj09xbyMbMcUW/FJDG0MMwreAYG6LxQTnuryihDp8PI8Z17nbSLsgK6mQFor0q0humSRGXJLsuCWJmFIwFozZ/bpPXu8IaAXrv8rWL/zgPlR/pfdywgO7HE7VbfOovdSRInPVFDUmh/zpdjneMedayocZCkM5LApz00lpCPck= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=altkosFx; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="altkosFx" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7B4711F000FF; Wed, 30 Sep 2026 17:18:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1790788688; bh=3PCwQ6OYls26fi/zsEy12M9XC2Qn0HwyqNpLDMM0peo=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=altkosFx5Z4rtmaQ9XSXq87AkkXxjaf2qmQyHpqAjxZBI1PaHOSb3WHx4cpCMRUxc Dm8kCt2h3/hVXTyn2iG0eCUQCAsYDIfsI+TKw86SlZbkF2dil6xSOIN3Z8AIf34Leg KfjcwiiPKoqwHhW3mG1NDq7TwdHJ892s/Z6tWlcU= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Zi Yan , Johannes Weiner , Baolin Wang , "Lorenzo Stoakes (ARM)" , Barry Song , David Hildenbrand , Dev Jain , Lance Yang , "Liam R. Howlett" , "Matthew Wilcox (Oracle)" , Ryan Roberts , William Kucharski , Andrew Morton , Sasha Levin Subject: [PATCH 6.12 158/877] mm/huge_memory: use folios memcg inside __folio_split() Date: Wed, 30 Sep 2026 17:17:49 +0200 Message-ID: <20260930152418.129969084@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260930152414.738996857@linuxfoundation.org> References: <20260930152414.738996857@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Zi Yan commit c299a2285d9d8bda4da024455de65e3d00de6f17 upstream. Patch series "Honor XA_FLAGS_ACCOUNT in xas_split_alloc() and charge to folio's memcg", v3. __GFP_ACCOUNT is needed for xarray node allocation accounting when XA_FLAGS_ACCOUNT is set. Commit 7b785645e8f13 ("mm: fix page cache convergence regression") fixed a workingset regression with it. xas_split_alloc() does not have it and needs to be fixed. In addition, based on Sashiko's review[1] and Johannes' confirmation[2], to charge the right memcg, folio's memcg needs to be active during folio split. Add that before adding __GFP_ACCOUNT. There is no workingset convergence regression related to missing __GFP_ACCOUNT in xas_split_alloc() and the impact to userspace should be minor. This patch (of 2): During a pagecache folio split, an xarray node allocation can happen and needs to charge at folio's memcg instead of folio split invoker's memcg, because for example folio split can happen during reclaim and reclaim's active memcg might not be folio's memcg. Switch to folio's memcg at the beginning and switch back afterwards. Link: https://lore.kernel.org/20260804-add-gfp_account-to-xas_split_alloc-v3-0-38cb3ff325c5@nvidia.com Link: https://lore.kernel.org/20260804-add-gfp_account-to-xas_split_alloc-v3-1-38cb3ff325c5@nvidia.com Link: https://sashiko.dev/#/patchset/20260727-add-gfp_account-to-xas_split_alloc-v1-1-9fae6bf64838%40nvidia.com?part=1 [1] Link: https://lore.kernel.org/all/amtcBZ-_QVRgCd6b@cmpxchg.org/ [2] Fixes: 6b24ca4a1a8d ("mm: Use multi-index entries in the page cache") Signed-off-by: Zi Yan Suggested-by: Johannes Weiner Reviewed-by: Baolin Wang Acked-by: Lorenzo Stoakes (ARM) Acked-by: Johannes Weiner Cc: Barry Song Cc: David Hildenbrand Cc: Dev Jain Cc: Lance Yang Cc: Liam R. Howlett Cc: Matthew Wilcox (Oracle) Cc: Ryan Roberts Cc: William Kucharski Cc: Signed-off-by: Andrew Morton (cherry picked from commit c299a2285d9d8bda4da024455de65e3d00de6f17) Signed-off-by: Zi Yan Signed-off-by: Sasha Levin --- mm/huge_memory.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 6fc4e1fb88ae6..1a76a21724d40 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -3420,6 +3420,7 @@ int split_huge_page_to_list_to_order(struct page *page, struct list_head *list, /* reset xarray order to new order after split */ XA_STATE_ORDER(xas, &folio->mapping->i_pages, folio->index, new_order); bool is_anon = folio_test_anon(folio); + struct mem_cgroup *memcg, *old_memcg; struct address_space *mapping = NULL; struct anon_vma *anon_vma = NULL; int order = folio_order(folio); @@ -3483,6 +3484,13 @@ int split_huge_page_to_list_to_order(struct page *page, struct list_head *list, if (folio_test_writeback(folio)) return -EBUSY; + /* + * switch to folio's memcg as xarray node allocation can happen and + * needs to charge to it. + */ + memcg = folio_memcg(folio); + old_memcg = set_active_memcg(memcg); + if (is_anon) { /* * The caller does not necessarily hold an mmap_lock that would @@ -3629,6 +3637,8 @@ int split_huge_page_to_list_to_order(struct page *page, struct list_head *list, if (mapping) i_mmap_unlock_read(mapping); out: + /* restore to caller's old_memcg */ + set_active_memcg(old_memcg); xas_destroy(&xas); if (order == HPAGE_PMD_ORDER) count_vm_event(!ret ? THP_SPLIT_PAGE : THP_SPLIT_PAGE_FAILED); -- 2.53.0