From nobody Wed Dec 17 15:34:56 2025 Received: from mail-yw1-f201.google.com (mail-yw1-f201.google.com [209.85.128.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 88BE81598FA for ; Mon, 6 May 2024 19:29:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715023769; cv=none; b=DnO2AyCSRJ/SB5X2EC3w0MdbTimyj5lIch3LXQ+iFK+Mv+5QNiq2Gxp1/46/JVmz6rhCtiQYR1IpATeYMBzu4UU1IjW6IjHNUft5w7R7qFHMzL4PEfaPZk5knDUctFnmyGXB/ij6ZQwTngvJmHmVqUlRclc+JWFocourUKhuefk= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715023769; c=relaxed/simple; bh=78VsLkCuW49vhVgkUXJxT+pNVEKkHi1mMQj62BGccng=; h=Date:Mime-Version:Message-ID:Subject:From:To:Cc:Content-Type; b=Sd1biJ2RuhgO2fP2K4knGTpkPsa+ZmRyuCklrcjULYb+6N+0Gq3Q/GAOt8t54x3Ooz3F9o/OTmgLWqVFHOFHLuffmPtLB1m9MBan9iNDuWvWuCTs8hmettq+G8ID9ELi9Er49oWncSxtrwD1MQ37NF0CSLAR6UmTA/PUeHvd61I= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--yosryahmed.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=o9hwrpB6; arc=none smtp.client-ip=209.85.128.201 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--yosryahmed.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="o9hwrpB6" Received: by mail-yw1-f201.google.com with SMTP id 00721157ae682-61df903af62so46917167b3.1 for ; Mon, 06 May 2024 12:29:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1715023766; x=1715628566; darn=vger.kernel.org; h=cc:to:from:subject:message-id:mime-version:date:from:to:cc:subject :date:message-id:reply-to; bh=vMsFvGn5E9drw/PQULeDN2NnDOV6ZTK3bSrrukYn3gE=; b=o9hwrpB6NbTHO0NadKc2rt6piAKOj5GzKtPIFzaiqwGV+ITfdeiQtvwVuLrxXaIzTf VtQJtXsaW894aFAIhX6lV8Lan29VutEspRHsqs1Yuk+7hmCaHZqLrnPjTibSC3GYQHrh CQGtv2NpTNkmwUISq7lkDGOh5tMcNFzsrsd4/poHlsnLNiYmrzNEoGxgD+j+ztESbLyl Kr/iTsUfeAQuCpNhfU2NoVN+TcmI5DvWOOuBxT7MievIgWs9lEshs42WYQ9vqsuhqwZV uomAXFkWCqQP5ZcxGKt+8KhisG5gpTGZeUTn0jYeDJUqM9Agn8xCPFIH+r29LzWlBMsF mTmg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1715023766; x=1715628566; h=cc:to:from:subject:message-id:mime-version:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=vMsFvGn5E9drw/PQULeDN2NnDOV6ZTK3bSrrukYn3gE=; b=N5rziKH/OpxSdbJVDxdSiINm7slgQcJai5YUHlf1/dJmAPTLq5TYHXIZnAN2YmGHyM tRZnfJIqv80q48GpbU09j2GE7aIVm1NjJj7yY0CSA9sGzIsSHM09Yk+7GS7nWcBoThzJ HLnOghgKnZLtIsSETKZu25MMSaGQuGstwPojEq33LbVHL43+UEuiXk0FfxD55nwwoa1+ ssM+/hHeozac8u3HXQA+gkUQCRK0i7KK/0YekO5Bjlt67+JbgWBOouwG5Jkq3y9mupK1 enhThNdRq1F1hAn1mh7A6xc6X5AYzUtYDffrl5D5w3XnenSmvSGXlXpqC0TPpis+fL9Q /C6g== X-Forwarded-Encrypted: i=1; AJvYcCX/3XuBLMgN251CnHSHhb/TwutSwl1vR/5bXGlFFa3dyJW+mdTlIgwBuBZqlYEjvyrrQPjN1CkLgZh35YZdlv66Wnn6FK8MAjAKDs9I X-Gm-Message-State: AOJu0YzGcSw14y6CudV/LZJepv0/TXiGL3QcY5zTOFDmHrn459QCAHFG 3V/f1BC9fPzXZxWhcXNvEuqykJLBF2aXglmukhw037N+vNyih4FewkHnjdPb/JSsz3w4BR5e5Ct 5Jt79tW5UiAXn7QAOAQ== X-Google-Smtp-Source: AGHT+IENOCELgpMw5VEmqAi5bqOPnEO/Pk6007gBdU/F+qmzq+7vIo3uBQyfw0E3lDsJXlJtZTiPMqjyGbUwAkXi X-Received: from yosry.c.googlers.com ([fda3:e722:ac3:cc00:20:ed76:c0a8:29b4]) (user=yosryahmed job=sendgmr) by 2002:a81:4f05:0:b0:61b:e75b:4806 with SMTP id d5-20020a814f05000000b0061be75b4806mr3003407ywb.1.1715023766466; Mon, 06 May 2024 12:29:26 -0700 (PDT) Date: Mon, 6 May 2024 19:29:24 +0000 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 X-Mailer: git-send-email 2.45.0.rc1.225.g2a3ae87e7f-goog Message-ID: <20240506192924.271999-1-yosryahmed@google.com> Subject: [PATCH v2] mm: do not update memcg stats for NR_{FILE/SHMEM}_PMDMAPPED From: Yosry Ahmed To: Andrew Morton Cc: Shakeel Butt , Johannes Weiner , Michal Hocko , Roman Gushchin , Muchun Song , David Hildenbrand , linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, Yosry Ahmed , syzbot+9319a4268a640e26b72b@syzkaller.appspotmail.com Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Previously, all NR_VM_EVENT_ITEMS stats were maintained per-memcg, although some of those fields are not exposed anywhere. Commit 14e0f6c957e39 ("memcg: reduce memory for the lruvec and memcg stats") changed this such that we only maintain the stats we actually expose per-memcg via a translation table. Additionally, commit 514462bbe927b ("memcg: warn for unexpected events and stats") added a warning if a per-memcg stat update is attempted for a stat that is not in the translation table. The warning started firing for the NR_{FILE/SHMEM}_PMDMAPPED stat updates in the rmap code. These stats are not maintained per-memcg, and hence are not in the translation table. Do not use __lruvec_stat_mod_folio() when updating NR_FILE_PMDMAPPED and NR_SHMEM_PMDMAPPED. Use __mod_node_page_state() instead, which updates the global per-node stats only. Reported-by: syzbot+9319a4268a640e26b72b@syzkaller.appspotmail.com Closes: https://lore.kernel.org/lkml/0000000000001b9d500617c8b23c@google.com Fixes: 514462bbe927 ("memcg: warn for unexpected events and stats") Acked-by: Shakeel Butt Signed-off-by: Yosry Ahmed Acked-by: David Hildenbrand Reviewed-by: Roman Gushchin --- mm/rmap.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-) diff --git a/mm/rmap.c b/mm/rmap.c index 12be4241474ab..ed7f820369864 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -1435,13 +1435,14 @@ static __always_inline void __folio_add_file_rmap(s= truct folio *folio, struct page *page, int nr_pages, struct vm_area_struct *vma, enum rmap_level level) { + pg_data_t *pgdat =3D folio_pgdat(folio); int nr, nr_pmdmapped =3D 0; =20 VM_WARN_ON_FOLIO(folio_test_anon(folio), folio); =20 nr =3D __folio_add_rmap(folio, page, nr_pages, level, &nr_pmdmapped); if (nr_pmdmapped) - __lruvec_stat_mod_folio(folio, folio_test_swapbacked(folio) ? + __mod_node_page_state(pgdat, folio_test_swapbacked(folio) ? NR_SHMEM_PMDMAPPED : NR_FILE_PMDMAPPED, nr_pmdmapped); if (nr) __lruvec_stat_mod_folio(folio, NR_FILE_MAPPED, nr); @@ -1493,6 +1494,7 @@ static __always_inline void __folio_remove_rmap(struc= t folio *folio, enum rmap_level level) { atomic_t *mapped =3D &folio->_nr_pages_mapped; + pg_data_t *pgdat =3D folio_pgdat(folio); int last, nr =3D 0, nr_pmdmapped =3D 0; bool partially_mapped =3D false; enum node_stat_item idx; @@ -1540,13 +1542,14 @@ static __always_inline void __folio_remove_rmap(str= uct folio *folio, } =20 if (nr_pmdmapped) { + /* NR_{FILE/SHMEM}_PMDMAPPED are not maintained per-memcg */ if (folio_test_anon(folio)) - idx =3D NR_ANON_THPS; - else if (folio_test_swapbacked(folio)) - idx =3D NR_SHMEM_PMDMAPPED; + __lruvec_stat_mod_folio(folio, NR_ANON_THPS, -nr_pmdmapped); else - idx =3D NR_FILE_PMDMAPPED; - __lruvec_stat_mod_folio(folio, idx, -nr_pmdmapped); + __mod_node_page_state(pgdat, + folio_test_swapbacked(folio) ? + NR_SHMEM_PMDMAPPED : NR_FILE_PMDMAPPED, + -nr_pmdmapped); } if (nr) { idx =3D folio_test_anon(folio) ? NR_ANON_MAPPED : NR_FILE_MAPPED; --=20 2.45.0.rc1.225.g2a3ae87e7f-goog