From nobody Wed Dec 17 21:39:51 2025 Received: from mail-pl1-f201.google.com (mail-pl1-f201.google.com [209.85.214.201]) (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 DDCB1188010 for ; Tue, 31 Dec 2024 04:35:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1735619760; cv=none; b=QjeUWKORCc9ZSuy78lXPnaB+GEv+NKVDLopVCIthQPDkb8Kms/t7jbfummrEwqMWnhFI6lFL2IZmD29j4tuGOX1SirjfdqB9Ox+mZgmBX2vLwgWHpC5JZZfARe/KsZCr/iqCajoPW5IqOc+hSu92GU3Me8EYpaqiymzgjD1K7VI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1735619760; c=relaxed/simple; bh=uTp7bD44RNzwMxHC/uNni/sVAGSpZwMMVsfwcGnYVDQ=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=RSDVEuyk7M0eR0IUtfpZQ8uon3Dc01fy1U/ZENoglkPta13J6grprDycbkH8qIrMGQgSxKRlOeP98CJM5UjbQz0xS/RRGszCL1Q7lE5AC3qFSd0W+a9GSfk7cpjjBGKaFfvhtyS8X4iVzw+mkJynlrQlhHJdvP4J11//uPxzVQI= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--yuzhao.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=09PoE1fx; arc=none smtp.client-ip=209.85.214.201 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--yuzhao.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="09PoE1fx" Received: by mail-pl1-f201.google.com with SMTP id d9443c01a7336-2161d185f04so96103355ad.3 for ; Mon, 30 Dec 2024 20:35:58 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1735619758; x=1736224558; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=o6XRtkbexDya+FE96V37S0c0XRTdkGfwnwLQlfXry/0=; b=09PoE1fxn/CkucqrPFzJ9Qsl19mQEdHbls4J0xjwWhpmmNgOFs3i4KRR9C2ZCNFqZf tdtVs2Lun+uVMdtjwGVjXCNJII1DTcwtObFdsGcclfN13a3a2iKMidTE8uYGyaza4uqi WlezcbEwfNcDjHWZvR6aQ2KzDi2OsYwtaEP1d+V26VWhRtrSXLm/6vm/aLQKHCg5L8dG Q7zDhJTiTpvfQR5b60Hy+QnQ7PBeLmWBX6Gi9S2SftSE89jfhnjZ2b2WmIbNzGLJsEDN SQOc9ko0BZpHwONLhFt4J75YNT2t0R9fcYuOEM2+nQpeP1AuCwDVNkuExMoEImNBs9bk 59ZA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1735619758; x=1736224558; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=o6XRtkbexDya+FE96V37S0c0XRTdkGfwnwLQlfXry/0=; b=kk0NbKAOCGaWvPRPR7ehBIJ8zC3fMfWchmSYeUX/MufkSBLzeK+46ijPq8OIMr1pPF gb/EF3eLGyanAsXj+IrTw2n1ateqzTO15WKpY7ld5E2JW2k99mBqjUe9BjAqWaQN7C5h AbX/K6aNupzjAuxpBwhXaRSekadbEPQeQ+9Xiv1YbQqotg6kmfuVGij99xvQtWy0sywN g41DQXHDxJqcumE8kEMoQEsE+J5I/Qxoc82udb9zVhKkM3sc6ij8roRdGtRo/kgaT5KU lNj7PhSoOYcmPBx53g5YPX6mlXfIknZwprPcpu4YzH0ISDcwTe9MG9t4ABi8LOET+JEK MO8Q== X-Forwarded-Encrypted: i=1; AJvYcCW1GDMPTkRcnKycm69bLbjRpJ07/5Hzx1YoBsTFHA47Bk56ZgwXUEj3Cjh2Ic7EcStlpxDD3GT8LIBIEgQ=@vger.kernel.org X-Gm-Message-State: AOJu0YyprlPIibxY/wpwY5k02c+5VUm4MHPvrtVWsJOXUmiZ15PBx2gi a8rbC9mgSVh+rmGFUQzy4dOo9KB8WvQNAjGv8qHUCjvbOltFZwKHVuTP0psiyfGX3Pdg+uHLbIo AsQ== X-Google-Smtp-Source: AGHT+IFGxXIKapCxHqzF+SSkn6gmP8awPE8NmQhmaf+NKsYjxZAWuTACPo/hzKbtWVqcyzBxJYfvlIdIpEw= X-Received: from plmm9.prod.google.com ([2002:a17:902:c449:b0:215:6f59:ff5f]) (user=yuzhao job=prod-delivery.src-stubby-dispatcher) by 2002:a17:902:d502:b0:216:4348:149d with SMTP id d9443c01a7336-219e6f25d60mr601318685ad.53.1735619758185; Mon, 30 Dec 2024 20:35:58 -0800 (PST) Date: Mon, 30 Dec 2024 21:35:36 -0700 In-Reply-To: <20241231043538.4075764-1-yuzhao@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20241231043538.4075764-1-yuzhao@google.com> X-Mailer: git-send-email 2.47.1.613.gc27f4b7a9f-goog Message-ID: <20241231043538.4075764-6-yuzhao@google.com> Subject: [PATCH mm-unstable v4 5/7] mm/mglru: rework refault detection From: Yu Zhao To: Andrew Morton Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Yu Zhao , Kairui Song , Kalesh Singh Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" With anon and file min_seq being able to move independently, rework workingset protection as well so that the comparison of refaults between anon and file is always on an equal footing. Specifically, make lru_gen_test_recent() return true for refaults happening within the distance of MAX_NR_GENS. For example, if min_seq of a type is max_seq-MIN_NR_GENS, refaults from min_seq-1, i.e., max_seq-MIN_NR_GENS-1, are also considered recent, since the distance max_seq-(max_seq-MIN_NR_GENS-1), i.e., MIN_NR_GENS+1 is less than MAX_NR_GENS. As an intermediate step to the final optimization, this change by itself should not have userspace-visiable effects beyond performance. Reported-by: Kairui Song Closes: https://lore.kernel.org/CAOUHufahuWcKf5f1Sg3emnqX+cODuR=3D2TQo7T4Gr= -QYLujn4RA@mail.gmail.com/ Signed-off-by: Yu Zhao Tested-by: Kalesh Singh --- mm/workingset.c | 17 +++++++++-------- 1 file changed, 9 insertions(+), 8 deletions(-) diff --git a/mm/workingset.c b/mm/workingset.c index ad181d1b8cf1..2c310c29f51e 100644 --- a/mm/workingset.c +++ b/mm/workingset.c @@ -260,11 +260,11 @@ static void *lru_gen_eviction(struct folio *folio) * Tests if the shadow entry is for a folio that was recently evicted. * Fills in @lruvec, @token, @workingset with the values unpacked from sha= dow. */ -static bool lru_gen_test_recent(void *shadow, bool file, struct lruvec **l= ruvec, +static bool lru_gen_test_recent(void *shadow, struct lruvec **lruvec, unsigned long *token, bool *workingset) { int memcg_id; - unsigned long min_seq; + unsigned long max_seq; struct mem_cgroup *memcg; struct pglist_data *pgdat; =20 @@ -273,8 +273,10 @@ static bool lru_gen_test_recent(void *shadow, bool fil= e, struct lruvec **lruvec, memcg =3D mem_cgroup_from_id(memcg_id); *lruvec =3D mem_cgroup_lruvec(memcg, pgdat); =20 - min_seq =3D READ_ONCE((*lruvec)->lrugen.min_seq[file]); - return (*token >> LRU_REFS_WIDTH) =3D=3D (min_seq & (EVICTION_MASK >> LRU= _REFS_WIDTH)); + max_seq =3D READ_ONCE((*lruvec)->lrugen.max_seq); + max_seq &=3D EVICTION_MASK >> LRU_REFS_WIDTH; + + return abs_diff(max_seq, *token >> LRU_REFS_WIDTH) < MAX_NR_GENS; } =20 static void lru_gen_refault(struct folio *folio, void *shadow) @@ -290,7 +292,7 @@ static void lru_gen_refault(struct folio *folio, void *= shadow) =20 rcu_read_lock(); =20 - recent =3D lru_gen_test_recent(shadow, type, &lruvec, &token, &workingset= ); + recent =3D lru_gen_test_recent(shadow, &lruvec, &token, &workingset); if (lruvec !=3D folio_lruvec(folio)) goto unlock; =20 @@ -331,7 +333,7 @@ static void *lru_gen_eviction(struct folio *folio) return NULL; } =20 -static bool lru_gen_test_recent(void *shadow, bool file, struct lruvec **l= ruvec, +static bool lru_gen_test_recent(void *shadow, struct lruvec **lruvec, unsigned long *token, bool *workingset) { return false; @@ -432,8 +434,7 @@ bool workingset_test_recent(void *shadow, bool file, bo= ol *workingset, bool recent; =20 rcu_read_lock(); - recent =3D lru_gen_test_recent(shadow, file, &eviction_lruvec, - &eviction, workingset); + recent =3D lru_gen_test_recent(shadow, &eviction_lruvec, &eviction, work= ingset); rcu_read_unlock(); return recent; } --=20 2.47.1.613.gc27f4b7a9f-goog