From nobody Fri Dec 19 07:03:24 2025 Received: from mail-pj1-f74.google.com (mail-pj1-f74.google.com [209.85.216.74]) (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 17EDB19539F for ; Sat, 7 Dec 2024 22:15:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.216.74 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733609741; cv=none; b=NYfM7ez4I+59CiMHQMQ8GYY+iSPReK/kYZsA0twPUuMtDDzeFdmgzKClFzDSST2EMl6pqOFdQ6p7THXSqKLxaQwK4AQiMNadkrlCXD1y7JSkR3fHrfkIMTIxo6qd70K+W1ulIfiOSoHO+9Zg1ssP5mi5CGTn5f5dlaAMAhKrm84= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733609741; c=relaxed/simple; bh=7eooM8lictiogeSqDWNnopPiMIbG0zFPlbWX1bsoFTE=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=qztlQ3/qTbwf2b+PYzav0ofeT2LBRxVWO51vfTd5aAJ8c6Z/xCWT1dD/REMLknMh92IO2pzv+jdupS14s56Gldzc42xl85M7cmRrmBTY9FNa4CiWcgpmG6ueS5DWdc8R3XIntFyWstzwd5CjMaQo4YUNSyvEFJXR7UJP3pE5pWA= 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=Sc82Jjhz; arc=none smtp.client-ip=209.85.216.74 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="Sc82Jjhz" Received: by mail-pj1-f74.google.com with SMTP id 98e67ed59e1d1-2ef79403c5eso2033974a91.0 for ; Sat, 07 Dec 2024 14:15:39 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1733609739; x=1734214539; 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=KW2cgcwHB51Y5IYZaisd+Bp0HxAyG3VEQ4AUms4DlWs=; b=Sc82Jjhzwf42VIpjTq25RTYjSwkXnlstTVLZ1431JTsgTyq3sR6YDdVyU4T39YT6+5 fK1TgrLrw38Vjl+3s/vtojjahZdNXVzgteeFRE0iIZN2nWKGhGz8e4fnrhvsewqBAhPP WwbWmwuzf5pvR4m6EWDYtLq33D9yWFWm9hJUgJUYOx1+jOY9TUI6BEJci08PdqYNvy+P LUS8+tLo0yEi5jNPwZge6XkD8YBYMiTrFecpiJWadFUCkXUHJyqkbT9/8ebDsFwkWKy/ 2w9/BHc3RPvHlCYk+czOMgkp6mD22/9PsnvGDI+LpsA4VdQ96SrXdmFVDGoJ3wVhQekE ajYQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1733609739; x=1734214539; 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=KW2cgcwHB51Y5IYZaisd+Bp0HxAyG3VEQ4AUms4DlWs=; b=GGQfOXzc5iNsLIw2vcyQTVailxAIsr3UIQ9Em97L7/Cyas928lm1bM/rbK7DtofYle +PDoXqIDbaTflRHAS9BVVcpL0u9epL+IIMQOBje2VZcTsN/g3dFpQEV8cfIUTDBG1I3y w08KuDQN2J5ijnuZEJBIBBTNhaW+SKK3MxwMc9g5BwXHNxzOmfGuTtU0mc7ifoNqOP9g KjCyWJGgVPWqplvn/MZLtjgQJDE0F/wLm8zpsIxhHLjF05YbokoO5XJuIUXawX1FJogD kOAt9EE+/WGJ5JIjTfUFtr2Uow81Qab0CEtV2/umUC846Tf0s2SIuNheDPcnW5W3zVQF Td5g== X-Forwarded-Encrypted: i=1; AJvYcCXcZiqUVBn6kwPcFi45K2Y1pq47Mp7aBVOvQ3ksqzimcThfRdquAFh6JqvM90cZJ3T2r/BlQ5xe9JfrWyw=@vger.kernel.org X-Gm-Message-State: AOJu0YyaWZLw7WOUKhaZJioUC6/9KpVCAAUnqiURSGhOF903A3R7U5JJ BfEJ//84bL22rHvnOoYShV7sEZsvD9//WHrDMsCuDeGYX7QRNsjpZ5CifNIX/gc5CPsHnPYXd9+ r8w== X-Google-Smtp-Source: AGHT+IGLJjHyW+Ykmm2+aL9lWknHp1gQ6xAIWeFiqeIX5Kn/EtyOEYWZv/R88rJ8RijCnornkXxmr9Is4Ew= X-Received: from pjboi8.prod.google.com ([2002:a17:90b:3a08:b0:2ea:4a74:ac2]) (user=yuzhao job=prod-delivery.src-stubby-dispatcher) by 2002:a17:90b:2d05:b0:2ee:7c02:8f08 with SMTP id 98e67ed59e1d1-2ef6ab29d43mr12407603a91.37.1733609739414; Sat, 07 Dec 2024 14:15:39 -0800 (PST) Date: Sat, 7 Dec 2024 15:15:21 -0700 In-Reply-To: <20241207221522.2250311-1-yuzhao@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20241207221522.2250311-1-yuzhao@google.com> X-Mailer: git-send-email 2.47.0.338.g60cca15819-goog Message-ID: <20241207221522.2250311-6-yuzhao@google.com> Subject: [PATCH mm-unstable v3 5/6] 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 2.47.0.338.g60cca15819-goog