From mboxrd@z Thu Jan 1 00:00:00 1970 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 BE8F71E32CD for ; Mon, 2 Dec 2024 03:28:41 +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=1733110123; cv=none; b=p9KrOAbkTyi1i29LNNGEzhnucxeN/k6Kvs8zJKuQZyDeAMtAOA+YjdiJgCMSOUAOJPZqL/4u5iLGawTDaNA5NcCpKvwF8hEUPe/rQ9f/P0jyHBlRKrpRwPryaWK7BvlRe6nKu7y7H6nqWIxtXd5ZF4+++oidYUwHe/PFQouoXO4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733110123; c=relaxed/simple; bh=7eooM8lictiogeSqDWNnopPiMIbG0zFPlbWX1bsoFTE=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=slvxahdBv8v/fcdrvLkx9ngWk6Hp41WUF+EkhpIH/p4hwR8D3tnl32dMQXJ9DR7XxVXpzr+lxwFAusjAz9p+m8ggvouDMUydtoBREB1qZAo/VdaVqj7Imk2XbnROyDbe7fmfLp6gs6TVuoUe5qbpzgCadVe1tM7ESN5l0NIZ91U= 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=dcrnSf8d; 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="dcrnSf8d" Received: by mail-pl1-f201.google.com with SMTP id d9443c01a7336-215699398bdso10445505ad.0 for ; Sun, 01 Dec 2024 19:28:41 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1733110121; x=1733714921; 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=dcrnSf8dHhji03PwfLKjPr1xsISY4MQ5sEKjRue9wdoXAmzMswifMuaKEU7l8zyL0S es+qQQ/6AP9DQyln8/X6CfLYvcActUXc1UIxd+XMDm/bOHK6dhJys77p8KpnQJ8J2VMD IvCjIUo0SwWyxCKMFSap36e15wvWw2O36t2djjv8lLNOuIbe59Q8092eh739hjz9iLiN lv4LY/ujBix+JLumG8VXgAntJAMdyaa7do30YqpkrHvYodF7+N0v9+HWJGQh7K6pkCEn fxGC2E65sfvkBbx5lUF776VBSZnr9kFH5T2Eqzov8maS2huvlQnVEmpBdxr+Sk+js0yd tt7A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1733110121; x=1733714921; 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=YAP2NhEgKw6In33FfqumPLDSBx3A4um9RS07u1BdBHzbTKm+OkoHSPFa3aoL5QndiQ sk1QcLD+bXvAD+RXcnKDw8Ns63JfDoRUWhGO7d1KCIg3RIAyaWvuK1LCsJkOfWbIJ/Y0 9pHESUHI/xStfvWYOMJYDnM44Yvqe9RyzSoBzYiSLvjCbHzMYM9MzFY3/DcombxgJf8s QY4kgbS3HJDv45rWWo29DtFOFb5wsPJZKcO4UF5E2DRx7J4MKPXNz4VDziqxwwNjRs9f HJhe0c1QTl0o2vZpN0K3p/MHw1BhQsJEQDlN0xD25Q/53begLpw2XZe0YtT37xwqQAqp DWFA== X-Forwarded-Encrypted: i=1; AJvYcCXo/WqtjGrxeQB04zUbbL9bD9ncWj1ufaZPuam5KQmC1ki4Z/bbLXyoU1JrFnDL5yrGP9m8JLIGPMCRJqk=@vger.kernel.org X-Gm-Message-State: AOJu0Yz972tzGBOgWdelJkCusZVGVc92eECiuLeJ23VPXlE52olgT8GB Zsq2WFI3hGobmDFxJYzTDWkl5nH7jCpmQf+BO8ppuHdQWWyWP5qnAYx/HP/yocZshU/mzBHn4SO jmg== X-Google-Smtp-Source: AGHT+IGV/8vBTUsUxmc+joe52tDW4U0gAzmSevdVnbajr1Q1NEr3Inb6b68KRcu10pksEIJ78suAm86dnjs= X-Received: from plgp12.prod.google.com ([2002:a17:902:ebcc:b0:212:3f35:e4bd]) (user=yuzhao job=prod-delivery.src-stubby-dispatcher) by 2002:a17:903:2452:b0:215:609f:3f9e with SMTP id d9443c01a7336-215609f4515mr110182305ad.40.1733110121122; Sun, 01 Dec 2024 19:28:41 -0800 (PST) Date: Sun, 1 Dec 2024 20:28:22 -0700 In-Reply-To: <20241202032823.2741019-1-yuzhao@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20241202032823.2741019-1-yuzhao@google.com> X-Mailer: git-send-email 2.47.0.338.g60cca15819-goog Message-ID: <20241202032823.2741019-6-yuzhao@google.com> Subject: [PATCH mm-unstable v1 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-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=2TQo7T4Gr-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 shadow. */ -static bool lru_gen_test_recent(void *shadow, bool file, struct lruvec **lruvec, +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; @@ -273,8 +273,10 @@ static bool lru_gen_test_recent(void *shadow, bool file, struct lruvec **lruvec, memcg = mem_cgroup_from_id(memcg_id); *lruvec = mem_cgroup_lruvec(memcg, pgdat); - min_seq = READ_ONCE((*lruvec)->lrugen.min_seq[file]); - return (*token >> LRU_REFS_WIDTH) == (min_seq & (EVICTION_MASK >> LRU_REFS_WIDTH)); + max_seq = READ_ONCE((*lruvec)->lrugen.max_seq); + max_seq &= EVICTION_MASK >> LRU_REFS_WIDTH; + + return abs_diff(max_seq, *token >> LRU_REFS_WIDTH) < MAX_NR_GENS; } static void lru_gen_refault(struct folio *folio, void *shadow) @@ -290,7 +292,7 @@ static void lru_gen_refault(struct folio *folio, void *shadow) rcu_read_lock(); - recent = lru_gen_test_recent(shadow, type, &lruvec, &token, &workingset); + recent = lru_gen_test_recent(shadow, &lruvec, &token, &workingset); if (lruvec != folio_lruvec(folio)) goto unlock; @@ -331,7 +333,7 @@ static void *lru_gen_eviction(struct folio *folio) return NULL; } -static bool lru_gen_test_recent(void *shadow, bool file, struct lruvec **lruvec, +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, bool *workingset, bool recent; rcu_read_lock(); - recent = lru_gen_test_recent(shadow, file, &eviction_lruvec, - &eviction, workingset); + recent = lru_gen_test_recent(shadow, &eviction_lruvec, &eviction, workingset); rcu_read_unlock(); return recent; } -- 2.47.0.338.g60cca15819-goog