From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on archive.lwn.net X-Spam-Level: X-Spam-Status: No, score=-13.6 required=5.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI,USER_IN_DEF_DKIM_WL autolearn=unavailable autolearn_force=no version=3.4.2 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by archive.lwn.net (Postfix) with ESMTP id 5467D7D04D for ; Thu, 24 Jan 2019 21:16:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728063AbfAXVQP (ORCPT ); Thu, 24 Jan 2019 16:16:15 -0500 Received: from mail-pg1-f195.google.com ([209.85.215.195]:42769 "EHLO mail-pg1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727988AbfAXVPt (ORCPT ); Thu, 24 Jan 2019 16:15:49 -0500 Received: by mail-pg1-f195.google.com with SMTP id d72so3213274pga.9 for ; Thu, 24 Jan 2019 13:15:48 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=Yle1TlNGJaGEEnORF+DKn94y7Tdky3DBMIMdCA8cBkQ=; b=G5aiYxByVc6VsErIA8+F4qk2siELUvTdPPrbChQIOsAm83h4aweDW1EtGssVAsYcqr d0Hbfi1U48XHWNKKSg6xfBhvQrj7g8/hZUrKv+aKhCRjAxjIsEjMdq9EtxxcRfVJu90f BX6molsDxFs4E2ZxSEKUqzNfPjR4gcB67U8DPKVZujIWJXG+/xQti5Q/HhQ39OkRPKta 4qHw9QqImaawmIin18WKnJassSVIia4mg97ND/pwSl+bQs6LEJIkMU8ykdXNaM3OntUy 4wCAEHFwa73hdoSX8Xisl4JJso5mKIZzv+rz5PzXQafcVRCiPugAP22E9Ys7jJVMBrL2 ulKw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=Yle1TlNGJaGEEnORF+DKn94y7Tdky3DBMIMdCA8cBkQ=; b=cAx4lUkmYt/g7OjcjdMN1DrcNq3XBcPnJs61XNQrIWYPV/2y6xiz4IP3iWQvy1/ZJC /G76i3faU6M0I3NYkERkk6LvqPJfwYpa3ACfsOcwtDJG3ZDABRL+YoYlZkqiU3Dgyqn7 +8Vp8PkRQVXt+Nv5FxUY+yYd2oUl+p1oo085GOfbnLiHqRzSmMNBQdeFM4TgyiLm8cVG XAwfLNzcIu8DHq9yB4yQ5aKorlZVnjkZsVFgGdVwu7fXRskkbPhLw8+h/0Lp5FabgSgy kEqcbpCFG907Sk4rwbSpXe7MKCAfTI1tXvdCJjsi/LewoeMZ7buYycj4eLDpObki5Ssk hfIg== X-Gm-Message-State: AJcUukeHxXMIb/VLB/kFup/78fJwW7I5vnef6o+20Kt9bdS2hWqIy0+H +A8D1worF1/hpNvK9DjCEJQbZQ== X-Google-Smtp-Source: ALg8bN7c9mCecQ7dN9e6nW340zvc5kgy4jrTniqrJWOGIuXa6rjmzTyuutcXsHTaWk10Kf/c9uFy0w== X-Received: by 2002:a63:ed42:: with SMTP id m2mr7480273pgk.147.1548364548221; Thu, 24 Jan 2019 13:15:48 -0800 (PST) Received: from surenb0.mtv.corp.google.com ([2620:0:1000:1612:3320:4357:47df:276b]) by smtp.googlemail.com with ESMTPSA id j197sm29626418pgc.76.2019.01.24.13.15.46 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 24 Jan 2019 13:15:47 -0800 (PST) From: Suren Baghdasaryan To: gregkh@linuxfoundation.org Cc: tj@kernel.org, lizefan@huawei.com, hannes@cmpxchg.org, axboe@kernel.dk, dennis@kernel.org, dennisszhou@gmail.com, mingo@redhat.com, peterz@infradead.org, akpm@linux-foundation.org, corbet@lwn.net, cgroups@vger.kernel.org, linux-mm@kvack.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-team@android.com, Suren Baghdasaryan Subject: [PATCH v3 3/5] psi: introduce state_mask to represent stalled psi states Date: Thu, 24 Jan 2019 13:15:16 -0800 Message-Id: <20190124211518.244221-4-surenb@google.com> X-Mailer: git-send-email 2.20.1.321.g9e740568ce-goog In-Reply-To: <20190124211518.244221-1-surenb@google.com> References: <20190124211518.244221-1-surenb@google.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-doc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org The psi monitoring patches will need to determine the same states as record_times(). To avoid calculating them twice, maintain a state mask that can be consulted cheaply. Do this in a separate patch to keep the churn in the main feature patch at a minimum. This adds 4-byte state_mask member into psi_group_cpu struct which results in its first cacheline-aligned part to become 52 bytes long. Add explicit values to enumeration element counters that affect psi_group_cpu struct size. Signed-off-by: Suren Baghdasaryan --- include/linux/psi_types.h | 9 ++++++--- kernel/sched/psi.c | 29 +++++++++++++++++++---------- 2 files changed, 25 insertions(+), 13 deletions(-) diff --git a/include/linux/psi_types.h b/include/linux/psi_types.h index 2cf422db5d18..762c6bb16f3c 100644 --- a/include/linux/psi_types.h +++ b/include/linux/psi_types.h @@ -11,7 +11,7 @@ enum psi_task_count { NR_IOWAIT, NR_MEMSTALL, NR_RUNNING, - NR_PSI_TASK_COUNTS, + NR_PSI_TASK_COUNTS = 3, }; /* Task state bitmasks */ @@ -24,7 +24,7 @@ enum psi_res { PSI_IO, PSI_MEM, PSI_CPU, - NR_PSI_RESOURCES, + NR_PSI_RESOURCES = 3, }; /* @@ -41,7 +41,7 @@ enum psi_states { PSI_CPU_SOME, /* Only per-CPU, to weigh the CPU in the global average: */ PSI_NONIDLE, - NR_PSI_STATES, + NR_PSI_STATES = 6, }; struct psi_group_cpu { @@ -53,6 +53,9 @@ struct psi_group_cpu { /* States of the tasks belonging to this group */ unsigned int tasks[NR_PSI_TASK_COUNTS]; + /* Aggregate pressure state derived from the tasks */ + u32 state_mask; + /* Period time sampling buckets for each state of interest (ns) */ u32 times[NR_PSI_STATES]; diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c index fe24de3fbc93..2262d920295f 100644 --- a/kernel/sched/psi.c +++ b/kernel/sched/psi.c @@ -212,17 +212,17 @@ static bool test_state(unsigned int *tasks, enum psi_states state) static void get_recent_times(struct psi_group *group, int cpu, u32 *times) { struct psi_group_cpu *groupc = per_cpu_ptr(group->pcpu, cpu); - unsigned int tasks[NR_PSI_TASK_COUNTS]; u64 now, state_start; + enum psi_states s; unsigned int seq; - int s; + u32 state_mask; /* Snapshot a coherent view of the CPU state */ do { seq = read_seqcount_begin(&groupc->seq); now = cpu_clock(cpu); memcpy(times, groupc->times, sizeof(groupc->times)); - memcpy(tasks, groupc->tasks, sizeof(groupc->tasks)); + state_mask = groupc->state_mask; state_start = groupc->state_start; } while (read_seqcount_retry(&groupc->seq, seq)); @@ -238,7 +238,7 @@ static void get_recent_times(struct psi_group *group, int cpu, u32 *times) * (u32) and our reported pressure close to what's * actually happening. */ - if (test_state(tasks, s)) + if (state_mask & (1 << s)) times[s] += now - state_start; delta = times[s] - groupc->times_prev[s]; @@ -406,15 +406,15 @@ static void record_times(struct psi_group_cpu *groupc, int cpu, delta = now - groupc->state_start; groupc->state_start = now; - if (test_state(groupc->tasks, PSI_IO_SOME)) { + if (groupc->state_mask & (1 << PSI_IO_SOME)) { groupc->times[PSI_IO_SOME] += delta; - if (test_state(groupc->tasks, PSI_IO_FULL)) + if (groupc->state_mask & (1 << PSI_IO_FULL)) groupc->times[PSI_IO_FULL] += delta; } - if (test_state(groupc->tasks, PSI_MEM_SOME)) { + if (groupc->state_mask & (1 << PSI_MEM_SOME)) { groupc->times[PSI_MEM_SOME] += delta; - if (test_state(groupc->tasks, PSI_MEM_FULL)) + if (groupc->state_mask & (1 << PSI_MEM_FULL)) groupc->times[PSI_MEM_FULL] += delta; else if (memstall_tick) { u32 sample; @@ -435,10 +435,10 @@ static void record_times(struct psi_group_cpu *groupc, int cpu, } } - if (test_state(groupc->tasks, PSI_CPU_SOME)) + if (groupc->state_mask & (1 << PSI_CPU_SOME)) groupc->times[PSI_CPU_SOME] += delta; - if (test_state(groupc->tasks, PSI_NONIDLE)) + if (groupc->state_mask & (1 << PSI_NONIDLE)) groupc->times[PSI_NONIDLE] += delta; } @@ -447,6 +447,8 @@ static void psi_group_change(struct psi_group *group, int cpu, { struct psi_group_cpu *groupc; unsigned int t, m; + enum psi_states s; + u32 state_mask = 0; groupc = per_cpu_ptr(group->pcpu, cpu); @@ -479,6 +481,13 @@ static void psi_group_change(struct psi_group *group, int cpu, if (set & (1 << t)) groupc->tasks[t]++; + /* Calculate state mask representing active states */ + for (s = 0; s < NR_PSI_STATES; s++) { + if (test_state(groupc->tasks, s)) + state_mask |= (1 << s); + } + groupc->state_mask = state_mask; + write_seqcount_end(&groupc->seq); if (!delayed_work_pending(&group->clock_work)) -- 2.20.1.321.g9e740568ce-goog