From patchwork Thu Mar 30 08:10:57 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Domenico Cerasuolo X-Patchwork-Id: 76939 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a59:b0ea:0:b0:3b6:4342:cba0 with SMTP id b10csp962344vqo; Thu, 30 Mar 2023 01:20:36 -0700 (PDT) X-Google-Smtp-Source: AKy350YfU1NRWZwk9bIybmxcaxHV96rk20iv4/gKloewYIz2Ue58Wp741jsJnZAXmqdW3Wytd1Zu X-Received: by 2002:a05:6402:752:b0:4aa:a280:55b5 with SMTP id p18-20020a056402075200b004aaa28055b5mr5122684edy.20.1680164436788; Thu, 30 Mar 2023 01:20:36 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1680164436; cv=none; d=google.com; s=arc-20160816; b=PvU5m6+KTn3Z7/HKErOYOtAq3FlDw6/hMVLRgt0tNLNJOh9GH2zAm+/3SW/S1SjOOm COSKl3f/K6Qo3IjOOpAgBextRfDwt2JVxv0y6tcp8g9gcTogxGR2BECPuUA2YsdLjrZL me3mok7M0PjNNNX3FJHCxRTia5eZp9PdsDbkDU1jnXfm/W1Kr81a6KOJ5tqHvdOc+eVR MCRAGyy9jQZcRKhf/bjurTP8Jx0ufYfot97i0ut1qcqRVOPUyi0FPPTpnoZfIqeicAFD u3ESaMTQ79f/fu0wvRshsrD6JX1WYmmEnLGZckWba9lQeROYluErrQOakopU/GacvlCu XQUQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:mime-version :references:in-reply-to:message-id:date:subject:cc:to:from :dkim-signature; bh=Sgclq3CwPySlcIw6eNZ6zuLOimqag1tJf0PxPQK2QJo=; b=hk4X73+zx5NPCuyJwY+HzBIK7kAV95tvvumfYlGMGpaMWY41rUsWkq1yRYo1iYLYY9 DhUSZw/B1aHeztsFbpTJRnryzSIwozIG5h48FPWtPpddcHv4U5deJNEi62dGJ1AGN1ca QSKHOLX039PZ5azexJFdXZ7MCbAU25pAvoxDWGTpo5wNiUMMMDJHGL6B1kEk/GNuTHeD 3HsFK+y+CIgu73Y4sU42q/bSyQ1uyQJ6bJ9KdUaPzemKy8bcK0uy/jP3tLOxiHoEX/bP EC+JXUscMZDW8z9GF6QLsJCGov/jGrQCqmEyS9jewAuxVkqbR5zBbgHZNL4Jyt1gNXH/ BkCA== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@gmail.com header.s=20210112 header.b=n3LqduWt; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id v7-20020aa7d647000000b004fb56076a23si31992957edr.12.2023.03.30.01.20.12; Thu, 30 Mar 2023 01:20:36 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20210112 header.b=n3LqduWt; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229676AbjC3ILK (ORCPT + 99 others); Thu, 30 Mar 2023 04:11:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49222 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230181AbjC3ILI (ORCPT ); Thu, 30 Mar 2023 04:11:08 -0400 Received: from mail-ed1-x531.google.com (mail-ed1-x531.google.com [IPv6:2a00:1450:4864:20::531]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B75FA40CA for ; Thu, 30 Mar 2023 01:11:06 -0700 (PDT) Received: by mail-ed1-x531.google.com with SMTP id ew6so73172330edb.7 for ; Thu, 30 Mar 2023 01:11:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; t=1680163865; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=Sgclq3CwPySlcIw6eNZ6zuLOimqag1tJf0PxPQK2QJo=; b=n3LqduWt+HEhW6EookUcJ5ttkN1rm1N83wJvGFCq9sSJKjDVdaVmtepvPTVlNKa0W9 uLEbbLnAurxcb88kjTJpE0RLqc0vgAuUR11IA3dMUOED9E0wdQskBprbOOhtXkqSjwm/ O7eeXDBT/rabkd0ff9gf2zNPjXfCw1zWvwPfthQJz9WJQnBf5ouURq0Mup9NjZ0qpyM3 pFA/chxVntmQjEaYHrXdUONAhG5TRKjfdcGAzvS+AmmjvS6D/Z/Z5sg3FwwFkCNzTkrd xQ+FAKYk8XQSij1zKa48Ysf5L7ayZEJPx+qlEg5xztX7gJHSUh0O4cj6udWy+Z18AROk HUpg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1680163865; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=Sgclq3CwPySlcIw6eNZ6zuLOimqag1tJf0PxPQK2QJo=; b=3ODTk7Ubdg0CAqiqtz6EQj4gmkE6LfwJfImAFoqqpFDF1Gab+6a8cu/4LE0eC3c5kK AGKlLoU9608dAheTg3M3OEG8sBiK5QDcPmCPd58Cv+SOvNfYa7+OE/c6ZSI3YDJF/v2d 9y4ehi7roHC3mtS0zngJGjG6bj3IK4NC/+0phwzuOjrzYCEvrQiC9CPGkbt655FMkjJA 55naklRyqzjgLBwV4o7t8k00D6+ZsKRKW3u5lcaTdRtwVip1OG584ZEcimvj3VYY5PyI WnZypbu/95xYv4aBa97NYuo/JeZMEfwZGHNmpg+Odov8QuXiGATOav9VLDltBiJHpA2A WXXA== X-Gm-Message-State: AAQBX9fduf4VlfoxuxdzfhfarMyAa/vOK4SVGMd7TmDBBcP5q2tTVLFW u+nj6S5G4b86gl+naHwQXfO7UwIe1TIW2w== X-Received: by 2002:a17:906:41:b0:934:286:f9 with SMTP id 1-20020a170906004100b00934028600f9mr5104906ejg.27.1680163864663; Thu, 30 Mar 2023 01:11:04 -0700 (PDT) Received: from lelloman-5950.. (host-80-182-134-1.pool80182.interbusiness.it. [80.182.134.1]) by smtp.gmail.com with ESMTPSA id sd24-20020a170906ce3800b00931024e96c5sm17589672ejb.99.2023.03.30.01.11.03 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 30 Mar 2023 01:11:04 -0700 (PDT) From: Domenico Cerasuolo To: linux-kernel@vger.kernel.org Cc: peterz@infradead.org, surenb@google.com, brauner@kernel.org, chris@chrisdown.name, hannes@cmpxchg.org, Domenico Cerasuolo Subject: [PATCH v5 1/4] sched/psi: rearrange polling code in preparation Date: Thu, 30 Mar 2023 10:10:57 +0200 Message-Id: <20230330081100.11871-2-cerasuolodomenico@gmail.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230330081100.11871-1-cerasuolodomenico@gmail.com> References: <20230330081100.11871-1-cerasuolodomenico@gmail.com> MIME-Version: 1.0 X-Spam-Status: No, score=-0.2 required=5.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,DKIM_VALID_EF,FREEMAIL_FROM,RCVD_IN_DNSWL_NONE, SPF_HELO_NONE,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1761780104529864673?= X-GMAIL-MSGID: =?utf-8?q?1761780104529864673?= Move a few functions up in the file to avoid forward declaration needed in the patch implementing unprivileged PSI triggers. Suggested-by: Johannes Weiner Signed-off-by: Domenico Cerasuolo Acked-by: Johannes Weiner --- kernel/sched/psi.c | 196 ++++++++++++++++++++++----------------------- 1 file changed, 98 insertions(+), 98 deletions(-) diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c index 02e011cabe91..fe9269f1d2a4 100644 --- a/kernel/sched/psi.c +++ b/kernel/sched/psi.c @@ -384,92 +384,6 @@ static void collect_percpu_times(struct psi_group *group, *pchanged_states = changed_states; } -static u64 update_averages(struct psi_group *group, u64 now) -{ - unsigned long missed_periods = 0; - u64 expires, period; - u64 avg_next_update; - int s; - - /* avgX= */ - expires = group->avg_next_update; - if (now - expires >= psi_period) - missed_periods = div_u64(now - expires, psi_period); - - /* - * The periodic clock tick can get delayed for various - * reasons, especially on loaded systems. To avoid clock - * drift, we schedule the clock in fixed psi_period intervals. - * But the deltas we sample out of the per-cpu buckets above - * are based on the actual time elapsing between clock ticks. - */ - avg_next_update = expires + ((1 + missed_periods) * psi_period); - period = now - (group->avg_last_update + (missed_periods * psi_period)); - group->avg_last_update = now; - - for (s = 0; s < NR_PSI_STATES - 1; s++) { - u32 sample; - - sample = group->total[PSI_AVGS][s] - group->avg_total[s]; - /* - * Due to the lockless sampling of the time buckets, - * recorded time deltas can slip into the next period, - * which under full pressure can result in samples in - * excess of the period length. - * - * We don't want to report non-sensical pressures in - * excess of 100%, nor do we want to drop such events - * on the floor. Instead we punt any overage into the - * future until pressure subsides. By doing this we - * don't underreport the occurring pressure curve, we - * just report it delayed by one period length. - * - * The error isn't cumulative. As soon as another - * delta slips from a period P to P+1, by definition - * it frees up its time T in P. - */ - if (sample > period) - sample = period; - group->avg_total[s] += sample; - calc_avgs(group->avg[s], missed_periods, sample, period); - } - - return avg_next_update; -} - -static void psi_avgs_work(struct work_struct *work) -{ - struct delayed_work *dwork; - struct psi_group *group; - u32 changed_states; - u64 now; - - dwork = to_delayed_work(work); - group = container_of(dwork, struct psi_group, avgs_work); - - mutex_lock(&group->avgs_lock); - - now = sched_clock(); - - collect_percpu_times(group, PSI_AVGS, &changed_states); - /* - * If there is task activity, periodically fold the per-cpu - * times and feed samples into the running averages. If things - * are idle and there is no data to process, stop the clock. - * Once restarted, we'll catch up the running averages in one - * go - see calc_avgs() and missed_periods. - */ - if (now >= group->avg_next_update) - group->avg_next_update = update_averages(group, now); - - if (changed_states & PSI_STATE_RESCHEDULE) { - schedule_delayed_work(dwork, nsecs_to_jiffies( - group->avg_next_update - now) + 1); - } - - mutex_unlock(&group->avgs_lock); -} - /* Trigger tracking window manipulations */ static void window_reset(struct psi_window *win, u64 now, u64 value, u64 prev_growth) @@ -516,18 +430,6 @@ static u64 window_update(struct psi_window *win, u64 now, u64 value) return growth; } -static void init_triggers(struct psi_group *group, u64 now) -{ - struct psi_trigger *t; - - list_for_each_entry(t, &group->triggers, node) - window_reset(&t->win, now, - group->total[PSI_POLL][t->state], 0); - memcpy(group->polling_total, group->total[PSI_POLL], - sizeof(group->polling_total)); - group->polling_next_update = now + group->poll_min_period; -} - static u64 update_triggers(struct psi_group *group, u64 now) { struct psi_trigger *t; @@ -590,6 +492,104 @@ static u64 update_triggers(struct psi_group *group, u64 now) return now + group->poll_min_period; } +static u64 update_averages(struct psi_group *group, u64 now) +{ + unsigned long missed_periods = 0; + u64 expires, period; + u64 avg_next_update; + int s; + + /* avgX= */ + expires = group->avg_next_update; + if (now - expires >= psi_period) + missed_periods = div_u64(now - expires, psi_period); + + /* + * The periodic clock tick can get delayed for various + * reasons, especially on loaded systems. To avoid clock + * drift, we schedule the clock in fixed psi_period intervals. + * But the deltas we sample out of the per-cpu buckets above + * are based on the actual time elapsing between clock ticks. + */ + avg_next_update = expires + ((1 + missed_periods) * psi_period); + period = now - (group->avg_last_update + (missed_periods * psi_period)); + group->avg_last_update = now; + + for (s = 0; s < NR_PSI_STATES - 1; s++) { + u32 sample; + + sample = group->total[PSI_AVGS][s] - group->avg_total[s]; + /* + * Due to the lockless sampling of the time buckets, + * recorded time deltas can slip into the next period, + * which under full pressure can result in samples in + * excess of the period length. + * + * We don't want to report non-sensical pressures in + * excess of 100%, nor do we want to drop such events + * on the floor. Instead we punt any overage into the + * future until pressure subsides. By doing this we + * don't underreport the occurring pressure curve, we + * just report it delayed by one period length. + * + * The error isn't cumulative. As soon as another + * delta slips from a period P to P+1, by definition + * it frees up its time T in P. + */ + if (sample > period) + sample = period; + group->avg_total[s] += sample; + calc_avgs(group->avg[s], missed_periods, sample, period); + } + + return avg_next_update; +} + +static void psi_avgs_work(struct work_struct *work) +{ + struct delayed_work *dwork; + struct psi_group *group; + u32 changed_states; + u64 now; + + dwork = to_delayed_work(work); + group = container_of(dwork, struct psi_group, avgs_work); + + mutex_lock(&group->avgs_lock); + + now = sched_clock(); + + collect_percpu_times(group, PSI_AVGS, &changed_states); + /* + * If there is task activity, periodically fold the per-cpu + * times and feed samples into the running averages. If things + * are idle and there is no data to process, stop the clock. + * Once restarted, we'll catch up the running averages in one + * go - see calc_avgs() and missed_periods. + */ + if (now >= group->avg_next_update) + group->avg_next_update = update_averages(group, now); + + if (changed_states & PSI_STATE_RESCHEDULE) { + schedule_delayed_work(dwork, nsecs_to_jiffies( + group->avg_next_update - now) + 1); + } + + mutex_unlock(&group->avgs_lock); +} + +static void init_triggers(struct psi_group *group, u64 now) +{ + struct psi_trigger *t; + + list_for_each_entry(t, &group->triggers, node) + window_reset(&t->win, now, + group->total[PSI_POLL][t->state], 0); + memcpy(group->polling_total, group->total[PSI_POLL], + sizeof(group->polling_total)); + group->polling_next_update = now + group->poll_min_period; +} + /* Schedule polling if it's not already scheduled or forced. */ static void psi_schedule_poll_work(struct psi_group *group, unsigned long delay, bool force)