From mboxrd@z Thu Jan 1 00:00:00 1970 From: Suren Baghdasaryan Subject: [PATCH v5 4/7] psi: split update_stats into parts Date: Fri, 8 Mar 2019 10:43:08 -0800 Message-ID: <20190308184311.144521-5-surenb@google.com> References: <20190308184311.144521-1-surenb@google.com> Mime-Version: 1.0 Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=5zrp8mnWP3uBM/Fizzp8Po+aOUFVr9GhLUoLscT+qvI=; b=N2+/GhOQIjgVthz+h+5kaB8hfb4yyrZZVmHe16ICqrfbYVc24XX7MCC9FuWksubwVU Xyjd64Yr/Z+WlCHwqfmHEv+CiriSFEdGbJ9EhGMGWuc80Qr3DgYdfRRtcofQeNGTEdK6 3T8qSakvYZgmXfkQbtgGE7jw2pDafLAazJmbRsYkcTi49Se0zeK6UtEa9Ve9E0guUnNS wL8US7Ad5FVeD8X6Dbv/kQhn8oAj8KtMLTIjQz2bKZGZyoHB2wqqUQfC1pY0+K6tFI9s dUnUhmXIejpHH3UJHFZ6OtQ1mkX12leikIcwcgQhb8msIez1QXxhLaRnmJcOLvQ207By Rpow== In-Reply-To: <20190308184311.144521-1-surenb@google.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit 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 Split update_stats into collect_percpu_times and update_averages for collect_percpu_times to be reused later inside psi monitor. Signed-off-by: Suren Baghdasaryan --- kernel/sched/psi.c | 55 +++++++++++++++++++++++++++------------------- 1 file changed, 32 insertions(+), 23 deletions(-) diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c index 4fb4d9913bc8..337a445aefa3 100644 --- a/kernel/sched/psi.c +++ b/kernel/sched/psi.c @@ -269,17 +269,13 @@ static void calc_avgs(unsigned long avg[3], int missed_periods, avg[2] = calc_load(avg[2], EXP_300s, pct); } -static bool update_stats(struct psi_group *group) +static bool collect_percpu_times(struct psi_group *group) { u64 deltas[NR_PSI_STATES - 1] = { 0, }; - unsigned long missed_periods = 0; unsigned long nonidle_total = 0; - u64 now, expires, period; int cpu; int s; - mutex_lock(&group->avgs_lock); - /* * Collect the per-cpu time buckets and average them into a * single time sample that is normalized to wallclock time. @@ -317,11 +313,18 @@ static bool update_stats(struct psi_group *group) for (s = 0; s < NR_PSI_STATES - 1; s++) group->total[s] += div_u64(deltas[s], max(nonidle_total, 1UL)); + return nonidle_total; +} + +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= */ - now = sched_clock(); expires = group->avg_next_update; - if (now < expires) - goto out; if (now - expires >= psi_period) missed_periods = div_u64(now - expires, psi_period); @@ -332,7 +335,7 @@ static bool update_stats(struct psi_group *group) * But the deltas we sample out of the per-cpu buckets above * are based on the actual time elapsing between clock ticks. */ - group->avg_next_update = expires + ((1 + missed_periods) * psi_period); + avg_next_update = expires + ((1 + missed_periods) * psi_period); period = now - (group->avg_last_update + (missed_periods * psi_period)); group->avg_last_update = now; @@ -362,9 +365,8 @@ static bool update_stats(struct psi_group *group) group->avg_total[s] += sample; calc_avgs(group->avg[s], missed_periods, sample, period); } -out: - mutex_unlock(&group->avgs_lock); - return nonidle_total; + + return avg_next_update; } static void psi_avgs_work(struct work_struct *work) @@ -372,10 +374,16 @@ static void psi_avgs_work(struct work_struct *work) struct delayed_work *dwork; struct psi_group *group; bool nonidle; + u64 now; dwork = to_delayed_work(work); group = container_of(dwork, struct psi_group, avgs_work); + mutex_lock(&group->avgs_lock); + + now = sched_clock(); + + nonidle = collect_percpu_times(group); /* * If there is task activity, periodically fold the per-cpu * times and feed samples into the running averages. If things @@ -384,18 +392,15 @@ static void psi_avgs_work(struct work_struct *work) * go - see calc_avgs() and missed_periods. */ - nonidle = update_stats(group); - if (nonidle) { - unsigned long delay = 0; - u64 now; - - now = sched_clock(); - if (group->avg_next_update > now) - delay = nsecs_to_jiffies( - group->avg_next_update - now) + 1; - schedule_delayed_work(dwork, delay); + if (now >= group->avg_next_update) + group->avg_next_update = update_averages(group, now); + + schedule_delayed_work(dwork, nsecs_to_jiffies( + group->avg_next_update - now) + 1); } + + mutex_unlock(&group->avgs_lock); } static void record_times(struct psi_group_cpu *groupc, int cpu, @@ -711,7 +716,11 @@ int psi_show(struct seq_file *m, struct psi_group *group, enum psi_res res) if (static_branch_likely(&psi_disabled)) return -EOPNOTSUPP; - update_stats(group); + /* Update averages before reporting them */ + mutex_lock(&group->avgs_lock); + collect_percpu_times(group); + update_averages(group, sched_clock()); + mutex_unlock(&group->avgs_lock); for (full = 0; full < 2 - (res == PSI_CPU); full++) { unsigned long avg[3]; -- 2.21.0.360.g471c308f928-goog