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[84.3.50.134]) by smtp.gmail.com with ESMTPSA id q15sm14227107wrr.11.2019.12.21.08.19.59 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 21 Dec 2019 08:20:00 -0800 (PST) Date: Sat, 21 Dec 2019 17:19:58 +0100 From: Ingo Molnar To: Linus Torvalds Cc: linux-kernel@vger.kernel.org, Peter Zijlstra , Thomas Gleixner , Andrew Morton Subject: [GIT PULL] scheduler fixes Message-ID: <20191221161958.GA15732@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Linus, Please pull the latest sched-urgent-for-linus git tree from: git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git sched-urgent-for-linus # HEAD: 6cf82d559e1a1d89f06ff4d428aca479c1dd0be6 sched/cfs: fix spurious active migration Misc fixes: a (rare) PSI crash fix, a CPU affinity related balancing fix, and a toning down of active migration attempts. Thanks, Ingo ------------------> Johannes Weiner (2): sched/psi: Fix sampling error and rare div0 crashes with cgroups and high uptime psi: Fix a division error in psi poll() Vincent Guittot (2): sched/fair: Fix find_idlest_group() to handle CPU affinity sched/cfs: fix spurious active migration kernel/sched/fair.c | 13 ++++++++++++- kernel/sched/psi.c | 5 +++-- 2 files changed, 15 insertions(+), 3 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 08a233e97a01..ba749f579714 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -7328,7 +7328,14 @@ static int detach_tasks(struct lb_env *env) load < 16 && !env->sd->nr_balance_failed) goto next; - if (load/2 > env->imbalance) + /* + * Make sure that we don't migrate too much load. + * Nevertheless, let relax the constraint if + * scheduler fails to find a good waiting task to + * migrate. + */ + if (load/2 > env->imbalance && + env->sd->nr_balance_failed <= env->sd->cache_nice_tries) goto next; env->imbalance -= load; @@ -8417,6 +8424,10 @@ find_idlest_group(struct sched_domain *sd, struct task_struct *p, if (!idlest) return NULL; + /* The local group has been skipped because of CPU affinity */ + if (!local) + return idlest; + /* * If the local group is idler than the selected idlest group * don't try and push the task. diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c index 517e3719027e..ce8f6748678a 100644 --- a/kernel/sched/psi.c +++ b/kernel/sched/psi.c @@ -185,7 +185,8 @@ static void group_init(struct psi_group *group) for_each_possible_cpu(cpu) seqcount_init(&per_cpu_ptr(group->pcpu, cpu)->seq); - group->avg_next_update = sched_clock() + psi_period; + group->avg_last_update = sched_clock(); + group->avg_next_update = group->avg_last_update + psi_period; INIT_DELAYED_WORK(&group->avgs_work, psi_avgs_work); mutex_init(&group->avgs_lock); /* Init trigger-related members */ @@ -481,7 +482,7 @@ static u64 window_update(struct psi_window *win, u64 now, u64 value) u32 remaining; remaining = win->size - elapsed; - growth += div_u64(win->prev_growth * remaining, win->size); + growth += div64_u64(win->prev_growth * remaining, win->size); } return growth;