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[35.195.168.105]) by smtp.gmail.com with ESMTPSA id z3sm5536231wrv.45.2021.07.01.03.07.20 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 01 Jul 2021 03:07:21 -0700 (PDT) Date: Thu, 1 Jul 2021 10:07:18 +0000 From: Quentin Perret To: Qais Yousef Cc: mingo@redhat.com, peterz@infradead.org, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rickyiu@google.com, wvw@google.com, patrick.bellasi@matbug.net, xuewen.yan94@gmail.com, linux-kernel@vger.kernel.org, kernel-team@android.com Subject: Re: [PATCH v3 1/3] sched: Fix UCLAMP_FLAG_IDLE setting Message-ID: References: <20210623123441.592348-1-qperret@google.com> <20210623123441.592348-2-qperret@google.com> <20210630145848.htb7pnwsl2gao77x@e107158-lin.cambridge.arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wednesday 30 Jun 2021 at 15:45:14 (+0000), Quentin Perret wrote: > diff --git a/kernel/sched/core.c b/kernel/sched/core.c > index b094da4c5fea..c0b999a8062a 100644 > --- a/kernel/sched/core.c > +++ b/kernel/sched/core.c > @@ -980,7 +980,6 @@ static inline void uclamp_idle_reset(struct rq *rq, enum uclamp_id clamp_id, > if (!(rq->uclamp_flags & UCLAMP_FLAG_IDLE)) > return; > > - rq->uclamp_flags &= ~UCLAMP_FLAG_IDLE; > WRITE_ONCE(rq->uclamp[clamp_id].value, clamp_value); > } > > @@ -1253,6 +1252,10 @@ static inline void uclamp_rq_inc(struct rq *rq, struct task_struct *p) > > for_each_clamp_id(clamp_id) > uclamp_rq_inc_id(rq, p, clamp_id); > + > + /* Reset clamp idle holding when there is one RUNNABLE task */ > + if (rq->uclamp_flags & UCLAMP_FLAG_IDLE) > + rq->uclamp_flags &= ~UCLAMP_FLAG_IDLE; > } > > static inline void uclamp_rq_dec(struct rq *rq, struct task_struct *p) > @@ -1300,6 +1303,13 @@ uclamp_update_active(struct task_struct *p, enum uclamp_id clamp_id) > if (p->uclamp[clamp_id].active) { > uclamp_rq_dec_id(rq, p, clamp_id); > uclamp_rq_inc_id(rq, p, clamp_id); > + > + /* > + * Make sure to clear the idle flag if we've transiently reached > + * 0 uclamp active tasks on the rq. > + */ > + if (rq->uclamp_flags & UCLAMP_FLAG_IDLE) > + rq->uclamp_flags &= ~UCLAMP_FLAG_IDLE; Bah, now that I had coffee I realize this has the exact same problem. Let me look at this again ...