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[84.3.50.134]) by smtp.gmail.com with ESMTPSA id h205sm22059049wmf.35.2019.11.18.05.50.19 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 18 Nov 2019 05:50:19 -0800 (PST) Date: Mon, 18 Nov 2019 14:50:17 +0100 From: Ingo Molnar To: Mel Gorman Cc: Vincent Guittot , linux-kernel@vger.kernel.org, mingo@redhat.com, peterz@infradead.org, pauld@redhat.com, valentin.schneider@arm.com, srikar@linux.vnet.ibm.com, quentin.perret@arm.com, dietmar.eggemann@arm.com, Morten.Rasmussen@arm.com, hdanton@sina.com, parth@linux.ibm.com, riel@surriel.com Subject: Re: [PATCH v4 04/11] sched/fair: rework load_balance Message-ID: <20191118135017.GA123637@gmail.com> References: <1571405198-27570-1-git-send-email-vincent.guittot@linaro.org> <1571405198-27570-5-git-send-email-vincent.guittot@linaro.org> <20191030154534.GJ3016@techsingularity.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191030154534.GJ3016@techsingularity.net> 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 * Mel Gorman wrote: > s/groupe_type/group_type/ > > > enum group_type { > > - group_other = 0, > > + group_has_spare = 0, > > + group_fully_busy, > > group_misfit_task, > > + group_asym_packing, > > group_imbalanced, > > - group_overloaded, > > + group_overloaded > > +}; > > + > > While not your fault, it would be nice to comment on the meaning of each > group type. From a glance, it's not obvious to me why a misfit task should > be a high priority to move a task than a fully_busy (but not overloaded) > group given that moving the misfit task might make a group overloaded. This part of your feedback should now be addressed in the scheduler tree via: a9723389cc75: sched/fair: Add comments for group_type and balancing at SD_NUMA level > > +enum migration_type { > > + migrate_load = 0, > > + migrate_util, > > + migrate_task, > > + migrate_misfit > > }; > > > > Could do with a comment explaining what migration_type is for because > the name is unhelpful. I *think* at a glance it's related to what sort > of imbalance is being addressed which is partially addressed by the > group_type. That understanding may change as I continue reading the series > but now I have to figure it out which means it'll be forgotten again in > 6 months. Agreed. Vincent, is any patch brewing here, or should I take a stab? Thanks, Ingo