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Sun, 13 Sep 2026 22:27:07 -0700 (PDT) From: Kayra Cizmeci To: yu.c.chen@intel.com Cc: brauner@kernel.org, bsegall@google.com, chen.yu@linux.dev, dietmar.eggemann@arm.com, imv4bel@gmail.com, jack@suse.cz, juri.lelli@redhat.com, kayracizmeci@gmail.com, kees@kernel.org, kprateek.nayak@amd.com, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, mgorman@suse.de, mingo@redhat.com, peterz@infradead.org, qyousef@layalina.io, ricardo.neri-calderon@linux.intel.com, rostedt@goodmis.org, srikar@linux.ibm.com, sshegde@linux.ibm.com, tim.c.chen@linux.intel.com, vincent.guittot@linaro.org, vineethr@linux.ibm.com, viro@zeniv.linux.org.uk, vschneid@redhat.com, wanglu.priv@gmail.com, yi1.lai@intel.com, zhanxusheng1024@gmail.com, zhanxusheng@xiaomi.com, ziqianlu@bytedance.com Subject: Re: [PATCH 1/4] sched/cache: Keep nr_pref_llc_running in the runnable domain Date: Mon, 14 Sep 2026 08:27:03 +0300 Message-ID: <20260914052703.1286495-1-kayracizmeci@gmail.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Hello Chen, > Hi Kayra, > I had a try according to your suggestion. It seems that the code becomes more complex > and brings more headache :-( due to several corner cases. The current version is a simpler > version with less code IMO. But I agree it looks a little hard to catch up with, so I added > some comments around account_llc_dequeue() and adjusted the code sequence of clear_delayed() > to make it easier to understand. Tim, could you please help check if this makes sense? I can't read your magnificent comment right now, I'm in a hurry. Sorry :-(. (But I will :>) > @@ -6415,23 +6465,18 @@ static __always_inline void return_cfs_rq_runtime(struct cfs_rq *cfs_rq); > static void set_delayed(struct sched_entity *se) > { > - /* > - * Drop a task leaving the runnable set. Must run before sched_delayed > - * is set, or task_pref_llc_runnable() would already exclude it; > - * clear_delayed() mirrors this after clearing the flag. > - */ > - if (entity_is_task(se)) > - pref_llc_running_dec(rq_of(cfs_rq_of(se)), task_of(se)); > - > - se->sched_delayed = 1; >- > /* > * Delayed se of cfs_rq have no tasks queued on them. > * Do not adjust h_nr_runnable since __dequeue_task() > * will account it for blocked tasks. > */ > - if (!entity_is_task(se)) > + if (!entity_is_task(se)) { > + se->sched_delayed = 1; > return; > + } > + > + pref_llc_running_dec(rq_of(cfs_rq_of(se)), task_of(se)); > + se->sched_delayed = 1; > > for_each_sched_entity(se) { > struct cfs_rq *cfs_rq = cfs_rq_of(se); Yeah, I think this is cleaner. I didn't read the comment tho :>. Thanks, Kayra :--)