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[109.81.25.183]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-48de0ab4f34sm14183540f8f.28.2026.10.14.12.30.14 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 14 Oct 2026 12:30:15 -0700 (PDT) Date: Wed, 14 Oct 2026 21:30:14 +0200 From: Michal Hocko To: Shakeel Butt Cc: Andrew Morton , Johannes Weiner , Roman Gushchin , Muchun Song , Tejun Heo , Meta kernel team , cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH for-7.5 5/5] memcg: simplify high limit handling after a charge Message-ID: References: <20261010210957.1350874-1-shakeel.butt@linux.dev> <20261010210957.1350874-6-shakeel.butt@linux.dev> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Wed 14-10-26 10:43:33, Shakeel Butt wrote: > On Wed, Oct 14, 2026 at 01:46:23PM +0200, Michal Hocko wrote: > > On Sat 10-10-26 14:09:57, Shakeel Butt wrote: > > [...] > > > - /* Interrupts, kernel threads, and remote chargers stop here. */ > > > - if (use_worker) > > > + /* > > > + * Use a worker for interrupts, kernel threads, and tasks whose mm > > > + * does not match the charged hierarchy. > > > + */ > > > + if (use_high_work) { > > > + if (!iter) > > > + return; > > > + if (allow_spinning) > > > + schedule_work(&iter->high_work); > > > + else > > > + irq_work_queue(&iter->high_irq_work); > > > return; > > > + } > > > + > > > + if (iter) { > > > > Would it be much simpler to bail out on iter==NULL (i.e. nothing over > > high limit) right after the loop? > > > > I want this patch to not change any behavior. If we return here when iter is > NULL, we will skip a potential call to __mem_cgroup_handle_over_high() when > current->memcg_nr_pages_over_high > MEMCG_CHARGE_BATCH. Though I agree that is > very subtle and most probably unexpected. If we decide to remove it, we should > do it in a separate patch. OK, makes sense. Acked-by: Michal Hocko -- Michal Hocko SUSE Labs