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[173.79.60.52]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-91252c7cb8bsm1199036d6.20.2026.09.17.09.14.33 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 17 Sep 2026 09:14:34 -0700 (PDT) Date: Thu, 17 Sep 2026 12:14:31 -0400 From: Gregory Price To: Peter Zijlstra Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel-team@meta.com, akpm@linux-foundation.org, david@kernel.org, ljs@kernel.org, liam@infradead.org, vbabka@kernel.org, rppt@kernel.org, surenb@google.com, mhocko@suse.com, mingo@redhat.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, vschneid@redhat.com, kprateek.nayak@amd.com, ziy@nvidia.com, baolin.wang@linux.alibaba.com, nico.pache@linux.dev, ryan.roberts@arm.com, dev.jain@arm.com, baohua@kernel.org, lance.yang@linux.dev, usama.arif@linux.dev, kas@kernel.org, matthew.brost@intel.com, joshua.hahnjy@gmail.com, rakie.kim@sk.com, byungchul@sk.com, ying.huang@linux.alibaba.com, apopple@nvidia.com, jannh@google.com, pfalcato@suse.de, osalvador@suse.de, hannes@cmpxchg.org, raghavendra.kt@amd.com, stable@vger.kernel.org Subject: Re: [PATCH v2 1/4] mm: support promotion-only NUMA hinting scans Message-ID: References: <20260911001826.2109390-1-gourry@gourry.net> <20260911001826.2109390-2-gourry@gourry.net> <20260917160328.GM4121339@noisy.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260917160328.GM4121339@noisy.programming.kicks-ass.net> X-Rspam-User: X-Rspamd-Queue-Id: 8AA9E10000B X-Stat-Signature: 5bzdzeo713qdzd8sp5jbzno5tmooq97g X-Rspamd-Server: rspam01 X-HE-Tag: 1789661676-957368 X-HE-Meta: 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 hAdeYTVd npy6Iak04dQxHxIb/Rs+RF1XRB5T4IrKYfl9HcuV+PfLlWNGqWtdAajoNDW8yNMvIR6+PHqKhQf/CZhzBy+ewM2J7+rDjN6qusCzwH2gCcis4hNsdxqF6uo8E/XUnnsY2w3KdJYp3Ob4nOBgw3tUkm4FGMKsxZE9BefNIvrtWruhQAuXh0uKsXnXyeFT0uSJAIvdC6ccs6ox9bdowJSN9xwpIwA1EdeDBvGwByB+9/yHfNTSL4vO7fivzyCW6CxXtvgE1NlR9jOBWHv0Q2RxLUM0SPxh3jgSYzZQaCkIWq2vhhBidYyny8WC73XgyBoG3hpH3boldx1KMQBbNpwPTCIflFi+TU1M3dKj/00xZquaVaqFm/78ONlY9soDZ0VuP7ttOyytxF4zWheS0VV7OZtaKrw== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, Sep 17, 2026 at 06:03:28PM +0200, Peter Zijlstra wrote: > On Thu, Sep 10, 2026 at 08:18:23PM -0400, Gregory Price wrote: > > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > > index 8dff37059faf..81359b414947 100644 > > --- a/kernel/sched/fair.c > > +++ b/kernel/sched/fair.c > > @@ -4129,8 +4129,10 @@ static void task_numa_work(struct callback_head *work) > > unsigned long nr_pte_updates = 0; > > long pages, virtpages; > > struct vma_iterator vmi; > > + unsigned int numab_mode = READ_ONCE(sysctl_numa_balancing_mode); > > This thing sticks out like a sort thumb, does that want to be on top? > Typically reverse xmas is preferred and all that. > oi yeah sorry, should have given this a closer style look. will fix it up. > > bool vma_pids_skipped; > > bool vma_pids_forced = false; > > + bool promo_only; > > > > WARN_ON_ONCE(p != container_of(work, struct task_struct, numa_work)); > > > > > --- a/mm/internal.h > > +++ b/mm/internal.h > > @@ -1237,11 +1237,12 @@ static inline bool vma_is_single_threaded_private(struct vm_area_struct *vma) > > > > #ifdef CONFIG_NUMA_BALANCING > > bool folio_can_map_prot_numa(struct folio *folio, struct vm_area_struct *vma, > > - bool is_private_single_threaded); > > + bool is_private_single_threaded, bool promo_only); > > Two bools rather than updating the existing bool to a flags? every time i've added a flag field someone screeches at me, so I tend to avoid it now - but i can do that's the preference here. Otherwise, i tend to follow rule of 3 for generalizing. ~Gregory