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Received: from 77-249-17-252.cable.dynamic.v4.ziggo.nl ([77.249.17.252] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.99.2 #2 (Red Hat Linux)) id 1x7EaA-00000009135-2mPg; Thu, 17 Sep 2026 16:03:33 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id 94F49301BD5; Thu, 17 Sep 2026 18:03:28 +0200 (CEST) Date: Thu, 17 Sep 2026 18:03:28 +0200 From: Peter Zijlstra To: Gregory Price 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: <20260917160328.GM4121339@noisy.programming.kicks-ass.net> References: <20260911001826.2109390-1-gourry@gourry.net> <20260911001826.2109390-2-gourry@gourry.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260911001826.2109390-2-gourry@gourry.net> X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: AAB1120004 X-Stat-Signature: ui6d9ew4xi7fqrhn38x3uzwihxts3u9p X-Rspam-User: X-HE-Tag: 1789661024-571747 X-HE-Meta: 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 dRlwiVVo Pu4hIFsvwRaZaPvFxXmyba/1tZc0vng4RQxAabY8MKHD5sNkT8mgxkIQ8jXSrOSGJbBFlKfOi7PZIFd1XtpCPOl8beb6dtsx9cdEF7naf0l51lBsRHVIiUMjOkL1dKKFhYu78UgRi/j6P7f4yadKYMIFRDw7KBeAjS2iAlhjDDpIyCG/fBa+Sv67c4x2w3/qJ/vSoHwvlCbS0rndn02pvYcX7IK50f+/vqGHrxNWwUqs64kAUrlnnJjezKTbNZf6wTWsaGfX186VT28KzsnHqxaHAzUCaxIkW2fXl Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 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. > 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?