From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2FA3B38A725; Tue, 13 Oct 2026 07:38:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791877106; cv=none; b=hmPdpSIGvnUh/AZ2Fub0X/cwQjwNHbAuBj4QWxFKG5Cr/NrigJ1Wrlr2w5CRBIiCAxiJ9DcvbFtd56DKSx4aXtQs5a8AkgyFXxeWYscPI/8caRn01lrB1i2tFXu1EKUgZh81cDDuc4CpDc54oyIedEjGFRoknrlSZ4WhcpexqgA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791877106; c=relaxed/simple; bh=ZyYqWXIUfrHec9/Q4SP2Vj1puzNLnZc//qGe5AvQoNM=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=l6eaYaeRHdI5fy99RlV/59A1FSvcfs81XYEY7RxorCtyKZtuwn660r/7PiXrGUtvhifsbkd3PoOsMmj1LVJD2tTPDNFrqighlv7gvEQaGxJ5jgDMv55GZvU0FXRQsUurtIFc08FV8E+0UAFOjXAJuV1D4w6hkLOWx/rYJ9qQguw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=DlB0kj8g; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="DlB0kj8g" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 47F001F00893; Tue, 13 Oct 2026 07:38:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1791877104; bh=DcuYY3+mv/Ns6uvfacyrd4dBgpfSbyMtyecX3H4y2hE=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=DlB0kj8gOlFNSD84BZwMWb5ZbV2oXW4IaLaFGcapmHBAUuLC7zPJAEShEflW7d90Z 2ITF8SGCDnhIDxAHfjDEwEtAvXceuwSpN5Fasml6JY9Wn9huixCPCLyT3uZ+1AsP/f QOGdh8bpPL2f7KQEgdkMQFTpJg+d/VB0ZERes3AU7EeweYpj1IPdrZRVasXloHdV2K FjdS4eNfe0CbiVGPsgPqkqk1Hc6oPE4Il1DhEwPDaQ3vfenYbgtC509EdQiZhRvTGK ukmwwkNFOwzqRryAIPa6FUnK5PNz4426a8gtHsmxyZGUcdlQo01a/ZMlDCQP2iOTA7 O7NL/VpOcZOZA== Message-ID: <96324eec-d307-4bbf-975e-3c9b3dd5e190@kernel.org> Date: Tue, 13 Oct 2026 09:38:14 +0200 Precedence: bulk X-Mailing-List: cgroups@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RFC PATCH v2 1/3] sched: add helpers for numa balancing To: Yafang Shao , ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, eddyz87@gmail.com, memxor@gmail.com, mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com, vincent.guittot@linaro.org, akpm@linux-foundation.org, gourry@gourry.net, tj@kernel.org, hannes@cmpxchg.org, mkoutny@suse.com, shakeel.butt@linux.dev, roman.gushchin@linux.dev, yu.c.chen@intel.com, zhao1.liu@intel.com Cc: bpf@vger.kernel.org, linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org References: <20261012120438.52849-1-laoar.shao@gmail.com> <20261012120438.52849-2-laoar.shao@gmail.com> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 10/12/26 14:04, Yafang Shao wrote: > Two new helpers task_numab_enabled() and numab_mode_tiering() are > introduced to replace the scattered direct accesses to the > sched_numa_balancing static key and the sysctl_numa_balancing_mode > bitmask. > I'll only comment on the new exposed helpers. Some of these might make sense even without the bigger series. (obviously, minus the task change) > No functional change. > > Signed-off-by: Yafang Shao > --- > include/linux/sched/numa_balancing.h | 31 ++++++++++++++++++++++++++++ > kernel/sched/fair.c | 16 +++++++------- > kernel/sched/sched.h | 1 - > mm/memory-tiers.c | 3 ++- > mm/migrate.c | 7 ++++--- > mm/vmscan.c | 6 +++--- > 6 files changed, 48 insertions(+), 16 deletions(-) > > diff --git a/include/linux/sched/numa_balancing.h b/include/linux/sched/numa_balancing.h > index 52b22c5c396d..353772b49c5f 100644 > --- a/include/linux/sched/numa_balancing.h > +++ b/include/linux/sched/numa_balancing.h > @@ -8,6 +8,7 @@ > */ > > #include > +#include > > #define TNF_MIGRATED 0x01 > #define TNF_NO_GROUP 0x02 > @@ -32,6 +33,28 @@ extern void set_numabalancing_state(bool enabled); > extern void task_numa_free(struct task_struct *p, bool final); > bool should_numa_migrate_memory(struct task_struct *p, struct folio *folio, > int src_nid, int dst_cpu); > + > +extern struct static_key_false sched_numa_balancing; > + > +/* > + * Whether NUMA balancing applies to @p. The @p argument is unused for > + * now: a later patch will consult a per-cgroup BPF policy with it. Talking about later patches in a function doc is ... wrong. > + */ > +static inline bool task_numab_enabled(struct task_struct *p) > +{ > + return static_branch_unlikely(&sched_numa_balancing); > +} > + > +/* > + * The global sysctl state, for the system-wide tiering machinery: this > + * reflects kernel.numa_balancing_mode only and takes no task. The latter part doesn't make a lot of sense in this documentation. > + */ > +static inline bool numab_mode_tiering(void) The function name isn't really intuitive. Should this be numab_in_tiering_mode numab_tiering_enabled or something like this. > +{ > + if (sysctl_numa_balancing_mode & NUMA_BALANCING_MEMORY_TIERING) > + return true; > + return false; return sysctl_numa_balancing_mode & NUMA_BALANCING_MEMORY_TIERING; ? Both functions could directly have proper kerneldoc if we are already documenting these. > +} > #else > static inline void task_numa_fault(int last_node, int node, int pages, > int flags) > @@ -52,6 +75,14 @@ static inline bool should_numa_migrate_memory(struct task_struct *p, > { > return true; > } > +static inline bool task_numab_enabled(struct task_struct *p) > +{ > + return false; > +} > +static inline bool numab_mode_tiering(void) > +{ > + return false; > +} -- Cheers, David