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X-IronPort-AV: E=McAfee;i="6600,9927,10950"; a="5658677" X-IronPort-AV: E=Sophos;i="6.04,186,1695711600"; d="scan'208";a="5658677" Received: from fmviesa001.fm.intel.com ([10.60.135.141]) by orvoesa103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 11 Jan 2024 09:50:22 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.04,186,1695711600"; d="scan'208";a="24710421" Received: from ldrake1-mobl3.amr.corp.intel.com (HELO [10.212.168.169]) ([10.212.168.169]) by smtpauth.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 11 Jan 2024 09:50:21 -0800 Message-ID: <1d9074955618ea0b4b155701f7c1b8b18a43fa8d.camel@linux.intel.com> Subject: Re: [PATCH v3 3/7] padata: dispatch works on different nodes From: Tim Chen To: Gang Li , David Hildenbrand , David Rientjes , Mike Kravetz , Muchun Song , Andrew Morton Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, ligang.bdlg@bytedance.com Date: Thu, 11 Jan 2024 09:50:20 -0800 In-Reply-To: <20240102131249.76622-4-gang.li@linux.dev> References: <20240102131249.76622-1-gang.li@linux.dev> <20240102131249.76622-4-gang.li@linux.dev> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.44.4 (3.44.4-2.fc36) MIME-Version: 1.0 X-Rspamd-Queue-Id: 50F5912002C X-Rspam-User: X-Rspamd-Server: rspam05 X-Stat-Signature: f4c71of6zzyiteukycipfdhxq1uhhbof X-HE-Tag: 1704995424-200086 X-HE-Meta: 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 b4jNf3hi tT/wI8ZSnPH205ubElOBFx0Zb7fGHjoz0jowXsRd0y/e6jgK28YQ31LBgy8yE9jIgMnWWzK7nfsMlvmbHsyvcsimNTu4/a8O/earvsGOl/IgZVtq1DE6OHT9SCLrrKu5sZGMw X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue, 2024-01-02 at 21:12 +0800, Gang Li wrote: > When a group of tasks that access different nodes are scheduled on the > same node, they may encounter bandwidth bottlenecks and access latency. >=20 > Thus, numa_aware flag is introduced here, allowing tasks to be > distributed across different nodes to fully utilize the advantage of > multi-node systems. >=20 > Signed-off-by: Gang Li > --- > include/linux/padata.h | 3 +++ > kernel/padata.c | 8 ++++++-- > mm/mm_init.c | 1 + > 3 files changed, 10 insertions(+), 2 deletions(-) >=20 > diff --git a/include/linux/padata.h b/include/linux/padata.h > index 495b16b6b4d72..f79ccd50e7f40 100644 > --- a/include/linux/padata.h > +++ b/include/linux/padata.h > @@ -137,6 +137,8 @@ struct padata_shell { > * appropriate for one worker thread to do at once. > * @max_threads: Max threads to use for the job, actual number may be le= ss > * depending on task size and minimum chunk size. > + * @numa_aware: Dispatch jobs to different nodes. If a node only has mem= ory but > + * no CPU, dispatch its jobs to a random CPU. > */ > struct padata_mt_job { > void (*thread_fn)(unsigned long start, unsigned long end, void *arg); > @@ -146,6 +148,7 @@ struct padata_mt_job { > unsigned long align; > unsigned long min_chunk; > int max_threads; > + bool numa_aware; > }; > =20 > /** > diff --git a/kernel/padata.c b/kernel/padata.c > index 179fb1518070c..1c2b3a337479e 100644 > --- a/kernel/padata.c > +++ b/kernel/padata.c > @@ -485,7 +485,7 @@ void __init padata_do_multithreaded(struct padata_mt_= job *job) > struct padata_work my_work, *pw; > struct padata_mt_job_state ps; > LIST_HEAD(works); > - int nworks; > + int nworks, nid =3D 0; If we always start from 0, we may be biased towards the low numbered node, and not use high numbered nodes at all. Suggest you do static nid =3D 0; =20 > =20 > if (job->size =3D=3D 0) > return; > @@ -517,7 +517,11 @@ void __init padata_do_multithreaded(struct padata_mt= _job *job) > ps.chunk_size =3D roundup(ps.chunk_size, job->align); > =20 > list_for_each_entry(pw, &works, pw_list) > - queue_work(system_unbound_wq, &pw->pw_work); > + if (job->numa_aware) > + queue_work_node((++nid % num_node_state(N_MEMORY)), > + system_unbound_wq, &pw->pw_work); I think we should use nid =3D next_node(nid, node_states[N_CPU]) instead of ++nid % num_node_state(N_MEMORY). You are picking the next node with CPU to handle the job. Tim > + else > + queue_work(system_unbound_wq, &pw->pw_work); > =20 > /* Use the current thread, which saves starting a workqueue worker. */ > padata_work_init(&my_work, padata_mt_helper, &ps, PADATA_WORK_ONSTACK); > diff --git a/mm/mm_init.c b/mm/mm_init.c > index 89dc29f1e6c6f..59fcffddf65a3 100644 > --- a/mm/mm_init.c > +++ b/mm/mm_init.c > @@ -2225,6 +2225,7 @@ static int __init deferred_init_memmap(void *data) > .align =3D PAGES_PER_SECTION, > .min_chunk =3D PAGES_PER_SECTION, > .max_threads =3D max_threads, > + .numa_aware =3D false, > }; > =20 > padata_do_multithreaded(&job);