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X-IronPort-AV: E=McAfee;i="6600,9927,10964"; a="9251528" X-IronPort-AV: E=Sophos;i="6.05,220,1701158400"; d="scan'208";a="9251528" Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by orvoesa103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Jan 2024 14:23:32 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10964"; a="906436829" X-IronPort-AV: E=Sophos;i="6.05,220,1701158400"; d="scan'208";a="906436829" Received: from dlberger-mobl.amr.corp.intel.com (HELO [10.209.52.191]) ([10.209.52.191]) by fmsmga002-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Jan 2024 14:23:31 -0800 Message-ID: <7379f03364a7291770f9622b91c4d84e26352b20.camel@linux.intel.com> Subject: Re: [PATCH v5 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: Fri, 26 Jan 2024 14:23:30 -0800 In-Reply-To: <20240126152411.1238072-4-gang.li@linux.dev> References: <20240126152411.1238072-1-gang.li@linux.dev> <20240126152411.1238072-4-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) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Fri, 2024-01-26 at 23:24 +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 > Tested-by: David Rientjes > Reviewed-by: Muchun Song Reviewed-by: Tim Chen > --- > include/linux/padata.h | 2 ++ > kernel/padata.c | 14 ++++++++++++-- > mm/mm_init.c | 1 + > 3 files changed, 15 insertions(+), 2 deletions(-) >=20 > diff --git a/include/linux/padata.h b/include/linux/padata.h > index 495b16b6b4d72..8f418711351bc 100644 > --- a/include/linux/padata.h > +++ b/include/linux/padata.h > @@ -137,6 +137,7 @@ 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: Distribute jobs to different nodes with CPU in a round r= obin fashion. > */ > struct padata_mt_job { > void (*thread_fn)(unsigned long start, unsigned long end, void *arg); > @@ -146,6 +147,7 @@ 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..e3f639ff16707 100644 > --- a/kernel/padata.c > +++ b/kernel/padata.c > @@ -485,7 +485,8 @@ 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; > + static atomic_t last_used_nid __initdata; > =20 > if (job->size =3D=3D 0) > return; > @@ -517,7 +518,16 @@ 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) { > + int old_node =3D atomic_read(&last_used_nid); > + > + do { > + nid =3D next_node_in(old_node, node_states[N_CPU]); > + } while (!atomic_try_cmpxchg(&last_used_nid, &old_node, nid)); > + queue_work_node(nid, system_unbound_wq, &pw->pw_work); > + } 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 2c19f5515e36c..549e76af8f82a 100644 > --- a/mm/mm_init.c > +++ b/mm/mm_init.c > @@ -2231,6 +2231,7 @@ 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);