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DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1708610697; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=MgzBTPzPKbW03C1p+bf5b2VOJPKCTieqosPALSU6d3A=; b=p1Ko7q4HwLZ8IRyvsRmFPEObb08w0kLTfT8Eo/yUShmw9X8SanRExrBoYN4E8QizQ7JtJr y6CDhqCmusgjbGbPQnWZj7zwS/EdtoiwysOQK8U4EQ2jhWPEDI0N15nmbWXhOwCYYBftee 20rXO2q25jdViRTYxjq4nVcOPEYzQBk= From: Gang Li To: Andrew Morton Cc: David Hildenbrand , David Rientjes , Muchun Song , Tim Chen , Steffen Klassert , Daniel Jordan , Jane Chu , "Paul E . McKenney" , Randy Dunlap , linux-mm@kvack.org, linux-kernel@vger.kernel.org, ligang.bdlg@bytedance.com, Gang Li Subject: [PATCH v6 4/8] padata: dispatch works on different nodes Date: Thu, 22 Feb 2024 22:04:17 +0800 Message-Id: <20240222140422.393911-5-gang.li@linux.dev> In-Reply-To: <20240222140422.393911-1-gang.li@linux.dev> References: <20240222140422.393911-1-gang.li@linux.dev> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Migadu-Flow: FLOW_OUT Content-Type: text/plain; charset="utf-8" When a group of tasks that access different nodes are scheduled on the same node, they may encounter bandwidth bottlenecks and access latency. Thus, numa_aware flag is introduced here, allowing tasks to be distributed across different nodes to fully utilize the advantage of multi-node systems. Signed-off-by: Gang Li Tested-by: David Rientjes Reviewed-by: Muchun Song Reviewed-by: Tim Chen Acked-by: Daniel Jordan --- include/linux/padata.h | 2 ++ kernel/padata.c | 14 ++++++++++++-- mm/mm_init.c | 1 + 3 files changed, 15 insertions(+), 2 deletions(-) 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 less * depending on task size and minimum chunk size. + * @numa_aware: Distribute jobs to different nodes with CPU in a round rob= in 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_jo= b *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_j= ob *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); --=20 2.20.1