From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 CC836144D01 for ; Wed, 7 Aug 2024 16:03:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723046592; cv=none; b=lVH0WJieNu4xTK3x09jTTkg53IxpZsXsPf3xF24RqeqnPMQVZhXusIBBDX/1rkby7azxt0Y6d7TglJprCdLakaXghs3i9oYZsMRKQpa04hfLXjpd72vXhVZK4nTzJUg1GglII/DpDpAsGitpnmrdpAuPJgl6robByO0nXEF6pvM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723046592; c=relaxed/simple; bh=qmoM3ChVAsHvS68tRvbUXn+/+j14ziiQAM+q5AQltms=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=HDcsdoK/j0nM/MocIPybYpK5YE4N8pHjyDGNEhWBO+5jhnsVNk6vDopmyx0cpEYBXALGRfmwQ+sNZDYAY6fGuip9Wt3ZWl+hOgXDsPi9ITOnMG0E2i/FirJQCC2r9OB5GiGeduqsjjf0cLV9cHB/GgOrZaWZyXGvLlLDafPjqpY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=bu6TAHyF; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="bu6TAHyF" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 62A95C32781; Wed, 7 Aug 2024 16:03:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1723046592; bh=qmoM3ChVAsHvS68tRvbUXn+/+j14ziiQAM+q5AQltms=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=bu6TAHyF65dcVtBsMxgQFbjWLLcB6hYmF0nqz+hgvPTCUJ6oME8WNz6xujIWX1x6d 9U2UjooEmv7VqxRrMmPuw8/rMMx0cTe+b2fm+llDWAOX8obM0LcpPtbjthUa56yl9q nxWziGvlKXzkZ/teC7N5ZIc1cJMgkhw7Af4QSFLu/TF8TyNE3PVT2Q2mM3Ao0wG5SO nIg+iWfAE3aqxhlzq/koVtfgFS17vb5t1MtFGLSbogK0RFv+gDQwBCUgwQ6L3voEEz vZgzzEwBSfB7F97wubui30XF/zluX0m9fhCYNN2GY68HJPHZK4BpiAUdX8jeN3LOq0 XWYw0LAP8k/+A== From: Frederic Weisbecker To: LKML Cc: Frederic Weisbecker , Michal Hocko , Vlastimil Babka , Andrew Morton , linux-mm@kvack.org, Peter Zijlstra , Thomas Gleixner Subject: [PATCH 13/19] mm: Create/affine kcompactd to its preferred node Date: Wed, 7 Aug 2024 18:02:19 +0200 Message-ID: <20240807160228.26206-14-frederic@kernel.org> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20240807160228.26206-1-frederic@kernel.org> References: <20240807160228.26206-1-frederic@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Kcompactd is dedicated to a specific node. As such it wants to be preferrably affine to it, memory and CPUs-wise. Use the proper kthread API to achieve that. As a bonus it takes care of CPU-hotplug events and CPU-isolation on its behalf. Signed-off-by: Frederic Weisbecker --- mm/compaction.c | 43 +++---------------------------------------- 1 file changed, 3 insertions(+), 40 deletions(-) diff --git a/mm/compaction.c b/mm/compaction.c index eb95e9b435d0..69742555f2e5 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -3179,15 +3179,9 @@ void wakeup_kcompactd(pg_data_t *pgdat, int order, int highest_zoneidx) static int kcompactd(void *p) { pg_data_t *pgdat = (pg_data_t *)p; - struct task_struct *tsk = current; long default_timeout = msecs_to_jiffies(HPAGE_FRAG_CHECK_INTERVAL_MSEC); long timeout = default_timeout; - const struct cpumask *cpumask = cpumask_of_node(pgdat->node_id); - - if (!cpumask_empty(cpumask)) - set_cpus_allowed_ptr(tsk, cpumask); - set_freezable(); pgdat->kcompactd_max_order = 0; @@ -3258,10 +3252,12 @@ void __meminit kcompactd_run(int nid) if (pgdat->kcompactd) return; - pgdat->kcompactd = kthread_run(kcompactd, pgdat, "kcompactd%d", nid); + pgdat->kcompactd = kthread_create_on_node(kcompactd, pgdat, nid, "kcompactd%d", nid); if (IS_ERR(pgdat->kcompactd)) { pr_err("Failed to start kcompactd on node %d\n", nid); pgdat->kcompactd = NULL; + } else { + wake_up_process(pgdat->kcompactd); } } @@ -3279,30 +3275,6 @@ void __meminit kcompactd_stop(int nid) } } -/* - * It's optimal to keep kcompactd on the same CPUs as their memory, but - * not required for correctness. So if the last cpu in a node goes - * away, we get changed to run anywhere: as the first one comes back, - * restore their cpu bindings. - */ -static int kcompactd_cpu_online(unsigned int cpu) -{ - int nid; - - for_each_node_state(nid, N_MEMORY) { - pg_data_t *pgdat = NODE_DATA(nid); - const struct cpumask *mask; - - mask = cpumask_of_node(pgdat->node_id); - - if (cpumask_any_and(cpu_online_mask, mask) < nr_cpu_ids) - /* One of our CPUs online: restore mask */ - if (pgdat->kcompactd) - set_cpus_allowed_ptr(pgdat->kcompactd, mask); - } - return 0; -} - static int proc_dointvec_minmax_warn_RT_change(const struct ctl_table *table, int write, void *buffer, size_t *lenp, loff_t *ppos) { @@ -3362,15 +3334,6 @@ static struct ctl_table vm_compaction[] = { static int __init kcompactd_init(void) { int nid; - int ret; - - ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, - "mm/compaction:online", - kcompactd_cpu_online, NULL); - if (ret < 0) { - pr_err("kcompactd: failed to register hotplug callbacks.\n"); - return ret; - } for_each_node_state(nid, N_MEMORY) kcompactd_run(nid); -- 2.45.2