From nobody Fri Dec 26 21:28:00 2025 Received: from mail-lf1-f43.google.com (mail-lf1-f43.google.com [209.85.167.43]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id AC716171D7 for ; Tue, 2 Jan 2024 18:47:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="mbWj9Eqr" Received: by mail-lf1-f43.google.com with SMTP id 2adb3069b0e04-50e8ca6c76dso4334342e87.3 for ; Tue, 02 Jan 2024 10:47:18 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1704221237; x=1704826037; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=36KamwtZGiOJ+iCEiFn7yiYoyZmI7LhL5vNG1kBAh/Y=; b=mbWj9EqrC4HIMlsTfAsHEcbfwNCgTFrjYtO5o6KeiT7Cf+zUTUFJoAWwuTBFtR+TJJ KqIhYe1ydLVim3Dv6eFxyLlTq9Cc6BGrVYvpyBxJZib7ospyLZSDppFuer2cMB1bLKeI ZQw6aeOkgy2kK7c+lFTqFpWR5AXdRL+d7Pbj7rR9Ky63sMzDszrR6aNSVDZWgVvqN9YX FiFLuNz9TCh+UqfDTcahYbCgJbuk096HtB4dvFR2Vluz3gTh6Ce4WbvmK8uaOM9KjMBs Ss6djungNmtXXKzVRWBs75W5byPFaUAOljj5dmg8pd8rBFPHHf/HZTaIcvyCRAQudzUo y6fg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1704221237; x=1704826037; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=36KamwtZGiOJ+iCEiFn7yiYoyZmI7LhL5vNG1kBAh/Y=; b=LhZnG8iccmzhl02s3103AAT3gIhiV+hcWGzH0Q8vBRNY/4aLgBAvhhIsWJxKjShx/z oeBfj/a3jnIPv03S1C40qLY6PgUpLfr1YdC0Lqi31sYNa82pDDWBePfOliZHy5oXXVGd vCrRu0hQ8P5NCOCJnXQDufrbw6IgBb0Btp0vkHBHrAFUb3UTjYRY5RcjVusisUotuiJj IPBpDb2NZkNwqPA4MT+OzpBLUlnDisu0FkGh8fjLeiUn4Pna4jMLhbOJg+aO/VANw9GC W+fjsR8o1cuIw81t8V0T2fznw2jLLxWnUHN7LYyJT48ou/ApbvwJvZWzpdd1zeiz454V HCmQ== X-Gm-Message-State: AOJu0YxQORKfiTfv3AjWgKYZJ/Cw74bfF+K561fkAzVGKLkJUr/Zrk3P EFC54b3Zm/lIYzSLogLPRs8= X-Google-Smtp-Source: AGHT+IFi7xrYzx6xhsiq08yLfVLl/kXBKY0Xd49T3HSM7WNrgq2+gVmjHodohn+UrhXHc14kRcbU4A== X-Received: by 2002:ac2:5d67:0:b0:50e:383b:19bd with SMTP id h7-20020ac25d67000000b0050e383b19bdmr6365437lft.102.1704221236664; Tue, 02 Jan 2024 10:47:16 -0800 (PST) Received: from pc638.lan (host-185-121-47-193.sydskane.nu. [185.121.47.193]) by smtp.gmail.com with ESMTPSA id q1-20020ac246e1000000b0050e7be886d9sm2592656lfo.56.2024.01.02.10.47.15 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 02 Jan 2024 10:47:16 -0800 (PST) From: "Uladzislau Rezki (Sony)" To: linux-mm@kvack.org, Andrew Morton Cc: LKML , Baoquan He , Lorenzo Stoakes , Christoph Hellwig , Matthew Wilcox , "Liam R . Howlett" , Dave Chinner , "Paul E . McKenney" , Joel Fernandes , Uladzislau Rezki , Oleksiy Avramchenko Subject: [PATCH v3 10/11] mm: vmalloc: Set nr_nodes based on CPUs in a system Date: Tue, 2 Jan 2024 19:46:32 +0100 Message-Id: <20240102184633.748113-11-urezki@gmail.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20240102184633.748113-1-urezki@gmail.com> References: <20240102184633.748113-1-urezki@gmail.com> 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 Content-Type: text/plain; charset="utf-8" A number of nodes which are used in the alloc/free paths is set based on num_possible_cpus() in a system. Please note a high limit threshold though is fixed and corresponds to 128 nodes. For 32-bit or single core systems an access to a global vmap heap is not balanced. Such small systems do not suffer from lock contentions due to low number of CPUs. In such case the nr_nodes is equal to 1. Test on AMD Ryzen Threadripper 3970X 32-Core Processor: sudo ./test_vmalloc.sh run_test_mask=3D7 nr_threads=3D64 94.41% 0.89% [kernel] [k] _raw_spin_lock 93.35% 93.07% [kernel] [k] native_queued_spin_lock_slowpath 76.13% 0.28% [kernel] [k] __vmalloc_node_range 72.96% 0.81% [kernel] [k] alloc_vmap_area 56.94% 0.00% [kernel] [k] __get_vm_area_node 41.95% 0.00% [kernel] [k] vmalloc 37.15% 0.01% [test_vmalloc] [k] full_fit_alloc_test 35.17% 0.00% [kernel] [k] ret_from_fork_asm 35.17% 0.00% [kernel] [k] ret_from_fork 35.17% 0.00% [kernel] [k] kthread 35.08% 0.00% [test_vmalloc] [k] test_func 34.45% 0.00% [test_vmalloc] [k] fix_size_alloc_test 28.09% 0.01% [test_vmalloc] [k] long_busy_list_alloc_test 23.53% 0.25% [kernel] [k] vfree.part.0 21.72% 0.00% [kernel] [k] remove_vm_area 20.08% 0.21% [kernel] [k] find_unlink_vmap_area 2.34% 0.61% [kernel] [k] free_vmap_area_noflush vs 82.32% 0.22% [test_vmalloc] [k] long_busy_list_alloc_test 63.36% 0.02% [kernel] [k] vmalloc 63.34% 2.64% [kernel] [k] __vmalloc_node_range 30.42% 4.46% [kernel] [k] vfree.part.0 28.98% 2.51% [kernel] [k] __alloc_pages_bulk 27.28% 0.19% [kernel] [k] __get_vm_area_node 26.13% 1.50% [kernel] [k] alloc_vmap_area 21.72% 21.67% [kernel] [k] clear_page_rep 19.51% 2.43% [kernel] [k] _raw_spin_lock 16.61% 16.51% [kernel] [k] native_queued_spin_lock_slowpath 13.40% 2.07% [kernel] [k] free_unref_page 10.62% 0.01% [kernel] [k] remove_vm_area 9.02% 8.73% [kernel] [k] insert_vmap_area 8.94% 0.00% [kernel] [k] ret_from_fork_asm 8.94% 0.00% [kernel] [k] ret_from_fork 8.94% 0.00% [kernel] [k] kthread 8.29% 0.00% [test_vmalloc] [k] test_func 7.81% 0.05% [test_vmalloc] [k] full_fit_alloc_test 5.30% 4.73% [kernel] [k] purge_vmap_node 4.47% 2.65% [kernel] [k] free_vmap_area_noflush confirms that a native_queued_spin_lock_slowpath goes down to 16.51% percent from 93.07%. The throughput is ~12x higher: urezki@pc638:~$ time sudo ./test_vmalloc.sh run_test_mask=3D7 nr_threads=3D= 64 Run the test with following parameters: run_test_mask=3D7 nr_threads=3D64 Done. Check the kernel ring buffer to see the summary. real 10m51.271s user 0m0.013s sys 0m0.187s urezki@pc638:~$ urezki@pc638:~$ time sudo ./test_vmalloc.sh run_test_mask=3D7 nr_threads=3D= 64 Run the test with following parameters: run_test_mask=3D7 nr_threads=3D64 Done. Check the kernel ring buffer to see the summary. real 0m51.301s user 0m0.015s sys 0m0.040s urezki@pc638:~$ Signed-off-by: Uladzislau Rezki (Sony) --- mm/vmalloc.c | 29 +++++++++++++++++++++++------ 1 file changed, 23 insertions(+), 6 deletions(-) diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 0c671cb96151..ef534c76daef 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -4879,10 +4879,27 @@ static void vmap_init_free_space(void) static void vmap_init_nodes(void) { struct vmap_node *vn; - int i, j; + int i, n; + +#if BITS_PER_LONG =3D=3D 64 + /* A high threshold of max nodes is fixed and bound to 128. */ + n =3D clamp_t(unsigned int, num_possible_cpus(), 1, 128); + + if (n > 1) { + vn =3D kmalloc_array(n, sizeof(*vn), GFP_NOWAIT | __GFP_NOWARN); + if (vn) { + /* Node partition is 16 pages. */ + vmap_zone_size =3D (1 << 4) * PAGE_SIZE; + nr_vmap_nodes =3D n; + vmap_nodes =3D vn; + } else { + pr_err("Failed to allocate an array. Disable a node layer\n"); + } + } +#endif =20 - for (i =3D 0; i < nr_vmap_nodes; i++) { - vn =3D &vmap_nodes[i]; + for (n =3D 0; n < nr_vmap_nodes; n++) { + vn =3D &vmap_nodes[n]; vn->busy.root =3D RB_ROOT; INIT_LIST_HEAD(&vn->busy.head); spin_lock_init(&vn->busy.lock); @@ -4891,9 +4908,9 @@ static void vmap_init_nodes(void) INIT_LIST_HEAD(&vn->lazy.head); spin_lock_init(&vn->lazy.lock); =20 - for (j =3D 0; j < MAX_VA_SIZE_PAGES; j++) { - INIT_LIST_HEAD(&vn->pool[j].head); - WRITE_ONCE(vn->pool[j].len, 0); + for (i =3D 0; i < MAX_VA_SIZE_PAGES; i++) { + INIT_LIST_HEAD(&vn->pool[i].head); + WRITE_ONCE(vn->pool[i].len, 0); } =20 spin_lock_init(&vn->pool_lock); --=20 2.39.2