From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 508E3C83F14 for ; Tue, 29 Aug 2023 08:12:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234131AbjH2IMU (ORCPT ); Tue, 29 Aug 2023 04:12:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49344 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234047AbjH2ILz (ORCPT ); Tue, 29 Aug 2023 04:11:55 -0400 Received: from mail-lf1-x131.google.com (mail-lf1-x131.google.com [IPv6:2a00:1450:4864:20::131]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EC4609E for ; Tue, 29 Aug 2023 01:11:52 -0700 (PDT) Received: by mail-lf1-x131.google.com with SMTP id 2adb3069b0e04-5009969be25so6453511e87.3 for ; Tue, 29 Aug 2023 01:11:52 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1693296711; x=1693901511; 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=WDP4tqNUhlNIFZZBcXRgHZdwRMYy1Esdu/NCW7wWlsU=; b=T6NvuHclCxEppT8nFMh71q62sGE+tZlEA3hwVNUz/ZA8HpvLfE+jVsPEvlDkp2T6JA BvVtxAhcubFWHDu5ZanFy0HlsbfyU3/qbdz4bPI28m2qBXIlGa0rCttCqxWc/uXOIkl6 6UE+UaAshUPaG0V/dJkZFtmhVNTtGPOu4CJjaX56Km4/Cqox9EMJRpbuy2p45aKZ3PEV ZfkG9G9bTOinVcpj5NxphQLFLuXXYYF71Lw3fOpDNkJDEWv7QBySNmUcO8Z9PAuRFoM/ JueZT8bnCq4JbJcus2pTRqEENYrYmcJdD3FqrPZwA6rzNqirwxtGgAkf/SOxs02IMk+2 BN3g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1693296711; x=1693901511; 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=WDP4tqNUhlNIFZZBcXRgHZdwRMYy1Esdu/NCW7wWlsU=; b=EGtcJEez1vphIilfyFXQgwexAXIatIulqe8PDKzuE36LWgm0vy1ND01cTsUt7oVFrZ UX5yzqU3kphgtUvDjhTWuDOWnzJgxFZKKT/UBnKle2/LgGSnNJeT1SbRDEF5uPs+9PtF 1GUvx5kmEFSLlZsZ8JAPyJlyHedRqYmCaGaAG9MNbshW7xTT+Mp1CtzTcbklYwbelm+Q Zx775IxvOI/Prrb0tVZjttQVFHsufTBX8963QCC6S7GaQJ+iLmYSsNOWSpmtZBAakQwb jXuWl4hxuEdCyOyldS2jauI3Wt+M1K9O13yqegIT+NvBndoPUxOGF26nLC3wQWw1Gu7/ opYg== X-Gm-Message-State: AOJu0YwjhuOIWTRfmmuIajMuTcCJaopYEZkmbiKJC4T2kG3Iy/HorynW 9mKyl+CjJ4IQklRafzQ4bOM= X-Google-Smtp-Source: AGHT+IHUJH0ptBLC+Y1DnxMxgzbKnbR/6Fjs1YJ0+fTGbIM1B2rz7XjXZu/5VMJRPZ0+lDrr4JRlNg== X-Received: by 2002:a19:ca12:0:b0:500:8fcd:c3b4 with SMTP id a18-20020a19ca12000000b005008fcdc3b4mr12372967lfg.69.1693296711166; Tue, 29 Aug 2023 01:11:51 -0700 (PDT) Received: from pc638.lan ([155.137.26.201]) by smtp.gmail.com with ESMTPSA id f25-20020a19ae19000000b004fbad341442sm1868026lfc.97.2023.08.29.01.11.50 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 29 Aug 2023 01:11:50 -0700 (PDT) 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 v2 9/9] mm: vmalloc: Set nr_nodes/node_size based on CPU-cores Date: Tue, 29 Aug 2023 10:11:42 +0200 Message-Id: <20230829081142.3619-10-urezki@gmail.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20230829081142.3619-1-urezki@gmail.com> References: <20230829081142.3619-1-urezki@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The density ratio is set to 2, i.e. two users per one node. For example if there are 6 cores in a system the "nr_nodes" is 3. The "node_size" also depends on number of physical cores. A high-threshold limit is hard-coded and set to SZ_4M. For 32-bit, single/dual core systems an access to a global vmap heap is not balanced. Such small systems do not suffer from lock contentions due to limitation of CPU-cores. Test on AMD Ryzen Threadripper 3970X 32-Core Processor: sudo ./test_vmalloc.sh run_test_mask=127 nr_threads=64 94.17% 0.90% [kernel] [k] _raw_spin_lock 93.27% 93.05% [kernel] [k] native_queued_spin_lock_slowpath 74.69% 0.25% [kernel] [k] __vmalloc_node_range 72.64% 0.01% [kernel] [k] __get_vm_area_node 72.04% 0.89% [kernel] [k] alloc_vmap_area 42.17% 0.00% [kernel] [k] vmalloc 32.53% 0.00% [kernel] [k] __vmalloc_node 24.91% 0.25% [kernel] [k] vfree 24.32% 0.01% [kernel] [k] remove_vm_area 22.63% 0.21% [kernel] [k] find_unlink_vmap_area 15.51% 0.00% [unknown] [k] 0xffffffffc09a74ac 14.35% 0.00% [kernel] [k] ret_from_fork_asm 14.35% 0.00% [kernel] [k] ret_from_fork 14.35% 0.00% [kernel] [k] kthread vs 74.32% 2.42% [kernel] [k] __vmalloc_node_range 69.58% 0.01% [kernel] [k] vmalloc 54.21% 1.17% [kernel] [k] __alloc_pages_bulk 48.13% 47.91% [kernel] [k] clear_page_orig 43.60% 0.01% [unknown] [k] 0xffffffffc082f16f 32.06% 0.00% [kernel] [k] ret_from_fork_asm 32.06% 0.00% [kernel] [k] ret_from_fork 32.06% 0.00% [kernel] [k] kthread 31.30% 0.00% [unknown] [k] 0xffffffffc082f889 22.98% 4.16% [kernel] [k] vfree 14.36% 0.28% [kernel] [k] __get_vm_area_node 13.43% 3.35% [kernel] [k] alloc_vmap_area 10.86% 0.04% [kernel] [k] remove_vm_area 8.89% 2.75% [kernel] [k] _raw_spin_lock 7.19% 0.00% [unknown] [k] 0xffffffffc082fba3 6.65% 1.37% [kernel] [k] free_unref_page 6.13% 6.11% [kernel] [k] native_queued_spin_lock_slowpath confirms that a native_queued_spin_lock_slowpath bottle-neck can be considered as negligible for the patch-series version. The throughput is ~15x higher: urezki@pc638:~$ time sudo ./test_vmalloc.sh run_test_mask=127 nr_threads=64 Run the test with following parameters: run_test_mask=127 nr_threads=64 Done. Check the kernel ring buffer to see the summary. real 24m3.305s user 0m0.361s sys 0m0.013s urezki@pc638:~$ urezki@pc638:~$ time sudo ./test_vmalloc.sh run_test_mask=127 nr_threads=64 Run the test with following parameters: run_test_mask=127 nr_threads=64 Done. Check the kernel ring buffer to see the summary. real 1m28.382s user 0m0.014s sys 0m0.026s urezki@pc638:~$ Signed-off-by: Uladzislau Rezki (Sony) --- mm/vmalloc.c | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 9cce012aecdb..08990f630c21 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -796,6 +796,9 @@ struct vmap_node { atomic_t fill_in_progress; }; +#define MAX_NODES U8_MAX +#define MAX_NODE_SIZE SZ_4M + static struct vmap_node *nodes, snode; static __read_mostly unsigned int nr_nodes = 1; static __read_mostly unsigned int node_size = 1; @@ -4803,11 +4806,24 @@ static void vmap_init_free_space(void) } } +static unsigned int calculate_nr_nodes(void) +{ + unsigned int nr_cpus; + + nr_cpus = num_present_cpus(); + if (nr_cpus <= 1) + nr_cpus = num_possible_cpus(); + + /* Density factor. Two users per a node. */ + return clamp_t(unsigned int, nr_cpus >> 1, 1, MAX_NODES); +} + static void vmap_init_nodes(void) { struct vmap_node *vn; int i; + nr_nodes = calculate_nr_nodes(); nodes = &snode; if (nr_nodes > 1) { @@ -4830,6 +4846,16 @@ static void vmap_init_nodes(void) INIT_LIST_HEAD(&vn->free.head); spin_lock_init(&vn->free.lock); } + + /* + * Scale a node size to number of CPUs. Each power of two + * value doubles a node size. A high-threshold limit is set + * to 4M. + */ +#if BITS_PER_LONG == 64 + if (nr_nodes > 1) + node_size = min(SZ_64K << fls(num_possible_cpus()), SZ_4M); +#endif } void __init vmalloc_init(void) -- 2.30.2