Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751973AbdI1VaF (ORCPT ); Thu, 28 Sep 2017 17:30:05 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:50472 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751490AbdI1V3w (ORCPT ); Thu, 28 Sep 2017 17:29:52 -0400 Date: Thu, 28 Sep 2017 14:29:50 -0700 From: Andrew Morton To: Kemi Wang Cc: "Luis R . Rodriguez" , Kees Cook , Jonathan Corbet , Michal Hocko , Mel Gorman , Johannes Weiner , Christopher Lameter , Sebastian Andrzej Siewior , Vlastimil Babka , Dave , Tim Chen , Andi Kleen , Jesper Dangaard Brouer , Ying Huang , Aaron Lu , Proc sysctl , Linux MM , Linux Kernel Subject: Re: [PATCH v3] mm, sysctl: make NUMA stats configurable Message-Id: <20170928142950.1a09090fe4baf4acdc1bbc35@linux-foundation.org> In-Reply-To: <1506579101-5457-1-git-send-email-kemi.wang@intel.com> References: <1506579101-5457-1-git-send-email-kemi.wang@intel.com> X-Mailer: Sylpheed 3.4.1 (GTK+ 2.24.23; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6951 Lines: 173 On Thu, 28 Sep 2017 14:11:41 +0800 Kemi Wang wrote: > This is the second step which introduces a tunable interface that allow > numa stats configurable for optimizing zone_statistics(), as suggested by > Dave Hansen and Ying Huang. Looks OK I guess. I fiddled with it a lot. Please consider: From: Andrew Morton Subject: mm-sysctl-make-numa-stats-configurable-fix - tweak documentation - move advisory message from start_kernel() into mm_init() (I'm not sure we really need this message) - use strcasecmp() in __parse_vm_numa_stats_mode() - clean up coding style amd nessages in sysctl_vm_numa_stats_mode_handler() Cc: Aaron Lu Cc: Andi Kleen Cc: Christopher Lameter Cc: Dave Hansen Cc: Jesper Dangaard Brouer Cc: Johannes Weiner Cc: Jonathan Corbet Cc: Kees Cook Cc: Kemi Wang Cc: "Luis R . Rodriguez" Cc: Mel Gorman Cc: Michal Hocko Cc: Sebastian Andrzej Siewior Cc: Tim Chen Cc: Vlastimil Babka Cc: Ying Huang Signed-off-by: Andrew Morton --- Documentation/sysctl/vm.txt | 15 ++++++------- init/main.c | 6 ++--- mm/vmstat.c | 39 +++++++++++++++------------------- 3 files changed, 29 insertions(+), 31 deletions(-) diff -puN Documentation/sysctl/vm.txt~mm-sysctl-make-numa-stats-configurable-fix Documentation/sysctl/vm.txt --- a/Documentation/sysctl/vm.txt~mm-sysctl-make-numa-stats-configurable-fix +++ a/Documentation/sysctl/vm.txt @@ -853,7 +853,7 @@ ten times more freeable objects than the numa_stats_mode -This interface allows numa statistics configurable. +This interface allows runtime configuration or numa statistics. When page allocation performance becomes a bottleneck and you can tolerate some possible tool breakage and decreased numa counter precision, you can @@ -864,13 +864,14 @@ When page allocation performance is not tooling to work, you can do: echo [S|s]trict > /proc/sys/vm/numa_stat_mode -We recommend automatic detection of numa statistics by system, because numa -statistics does not affect system's decision and it is very rarely -consumed. you can do: +We recommend automatic detection of numa statistics by system, because +numa statistics do not affect system decisions and it is very rarely +consumed. In this case you can do: echo [A|a]uto > /proc/sys/vm/numa_stats_mode -This is also system default configuration, with this default setting, numa -counters update is skipped unless the counter is *read* by users at least -once. + +This is the system default configuration. With this default setting, numa +counter updates are skipped until the counter is *read* by userspace at +least once. ============================================================== diff -puN drivers/base/node.c~mm-sysctl-make-numa-stats-configurable-fix drivers/base/node.c diff -puN include/linux/vmstat.h~mm-sysctl-make-numa-stats-configurable-fix include/linux/vmstat.h diff -puN init/main.c~mm-sysctl-make-numa-stats-configurable-fix init/main.c --- a/init/main.c~mm-sysctl-make-numa-stats-configurable-fix +++ a/init/main.c @@ -504,6 +504,9 @@ static void __init mm_init(void) pgtable_init(); vmalloc_init(); ioremap_huge_init(); +#ifdef CONFIG_NUMA + pr_info("vmstat: NUMA stat updates are skipped unless they have been used\n"); +#endif } asmlinkage __visible void __init start_kernel(void) @@ -567,9 +570,6 @@ asmlinkage __visible void __init start_k sort_main_extable(); trap_init(); mm_init(); -#ifdef CONFIG_NUMA - pr_info("vmstat: NUMA stats is skipped unless it has been consumed\n"); -#endif ftrace_init(); diff -puN kernel/sysctl.c~mm-sysctl-make-numa-stats-configurable-fix kernel/sysctl.c diff -puN mm/page_alloc.c~mm-sysctl-make-numa-stats-configurable-fix mm/page_alloc.c diff -puN mm/vmstat.c~mm-sysctl-make-numa-stats-configurable-fix mm/vmstat.c --- a/mm/vmstat.c~mm-sysctl-make-numa-stats-configurable-fix +++ a/mm/vmstat.c @@ -40,13 +40,11 @@ static DEFINE_MUTEX(vm_numa_stats_mode_l static int __parse_vm_numa_stats_mode(char *s) { - const char *str = s; - - if (strcmp(str, "auto") == 0 || strcmp(str, "Auto") == 0) + if (strcasecmp(s, "auto")) vm_numa_stats_mode = VM_NUMA_STAT_AUTO_MODE; - else if (strcmp(str, "strict") == 0 || strcmp(str, "Strict") == 0) + else if (strcasecmp(s, "strict") == 0) vm_numa_stats_mode = VM_NUMA_STAT_STRICT_MODE; - else if (strcmp(str, "coarse") == 0 || strcmp(str, "Coarse") == 0) + else if (strcasecmp(s, "coarse")) vm_numa_stats_mode = VM_NUMA_STAT_COARSE_MODE; else { pr_warn("Ignoring invalid vm_numa_stats_mode value: %s\n", s); @@ -86,30 +84,29 @@ int sysctl_vm_numa_stats_mode_handler(st /* no change */ mutex_unlock(&vm_numa_stats_mode_lock); return 0; - } else if (vm_numa_stats_mode == VM_NUMA_STAT_AUTO_MODE) + } else if (vm_numa_stats_mode == VM_NUMA_STAT_AUTO_MODE) { /* - * Keep the branch selection in last time when numa stats - * is changed to auto mode. + * Keep the branch selection in last time when numa + * stats is changed to auto mode. */ - pr_info("numa stats changes from %s mode to auto mode\n", - vm_numa_stats_mode_name[oldval]); - else if (vm_numa_stats_mode == VM_NUMA_STAT_STRICT_MODE) { + pr_info("numa stats changed from %s to auto mode\n", + vm_numa_stats_mode_name[oldval]); + } else if (vm_numa_stats_mode == VM_NUMA_STAT_STRICT_MODE) { static_branch_enable(&vm_numa_stats_mode_key); - pr_info("numa stats changes from %s mode to strict mode\n", - vm_numa_stats_mode_name[oldval]); + pr_info("numa stats changes from %s to strict mode\n", + vm_numa_stats_mode_name[oldval]); } else if (vm_numa_stats_mode == VM_NUMA_STAT_COARSE_MODE) { static_branch_disable(&vm_numa_stats_mode_key); /* - * Invalidate numa counters when vmstat mode is set to coarse - * mode, because users can't tell the difference between the - * dead state and when allocator activity is quiet once - * zone_statistics() is turned off. + * Invalidate numa counters when vmstat mode is set to + * coarse mode, because users can't tell the difference + * between the dead state and when allocator activity is + * quiet once zone_statistics() is turned off. */ invalid_numa_statistics(); - pr_info("numa stats changes from %s mode to coarse mode\n", - vm_numa_stats_mode_name[oldval]); - } else - pr_warn("invalid vm_numa_stats_mode:%d\n", vm_numa_stats_mode); + pr_info("numa stats changes from %s to coarse mode\n", + vm_numa_stats_mode_name[oldval]); + } } mutex_unlock(&vm_numa_stats_mode_lock); _