From patchwork Fri Jan 28 08:27:50 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Huang, Ying" X-Patchwork-Id: 12728088 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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 41181C433EF for ; Fri, 28 Jan 2022 08:28:19 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id CAD486B0073; Fri, 28 Jan 2022 03:28:18 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id C5D606B0074; Fri, 28 Jan 2022 03:28:18 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id AFD836B0075; Fri, 28 Jan 2022 03:28:18 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0252.hostedemail.com [216.40.44.252]) by kanga.kvack.org (Postfix) with ESMTP id A30996B0073 for ; Fri, 28 Jan 2022 03:28:18 -0500 (EST) Received: from smtpin04.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 689EB181CAEF3 for ; Fri, 28 Jan 2022 08:28:18 +0000 (UTC) X-FDA: 79079018676.04.4FC2184 Received: from mga02.intel.com (mga02.intel.com [134.134.136.20]) by imf17.hostedemail.com (Postfix) with ESMTP id 748DF40007 for ; Fri, 28 Jan 2022 08:28:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1643358497; x=1674894497; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=WC4PhiGrPDzzmC5jvoDf7DFGko0uF8nz7i7hvigSZ+Q=; b=br5InRKE5NqSg0DtWFv69urIGvU67B5m7BdBpvCv8oNexzNxeaRLT3tL xStU0HUInYkNfxz1/uFiP+AhnnYbUY2XmJSMXv2e34BXLFURzage7nQJG 64jD7tAmdSzWtJZXIX9fcU8RVu+Hdg6S4ttQvI2eEXQGB2wnD80rci2u5 wdbDfOGQu50PNwA/MevhxpeFiRZeg/LGQ5aiDlsg6NJvw0icSASzh/u2R fo2LL5SeiRTuZvfhKL/cXjMqqP4gMlxrkFmbFx68XkWSQvsq86u3FBTYK 1WpusfyqaFknBYPrhrUCf7JAc+SkqvN9CM3GKAF2arSh8VR7GmKCye1vt w==; X-IronPort-AV: E=McAfee;i="6200,9189,10240"; a="234454533" X-IronPort-AV: E=Sophos;i="5.88,323,1635231600"; d="scan'208";a="234454533" Received: from orsmga005.jf.intel.com ([10.7.209.41]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 28 Jan 2022 00:28:17 -0800 X-IronPort-AV: E=Sophos;i="5.88,323,1635231600"; d="scan'208";a="697019661" Received: from yhuang6-desk2.sh.intel.com ([10.239.13.11]) by orsmga005-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 28 Jan 2022 00:28:12 -0800 From: Huang Ying To: Peter Zijlstra , Mel Gorman Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Feng Tang , Huang Ying , Baolin Wang , Andrew Morton , Michal Hocko , Rik van Riel , Mel Gorman , Dave Hansen , Yang Shi , Zi Yan , Wei Xu , osalvador , Shakeel Butt , zhongjiang-ali Subject: [PATCH -V11 2/3] NUMA balancing: optimize page placement for memory tiering system Date: Fri, 28 Jan 2022 16:27:50 +0800 Message-Id: <20220128082751.593478-3-ying.huang@intel.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220128082751.593478-1-ying.huang@intel.com> References: <20220128082751.593478-1-ying.huang@intel.com> MIME-Version: 1.0 X-Rspamd-Queue-Id: 748DF40007 X-Rspam-User: nil Authentication-Results: imf17.hostedemail.com; dkim=pass header.d=intel.com header.s=Intel header.b=br5InRKE; dmarc=pass (policy=none) header.from=intel.com; spf=none (imf17.hostedemail.com: domain of ying.huang@intel.com has no SPF policy when checking 134.134.136.20) smtp.mailfrom=ying.huang@intel.com X-Stat-Signature: poog5g9xdwom7qrxowsitbis3w4jeghh X-Rspamd-Server: rspam08 X-HE-Tag: 1643358497-917687 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: With the advent of various new memory types, some machines will have multiple types of memory, e.g. DRAM and PMEM (persistent memory). The memory subsystem of these machines can be called memory tiering system, because the performance of the different types of memory are usually different. In such system, because of the memory accessing pattern changing etc, some pages in the slow memory may become hot globally. So in this patch, the NUMA balancing mechanism is enhanced to optimize the page placement among the different memory types according to hot/cold dynamically. In a typical memory tiering system, there are CPUs, fast memory and slow memory in each physical NUMA node. The CPUs and the fast memory will be put in one logical node (called fast memory node), while the slow memory will be put in another (faked) logical node (called slow memory node). That is, the fast memory is regarded as local while the slow memory is regarded as remote. So it's possible for the recently accessed pages in the slow memory node to be promoted to the fast memory node via the existing NUMA balancing mechanism. The original NUMA balancing mechanism will stop to migrate pages if the free memory of the target node becomes below the high watermark. This is a reasonable policy if there's only one memory type. But this makes the original NUMA balancing mechanism almost do not work to optimize page placement among different memory types. Details are as follows. It's the common cases that the working-set size of the workload is larger than the size of the fast memory nodes. Otherwise, it's unnecessary to use the slow memory at all. So, there are almost always no enough free pages in the fast memory nodes, so that the globally hot pages in the slow memory node cannot be promoted to the fast memory node. To solve the issue, we have 2 choices as follows, a. Ignore the free pages watermark checking when promoting hot pages from the slow memory node to the fast memory node. This will create some memory pressure in the fast memory node, thus trigger the memory reclaiming. So that, the cold pages in the fast memory node will be demoted to the slow memory node. b. Make kswapd of the fast memory node to reclaim pages until the free pages are a little (for example, high_watermark / 4) more than the high watermark. Then, if the free pages of the fast memory node reaches high watermark, and some hot pages need to be promoted, kswapd of the fast memory node will be waken up to demote more cold pages in the fast memory node to the slow memory node. This will free some extra space in the fast memory node, so the hot pages in the slow memory node can be promoted to the fast memory node. The choice "a" may create high memory pressure in the fast memory node. If the memory pressure of the workload is high, the memory pressure may become so high that the memory allocation latency of the workload is influenced, e.g. the direct reclaiming may be triggered. The choice "b" works much better at this aspect. If the memory pressure of the workload is high, the hot pages promotion will stop earlier because its allocation watermark is higher than that of the normal memory allocation. So in this patch, choice "b" is implemented. In addition to the original page placement optimization among sockets, the NUMA balancing mechanism is extended to be used to optimize page placement according to hot/cold among different memory types. So the sysctl user space interface (numa_balancing) is extended in a backward compatible way as follow, so that the users can enable/disable these functionality individually. The sysctl is converted from a Boolean value to a bits field. The definition of the flags is, - 0x0: NUMA_BALANCING_DISABLED - 0x1: NUMA_BALANCING_NORMAL - 0x2: NUMA_BALANCING_MEMORY_TIERING We have tested the patch with the pmbench memory accessing benchmark with the 80:20 read/write ratio and the Gauss access address distribution on a 2 socket Intel server with Optane DC Persistent Memory Model. The test results shows that the pmbench score can improve up to 95.9%. Signed-off-by: "Huang, Ying" Tested-by: Baolin Wang Reviewed-by: Baolin Wang Cc: Andrew Morton Cc: Michal Hocko Cc: Rik van Riel Cc: Mel Gorman Cc: Peter Zijlstra Cc: Dave Hansen Cc: Yang Shi Cc: Zi Yan Cc: Wei Xu Cc: osalvador Cc: Shakeel Butt Cc: zhongjiang-ali Cc: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org --- Documentation/admin-guide/sysctl/kernel.rst | 29 ++++++++++++++------- include/linux/sched/sysctl.h | 10 +++++++ kernel/sched/core.c | 21 ++++++++++++--- kernel/sysctl.c | 2 +- mm/migrate.c | 19 ++++++++++++-- mm/vmscan.c | 17 ++++++++++++ 6 files changed, 82 insertions(+), 16 deletions(-) diff --git a/Documentation/admin-guide/sysctl/kernel.rst b/Documentation/admin-guide/sysctl/kernel.rst index d359bcfadd39..ea32ba0c5d3c 100644 --- a/Documentation/admin-guide/sysctl/kernel.rst +++ b/Documentation/admin-guide/sysctl/kernel.rst @@ -595,16 +595,23 @@ Documentation/admin-guide/kernel-parameters.rst). numa_balancing ============== -Enables/disables automatic page fault based NUMA memory -balancing. Memory is moved automatically to nodes -that access it often. +Enables/disables and configure automatic page fault based NUMA memory +balancing. Memory is moved automatically to nodes that access it +often. The value to set can be the result to OR the following, -Enables/disables automatic NUMA memory balancing. On NUMA machines, there -is a performance penalty if remote memory is accessed by a CPU. When this -feature is enabled the kernel samples what task thread is accessing memory -by periodically unmapping pages and later trapping a page fault. At the -time of the page fault, it is determined if the data being accessed should -be migrated to a local memory node. += ================================= +0x0 NUMA_BALANCING_DISABLED +0x1 NUMA_BALANCING_NORMAL +0x2 NUMA_BALANCING_MEMORY_TIERING += ================================= + +Or NUMA_BALANCING_NORMAL to optimize page placement among different +NUMA nodes to reduce remote accessing. On NUMA machines, there is a +performance penalty if remote memory is accessed by a CPU. When this +feature is enabled the kernel samples what task thread is accessing +memory by periodically unmapping pages and later trapping a page +fault. At the time of the page fault, it is determined if the data +being accessed should be migrated to a local memory node. The unmapping of pages and trapping faults incur additional overhead that ideally is offset by improved memory locality but there is no universal @@ -615,6 +622,10 @@ faults may be controlled by the `numa_balancing_scan_period_min_ms, numa_balancing_scan_delay_ms, numa_balancing_scan_period_max_ms, numa_balancing_scan_size_mb`_, and numa_balancing_settle_count sysctls. +Or NUMA_BALANCING_MEMORY_TIERING to optimize page placement among +different types of memory (represented as different NUMA nodes) to +place the hot pages in the fast memory. This is implemented based on +unmapping and page fault too. numa_balancing_scan_period_min_ms, numa_balancing_scan_delay_ms, numa_balancing_scan_period_max_ms, numa_balancing_scan_size_mb =============================================================================================================================== diff --git a/include/linux/sched/sysctl.h b/include/linux/sched/sysctl.h index c19dd5a2c05c..b5eec8854c5a 100644 --- a/include/linux/sched/sysctl.h +++ b/include/linux/sched/sysctl.h @@ -23,6 +23,16 @@ enum sched_tunable_scaling { SCHED_TUNABLESCALING_END, }; +#define NUMA_BALANCING_DISABLED 0x0 +#define NUMA_BALANCING_NORMAL 0x1 +#define NUMA_BALANCING_MEMORY_TIERING 0x2 + +#ifdef CONFIG_NUMA_BALANCING +extern int sysctl_numa_balancing_mode; +#else +#define sysctl_numa_balancing_mode 0 +#endif + /* * control realtime throttling: * diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 848eaa0efe0e..b8b8e5feb8ef 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -4279,7 +4279,9 @@ DEFINE_STATIC_KEY_FALSE(sched_numa_balancing); #ifdef CONFIG_NUMA_BALANCING -void set_numabalancing_state(bool enabled) +int sysctl_numa_balancing_mode; + +static void __set_numabalancing_state(bool enabled) { if (enabled) static_branch_enable(&sched_numa_balancing); @@ -4287,13 +4289,22 @@ void set_numabalancing_state(bool enabled) static_branch_disable(&sched_numa_balancing); } +void set_numabalancing_state(bool enabled) +{ + if (enabled) + sysctl_numa_balancing_mode = NUMA_BALANCING_NORMAL; + else + sysctl_numa_balancing_mode = NUMA_BALANCING_DISABLED; + __set_numabalancing_state(enabled); +} + #ifdef CONFIG_PROC_SYSCTL int sysctl_numa_balancing(struct ctl_table *table, int write, void *buffer, size_t *lenp, loff_t *ppos) { struct ctl_table t; int err; - int state = static_branch_likely(&sched_numa_balancing); + int state = sysctl_numa_balancing_mode; if (write && !capable(CAP_SYS_ADMIN)) return -EPERM; @@ -4303,8 +4314,10 @@ int sysctl_numa_balancing(struct ctl_table *table, int write, err = proc_dointvec_minmax(&t, write, buffer, lenp, ppos); if (err < 0) return err; - if (write) - set_numabalancing_state(state); + if (write) { + sysctl_numa_balancing_mode = state; + __set_numabalancing_state(state); + } return err; } #endif diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 5ae443b2882e..c90a564af720 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -1689,7 +1689,7 @@ static struct ctl_table kern_table[] = { .mode = 0644, .proc_handler = sysctl_numa_balancing, .extra1 = SYSCTL_ZERO, - .extra2 = SYSCTL_ONE, + .extra2 = SYSCTL_FOUR, }, #endif /* CONFIG_NUMA_BALANCING */ { diff --git a/mm/migrate.c b/mm/migrate.c index a5971e9f6e6a..61f7e82e6708 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -51,6 +51,7 @@ #include #include #include +#include #include @@ -2034,16 +2035,30 @@ static int numamigrate_isolate_page(pg_data_t *pgdat, struct page *page) { int page_lru; int nr_pages = thp_nr_pages(page); + int order = compound_order(page); - VM_BUG_ON_PAGE(compound_order(page) && !PageTransHuge(page), page); + VM_BUG_ON_PAGE(order && !PageTransHuge(page), page); /* Do not migrate THP mapped by multiple processes */ if (PageTransHuge(page) && total_mapcount(page) > 1) return 0; /* Avoid migrating to a node that is nearly full */ - if (!migrate_balanced_pgdat(pgdat, nr_pages)) + if (!migrate_balanced_pgdat(pgdat, nr_pages)) { + int z; + + if (!(sysctl_numa_balancing_mode & NUMA_BALANCING_MEMORY_TIERING) || + !numa_demotion_enabled) + return 0; + if (next_demotion_node(pgdat->node_id) == NUMA_NO_NODE) + return 0; + for (z = pgdat->nr_zones - 1; z >= 0; z--) { + if (populated_zone(pgdat->node_zones + z)) + break; + } + wakeup_kswapd(pgdat->node_zones + z, 0, order, ZONE_MOVABLE); return 0; + } if (isolate_lru_page(page)) return 0; diff --git a/mm/vmscan.c b/mm/vmscan.c index 08ab556c7678..bc6fbbc8bedd 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -56,6 +56,7 @@ #include #include +#include #include "internal.h" @@ -3966,6 +3967,13 @@ static bool pgdat_watermark_boosted(pg_data_t *pgdat, int highest_zoneidx) return false; } +/* + * Keep the free pages on fast memory node a little more than the high + * watermark to accommodate the promoted pages. + */ +#define NUMA_BALANCING_PROMOTE_WATERMARK_DIV 4 +#define NUMA_BALANCING_PROMOTE_WATERMARK_MIN (10UL * 1024 * 1024 >> PAGE_SHIFT) + /* * Returns true if there is an eligible zone balanced for the request order * and highest_zoneidx @@ -3987,6 +3995,15 @@ static bool pgdat_balanced(pg_data_t *pgdat, int order, int highest_zoneidx) continue; mark = high_wmark_pages(zone); + if (sysctl_numa_balancing_mode & NUMA_BALANCING_MEMORY_TIERING && + numa_demotion_enabled && + next_demotion_node(pgdat->node_id) != NUMA_NO_NODE) { + unsigned long promote_mark; + + promote_mark = max(NUMA_BALANCING_PROMOTE_WATERMARK_MIN, + mark / NUMA_BALANCING_PROMOTE_WATERMARK_DIV); + mark += promote_mark; + } if (zone_watermark_ok_safe(zone, order, mark, highest_zoneidx)) return true; }