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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id A092EC43334 for ; Tue, 26 Jul 2022 08:02:44 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 1B6988E0002; Tue, 26 Jul 2022 04:02:44 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 1673B8E0001; Tue, 26 Jul 2022 04:02:44 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 006998E0002; Tue, 26 Jul 2022 04:02:43 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id C14468E0001 for ; Tue, 26 Jul 2022 04:02:43 -0400 (EDT) Received: from smtpin13.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id 7637FA2460 for ; Tue, 26 Jul 2022 08:02:43 +0000 (UTC) X-FDA: 79728509406.13.AC8FF6D Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) by imf14.hostedemail.com (Postfix) with ESMTP id 52E8A1000C8 for ; Tue, 26 Jul 2022 08:02:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1658822562; x=1690358562; h=from:to:cc:subject:references:date:in-reply-to: message-id:mime-version; bh=CUZxTvCqlorgPopyQrREkP5nuwha/hRCiZS4ejKQGYk=; b=BRTJCT1bGZa0Xpekek1Iyq/0r98w1vwS+7dr9FxQXfsrQXUnONlzmqhK dEG7TJqOzFh1pBmmVqHCFyxxsCvaYOtoaNkUlOjnaxTzNo2/5Ygv3IQzD YlAIaJ+dpbQt2ze858Rsvi71M/izN6Uv2cOAgRvmWH05TfXZ1f2BQr7H0 B8P+UZB6bofdWkFHpZ8IbGkf5/A1eMNso5zQmkWYJgY3JDtyecRjYHVPv 87eq4fIOR6dCEhwRr8ylSEWQDn7L9DwdA1IjEXW2fgtV1e1fQrlnAXnsJ v09gW0wnGpQzO5q0c5LbgfMGaNZ+OnnOE3OawEQALOSOhWIpw94/tZXmY A==; X-IronPort-AV: E=McAfee;i="6400,9594,10419"; a="288646208" X-IronPort-AV: E=Sophos;i="5.93,193,1654585200"; d="scan'208";a="288646208" Received: from orsmga006.jf.intel.com ([10.7.209.51]) by orsmga102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Jul 2022 01:02:40 -0700 X-IronPort-AV: E=Sophos;i="5.93,193,1654585200"; d="scan'208";a="575389671" Received: from yhuang6-desk2.sh.intel.com (HELO yhuang6-desk2.ccr.corp.intel.com) ([10.239.13.94]) by orsmga006-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Jul 2022 01:02:36 -0700 From: "Huang, Ying" To: "Aneesh Kumar K.V" Cc: linux-mm@kvack.org, akpm@linux-foundation.org, Wei Xu , Yang Shi , Davidlohr Bueso , Tim C Chen , Michal Hocko , Linux Kernel Mailing List , Hesham Almatary , Dave Hansen , Jonathan Cameron , Alistair Popple , Dan Williams , Johannes Weiner , jvgediya.oss@gmail.com Subject: Re: [PATCH v10 6/8] mm/demotion: Add pg_data_t member to track node memory tier details References: <20220720025920.1373558-1-aneesh.kumar@linux.ibm.com> <20220720025920.1373558-7-aneesh.kumar@linux.ibm.com> Date: Tue, 26 Jul 2022 16:02:33 +0800 In-Reply-To: <20220720025920.1373558-7-aneesh.kumar@linux.ibm.com> (Aneesh Kumar K. V.'s message of "Wed, 20 Jul 2022 08:29:18 +0530") Message-ID: <87wnc0uwrq.fsf@yhuang6-desk2.ccr.corp.intel.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=ascii ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1658822563; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=e9x0odgcRpHBXL1A2zYg94P0rW5kAwqrGGOU2L6Zvk8=; b=Wsn7C6p+NIJgIlT7QQOzL0kKRZx3rePIBEFZobsSSKnD0uMNZVp5a47Ywb9I3ugkTeS8J5 DT7dRoImELZ7czeOLTDapHcWgOeh2ArGOtS/ydDZcjYQLBRtoLeoqtI/CbZPOm0D16g0js gXf6pE7zzb8+aI+UBCmUW/9CbE7YklE= ARC-Authentication-Results: i=1; imf14.hostedemail.com; dkim=pass header.d=intel.com header.s=Intel header.b=BRTJCT1b; dmarc=pass (policy=none) header.from=intel.com; spf=none (imf14.hostedemail.com: domain of ying.huang@intel.com has no SPF policy when checking 134.134.136.24) smtp.mailfrom=ying.huang@intel.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1658822563; a=rsa-sha256; cv=none; b=kEDKoMLuixVKRUSjs8vA9HPrLid9q3siV5QOVoHCZuL9C8LbSl4a+baoWcRhcUcH0w2rk1 Ah9Je0JPKhJPWxYVjNocMsiKcavfIgd3IVDFw6AwVv8VML17dr0YLpBKksirOoyUrE2hem m8ovQ2zhiFuXGehdp0wo/Fmj5e5e+ac= X-Stat-Signature: 9btko1prcg74kou969fzki6r94881p4s X-Rspamd-Queue-Id: 52E8A1000C8 X-Rspam-User: X-Rspamd-Server: rspam12 Authentication-Results: imf14.hostedemail.com; dkim=pass header.d=intel.com header.s=Intel header.b=BRTJCT1b; dmarc=pass (policy=none) header.from=intel.com; spf=none (imf14.hostedemail.com: domain of ying.huang@intel.com has no SPF policy when checking 134.134.136.24) smtp.mailfrom=ying.huang@intel.com X-HE-Tag: 1658822562-187662 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: "Aneesh Kumar K.V" writes: > Also update different helpes to use NODE_DATA()->memtier. Since > node specific memtier can change based on the reassignment of > NUMA node to a different memory tiers, accessing NODE_DATA()->memtier > needs to happen under an rcu read lock or memory_tier_lock. > > Signed-off-by: Aneesh Kumar K.V > --- > include/linux/mmzone.h | 3 ++ > mm/memory-tiers.c | 65 +++++++++++++++++++++++++++++++++++------- > 2 files changed, 57 insertions(+), 11 deletions(-) > > diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h > index aab70355d64f..353812495a70 100644 > --- a/include/linux/mmzone.h > +++ b/include/linux/mmzone.h > @@ -928,6 +928,9 @@ typedef struct pglist_data { > /* Per-node vmstats */ > struct per_cpu_nodestat __percpu *per_cpu_nodestats; > atomic_long_t vm_stat[NR_VM_NODE_STAT_ITEMS]; > +#ifdef CONFIG_NUMA > + struct memory_tier __rcu *memtier; > +#endif > } pg_data_t; > > #define node_present_pages(nid) (NODE_DATA(nid)->node_present_pages) > diff --git a/mm/memory-tiers.c b/mm/memory-tiers.c > index a8cfe2ca3903..4715f9b96a44 100644 > --- a/mm/memory-tiers.c > +++ b/mm/memory-tiers.c > @@ -138,13 +138,18 @@ static struct memory_tier *find_create_memory_tier(unsigned int perf_level) > > static struct memory_tier *__node_get_memory_tier(int node) > { > - struct memory_tier *memtier; > + pg_data_t *pgdat; > > - list_for_each_entry(memtier, &memory_tiers, list) { > - if (node_isset(node, memtier->nodelist)) > - return memtier; > - } > - return NULL; > + pgdat = NODE_DATA(node); > + if (!pgdat) > + return NULL; > + /* > + * Since we hold memory_tier_lock, we can avoid > + * RCU read locks when accessing the details. No > + * parallel updates are possible here. > + */ > + return rcu_dereference_check(pgdat->memtier, > + lockdep_is_held(&memory_tier_lock)); > } > > #ifdef CONFIG_MIGRATION > @@ -277,6 +282,29 @@ static inline void disable_all_migrate_targets(void) {} > static inline void establish_migration_targets(void) {} > #endif /* CONFIG_MIGRATION */ > > +static void memtier_node_set(int node, struct memory_tier *memtier) > +{ > + pg_data_t *pgdat; > + struct memory_tier *current_memtier; > + > + pgdat = NODE_DATA(node); > + if (!pgdat) > + return; > + /* > + * Make sure we mark the memtier NULL before we assign the new memory tier > + * to the NUMA node. This make sure that anybody looking at NODE_DATA > + * finds a NULL memtier or the one which is still valid. > + */ > + current_memtier = rcu_dereference_check(pgdat->memtier, > + lockdep_is_held(&memory_tier_lock)); > + rcu_assign_pointer(pgdat->memtier, NULL); > + synchronize_rcu(); > + if (current_memtier) > + node_clear(node, current_memtier->nodelist); If pgdat->memtier == NULL, we don't need to set it to NULL and call synchronize_rcu(). That is, + current_memtier = rcu_dereference_check(pgdat->memtier, + lockdep_is_held(&memory_tier_lock)); + if (current_memtier) { + rcu_assign_pointer(pgdat->memtier, NULL); + synchronize_rcu(); + node_clear(node, current_memtier->nodelist); + } Same for clear_node_memory_tier(). Best Regards, Huang, Ying > + node_set(node, memtier->nodelist); > + rcu_assign_pointer(pgdat->memtier, memtier); > +} > + > static void init_node_memory_tier(int node) > { > int perf_level; > @@ -295,7 +323,7 @@ static void init_node_memory_tier(int node) > if (!memtier) { > perf_level = node_devices[node]->perf_level; > memtier = find_create_memory_tier(perf_level); > - node_set(node, memtier->nodelist); > + memtier_node_set(node, memtier); > } > establish_migration_targets(); > mutex_unlock(&memory_tier_lock); > @@ -303,12 +331,25 @@ static void init_node_memory_tier(int node) > > static void clear_node_memory_tier(int node) > { > - struct memory_tier *memtier; > + pg_data_t *pgdat; > + struct memory_tier *current_memtier; > + > + pgdat = NODE_DATA(node); > + if (!pgdat) > + return; > > mutex_lock(&memory_tier_lock); > - memtier = __node_get_memory_tier(node); > - if (memtier) { > - node_clear(node, memtier->nodelist); > + /* > + * Make sure we mark the memtier NULL before we assign the new memory tier > + * to the NUMA node. This make sure that anybody looking at NODE_DATA > + * finds a NULL memtier or the one which is still valid. > + */ > + current_memtier = rcu_dereference_check(pgdat->memtier, > + lockdep_is_held(&memory_tier_lock)); > + rcu_assign_pointer(pgdat->memtier, NULL); > + synchronize_rcu(); > + if (current_memtier) { > + node_clear(node, current_memtier->nodelist); > establish_migration_targets(); > } > mutex_unlock(&memory_tier_lock); > @@ -383,6 +424,8 @@ static int __init memory_tier_init(void) > > if (!node_property->perf_level) > node_property->perf_level = default_memtier_perf_level; > + > + rcu_assign_pointer(NODE_DATA(node)->memtier, memtier); > } > mutex_unlock(&memory_tier_lock);