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 59C14C00140 for ; Tue, 9 Aug 2022 03:07:27 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 9989F6B0071; Mon, 8 Aug 2022 23:07:26 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 9477D6B0072; Mon, 8 Aug 2022 23:07:26 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 810AF8E0001; Mon, 8 Aug 2022 23:07:26 -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 72BD36B0071 for ; Mon, 8 Aug 2022 23:07:26 -0400 (EDT) Received: from smtpin23.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay01.hostedemail.com (Postfix) with ESMTP id 4FBFE1C5C46 for ; Tue, 9 Aug 2022 03:07:26 +0000 (UTC) X-FDA: 79778568492.23.5F557D5 Received: from mga02.intel.com (mga02.intel.com [134.134.136.20]) by imf16.hostedemail.com (Postfix) with ESMTP id 9619218001A for ; Tue, 9 Aug 2022 03:07:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1660014445; x=1691550445; h=from:to:cc:subject:references:date:in-reply-to: message-id:mime-version; bh=UbJ/HBFckkQ6tZf+/b1u3HTfo3CBwfQHw0C3q+PeE2c=; b=Tj2thpUyo+zXKppiKeG8mZP87imT6fYRz/ekJ/cAg0p5MzCjX/mAWVIl 23ZmH+ivkGiX4bBdmtub4T3ZBTmrnrCOaR3pKBXQIt1qpiFfKXDZM55kI U5u0Da9RwG8SwisaYDRueMb9asBdBpaCnIMZ5rWlCCoqf3GM95xnnbyzf I+f5gJuDjwSDWzb5JVBW0RK7yVqiAuoo5q5uXNBeYnkyNjBNIUX0yuEhq GEgcLZfPa4KzdAdP9mjkfQTL3lPQfT1axrnvpxzniiPYm7EJ1HC3JJogQ fdit/vMH0C5LrnDRACx2+FpfKwCIr4HMItM6gFOc9tsWOXClH2dGAMt9S Q==; X-IronPort-AV: E=McAfee;i="6400,9594,10433"; a="277676218" X-IronPort-AV: E=Sophos;i="5.93,223,1654585200"; d="scan'208";a="277676218" Received: from orsmga001.jf.intel.com ([10.7.209.18]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 Aug 2022 20:07:24 -0700 X-IronPort-AV: E=Sophos;i="5.93,223,1654585200"; d="scan'208";a="637554673" Received: from yhuang6-desk2.sh.intel.com (HELO yhuang6-desk2.ccr.corp.intel.com) ([10.238.208.55]) by orsmga001-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 Aug 2022 20:07:20 -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 v13 6/9] mm/demotion: Add pg_data_t member to track node memory tier details References: <20220808062601.836025-1-aneesh.kumar@linux.ibm.com> <20220808062601.836025-7-aneesh.kumar@linux.ibm.com> Date: Tue, 09 Aug 2022 11:07:17 +0800 In-Reply-To: <20220808062601.836025-7-aneesh.kumar@linux.ibm.com> (Aneesh Kumar K. V.'s message of "Mon, 8 Aug 2022 11:55:58 +0530") Message-ID: <87k07iglne.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-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1660014445; a=rsa-sha256; cv=none; b=C+/CpFpABXEPTCqBVdbJ9p9yk+kTFRl0LYqU9zyyz2L6KoGUiuYhk0jCJ4OcrmA/qVqdtz CRcRAf2QGNpyOk3haZbzWjfgIFVlfVFyDjiKqITFtwU/WDgLPGmzzM8Pb8YMj+26cztFUl jwLWappV3ViaM3TqzxnQjrz5yPiN+hc= ARC-Authentication-Results: i=1; imf16.hostedemail.com; dkim=none ("invalid DKIM record") header.d=intel.com header.s=Intel header.b=Tj2thpUy; dmarc=pass (policy=none) header.from=intel.com; spf=pass (imf16.hostedemail.com: domain of ying.huang@intel.com designates 134.134.136.20 as permitted sender) smtp.mailfrom=ying.huang@intel.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1660014445; 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=a2qILQ2qZZhGO1SSX2rJHyV7xUKQtzR6m6rdI6/yHjE=; b=FoTWdkHvZUV4yw86Ipe4/RmE4ida0qVy5Xm2e01MAPPbBXVazWaoEN/HHSt8jnoIgCX/Fg tsyzfgEepKvhGazUNhUERmkM9o4MNbiNup8ALLtvVKvj+/zdIJ/pLP512oBIwF7IK3egE0 8GYbGV/oaAio/kTvlXcVV0bA6gwSD6s= X-Rspamd-Server: rspam10 X-Stat-Signature: b9ti1nn7wykn8xtpphtqp4ufanyuezuy Authentication-Results: imf16.hostedemail.com; dkim=none ("invalid DKIM record") header.d=intel.com header.s=Intel header.b=Tj2thpUy; dmarc=pass (policy=none) header.from=intel.com; spf=pass (imf16.hostedemail.com: domain of ying.huang@intel.com designates 134.134.136.20 as permitted sender) smtp.mailfrom=ying.huang@intel.com X-Rspam-User: X-Rspamd-Queue-Id: 9619218001A X-HE-Tag: 1660014445-75199 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 | 38 ++++++++++++++++++++++++++++++++------ > 2 files changed, 35 insertions(+), 6 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 02e514e87d5c..3778ac6a44a1 100644 > --- a/mm/memory-tiers.c > +++ b/mm/memory-tiers.c > @@ -5,6 +5,7 @@ > #include > #include > #include > +#include > #include > > #include "internal.h" > @@ -137,12 +138,18 @@ static struct memory_tier *find_create_memory_tier(struct memory_dev_type *memty > > static struct memory_tier *__node_get_memory_tier(int node) > { > - struct memory_dev_type *memtype; > + pg_data_t *pgdat; > > - memtype = node_memory_types[node]; > - if (memtype && node_isset(node, memtype->nodes)) > - return memtype->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 > @@ -295,6 +302,8 @@ static struct memory_tier *set_node_memory_tier(int node) > { > struct memory_tier *memtier; > struct memory_dev_type *memtype; > + pg_data_t *pgdat = NODE_DATA(node); > + > > lockdep_assert_held_once(&memory_tier_lock); > > @@ -307,6 +316,8 @@ static struct memory_tier *set_node_memory_tier(int node) > memtype = node_memory_types[node]; > node_set(node, memtype->nodes); > memtier = find_create_memory_tier(memtype); > + if (!IS_ERR(memtier)) > + rcu_assign_pointer(pgdat->memtier, memtier); > return memtier; > } > > @@ -319,12 +330,25 @@ static void destroy_memory_tier(struct memory_tier *memtier) > static bool clear_node_memory_tier(int node) > { > bool cleared = false; > + pg_data_t *pgdat; > struct memory_tier *memtier; > > + pgdat = NODE_DATA(node); > + if (!pgdat) > + return false; > + > + /* > + * Make sure that anybody looking at NODE_DATA who finds > + * a valid memtier finds memory_dev_types with nodes still > + * linked to the memtier. We achieve this by waiting for > + * rcu read section to finish using synchronize_rcu. > + */ The synchronize_rcu() is also needed because we may free the memory tier. Best Regards, Huang, Ying > memtier = __node_get_memory_tier(node); > if (memtier) { > struct memory_dev_type *memtype; > > + rcu_assign_pointer(pgdat->memtier, NULL); > + synchronize_rcu(); > memtype = node_memory_types[node]; > node_clear(node, memtype->nodes); > if (nodes_empty(memtype->nodes)) { > @@ -422,8 +446,10 @@ static int __init memory_tier_init(void) > panic("%s() failed to register memory tier: %ld\n", > __func__, PTR_ERR(memtier)); > > - for_each_node_state(node, N_MEMORY) > + for_each_node_state(node, N_MEMORY) { > __init_node_memory_type(node, default_dram_type); > + rcu_assign_pointer(NODE_DATA(node)->memtier, memtier); > + } > > mutex_unlock(&memory_tier_lock); > #ifdef CONFIG_MIGRATION