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 X-Spam-Level: X-Spam-Status: No, score=-15.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A3561C433ED for ; Thu, 13 May 2021 07:24:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 662CC6134F for ; Thu, 13 May 2021 07:24:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231699AbhEMHZd (ORCPT ); Thu, 13 May 2021 03:25:33 -0400 Received: from mga06.intel.com ([134.134.136.31]:29100 "EHLO mga06.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231626AbhEMHZV (ORCPT ); Thu, 13 May 2021 03:25:21 -0400 IronPort-SDR: aKlQupy4DDdl5UQdyYVgT7D9PmfEoRbE059RU7C0JDNYqZwubq+bBM086AU7+lNScsQ8UBhmkf qpQWcQ/p7VJQ== X-IronPort-AV: E=McAfee;i="6200,9189,9982"; a="261138254" X-IronPort-AV: E=Sophos;i="5.82,296,1613462400"; d="scan'208";a="261138254" Received: from orsmga006.jf.intel.com ([10.7.209.51]) by orsmga104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 13 May 2021 00:23:56 -0700 IronPort-SDR: Fxhbhcb7CPja7qc1bALQnbiZn28dcWXEFArRdDaRF8+q934+FIp4adQrHUwPFBlmiyes6I/Xo8 bvjTvev1KfbA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.82,296,1613462400"; d="scan'208";a="393101595" Received: from shbuild999.sh.intel.com (HELO localhost) ([10.239.147.94]) by orsmga006.jf.intel.com with ESMTP; 13 May 2021 00:23:51 -0700 Date: Thu, 13 May 2021 15:23:50 +0800 From: Feng Tang To: Michal Hocko , "Hansen, Dave" , "Widawsky, Ben" Cc: "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , Andrew Morton , Andrea Arcangeli , David Rientjes , Mel Gorman , Mike Kravetz , Randy Dunlap , Vlastimil Babka , Andi Kleen , "Williams, Dan J" , ying.huang@intel.com Subject: Re: [PATCH v4 03/13] mm/mempolicy: Add MPOL_PREFERRED_MANY for multiple preferred nodes Message-ID: <20210513072350.GB44993@shbuild999.sh.intel.com> References: <1615952410-36895-1-git-send-email-feng.tang@intel.com> <1615952410-36895-4-git-send-email-feng.tang@intel.com> <20210420071625.GB48282@shbuild999.sh.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210420071625.GB48282@shbuild999.sh.intel.com> User-Agent: Mutt/1.5.24 (2015-08-30) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org mempolicy: don't handle MPOL_LOCAL as a fake MPOL_PREFERRED policy MPOL_LOCAL policy has been setup as a real policy, but it is still handled as a faked POL_PREFERRED policy with one internal MPOL_F_LOCAL flag bit set, and there are many places having to judge the real 'prefer' or the 'local' policy, which are quite confusing. In current code, there are four cases that MPOL_LOCAL are used: * user specifies 'local' policy * user specifies 'prefer' policy, but with empty nodemask * system 'default' policy is used * 'prefer' policy + valid 'preferred' node with MPOL_F_STATIC_NODES flag set, and when it is 'rebind' to a nodemask which doesn't contains the 'preferred' node, it will add the MPOL_F_LOCAL bit and performs as 'local' policy. In future if it is 'rebind' again with valid nodemask, the policy will be restored back to 'prefer' So for the first three cases, we make 'local' a real policy instead of a fake 'prefer' one, this will reduce confusion and make it easier to integrate our new 'prefer-many' policy And next optional patch will kill the 'MPOL_F_LOCAL' bit. Signed-off-by: Feng Tang --- mm/mempolicy.c | 60 ++++++++++++++++++++++++++++++++-------------------------- 1 file changed, 33 insertions(+), 27 deletions(-) diff --git a/mm/mempolicy.c b/mm/mempolicy.c index d79fa29..2f20f079 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -121,8 +121,7 @@ enum zone_type policy_zone = 0; */ static struct mempolicy default_policy = { .refcnt = ATOMIC_INIT(1), /* never free it */ - .mode = MPOL_PREFERRED, - .flags = MPOL_F_LOCAL, + .mode = MPOL_LOCAL, }; static struct mempolicy preferred_node_policy[MAX_NUMNODES]; @@ -200,12 +199,9 @@ static int mpol_new_interleave(struct mempolicy *pol, const nodemask_t *nodes) static int mpol_new_preferred(struct mempolicy *pol, const nodemask_t *nodes) { - if (!nodes) - pol->flags |= MPOL_F_LOCAL; /* local allocation */ - else if (nodes_empty(*nodes)) - return -EINVAL; /* no allowed nodes */ - else - pol->v.preferred_node = first_node(*nodes); + if (nodes_empty(*nodes)) + return -EINVAL; + pol->v.preferred_node = first_node(*nodes); return 0; } @@ -239,25 +235,19 @@ static int mpol_set_nodemask(struct mempolicy *pol, cpuset_current_mems_allowed, node_states[N_MEMORY]); VM_BUG_ON(!nodes); - if (pol->mode == MPOL_PREFERRED && nodes_empty(*nodes)) - nodes = NULL; /* explicit local allocation */ - else { - if (pol->flags & MPOL_F_RELATIVE_NODES) - mpol_relative_nodemask(&nsc->mask2, nodes, &nsc->mask1); - else - nodes_and(nsc->mask2, *nodes, nsc->mask1); - if (mpol_store_user_nodemask(pol)) - pol->w.user_nodemask = *nodes; - else - pol->w.cpuset_mems_allowed = - cpuset_current_mems_allowed; - } + if (pol->flags & MPOL_F_RELATIVE_NODES) + mpol_relative_nodemask(&nsc->mask2, nodes, &nsc->mask1); + else + nodes_and(nsc->mask2, *nodes, nsc->mask1); - if (nodes) - ret = mpol_ops[pol->mode].create(pol, &nsc->mask2); + if (mpol_store_user_nodemask(pol)) + pol->w.user_nodemask = *nodes; else - ret = mpol_ops[pol->mode].create(pol, NULL); + pol->w.cpuset_mems_allowed = + cpuset_current_mems_allowed; + + ret = mpol_ops[pol->mode].create(pol, &nsc->mask2); return ret; } @@ -290,13 +280,14 @@ static struct mempolicy *mpol_new(unsigned short mode, unsigned short flags, if (((flags & MPOL_F_STATIC_NODES) || (flags & MPOL_F_RELATIVE_NODES))) return ERR_PTR(-EINVAL); + + mode = MPOL_LOCAL; } } else if (mode == MPOL_LOCAL) { if (!nodes_empty(*nodes) || (flags & MPOL_F_STATIC_NODES) || (flags & MPOL_F_RELATIVE_NODES)) return ERR_PTR(-EINVAL); - mode = MPOL_PREFERRED; } else if (nodes_empty(*nodes)) return ERR_PTR(-EINVAL); policy = kmem_cache_alloc(policy_cache, GFP_KERNEL); @@ -427,6 +418,9 @@ static const struct mempolicy_operations mpol_ops[MPOL_MAX] = { .create = mpol_new_bind, .rebind = mpol_rebind_nodemask, }, + [MPOL_LOCAL] = { + .rebind = mpol_rebind_default, + }, }; static int migrate_page_add(struct page *page, struct list_head *pagelist, @@ -1960,6 +1954,8 @@ unsigned int mempolicy_slab_node(void) &policy->v.nodes); return z->zone ? zone_to_nid(z->zone) : node; } + case MPOL_LOCAL: + return node; default: BUG(); @@ -2084,6 +2080,11 @@ bool init_nodemask_of_mempolicy(nodemask_t *mask) *mask = mempolicy->v.nodes; break; + case MPOL_LOCAL: + nid = numa_node_id(); + init_nodemask_of_node(mask, nid); + break; + default: BUG(); } @@ -2344,6 +2345,8 @@ bool __mpol_equal(struct mempolicy *a, struct mempolicy *b) if (a->flags & MPOL_F_LOCAL) return true; return a->v.preferred_node == b->v.preferred_node; + case MPOL_LOCAL: + return true; default: BUG(); return false; @@ -2487,6 +2490,10 @@ int mpol_misplaced(struct page *page, struct vm_area_struct *vma, unsigned long polnid = pol->v.preferred_node; break; + case MPOL_LOCAL: + polnid = numa_node_id(); + break; + case MPOL_BIND: /* Optimize placement among multiple nodes via NUMA balancing */ if (pol->flags & MPOL_F_MORON) { @@ -2931,7 +2938,6 @@ int mpol_parse_str(char *str, struct mempolicy **mpol) */ if (nodelist) goto out; - mode = MPOL_PREFERRED; break; case MPOL_DEFAULT: /* @@ -2975,7 +2981,7 @@ int mpol_parse_str(char *str, struct mempolicy **mpol) else if (nodelist) new->v.preferred_node = first_node(nodes); else - new->flags |= MPOL_F_LOCAL; + new->mode = MPOL_LOCAL; /* * Save nodes for contextualization: this will be used to "clone" -- 2.7.4