From patchwork Wed May 26 05:01:39 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Feng Tang X-Patchwork-Id: 12280627 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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham 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 333F4C47088 for ; Wed, 26 May 2021 05:01:54 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id B2E9F610CB for ; Wed, 26 May 2021 05:01:53 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B2E9F610CB Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id BB3F36B006E; Wed, 26 May 2021 01:01:52 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id B8AB76B0070; Wed, 26 May 2021 01:01:52 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A59556B0071; Wed, 26 May 2021 01:01:52 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0096.hostedemail.com [216.40.44.96]) by kanga.kvack.org (Postfix) with ESMTP id 6D1476B006E for ; Wed, 26 May 2021 01:01:52 -0400 (EDT) Received: from smtpin21.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id F1E07989B for ; Wed, 26 May 2021 05:01:51 +0000 (UTC) X-FDA: 78182184822.21.C8BE389 Received: from mga04.intel.com (mga04.intel.com [192.55.52.120]) by imf01.hostedemail.com (Postfix) with ESMTP id A4ACA5001649 for ; Wed, 26 May 2021 05:01:44 +0000 (UTC) IronPort-SDR: Iv5738KtrO/I2SuT5wgtZBIda2jG6cwqfvvBNELEESK3XaYAYCAQnDc2UN9wP2GMrp2VzGVi0Y G1GUtIId7h2w== X-IronPort-AV: E=McAfee;i="6200,9189,9995"; a="200480065" X-IronPort-AV: E=Sophos;i="5.82,330,1613462400"; d="scan'208";a="200480065" Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 25 May 2021 22:01:50 -0700 IronPort-SDR: rHJTpW6ue71FjKcagiwVlhtoj6dWxRqE9aEHOu+VCRNJw6PuzQq0hdq/IBaFGfJO8T2JhV48Jy xCdE/41/iYXw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.82,330,1613462400"; d="scan'208";a="479700238" Received: from shbuild999.sh.intel.com ([10.239.147.94]) by fmsmga002.fm.intel.com with ESMTP; 25 May 2021 22:01:47 -0700 From: Feng Tang To: linux-mm@kvack.org, Andrew Morton , Michal Hocko , David Rientjes , Dave Hansen , Ben Widawsky Cc: linux-kernel@vger.kernel.org, Andrea Arcangeli , Mel Gorman , Mike Kravetz , Randy Dunlap , Vlastimil Babka , Andi Kleen , Dan Williams , ying.huang@intel.com, Feng Tang Subject: [PATCH v1 1/4] mm/mempolicy: skip nodemask intersect check for 'interleave' when oom Date: Wed, 26 May 2021 13:01:39 +0800 Message-Id: <1622005302-23027-2-git-send-email-feng.tang@intel.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1622005302-23027-1-git-send-email-feng.tang@intel.com> References: <1622005302-23027-1-git-send-email-feng.tang@intel.com> Authentication-Results: imf01.hostedemail.com; dkim=none; dmarc=fail reason="No valid SPF, No valid DKIM" header.from=intel.com (policy=none); spf=none (imf01.hostedemail.com: domain of feng.tang@intel.com has no SPF policy when checking 192.55.52.120) smtp.mailfrom=feng.tang@intel.com X-Stat-Signature: d83o71ni5dz9p9w94ryws8a9tcsgk6zt X-Rspamd-Queue-Id: A4ACA5001649 X-Rspamd-Server: rspam02 X-HE-Tag: 1622005304-26729 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: mempolicy_nodemask_intersects() is used in oom case to check if a task may have memory allocated on some memory nodes. Currently, the nodes_intersects() is run for both 'bind' and 'interleave' policies. But they are different regarding memory allocation, the nodemask is a forced requirement for 'bind', while just a hint for 'interleave'. Like in alloc_pages_vma(): nmask = policy_nodemask(gfp, pol); preferred_nid = policy_node(gfp, pol, node); page = __alloc_pages(gfp, order, preferred_nid, nmask); in plicy_nodemask(), only 'bind' policy may return its desired nodemask, while others return NULL. And this 'NULL' enables the 'interleave' policy can get memory from other nodes than its nodemask. So skip the nodemask intersect check for 'interleave' policy. Suggested-by: Michal Hocko Signed-off-by: Feng Tang --- mm/mempolicy.c | 24 ++++-------------------- 1 file changed, 4 insertions(+), 20 deletions(-) diff --git a/mm/mempolicy.c b/mm/mempolicy.c index d79fa29..1964cca 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -2098,7 +2098,7 @@ bool init_nodemask_of_mempolicy(nodemask_t *mask) * * If tsk's mempolicy is "default" [NULL], return 'true' to indicate default * policy. Otherwise, check for intersection between mask and the policy - * nodemask for 'bind' or 'interleave' policy. For 'preferred' or 'local' + * nodemask for 'bind' policy. For 'interleave', 'preferred' or 'local' * policy, always return true since it may allocate elsewhere on fallback. * * Takes task_lock(tsk) to prevent freeing of its mempolicy. @@ -2111,29 +2111,13 @@ bool mempolicy_nodemask_intersects(struct task_struct *tsk, if (!mask) return ret; + task_lock(tsk); mempolicy = tsk->mempolicy; - if (!mempolicy) - goto out; - - switch (mempolicy->mode) { - case MPOL_PREFERRED: - /* - * MPOL_PREFERRED and MPOL_F_LOCAL are only preferred nodes to - * allocate from, they may fallback to other nodes when oom. - * Thus, it's possible for tsk to have allocated memory from - * nodes in mask. - */ - break; - case MPOL_BIND: - case MPOL_INTERLEAVE: + if (mempolicy && mempolicy->mode == MPOL_BIND) ret = nodes_intersects(mempolicy->v.nodes, *mask); - break; - default: - BUG(); - } -out: task_unlock(tsk); + return ret; }