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=-18.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL 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 9038AC47080 for ; Mon, 24 May 2021 05:17:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6180761139 for ; Mon, 24 May 2021 05:17:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232114AbhEXFQd (ORCPT ); Mon, 24 May 2021 01:16:33 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48750 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229572AbhEXFQa (ORCPT ); Mon, 24 May 2021 01:16:30 -0400 Received: from mail-pj1-x102f.google.com (mail-pj1-x102f.google.com [IPv6:2607:f8b0:4864:20::102f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8C3E0C061574 for ; Sun, 23 May 2021 22:15:02 -0700 (PDT) Received: by mail-pj1-x102f.google.com with SMTP id g6-20020a17090adac6b029015d1a9a6f1aso9713445pjx.1 for ; Sun, 23 May 2021 22:15:02 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:from:to:cc:subject:in-reply-to:message-id:references :mime-version; bh=/EUmhL8O/6C6s2ym0jeZMd3h5j+uY9ZLba6aQ9iY5t0=; b=fvEmZIDKyXvyOLe5GS631DgmBBGCSuKQWAbo1zf5iQd26iAszG3JmoWJXgcGWeeQgR 53lYlCdcQPz0ChKhF/gSUELKziE27UUdQI/0HBqaodhZrA0QIeNbVMB+RazDQzghAD9t Qdp4ufeXx0BYDnmVSNxwclI/rGafSZrszmbFlxbcq1SVnptG+PQl4By6YItLilCJ+cem QD6Mm01KEbz/tATF3JIs4pPO7Uw2oWsroImFSghMRtSvAITg8HkfAevcwBhuzSsh6Eoo wesuomRUgQ6iSODerJ3R7HDsQuV0BTtnVLhPRXslDUHZt2epNVnFFMsH/bRTTs0FmfRr z0mw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:in-reply-to:message-id :references:mime-version; bh=/EUmhL8O/6C6s2ym0jeZMd3h5j+uY9ZLba6aQ9iY5t0=; b=XvCXySfDnG6irRI3AUizHn5PlOwajVpZn4BgteYbphH4UPiJMDUa0H5TVklkmIkoOY KqJH5FKimucogjusI6yfF786gGx5VGttn94npZh14yOLRQPFz6l5/ZFPlRnKHAUSYc2w AQpm4MiXhUartxNRvN4ABODGwvu9MhAB74DHehi+SSm0pg6NCEVJZo7AfvrPP2ymESU3 VhUXasORDE2/YE/Z9TWEr6mmgqhtXplJTWUMUM0LoH/grJwfXGx7dpgLblKu1CNGavSP HSzX07qp3YUjy5KOpSRp+jjR2D44AFo8LWXK+H5OE2GiXWnOK8JNgY8MEsMcv3EaPNL+ 5sQw== X-Gm-Message-State: AOAM531rydyaeS6jBLjVl9GzmSXRMJudvxivzknrl2J2/I4XKS+FLGGb BjKZ+X2i+4XBeQlVy2sFm2GUBw== X-Google-Smtp-Source: ABdhPJwRcRWbq8UVhU8Q8uxV+T8q9AR+Ax7DpNA9MPX19ZzG8+nBt4bd79JBqxnUdvl+w0ZffLNUEQ== X-Received: by 2002:a17:902:d4c6:b029:ef:80f3:c543 with SMTP id o6-20020a170902d4c6b02900ef80f3c543mr23899565plg.85.1621833301829; Sun, 23 May 2021 22:15:01 -0700 (PDT) Received: from [2620:15c:17:3:9016:8a6d:7de4:aa23] ([2620:15c:17:3:9016:8a6d:7de4:aa23]) by smtp.gmail.com with ESMTPSA id s3sm10932299pgs.62.2021.05.23.22.15.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 23 May 2021 22:15:01 -0700 (PDT) Date: Sun, 23 May 2021 22:15:00 -0700 (PDT) From: David Rientjes To: Feng Tang cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andrew Morton , Michal Hocko , Andrea Arcangeli , Mel Gorman , Mike Kravetz , Randy Dunlap , Vlastimil Babka , Dave Hansen , Ben Widawsky , Andi Kleen , Dan Williams , ying.huang@intel.com Subject: Re: [RFC Patch v2 1/4] mm/mempolicy: skip nodemask intersect check for 'interleave' when oom In-Reply-To: <1621499404-67756-2-git-send-email-feng.tang@intel.com> Message-ID: <682c92e5-ccb3-4b76-1f56-617f8e6e8f2@google.com> References: <1621499404-67756-1-git-send-email-feng.tang@intel.com> <1621499404-67756-2-git-send-email-feng.tang@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 20 May 2021, Feng Tang wrote: > 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); If MPOL_INTERLEAVE is deemed only a suggestion, the same could be considered true of MPOL_BIND intersection as well, no? > - break; > - default: > - BUG(); > - } > -out: > task_unlock(tsk); > + > return ret; > } > > -- > 2.7.4 > >