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=-0.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS 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 C39A4C10F0E for ; Thu, 18 Apr 2019 23:18:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 93D0421479 for ; Thu, 18 Apr 2019 23:18:05 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="IG4p+iPb" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726344AbfDRXSE (ORCPT ); Thu, 18 Apr 2019 19:18:04 -0400 Received: from mail-pg1-f193.google.com ([209.85.215.193]:41127 "EHLO mail-pg1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725855AbfDRXSE (ORCPT ); Thu, 18 Apr 2019 19:18:04 -0400 Received: by mail-pg1-f193.google.com with SMTP id f6so1847716pgs.8 for ; Thu, 18 Apr 2019 16:18:03 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=4+PQ66vk9KRKMNJbABmZKkCe2bugk7ReMnXEdIYwvBI=; b=IG4p+iPbyNpA5DfvBrjqIkow9ZGDTP4e5I92dn3w4N+2Gm8e1YPVxWOSqMwO7+nfqW KBqVgIaOtusZYM2UznQkt1u/GTa/RjF97Tn4CK4aR1XMtWrZUhRrzIwOS+XF41m/caRt Xe3qhavnAYKbnXpaZaimmlEHpHTcGXwNM4FVKvkvbVPxecn6SHzy0kXcICSc8ad1qe74 rpyayAmTDI80FcovexHR4e6OtnoXU+X1oHhxr4Ale5TGMFK+9wM6glimRsoW5xE+csel OjNIVFxInhM8hQ3XHhc44Efw+lv1csq6qw/+d/XGUT7NX8QO6SS1hEN/vZww+7g7SGhq zTfA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=4+PQ66vk9KRKMNJbABmZKkCe2bugk7ReMnXEdIYwvBI=; b=FuWDWA6OBwGzvtVI3ajg1qcERzHT0n6nNl/4RHwgPFc7P7JKYDj2AavhJa5HlCoMIr 6NDHE5briVD/uJlQAB/c6vBIRFpCx4xjM7e68Hj998VbQSIdRVxuZyTIh2kNi2Mqqget xMKpEOSNiMYFERle+L5IH2ippibxUPteDHZTGYXqr2Lo1ZPEco5ZZz1Fl9Po3nRtFdmF 9UGGlDPKQ/fH2UpcT38nWkn3Dqvo9c2irV4iAfJP/YPrup7hcGvUtntCZaejuUIdUVuU aCzob1LIYSN5EfbjDm4DWoDYdLJ3tLsmXY7K+x3mmvw3w2TDyoCXwLML/CB71utPe/Me 27gw== X-Gm-Message-State: APjAAAUNTPFOvbYkzMF6mRmTErYj/FT4SAfNrzP2rMEVurjB7g8RA61c QILWKlmZfcIABLkiFMlvqBU= X-Google-Smtp-Source: APXvYqw4vd2gL8+Fu3zj86IT1o3HvPj5kfYzJY4yaXJLzb8gGzdXkUH13mg1+4utQSv2fmW4Y0T3iA== X-Received: by 2002:a65:5189:: with SMTP id h9mr637421pgq.304.1555629483663; Thu, 18 Apr 2019 16:18:03 -0700 (PDT) Received: from ?IPv6:2620:15c:2c1:200:55c7:81e6:c7d8:94b? ([2620:15c:2c1:200:55c7:81e6:c7d8:94b]) by smtp.gmail.com with ESMTPSA id g4sm4832243pfm.115.2019.04.18.16.18.01 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 18 Apr 2019 16:18:02 -0700 (PDT) Subject: Re: [PATCH v4 1/2] mm: refactor __vunmap() to avoid duplicated call to find_vm_area() To: Andrew Morton , Matthew Wilcox Cc: Roman Gushchin , linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel-team@fb.com, Johannes Weiner , Vlastimil Babka , Roman Gushchin , Christoph Hellwig , Joel Fernandes References: <20190417194002.12369-1-guro@fb.com> <20190417194002.12369-2-guro@fb.com> <20190417145827.8b1c83bf22de8ba514f157e3@linux-foundation.org> <20190418111834.GE7751@bombadil.infradead.org> <20190418152431.c583ef892a8028c662db3e6a@linux-foundation.org> From: Eric Dumazet Message-ID: <05c40b0b-3621-6c07-346b-478679949d92@gmail.com> Date: Thu, 18 Apr 2019 16:17:59 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20190418152431.c583ef892a8028c662db3e6a@linux-foundation.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04/18/2019 03:24 PM, Andrew Morton wrote: > afaict, vfree() will only do a mutex_trylock() in > try_purge_vmap_area_lazy(). So does vfree actually sleep in any > situation? Whether or not local interrupts are enabled? We would be in a big trouble if vfree() could potentially sleep... Random example : __free_fdtable() called from rcu callback.