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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no 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 2547EC4338F for ; Fri, 23 Jul 2021 06:20:24 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id A68B960EFD for ; Fri, 23 Jul 2021 06:20:23 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org A68B960EFD Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id B97FD6B005D; Fri, 23 Jul 2021 02:20:22 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id B48B96B006C; Fri, 23 Jul 2021 02:20:22 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A37436B0070; Fri, 23 Jul 2021 02:20:22 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0152.hostedemail.com [216.40.44.152]) by kanga.kvack.org (Postfix) with ESMTP id 88E666B005D for ; Fri, 23 Jul 2021 02:20:22 -0400 (EDT) Received: from smtpin30.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 3805B82499A8 for ; Fri, 23 Jul 2021 06:20:22 +0000 (UTC) X-FDA: 78392853084.30.E47C1B3 Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.220.29]) by imf10.hostedemail.com (Postfix) with ESMTP id AD56960083E7 for ; Fri, 23 Jul 2021 06:20:21 +0000 (UTC) Received: from relay2.suse.de (relay2.suse.de [149.44.160.134]) by smtp-out2.suse.de (Postfix) with ESMTP id 5D0521FF53; Fri, 23 Jul 2021 06:20:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1627021220; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=v8uQ4/E3Pg2AaedWhgz8TbxdBCTE3NVNf26n2c3ARfE=; b=Fitv+2rBlAONt3Ul0ivrD3yXXmi9oKL+oO7Ox7WlnJ2NUNdmDc1v77oKiYkcu9cD7/+soA XTDUsHdv00QaXiHZMYR6/OBlrF1TDLJIdzHP9CIOn1gfKTaCTMj2cnqcLfYUzG1pnCkTe9 2lkTTuRTtzv8CgTPlhOL9EI2R6g3AuU= Received: from suse.cz (tiehlicka.dhcp.prg.suse.com [10.156.228.52]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by relay2.suse.de (Postfix) with ESMTPS id 12EDBA3B87; Fri, 23 Jul 2021 06:20:20 +0000 (UTC) Date: Fri, 23 Jul 2021 08:20:19 +0200 From: Michal Hocko To: Suren Baghdasaryan Cc: Shakeel Butt , Andrew Morton , David Rientjes , Matthew Wilcox , Johannes Weiner , Roman Gushchin , Rik van Riel , Minchan Kim , Christian Brauner , Christoph Hellwig , Oleg Nesterov , David Hildenbrand , Jann Horn , Andy Lutomirski , Christian Brauner , Florian Weimer , Jan Engelhardt , Tim Murray , Linux API , Linux MM , LKML , kernel-team Subject: Re: [PATCH v3 1/2] mm: introduce process_mrelease system call Message-ID: References: <20210723011436.60960-1-surenb@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: AD56960083E7 Authentication-Results: imf10.hostedemail.com; dkim=pass header.d=suse.com header.s=susede1 header.b=Fitv+2rB; dmarc=pass (policy=quarantine) header.from=suse.com; spf=pass (imf10.hostedemail.com: domain of mhocko@suse.com designates 195.135.220.29 as permitted sender) smtp.mailfrom=mhocko@suse.com X-Stat-Signature: w75wopgi6tmho9ntz7kmbnakfn15uzfo X-HE-Tag: 1627021221-506419 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: On Thu 22-07-21 21:47:56, Suren Baghdasaryan wrote: > On Thu, Jul 22, 2021, 7:04 PM Shakeel Butt wrote: > > > On Thu, Jul 22, 2021 at 6:14 PM Suren Baghdasaryan > > wrote: > > > > > [...] > > > + > > > + mmap_read_lock(mm); > > > > How about mmap_read_trylock(mm) and return -EAGAIN on failure? > > > > That sounds like a good idea. Thanks! I'll add that in the next respin. Why is that a good idea? Can you do anything meaningful about the failure other than immediately retry the syscall and hope for the best? -- Michal Hocko SUSE Labs