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 76A50C4320A for ; Fri, 6 Aug 2021 06:41:48 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 1F69A611CE for ; Fri, 6 Aug 2021 06:41:48 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 1F69A611CE 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 747956B006C; Fri, 6 Aug 2021 02:41:47 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 6F95B6B0071; Fri, 6 Aug 2021 02:41:47 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 5E7026B0072; Fri, 6 Aug 2021 02:41:47 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 44CAA6B006C for ; Fri, 6 Aug 2021 02:41:47 -0400 (EDT) Received: from smtpin08.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id DFE778249980 for ; Fri, 6 Aug 2021 06:41:46 +0000 (UTC) X-FDA: 78443710212.08.A952351 Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.220.28]) by imf23.hostedemail.com (Postfix) with ESMTP id 706589004164 for ; Fri, 6 Aug 2021 06:41:46 +0000 (UTC) Received: from relay2.suse.de (relay2.suse.de [149.44.160.134]) by smtp-out1.suse.de (Postfix) with ESMTP id 6B4D9223AD; Fri, 6 Aug 2021 06:41:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1628232105; 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=L3TW/hbpU2iIogA7/HVgljoLbJH3MuJbKrYqp6bZxa8=; b=lcGg7DjCd59pnNkutnkEqAUCpfRkb+2fqXYTowV1MgFCNq9kTkwmrTFxey1/CHITdFK8PR 8w/YX1C4MaaLQ/bnVpn3lSAxPaNjXCEqViCXRXq6j5H3izcB/1GkUsDh/q3x/dmwfYfyp0 mdUJfzAila9qn2TVoUc8Arqgr8gQdHA= Received: from suse.cz (unknown [10.100.201.86]) (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 2DE98A3B87; Fri, 6 Aug 2021 06:41:45 +0000 (UTC) Date: Fri, 6 Aug 2021 08:41:44 +0200 From: Michal Hocko To: Suren Baghdasaryan Cc: Shakeel Butt , David Hildenbrand , Andrew Morton , David Rientjes , Matthew Wilcox , Johannes Weiner , Roman Gushchin , Rik van Riel , Minchan Kim , Christian Brauner , Christoph Hellwig , Oleg Nesterov , Jann Horn , Andy Lutomirski , Christian Brauner , Florian Weimer , Jan Engelhardt , Tim Murray , Linux API , linux-mm , LKML , kernel-team Subject: Re: [PATCH v7 1/2] mm: introduce process_mrelease system call Message-ID: References: <20210805170859.2389276-1-surenb@google.com> <46998d10-d0ca-aeeb-8dcd-41b8130fb756@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 706589004164 Authentication-Results: imf23.hostedemail.com; dkim=pass header.d=suse.com header.s=susede1 header.b=lcGg7DjC; dmarc=pass (policy=quarantine) header.from=suse.com; spf=pass (imf23.hostedemail.com: domain of mhocko@suse.com designates 195.135.220.28 as permitted sender) smtp.mailfrom=mhocko@suse.com X-Stat-Signature: d31whijw845ha9b1pkngyu1o6ero836e X-HE-Tag: 1628232106-690 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 05-08-21 11:37:06, Suren Baghdasaryan wrote: [...] > > One question I have is why mmget() and not mmgrab()? I see mmgrab() in > > oom_kill.c. > > You are likely right here. The caller's context probably can't be > considered a "real user" when reaping the mm. However, we take an > mmap_lock shortly after, so not sure if in practice there is much > difference. > Michal, WDYT? As explained in other response. mmget is to pin address space to not go away. You do not need that for this purpose. All you need is to pin mm to not go away. Address space can be unmapped concurrently. -- Michal Hocko SUSE Labs