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 1AED8C432BE for ; Fri, 6 Aug 2021 06:41:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0108B611CE for ; Fri, 6 Aug 2021 06:41:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243404AbhHFGmC (ORCPT ); Fri, 6 Aug 2021 02:42:02 -0400 Received: from smtp-out1.suse.de ([195.135.220.28]:55344 "EHLO smtp-out1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230386AbhHFGmB (ORCPT ); Fri, 6 Aug 2021 02:42:01 -0400 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: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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