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=-2.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, 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 757B8C433B4 for ; Fri, 23 Apr 2021 07:02:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 34B3E613F2 for ; Fri, 23 Apr 2021 07:02:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229991AbhDWHCd (ORCPT ); Fri, 23 Apr 2021 03:02:33 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56500 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229456AbhDWHCc (ORCPT ); Fri, 23 Apr 2021 03:02:32 -0400 Received: from mail-pg1-x536.google.com (mail-pg1-x536.google.com [IPv6:2607:f8b0:4864:20::536]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5741EC061574; Fri, 23 Apr 2021 00:01:56 -0700 (PDT) Received: by mail-pg1-x536.google.com with SMTP id j7so25169062pgi.3; Fri, 23 Apr 2021 00:01:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=iR04QyRnmu5wEXEE6wM7+aMFMLtZ8Zhvq8vbG05BPrs=; b=CnEwX0wiZJDXMUjybp0vJt6OSKilTaK8SUbCh2Z7VN0jFhppEgE1jILT3h7LEp3i2F FVvXcsdWP0oNqBALdy0YY//yHhSDNalPYlif2PQoq84tyO+jffky/ShIk3PwsKJBWN3D c1h3rdCkODVeaz54jDO0001i411M4PtisKj2fBatWuUtqBrq6bJvbvUzJAlNPbfWJEIr 1Gh2CUwl6P/0hRP0KOKADs6ZfXIaRxXuZBHw7rbZzy+AX2WnVQs8rzjFIEJ6JAyU937a 1vUzOI6cZnqqGEzNNmmdgYBLuB9pXSNcfCpuwhV5L7rgCHSNNJrF8eg4CmmNeBGhITXw B4Qw== 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:message-id:references :mime-version:content-disposition:in-reply-to; bh=iR04QyRnmu5wEXEE6wM7+aMFMLtZ8Zhvq8vbG05BPrs=; b=SL9xUqO3vSVNOSpOGq6+4BLCA0NfsG1f55MXpSpXSAUDR0c0z5iEaV+eCVLgKCkRN0 c1ULa886vkMqQo+UBYSF7xxkTsaSI6ROE9EvtEI/ruizc41A74t5Pc9vaU4G8ZTdHwC8 6iUB8eC1+5wmnmKWm7gfn5/EfXoCPE+w0mdKlFWRgf0Az/reoTCz/zMrcgWl+gDF5xo8 gVgoKKzWbIDquT3t8F7j4D1ejfIkhK7zPRyKZFYzv2mjcMzpApDWDNdqG9n95TovTU3X UVvDyQ04+jer5VN0ZvUf/CIE5yZfMe3EMECL19hIjyr/w91MxcprDRTSHSDUsxL844DB AwhQ== X-Gm-Message-State: AOAM533i4Kw24bJU4OoWFs7QmgYdZBbxAX0K+SpxlZdpBMrrbIUdlH9g Eq9yHTbn5kYIiNBSm9nm7oA= X-Google-Smtp-Source: ABdhPJwJLGXDtvvPq5MYMgWv94xYQVKgsvTTkmk6unpZZXoRlCWkxw97MYvUeef51H1cj3qDV1rmcw== X-Received: by 2002:a63:2211:: with SMTP id i17mr2402206pgi.431.1619161315742; Fri, 23 Apr 2021 00:01:55 -0700 (PDT) Received: from gmail.com ([2601:600:8500:5f14:d627:c51e:516e:a105]) by smtp.gmail.com with ESMTPSA id f19sm3988160pga.71.2021.04.23.00.01.54 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 23 Apr 2021 00:01:55 -0700 (PDT) Date: Thu, 22 Apr 2021 23:59:15 -0700 From: Andrei Vagin To: Oleg Nesterov Cc: linux-kernel@vger.kernel.org, linux-api@vger.kernel.org, linux-um@lists.infradead.org, criu@openvz.org, avagin@google.com, Andrew Morton , Andy Lutomirski , Anton Ivanov , Christian Brauner , Dmitry Safonov <0x7f454c46@gmail.com>, Ingo Molnar , Jeff Dike , Mike Rapoport , Michael Kerrisk , Peter Zijlstra , Richard Weinberger , Thomas Gleixner Subject: Re: [PATCH 2/4] arch/x86: implement the process_vm_exec syscall Message-ID: References: <20210414055217.543246-1-avagin@gmail.com> <20210414055217.543246-3-avagin@gmail.com> <20210414170915.GB22294@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=koi8-r Content-Disposition: inline In-Reply-To: <20210414170915.GB22294@redhat.com> Precedence: bulk List-ID: X-Mailing-List: linux-api@vger.kernel.org On Wed, Apr 14, 2021 at 07:09:15PM +0200, Oleg Nesterov wrote: > On 04/13, Andrei Vagin wrote: > > > > +static void swap_mm(struct mm_struct *prev_mm, struct mm_struct *target_mm) > > +{ > > + struct task_struct *tsk = current; > > + struct mm_struct *active_mm; > > + > > + task_lock(tsk); > > + /* Hold off tlb flush IPIs while switching mm's */ > > + local_irq_disable(); > > + > > + sync_mm_rss(prev_mm); > > + > > + vmacache_flush(tsk); > > + > > + active_mm = tsk->active_mm; > > + if (active_mm != target_mm) { > > + mmgrab(target_mm); > > + tsk->active_mm = target_mm; > > + } > > + tsk->mm = target_mm; > > + switch_mm_irqs_off(active_mm, target_mm, tsk); > > + local_irq_enable(); > > + task_unlock(tsk); > > +#ifdef finish_arch_post_lock_switch > > + finish_arch_post_lock_switch(); > > +#endif > > + > > + if (active_mm != target_mm) > > + mmdrop(active_mm); > > +} > > I think this should be unified with kthread_use_mm() somehow... I agree. > > And does it really need the "prev_mm" argument? It must be tsk->mm, no? No, it doesn't. It is leftover of unuse_mm. BTW why do we pass mm to kthread_unuse_mm? Thanks, Andrei.