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=-13.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_IN_DEF_DKIM_WL 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 2F33CC432BE for ; Fri, 6 Aug 2021 09:23:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1351D61102 for ; Fri, 6 Aug 2021 09:23:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244521AbhHFJXr (ORCPT ); Fri, 6 Aug 2021 05:23:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44346 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244500AbhHFJXq (ORCPT ); Fri, 6 Aug 2021 05:23:46 -0400 Received: from mail-lf1-x133.google.com (mail-lf1-x133.google.com [IPv6:2a00:1450:4864:20::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 67E03C061798 for ; Fri, 6 Aug 2021 02:23:30 -0700 (PDT) Received: by mail-lf1-x133.google.com with SMTP id b6so333895lff.10 for ; Fri, 06 Aug 2021 02:23:30 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=Pz/ZNLrZ0O+ZYLO34S4orrCykgTqtG1p1sxk4AuVhP8=; b=cGHj/WVq/vdRsPecp7h5K9JfcZgFhYagyOxvNOodNjPWx1ajkrEXS3JlyTiNibU3Zp SwCEr2nxYnnoN/rDaQwb38GFSgdZl2Kq0S1ZixHKqp+2avGFzfRNz6/iVMXsnP13GDXH RgM2ccrAp/Y1PFbzphGj/HwyUf/rf0UTzlmJOICfUXjvGmeePTEJrpD9OV4lH2mafCPY EUwoVZfgNlJ5UV5dhZ/CcQ8uSISli8alXXvbGedEUPmFhOF7U0zEPU4QCO18qhf9yaxy TcA08g0vlBeSatSxXBIZQVQuFf1Og0jFqjL2CJHgmHoOtEAS/Q+fp37wUoAuWgX6aBA1 VJjQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=Pz/ZNLrZ0O+ZYLO34S4orrCykgTqtG1p1sxk4AuVhP8=; b=arTjRP92trpmG+VHt0ABfsziko5n1/X8leW904+QRGYD3de7a+BlqVdiYN18p+iZ2b yCMzp3Zt8OtrxFF1eCSOWgyIN54dqEnwKP+MOOVYu9/rGtPI+h9L0Fa+Do2MP1fQ0Xe9 bNonbazdxo2DghOsAqAAhxnX1QWbPk+iyUkKIv/0sM6dASqHgKKB5DBQ4G52gNLQxh2j IrnDxa5wTRJxm/ZD1IS+0TvUXApLFWNsAEzecse0izS+FJMi8f1aXL+Qq4gqLxmFGJ7X oKpYIlxuqktkwa3V8VFl6Wz+HcPK699L6TvJg8sPdgvi/A5yCTe1BgRg04kM/Fun/Y7f j3zQ== X-Gm-Message-State: AOAM530w/cvrtEncb9sDlgNby4EOJa7R0RfNn0eZOXoZ7y+QiVrowdaV /l8gGJYWCUwd4E5fidEzdssbQAQEAY191RQOlP8FFw== X-Google-Smtp-Source: ABdhPJxF+e96ji6+s/JU3AfUGss3Zf7f2U0jNy8HR7IhhDpf9cNHe8wRq2148ITd4iRoh3nJDaO7hsQbtRbL15dwnV8= X-Received: by 2002:ac2:57cd:: with SMTP id k13mr7112194lfo.117.1628241808578; Fri, 06 Aug 2021 02:23:28 -0700 (PDT) MIME-Version: 1.0 References: <20210805170859.2389276-1-surenb@google.com> In-Reply-To: From: Shakeel Butt Date: Fri, 6 Aug 2021 02:23:17 -0700 Message-ID: Subject: Re: [PATCH v7 1/2] mm: introduce process_mrelease system call To: Michal Hocko Cc: Suren Baghdasaryan , 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 Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Aug 5, 2021 at 11:40 PM Michal Hocko wrote: > [...] > I think you really want something like this: > > if (flags) > return -EINVAL; > > pid = pidfd_get_pid(fd, &f_flags); > if (IS_ERR(pid)) > return PTR_ERR(pid); > task = get_pid_task(pid, PIDTYPE_PID); > if (!task) { > ret = -ESRCH; > goto put_pid; > } > > /* > * Make sure to chose a thread which still has a reference to mm > * during the group exit > */ > p = find_lock_task_mm(task); > if (!p) { > ret = -ESRCH; > goto put_task; > } > > mm = task->mm; mm = p->mm; > mmgrab(mm); > reap = true; > /* If the work has been done already, just exit with success */ > if (test_bit(MMF_OOM_SKIP, &mm->flags)) { > reap = false; > } else if (!task_will_free_mem(p)) { > reap = false; > ret = -EINVAL; > } > task_unlock(p); > > if (!reap) > goto dropmm;; > > /* Do the work*/ > > > dropmm: > mmdrop(mm); > put_task: > put_task(task); > put_pid: > put_pid(pid); > > return ret; > > -- > Michal Hocko > SUSE Labs