From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-la0-f48.google.com (mail-la0-f48.google.com [209.85.215.48]) by kanga.kvack.org (Postfix) with ESMTP id CE64F82BDD for ; Tue, 21 Oct 2014 09:22:03 -0400 (EDT) Received: by mail-la0-f48.google.com with SMTP id gi9so997665lab.21 for ; Tue, 21 Oct 2014 06:22:01 -0700 (PDT) Received: from v094114.home.net.pl (v094114.home.net.pl. [79.96.170.134]) by mx.google.com with SMTP id ui10si14664851lbb.62.2014.10.21.06.21.58 for ; Tue, 21 Oct 2014 06:21:59 -0700 (PDT) From: "Rafael J. Wysocki" Subject: Re: [PATCH 3/4] OOM, PM: OOM killed task shouldn't escape PM suspend Date: Tue, 21 Oct 2014 15:42:23 +0200 Message-ID: <2156351.pWp6MNRoWm@vostro.rjw.lan> In-Reply-To: <20141021131445.GC9415@dhcp22.suse.cz> References: <1413876435-11720-1-git-send-email-mhocko@suse.cz> <3778374.avm26S62SZ@vostro.rjw.lan> <20141021131445.GC9415@dhcp22.suse.cz> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="utf-8" Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko Cc: Andrew Morton , Cong Wang , David Rientjes , Tejun Heo , Oleg Nesterov , LKML , linux-mm@kvack.org, Linux PM list On Tuesday, October 21, 2014 03:14:45 PM Michal Hocko wrote: > On Tue 21-10-14 14:09:27, Rafael J. Wysocki wrote: > [...] > > > @@ -131,12 +132,40 @@ int freeze_processes(void) > > > > > > printk("Freezing user space processes ... "); > > > pm_freezing = true; > > > + oom_kills_saved = oom_kills_count(); > > > error = try_to_freeze_tasks(true); > > > if (!error) { > > > - printk("done."); > > > __usermodehelper_set_disable_depth(UMH_DISABLED); > > > oom_killer_disable(); > > > + > > > + /* > > > + * There might have been an OOM kill while we were > > > + * freezing tasks and the killed task might be still > > > + * on the way out so we have to double check for race. > > > + */ > > > + if (oom_kills_count() != oom_kills_saved) { > > > + struct task_struct *g, *p; > > > + > > > + read_lock(&tasklist_lock); > > > + for_each_process_thread(g, p) { > > > + if (p == current || freezer_should_skip(p) || > > > + frozen(p)) > > > + continue; > > > + error = -EBUSY; > > > + goto out_loop; > > > + } > > > +out_loop: > > > > Well, it looks like this will work here too: > > > > for_each_process_thread(g, p) > > if (p != current && !frozen(p) && > > !freezer_should_skip(p)) { > > error = -EBUSY; > > break; > > } > > > > or I am helplessly misreading the code. > > break will not work because for_each_process_thread is a double loop. I see. In that case I'd do: for_each_process_thread(g, p) if (p != current && !frozen(p) && !freezer_should_skip(p)) { read_unlock(&tasklist_lock); __usermodehelper_set_disable_depth(UMH_ENABLED); printk("OOM in progress."); error = -EBUSY; goto done; } to avoid adding the new label that looks odd. -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org