From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx200.postini.com [74.125.245.200]) by kanga.kvack.org (Postfix) with SMTP id 00C986B00D7 for ; Tue, 17 Jan 2012 11:36:10 -0500 (EST) Message-ID: <4F15A34F.40808@redhat.com> Date: Tue, 17 Jan 2012 11:35:27 -0500 From: Rik van Riel MIME-Version: 1.0 Subject: Re: [RFC 1/3] /dev/low_mem_notify References: <1326788038-29141-1-git-send-email-minchan@kernel.org> <1326788038-29141-2-git-send-email-minchan@kernel.org> In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Pekka Enberg Cc: Minchan Kim , linux-mm , LKML , leonid.moiseichuk@nokia.com, kamezawa.hiroyu@jp.fujitsu.com, mel@csn.ul.ie, rientjes@google.com, KOSAKI Motohiro , Johannes Weiner , Marcelo Tosatti , Andrew Morton , Ronen Hod , KOSAKI Motohiro On 01/17/2012 04:27 AM, Pekka Enberg wrote: > On Tue, Jan 17, 2012 at 10:13 AM, Minchan Kim wrote: >> +static unsigned int low_mem_notify_poll(struct file *file, poll_table *wait) >> +{ >> + unsigned int ret = 0; >> + >> + poll_wait(file,&low_mem_wait, wait); >> + >> + if (atomic_read(&nr_low_mem) != 0) { >> + ret = POLLIN; >> + atomic_set(&nr_low_mem, 0); >> + } >> + >> + return ret; >> +} > > Doesn't this mean that only one application will receive the notification? One at a time, which could be a good thing since the last thing we want to do when the system is under memory pressure is create a thundering herd. OTOH, we do need to ensure that programs take turns getting the memory pressure notification. I do not know whether poll_wait automatically takes care of that... -- All rights reversed -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org