From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx131.postini.com [74.125.245.131]) by kanga.kvack.org (Postfix) with SMTP id EF3266B13F0 for ; Thu, 2 Feb 2012 07:26:54 -0500 (EST) Date: Thu, 2 Feb 2012 14:27:47 +0200 From: "Kirill A. Shutemov" Subject: Re: [PATCH] memcg: make threshold index in the right position Message-ID: <20120202122747.GA12575@shutemov.name> References: <1328175919-11209-1-git-send-email-handai.szj@taobao.com> <20120202101410.GA12291@shutemov.name> <4F2A6B5F.3090303@gmail.com> <4F2A6EBC.5090207@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4F2A6EBC.5090207@gmail.com> Sender: owner-linux-mm@kvack.org List-ID: To: Sha Zhengju Cc: linux-mm@kvack.org, cgroups@vger.kernel.org, KAMEZAWA Hiroyuki On Thu, Feb 02, 2012 at 07:08:44PM +0800, Sha Zhengju wrote: > On 02/02/2012 06:54 PM, Sha Zhengju wrote: > >On 02/02/2012 06:14 PM, Kirill A. Shutemov wrote: > >>On Thu, Feb 02, 2012 at 05:45:19PM +0800, Sha Zhengju wrote: > >>>From: Sha Zhengju > >>> > >>>Index current_threshold may point to threshold that just equal to > >>>usage after __mem_cgroup_threshold is triggerd. > >>I don't see it. Could you describe conditions? > >> > >It is because of the following code path in __mem_cgroup_threshold: > >{ > > ... > > i = t->current_threshold; > > > > for (; i >= 0 && unlikely(t->entries[i].threshold > usage); i--) > > eventfd_signal(t->entries[i].eventfd, 1); > > i++; > > > > for (; i < t->size && unlikely(t->entries[i].threshold <= > >usage); i++) > > eventfd_signal(t->entries[i].eventfd, 1); > > > > t->current_threshold = i - 1; > > ... > >} > > > >For example: > >now: > > threshold array: 3 5 7 9 (usage = 6) > > ^ > > index > > > >next turn: > > threshold array: 3 5 7 9 (usage = 7) > > ^ > > index > > > >after registering a new event(threshold = 10): > > threshold array: 3 5 7 9 10 (usage = 7) > > ^ > > index > Err.. Sorry for showing inaccurate index position... (may because of > the mail format) > > now: > threshold array: 3 [5] 7 9 (usage = 6, index = 5) > > next turn: > threshold array: 3 5 [7] 9 (usage = 7, index = 7) > > after registering a new event(threshold = 10): > threshold array: 3 [5] 7 9 10 (usage = 7, index = 5) Good catch! Thank you. Reviewed-by: Kirill A. Shutemov -- Kirill A. Shutemov -- 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