Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751841AbZGNAcO (ORCPT ); Mon, 13 Jul 2009 20:32:14 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751359AbZGNAcN (ORCPT ); Mon, 13 Jul 2009 20:32:13 -0400 Received: from fgwmail7.fujitsu.co.jp ([192.51.44.37]:40082 "EHLO fgwmail7.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751142AbZGNAcM (ORCPT ); Mon, 13 Jul 2009 20:32:12 -0400 X-SecurityPolicyCheck-FJ: OK by FujitsuOutboundMailChecker v1.3.1 Date: Tue, 14 Jul 2009 09:30:22 +0900 From: KAMEZAWA Hiroyuki To: Vladislav Buzov Cc: Linux Kernel Mailing List , Linux Containers Mailing List , Linux memory management list , Dan Malek , Andrew Morton , Paul Menage , Balbir Singh Subject: Re: [PATCH 1/2] Resource usage threshold notification addition to res_counter (v3) Message-Id: <20090714093022.6e8c1cc0.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <1247530581-31416-2-git-send-email-vbuzov@embeddedalley.com> References: <1246998310-16764-1-git-send-email-vbuzov@embeddedalley.com> <1247530581-31416-1-git-send-email-vbuzov@embeddedalley.com> <1247530581-31416-2-git-send-email-vbuzov@embeddedalley.com> Organization: FUJITSU Co. LTD. X-Mailer: Sylpheed 2.5.0 (GTK+ 2.10.14; i686-pc-mingw32) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7808 Lines: 254 On Mon, 13 Jul 2009 17:16:20 -0700 Vladislav Buzov wrote: > This patch updates the Resource Counter to add a configurable resource usage > threshold notification mechanism. > > Signed-off-by: Vladislav Buzov > Signed-off-by: Dan Malek > --- > Documentation/cgroups/resource_counter.txt | 21 ++++++++- > include/linux/res_counter.h | 69 ++++++++++++++++++++++++++++ > kernel/res_counter.c | 7 +++ > 3 files changed, 95 insertions(+), 2 deletions(-) > > diff --git a/Documentation/cgroups/resource_counter.txt b/Documentation/cgroups/resource_counter.txt > index 95b24d7..1369dff 100644 > --- a/Documentation/cgroups/resource_counter.txt > +++ b/Documentation/cgroups/resource_counter.txt > @@ -39,7 +39,20 @@ to work with it. > The failcnt stands for "failures counter". This is the number of > resource allocation attempts that failed. > > - c. spinlock_t lock > + e. unsigned long long threshold > + > + The resource usage threshold to notify the resouce controller. This is > + the minimal difference between the resource limit and current usage > + to fire a notification. > + > + f. void (*threshold_notifier)(struct res_counter *counter) > + > + The threshold notification callback installed by the resource > + controller. Called when the usage reaches or exceeds the threshold. > + Should be fast and not sleep because called when interrupts are > + disabled. > + This interface isn't very useful..hard to use..can't you just return the result as "exceeds threshold" to the callers ? If I was you, I'll add following state to res_counter enum { RES_BELOW_THRESH, RES_OVER_THRESH, } res_state; struct res_counter { ..... enum res_state state; } Then, caller does example) prev_state = res->state; res_counter_charge(res....) if (prev_state != res->state) do_xxxxx.. notifier under spinlock is not usual interface. And if this is "notifier", something generic, notifier_call_chain should be used rather than original one, IIUC. So, avoiding to use "callback" is a way to go, I think. Thanks, -Kame > + g. spinlock_t lock > > Protects changes of the above values. > > @@ -140,6 +153,7 @@ counter fields. They are recommended to adhere to the following rules: > usage usage_in_ > max_usage max_usage_in_ > limit limit_in_ > + threshold notify_threshold_in_ > failcnt failcnt > lock no file :) > > @@ -153,9 +167,12 @@ counter fields. They are recommended to adhere to the following rules: > usage prohibited > max_usage reset to usage > limit set the limit > + threshold set the threshold > failcnt reset to zero > > - > + d. Notification is enabled by installing the threshold notifier callback. It > + is up to the resouce controller to communicate the notification to user > + space tasks. > > 5. Usage example > > diff --git a/include/linux/res_counter.h b/include/linux/res_counter.h > index 511f42f..5ec98d7 100644 > --- a/include/linux/res_counter.h > +++ b/include/linux/res_counter.h > @@ -9,6 +9,11 @@ > * > * Author: Pavel Emelianov > * > + * Resouce usage threshold notification update > + * Copyright 2009 CE Linux Forum and Embedded Alley Solutions, Inc. > + * Author: Dan Malek > + * Author: Vladislav Buzov > + * > * See Documentation/cgroups/resource_counter.txt for more > * info about what this counter is. > */ > @@ -35,6 +40,19 @@ struct res_counter { > */ > unsigned long long limit; > /* > + * the resource usage threshold to notify the resouce controller. This > + * is the minimal difference between the resource limit and current > + * usage to fire a notification. > + */ > + unsigned long long threshold; > + /* > + * the threshold notification callback installed by the resource > + * controller. Called when the usage reaches or exceeds the threshold. > + * Should be fast and not sleep because called when interrupts are > + * disabled. > + */ > + void (*threshold_notifier)(struct res_counter *counter); > + /* > * the number of unsuccessful attempts to consume the resource > */ > unsigned long long failcnt; > @@ -87,6 +105,7 @@ enum { > RES_MAX_USAGE, > RES_LIMIT, > RES_FAILCNT, > + RES_THRESHOLD, > }; > > /* > @@ -132,6 +151,21 @@ static inline bool res_counter_limit_check_locked(struct res_counter *cnt) > return false; > } > > +static inline bool res_counter_threshold_check_locked(struct res_counter *cnt) > +{ > + if (cnt->usage + cnt->threshold < cnt->limit) > + return true; > + > + return false; > +} > + > +static inline void res_counter_threshold_notify_locked(struct res_counter *cnt) > +{ > + if (!res_counter_threshold_check_locked(cnt) && > + cnt->threshold_notifier) > + cnt->threshold_notifier(cnt); > +} > + > /* > * Helper function to detect if the cgroup is within it's limit or > * not. It's currently called from cgroup_rss_prepare() > @@ -147,6 +181,21 @@ static inline bool res_counter_check_under_limit(struct res_counter *cnt) > return ret; > } > > +/* > + * Helper function to detect if the cgroup usage is under it's threshold or > + * not. > + */ > +static inline bool res_counter_check_under_threshold(struct res_counter *cnt) > +{ > + bool ret; > + unsigned long flags; > + > + spin_lock_irqsave(&cnt->lock, flags); > + ret = res_counter_threshold_check_locked(cnt); > + spin_unlock_irqrestore(&cnt->lock, flags); > + return ret; > +} > + > static inline void res_counter_reset_max(struct res_counter *cnt) > { > unsigned long flags; > @@ -174,6 +223,26 @@ static inline int res_counter_set_limit(struct res_counter *cnt, > spin_lock_irqsave(&cnt->lock, flags); > if (cnt->usage <= limit) { > cnt->limit = limit; > + if (limit <= cnt->threshold) > + cnt->threshold = 0; > + else > + res_counter_threshold_notify_locked(cnt); > + ret = 0; > + } > + spin_unlock_irqrestore(&cnt->lock, flags); > + return ret; > +} > + > +static inline int res_counter_set_threshold(struct res_counter *cnt, > + unsigned long long threshold) > +{ > + unsigned long flags; > + int ret = -EINVAL; > + > + spin_lock_irqsave(&cnt->lock, flags); > + if (cnt->limit > threshold) { > + cnt->threshold = threshold; > + res_counter_threshold_notify_locked(cnt); > ret = 0; > } > spin_unlock_irqrestore(&cnt->lock, flags); > diff --git a/kernel/res_counter.c b/kernel/res_counter.c > index e1338f0..9b36748 100644 > --- a/kernel/res_counter.c > +++ b/kernel/res_counter.c > @@ -5,6 +5,10 @@ > * > * Author: Pavel Emelianov > * > + * Resouce usage threshold notification update > + * Copyright 2009 CE Linux Forum and Embedded Alley Solutions, Inc. > + * Author: Dan Malek > + * Author: Vladislav Buzov > */ > > #include > @@ -32,6 +36,7 @@ int res_counter_charge_locked(struct res_counter *counter, unsigned long val) > counter->usage += val; > if (counter->usage > counter->max_usage) > counter->max_usage = counter->usage; > + res_counter_threshold_notify_locked(counter); > return 0; > } > > @@ -101,6 +106,8 @@ res_counter_member(struct res_counter *counter, int member) > return &counter->limit; > case RES_FAILCNT: > return &counter->failcnt; > + case RES_THRESHOLD: > + return &counter->threshold; > }; > > BUG(); > -- > 1.5.6.3 > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/