From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <47D8EC5A.20907@openvz.org> Date: Thu, 13 Mar 2008 11:56:58 +0300 From: Pavel Emelyanov MIME-Version: 1.0 Subject: Re: [PATCH 2/2] Make res_counter hierarchical References: <47D16004.7050204@openvz.org> <20080312230541.CB9021E703D@siro.lan> In-Reply-To: <20080312230541.CB9021E703D@siro.lan> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: YAMAMOTO Takashi Cc: balbir@linux.vnet.ibm.com, kamezawa.hiroyu@jp.fujitsu.com, menage@google.com, containers@lists.osdl.org, linux-mm@kvack.org List-ID: YAMAMOTO Takashi wrote: >> @@ -36,10 +37,26 @@ int res_counter_charge(struct res_counter *counter, unsigned long val) >> { >> int ret; >> unsigned long flags; >> + struct res_counter *c, *unroll_c; >> + >> + local_irq_save(flags); >> + for (c = counter; c != NULL; c = c->parent) { >> + spin_lock(&c->lock); >> + ret = res_counter_charge_locked(c, val); >> + spin_unlock(&c->lock); >> + if (ret < 0) >> + goto unroll; >> + } >> + local_irq_restore(flags); >> + return 0; >> >> - spin_lock_irqsave(&counter->lock, flags); >> - ret = res_counter_charge_locked(counter, val); >> - spin_unlock_irqrestore(&counter->lock, flags); >> +unroll: >> + for (unroll_c = counter; unroll_c != c; unroll_c = unroll_c->parent) { >> + spin_lock(&unroll_c->lock); >> + res_counter_uncharge_locked(unroll_c, val); >> + spin_unlock(&unroll_c->lock); >> + } >> + local_irq_restore(flags); >> return ret; >> } > > what prevents the topology (in particular, ->parent pointers) from > changing behind us? The res_counter client must provide this. Currently cgroup subsystem does this. > YAMAMOTO Takashi > -- 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