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Date: Sun, 2 Aug 2009 21:57:32 +0530
From: Balbir Singh <balbir@linux.vnet.ibm.com>
To: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Jiri Slaby <jirislaby@gmail.com>,
       Andrew Morton <akpm@linux-foundation.org>,
       Linux kernel mailing list <linux-kernel@vger.kernel.org>,
       KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
       Li Zefan <lizf@cn.fujitsu.com>,
       KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Subject: Re: memory-controller patch fails to boot in qemu [mmotm]
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* Hugh Dickins <hugh.dickins@tiscali.co.uk> [2009-08-02 17:12:53]:

> On Sun, 2 Aug 2009, Balbir Singh wrote:
> > * Hugh Dickins <hugh.dickins@tiscali.co.uk> [2009-08-01 23:09:09]:
> > > 
> > > Hmm, this a weird function, passed an argument just to tell it to do
> > > nothing.  Perhaps a placeholder for something more sensible to come?
> > 
> > The argument is passed a result of a function, It no-ops quite
> > frequently for the root cgroup.
> 
> The more often it no-ops, the sillier it is to be called in
> the first place: here's an updated patch which fixes that too.
> 
> 
> [PATCH mmotm] memory controller: soft limit organize cgroups v9 fix
> 
> CONFIG_CGROUP_MEM_RES_CTLR=y CONFIG_PREEMPT=y mmotm fails to boot:
> Kernel panic - not syncing: No init found; after lots of scheduling
> while atomics, starting from when async_thread does sd_probe_async.
> 
> mem_cgroup_soft_limit_check() was doing an unbalanced get_cpu():
> don't get_cpu if we won't need it, and put_cpu if we did get_cpu.
> 
> And fix the silliness of passing it an "over_soft_limit" argument
> that just tells it to return false when false.
> 
> Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>

Fair enough (I guess my intention of keeping if blocks outside for
each call site, does not pay sufficiently enough), Thanks for the cleanup


Reviewed-by: Balbir Singh <balbir@linux.vnet.ibm.com>
 

-- 
	Balbir