linux-kernel - Re: [RFC PATCH v1 2/3] PM / Runtime: force memory allocation with no I/O during runtime

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Message-ID: <11374134.vToUn932b7@vostro.rjw.lan>
Date:	Fri, 19 Oct 2012 01:16:58 +0200
From:	"Rafael J. Wysocki" <rjw@...k.pl>
To:	Ming Lei <ming.lei@...onical.com>
Cc:	linux-kernel@...r.kernel.org,
	Alan Stern <stern@...land.harvard.edu>,
	Oliver Neukum <oneukum@...e.de>,
	Minchan Kim <minchan@...nel.org>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	linux-usb@...r.kernel.org, linux-pm@...r.kernel.org
Subject: Re: [RFC PATCH v1 2/3] PM / Runtime: force memory allocation with no I/O during runtime_resume callbcack

On Wednesday 17 of October 2012 19:07:25 Ming Lei wrote:
> On Wed, Oct 17, 2012 at 1:43 PM, Rafael J. Wysocki <rjw@...k.pl> wrote:
> >
> > This appears to be a bit too heavy handed.  First of all, it seems to affect
> > all memory allocations going in parallel with the resume callback.  Second,
> 
> No, the flag is per task, only memory allocation inside resume callback
> is effected.

OK

> > it affects all resume callbacks, not only those where the problem really
> 
> We can do it only on block device, block device's ancestor and network
> devices(iSCSI case), but that may introduce policy into PM core or add
> one flag of memalloc_noio_resume into 'dev_pm_info', could you agree
> on it?

Well, the question is how many runtime resume callbacks actually allocate
memory.  If they are not too many, we can just flag all of them.  Otherwise,
adding a flag may be a better approach.  I'm not sure ATM.

Thanks,
Rafael


-- 
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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