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From: Alan Stern <stern@rowland.harvard.edu>
To: Ming Lei <ming.lei@canonical.com>
Cc: linux-kernel@vger.kernel.org, Oliver Neukum <oneukum@suse.de>,
	Minchan Kim <minchan@kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	"Rafael J. Wysocki" <rjw@sisk.pl>, Jens Axboe <axboe@kernel.dk>,
	"David S. Miller" <davem@davemloft.net>,
	Andrew Morton <akpm@linux-foundation.org>,
	<netdev@vger.kernel.org>, <linux-usb@vger.kernel.org>,
	<linux-pm@vger.kernel.org>, <linux-mm@kvack.org>,
	Eric Dumazet <eric.dumazet@gmail.com>,
	David Decotigny <david.decotigny@google.com>,
	Tom Herbert <therbert@google.com>, Ingo Molnar <mingo@elte.hu>
Subject: Re: [PATCH v3 4/6] net/core: apply pm_runtime_set_memalloc_noio on network devices
Date: Mon, 29 Oct 2012 11:44:03 -0400 (EDT)	[thread overview]
Message-ID: <Pine.LNX.4.44L0.1210291142000.22882-100000@netrider.rowland.org> (raw)
In-Reply-To: <1351513440-9286-5-git-send-email-ming.lei@canonical.com>

On Mon, 29 Oct 2012, Ming Lei wrote:

> Deadlock might be caused by allocating memory with GFP_KERNEL in
> runtime_resume callback of network devices in iSCSI situation, so
> mark network devices and its ancestor as 'memalloc_noio_resume'
> with the introduced pm_runtime_set_memalloc_noio().

> @@ -1411,6 +1414,8 @@ int netdev_register_kobject(struct net_device *net)
>  	*groups++ = &netstat_group;
>  #endif /* CONFIG_SYSFS */
>  
> +	pm_runtime_set_memalloc_noio(dev, true);
> +
>  	error = device_add(dev);
>  	if (error)
>  		return error;

This is an example of what I described earlier.  The 
pm_runtime_set_memalloc_noio() call should come after device_add(), not 
before.

(Not to mention that this version of the code doesn't correctly handle
the case where device_add() fails.)

Alan Stern


  reply	other threads:[~2012-10-29 15:44 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-10-29 12:23 [PATCH v3 0/6] solve deadlock caused by memory allocation with I/O Ming Lei
2012-10-29 12:23 ` [PATCH v3 1/6] mm: teach mm by current context info to not do I/O during memory allocation Ming Lei
2012-10-29 12:23 ` [PATCH v3 2/6] PM / Runtime: introduce pm_runtime_set[get]_memalloc_noio() Ming Lei
2012-10-29 15:41   ` Alan Stern
2012-10-30  3:21     ` Ming Lei
2012-10-30 10:57       ` Oliver Neukum
2012-10-30 11:30         ` Ming Lei
2012-10-30 15:38       ` Alan Stern
2012-10-30 16:00         ` Ming Lei
2012-10-30 16:15           ` Ming Lei
2012-10-30 16:30           ` Oliver Neukum
2012-10-31  2:08             ` Ming Lei
2012-10-31  3:05               ` Ming Lei
2012-10-31  8:37                 ` Oliver Neukum
2012-10-31 15:20                 ` Alan Stern
2012-10-31 15:41                   ` Alan Stern
2012-10-31 23:18                     ` Ming Lei
2012-10-30 16:54           ` Alan Stern
2012-10-29 12:23 ` [PATCH v3 3/6] block/genhd.c: apply pm_runtime_set_memalloc_noio on block devices Ming Lei
2012-10-29 12:23 ` [PATCH v3 4/6] net/core: apply pm_runtime_set_memalloc_noio on network devices Ming Lei
2012-10-29 15:44   ` Alan Stern [this message]
2012-10-29 12:23 ` [PATCH v3 5/6] PM / Runtime: force memory allocation with no I/O during runtime_resume callbcack Ming Lei
2012-10-29 12:24 ` [PATCH v3 6/6] USB: forbid memory allocation with I/O during bus reset Ming Lei

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