On Tue, Dec 1, 2015 at 12:35 PM David Miller <davem@xxxxxxxxxxxxx> wrote:
From: Michal Hocko <mhocko@xxxxxxxxxx>
Date: Mon, 30 Nov 2015 14:21:29 +0100
> On Sat 28-11-15 15:51:13, Pavel Machek wrote:
>>
>> atl1c driver is doing order-4 allocation with GFP_ATOMIC
>> priority. That often breaks networking after resume. Switch to
>> GFP_KERNEL. Still not ideal, but should be significantly better.
>
> It is not clear why GFP_KERNEL can replace GFP_ATOMIC safely neither
> from the changelog nor from the patch context.
Earlier in the function we do a GFP_KERNEL kmalloc so:
¯\_(ツ)_/¯
It should be fine.
AFAICT, the people who benefit from GFP_ATOMIC are the people running all their storage over NFS/iSCSI who are suspending their machines while they're so busy they don't have any clean order 4 pagecache to drop, and want the machine to panic rather than hang. The people who benefit from GFP_KERNEL are the people who use their laptop for a while, put it to sleep, and then wake it up again. I think the latter is the use case we should be optimizing for.
-- Chris