Subject: Re: [PATCH] Improve Atheros ethernet driver not to do order 4 GFP_ATOMIC allocation

From: Pavel Machek <[email-masked]>
Date: Thu, 3 Dec 2015 08:49:02 +0100

On Wed 2015-12-02 22:43:31, Chris Snook wrote:
> On Tue, Dec 1, 2015 at 12:35 PM David Miller <[email-masked]> wrote:
> 
> > From: Michal Hocko <[email-masked]>
> > 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

iSCSI on machine that suspends... is that a joke or complicated way of
saying that noone benefits? And code uses... both GFP_ATOMIC and
GFP_KERNEL so that both sides are equally unhappy? :-).

Do you want to test the patch, update the subject line and send it to
Davem, or should I do it?

Do you see a way to split the allocation? Not even order 4 GFP_KERNEL
allocation is a nice thing to do...

									Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to [email-masked].  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"[email-masked]"> [email-masked] </a>