netdev - Re: [PATCH net-next] page_pool: always add GFP

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Message-ID: <20250908132041.5ae74626@kernel.org>
Date: Mon, 8 Sep 2025 13:20:41 -0700
From: Jakub Kicinski <kuba@...nel.org>
To: Mina Almasry <almasrymina@...gle.com>
Cc: davem@...emloft.net, netdev@...r.kernel.org, edumazet@...gle.com,
 pabeni@...hat.com, andrew+netdev@...n.ch, horms@...nel.org,
 hawk@...nel.org, ilias.apalodimas@...aro.org, nathan@...nel.org,
 nick.desaulniers+lkml@...il.com, morbo@...gle.com, justinstitt@...gle.com,
 llvm@...ts.linux.dev
Subject: Re: [PATCH net-next] page_pool: always add GFP_NOWARN for ATOMIC
 allocations

On Mon, 8 Sep 2025 09:15:07 -0700 Mina Almasry wrote:
> > +       /* Unconditionally set NOWARN if allocating from the datapath.
> > +        * Use a single bit from the ATOMIC mask to help compiler optimize.
> > +        */
> > +       BUILD_BUG_ON(!(GFP_ATOMIC & __GFP_HIGH));
> > +       if (gfp & __GFP_HIGH)
> > +               gfp |= __GFP_NOWARN;
> > +  
> 
> I wonder if pp allocs are ever used for anything other than datapath
> pages (and if not, we can add __GPF_NOWARN here unconditionally. But
> this is good too I think.

datapath == in NAPI context, here. We still want the warning if 
the allocations fail with GFP_KERNEL, e.g. during ndo_open.