linux-kernel - Re: [PATCH v2] mm: remove redundant __GFP

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Message-ID: <aJt__zOHjGcaghNf@fedora>
Date: Tue, 12 Aug 2025 10:55:11 -0700
From: "Vishal Moola (Oracle)" <vishal.moola@...il.com>
To: Lorenzo Stoakes <lorenzo.stoakes@...cle.com>
Cc: Qianfeng Rong <rongqianfeng@...o.com>, SeongJae Park <sj@...nel.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	"Matthew Wilcox (Oracle)" <willy@...radead.org>,
	Will Deacon <will@...nel.org>,
	"Aneesh Kumar K.V" <aneesh.kumar@...nel.org>,
	Nick Piggin <npiggin@...il.com>,
	Peter Zijlstra <peterz@...radead.org>,
	David Hildenbrand <david@...hat.com>,
	Rik van Riel <riel@...riel.com>,
	"Liam R. Howlett" <Liam.Howlett@...cle.com>,
	Vlastimil Babka <vbabka@...e.cz>, Harry Yoo <harry.yoo@...cle.com>,
	Uladzislau Rezki <urezki@...il.com>, damon@...ts.linux.dev,
	linux-mm@...ck.org, linux-kernel@...r.kernel.org,
	linux-fsdevel@...r.kernel.org, linux-arch@...r.kernel.org
Subject: Re: [PATCH v2] mm: remove redundant __GFP_NOWARN

On Tue, Aug 12, 2025 at 05:46:47PM +0100, Lorenzo Stoakes wrote:
> On Tue, Aug 12, 2025 at 09:52:25PM +0800, Qianfeng Rong wrote:
> > Commit 16f5dfbc851b ("gfp: include __GFP_NOWARN in GFP_NOWAIT") made
> > GFP_NOWAIT implicitly include __GFP_NOWARN.
> >
> > Therefore, explicit __GFP_NOWARN combined with GFP_NOWAIT (e.g.,
> > `GFP_NOWAIT | __GFP_NOWARN`) is now redundant.  Let's clean up these
> > redundant flags across subsystems.
> >
> > No functional changes.
> >
> > Reviewed-by: Harry Yoo <harry.yoo@...cle.com>
> > Signed-off-by: Qianfeng Rong <rongqianfeng@...o.com>
> 
> LGTM, I wonder if there are other such redundancies in the kernel?

Looks like theres a lot left for this specific case. At least 48 show up
that are spread out across subsystems when running 'git grep
"GFP_NOWAIT.*GFP_NOWARN"'.

I think they should be cleaned up in sets per-subsystem to minimize
merge conflicts, as suggested in the commit mentioned above (16f5dfbc851b).