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Date: Tue, 26 Mar 2024 16:43:20 -0400
From: Peter Xu <peterx@redhat.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	SeongJae Park <sj@kernel.org>, Jason Gunthorpe <jgg@nvidia.com>,
	Mike Rapoport <rppt@kernel.org>,
	Matthew Wilcox <willy@infradead.org>,
	kernel test robot <lkp@intel.com>
Subject: Re: [PATCH] mm/arch: Provide pud_pfn() fallback
Message-ID: <ZgMzaMu7oILiNLcG@x1n>
References: <20240323151643.1047281-1-peterx@redhat.com>
 <20240326132726.67e82559a928ac1636c8050c@linux-foundation.org>
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On Tue, Mar 26, 2024 at 01:27:26PM -0700, Andrew Morton wrote:
> On Sat, 23 Mar 2024 11:16:43 -0400 peterx@redhat.com wrote:
> 
> > From: Peter Xu <peterx@redhat.com>
> > 
> > The comment in the code explains the reasons.  We took a different approach
> > comparing to pmd_pfn() by providing a fallback function.
> > 
> > Another option is to provide some lower level config options (compare to
> > HUGETLB_PAGE or THP) to identify which layer an arch can support for such
> > huge mappings.  However that can be an overkill.
> > 
> > ...
> >
> > If we care about per-commit build errors (and if it is ever feasible to
> > reorder), we can move this patch to be before the patch "mm/gup: handle
> > huge pud for follow_pud_mask()" in mm-unstable to unbreak build on that
> > commit.
> 
> I temporarily disabled that whole series a few days ago.  Because of
> multiple build issues, iirc.
> 
> Let's make that permanent.  Please redo the whole series against
> mm-unstable and resend?

Yes, that's the plan.  Feel free to ignore this as this is not used until
that GUP rework series, I'll include it in the whole set to be reposted.

I'm currently doing the build tests; just finished writting the harness for
testing the matrix.  It'll take a bit time to run through the tests I
specified (I tried to cover a few more archs/configs), and I'll repost with
all patches included (fixups squashed) when test finished.

[side note: I think I can reproduce the other not-reported issue, on
 arm+alldefconfig; that'll get covered too]

Thanks,

-- 
Peter Xu