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Date:   Thu, 23 Nov 2023 11:05:42 -0500
From:   Peter Xu <peterx@redhat.com>
To:     Christoph Hellwig <hch@infradead.org>
Cc:     linux-kernel@vger.kernel.org, linux-mm@kvack.org,
        Mike Kravetz <mike.kravetz@oracle.com>,
        "Kirill A . Shutemov" <kirill@shutemov.name>,
        Lorenzo Stoakes <lstoakes@gmail.com>,
        Axel Rasmussen <axelrasmussen@google.com>,
        Matthew Wilcox <willy@infradead.org>,
        John Hubbard <jhubbard@nvidia.com>,
        Mike Rapoport <rppt@kernel.org>,
        Hugh Dickins <hughd@google.com>,
        David Hildenbrand <david@redhat.com>,
        Andrea Arcangeli <aarcange@redhat.com>,
        Rik van Riel <riel@surriel.com>,
        James Houghton <jthoughton@google.com>,
        Yang Shi <shy828301@gmail.com>,
        Jason Gunthorpe <jgg@nvidia.com>,
        Vlastimil Babka <vbabka@suse.cz>,
        Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH RFC 01/12] mm/hugetlb: Export
 hugetlbfs_pagecache_present()
Message-ID: <ZV94VsUOE34B1H-i@x1n>
References: <20231116012908.392077-1-peterx@redhat.com>
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 <ZV7923j4gQOZYAqe@infradead.org>
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On Wed, Nov 22, 2023 at 11:23:07PM -0800, Christoph Hellwig wrote:
> You're (thankfully) not actually exporting anything, so please
> don't claim that in the subject.

Ah, I'll rename the subject to "mm/hugetlb: Declare
hugetlbfs_pagecache_present() non-static".

> 
> >  pte_t *huge_pmd_share(struct mm_struct *mm, struct vm_area_struct *vma,
> >  		      unsigned long addr, pud_t *pud);
> > +bool hugetlbfs_pagecache_present(struct hstate *h,
> > +				 struct vm_area_struct *vma,
> > +				 unsigned long address);
> 
> Can you just follow the much more readable two tab indent of the
> function above?
> 
> > -static bool hugetlbfs_pagecache_present(struct hstate *h,
> > -			struct vm_area_struct *vma, unsigned long address)
> > +bool hugetlbfs_pagecache_present(struct hstate *h,
> > +				 struct vm_area_struct *vma, unsigned long address)
> 
> Same here.  The new indentation not only is less readable but also
> creates a pointlessly overlong line.

I can easily follow what you suggest for this single patch, but afaict the
kernel doesn't document that in the style guide.

https://www.kernel.org/doc/html/v4.10/process/coding-style.html#functions

And the reality is at least across mm codes it's used in a mixture of ways,
even more than these two major forms of indentations.

To be explicit, I think 2-tab is Vim's default, while this patch follows
Emacs's c-mode default.  It means if this patch indents wrongly, probably
99% of Emacs users are doomed. :(

Before we have a clear and thorough rule over this, shall we just allow
either sane indent to still be accepted?  Or maybe there's some rule that I
have missed?  Personally I actually prefer Emacs's indentations to align
with left bracket, but that's just subjective so doesn't count.

Thanks,

-- 
Peter Xu