Received-SPF: pass (google.com: domain of linux-kernel+bounces-206117-linux.lists.archive=gmail.com@vger.kernel.org designates 139.178.88.99 as permitted sender) client-ip=139.178.88.99;
From: Oscar Salvador <osalvador@suse.com>
Date: Fri, 7 Jun 2024 15:18:40 +0200
To: David Hildenbrand <david@redhat.com>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	linux-doc@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	Andrew Morton <akpm@linux-foundation.org>,
	Jonathan Corbet <corbet@lwn.net>
Subject: Re: [PATCH v1 0/6] fs/proc: move page_mapcount() to
 fs/proc/internal.h
Message-ID: <ZmMIsJ4Yg2r9bT81@localhost.localdomain>
References: <20240607122357.115423-1-david@redhat.com>
Precedence: bulk
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20240607122357.115423-1-david@redhat.com>

On Fri, Jun 07, 2024 at 02:23:51PM +0200, David Hildenbrand wrote:
> With all other page_mapcount() users in the tree gone, move
> page_mapcount() to fs/proc/internal.h, rename it and extend the
> documentation to prevent future (ab)use.
> 
> ... of course, I find some issues while working on that code that I sort
> first ;)
> 
> We'll now only end up calling page_mapcount()
> [now folio_precise_page_mapcount()] on pages mapped via present page table
> entries. Except for /proc/kpagecount, that still does questionable things,
> but we'll leave that legacy interface as is for now.
> 
> Did a quick sanity check. Likely we would want some better selfestest
> for /proc/$/pagemap + smaps. I'll see if I can find some time to write
> some more.

I stumbled upon some of these issues while unifying .{pud/pmd}_entry and
.hugetlb_entry.
I am not sure what is the current state of pagemap/smaps selftest, but
since I am going to need them anyway to keep me in check and making sure
I do not break anything hugetlb-related, I might as well write some of
them.


-- 
Oscar Salvador
SUSE Labs