From: Michal Hocko <mhocko@suse.com>
To: Xiongwei Song <sxwjean@gmail.com>
Cc: Xiongwei Song <sxwjean@me.com>,
akpm@linux-foundation.org, David Hildenbrand <david@redhat.com>,
dan.j.williams@intel.com, osalvador@suse.de,
naoya.horiguchi@nec.com, thunder.leizhen@huawei.com,
linux-mm@kvack.org, linux-fsdevel@vger.kernel.org,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v3 2/2] proc: Add getting pages info of ZONE_DEVICE support
Date: Fri, 14 Jan 2022 11:18:45 +0100 [thread overview]
Message-ID: <YeFOBWz1OZTpEuwt@dhcp22.suse.cz> (raw)
In-Reply-To: <CAEVVKH-L-6Yra75XEWUNiq=ajJmtWauDTcmN=b1VCcJ0NVS7OA@mail.gmail.com>
On Fri 14-01-22 18:03:04, Xiongwei Song wrote:
> HI Michal,
>
> On Thu, Jan 13, 2022 at 11:31 PM Michal Hocko <mhocko@suse.com> wrote:
> >
> > On Wed 12-01-22 22:35:17, sxwjean@me.com wrote:
> > > From: Xiongwei Song <sxwjean@gmail.com>
> > >
> > > When requesting pages info by /proc/kpage*, the pages in ZONE_DEVICE were
> > > ignored.
> > >
> > > The pfn_to_devmap_page() function can help to get page that belongs to
> > > ZONE_DEVICE.
> >
> > Why is this needed? Who would consume that information and what for?
>
> It's for debug purpose, which checks page flags in system wide. No any other
> special thought. But it looks like it's not appropriate to expose now from my
> understand, which is from David's comment.
> https://lore.kernel.org/linux-mm/20220110141957.259022-1-sxwjean@me.com/T/#m4eccbb2698dbebc80ec00be47382b34b0f64b4fc
yes, I do agree with David. This is the reason I am asking because I do
remember we have deliberately excluded those pages. If there is no real
user to use that information then I do not think we want to make the
code more complex and check for memmap and other peculiarities.
Thanks!
--
Michal Hocko
SUSE Labs
prev parent reply other threads:[~2022-01-14 10:18 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-12 14:35 [PATCH v3 0/2] Add support for getting page info of ZONE_DEVICE by /proc/kpage* sxwjean
2022-01-12 14:35 ` [PATCH v3 1/2] mm/memremap.c: Add pfn_to_devmap_page() to get page in ZONE_DEVICE sxwjean
2022-01-12 14:35 ` [PATCH v3 2/2] proc: Add getting pages info of ZONE_DEVICE support sxwjean
2022-01-13 15:31 ` Michal Hocko
2022-01-14 10:03 ` Xiongwei Song
2022-01-14 10:18 ` Michal Hocko [this message]
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