From: Jann Horn <jannh@google.com>
To: Prakash Sangappa <prakash.sangappa@oracle.com>
Cc: Dave Hansen <dave.hansen@intel.com>,
Anshuman Khandual <khandual@linux.vnet.ibm.com>,
Andrew Morton <akpm@linux-foundation.org>,
kernel list <linux-kernel@vger.kernel.org>,
Linux-MM <linux-mm@kvack.org>,
Linux API <linux-api@vger.kernel.org>,
Michal Hocko <mhocko@suse.com>,
"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
n-horiguchi@ah.jp.nec.com, drepper@gmail.com,
rientjes@google.com, nao.horiguchi@gmail.com,
steven.sistare@oracle.com
Subject: Re: [RFC PATCH] Add /proc/<pid>/numa_vamaps for numa node information
Date: Fri, 14 Sep 2018 03:33:28 +0200 [thread overview]
Message-ID: <CAG48ez1YhHKTDHZoH2tEFaLk4LcCSw5G60=+KpGRaMQxvw1qLw@mail.gmail.com> (raw)
In-Reply-To: <94ee0b6c-4663-0705-d4a8-c50342f6b483@oracle.com>
On Wed, Sep 12, 2018 at 10:43 PM prakash.sangappa
<prakash.sangappa@oracle.com> wrote:
> On 05/09/2018 04:31 PM, Dave Hansen wrote:
> > On 05/07/2018 06:16 PM, prakash.sangappa wrote:
> >> It will be /proc/<pid>/numa_vamaps. Yes, the behavior will be
> >> different with respect to seeking. Output will still be text and
> >> the format will be same.
> >>
> >> I want to get feedback on this approach.
> > I think it would be really great if you can write down a list of the
> > things you actually want to accomplish. Dare I say: you need a
> > requirements list.
> >
> > The numa_vamaps approach continues down the path of an ever-growing list
> > of highly-specialized /proc/<pid> files. I don't think that is
> > sustainable, even if it has been our trajectory for many years.
> >
> > Pagemap wasn't exactly a shining example of us getting new ABIs right,
> > but it sounds like something along those is what we need.
>
> Just sent out a V2 patch. This patch simplifies the file content. It
> only provides VA range to numa node id information.
>
> The requirement is basically observability for performance analysis.
>
> - Need to be able to determine VA range to numa node id information.
> Which also gives an idea of which range has memory allocated.
>
> - The proc file /proc/<pid>/numa_vamaps is in text so it is easy to
> directly view.
>
> The V2 patch supports seeking to a particular process VA from where
> the application could read the VA to numa node id information.
>
> Also added the 'PTRACE_MODE_READ_REALCREDS' check when opening the
> file /proc file as was indicated by Michal Hacko
procfs files should use PTRACE_MODE_*_FSCREDS, not PTRACE_MODE_*_REALCREDS.
next prev parent reply other threads:[~2018-09-14 1:33 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-02 5:58 [RFC PATCH] Add /proc/<pid>/numa_vamaps for numa node information Prakash Sangappa
2018-05-02 21:33 ` Andrew Morton
2018-05-02 22:28 ` Dave Hansen
2018-05-02 23:17 ` prakash.sangappa
2018-05-03 8:46 ` Anshuman Khandual
2018-05-03 22:27 ` prakash.sangappa
2018-05-03 22:26 ` Dave Hansen
2018-05-07 23:22 ` prakash.sangappa
2018-05-08 0:05 ` Dave Hansen
2018-05-08 1:16 ` prakash.sangappa
2018-05-09 23:31 ` Dave Hansen
2018-09-12 20:42 ` prakash.sangappa
2018-09-12 20:57 ` prakash.sangappa
2018-09-14 1:33 ` Jann Horn [this message]
2018-09-14 6:21 ` Michal Hocko
2018-09-14 12:49 ` Jann Horn
2018-09-14 13:49 ` Michal Hocko
2018-09-14 18:07 ` Prakash Sangappa
2018-09-14 18:14 ` Jann Horn
2018-05-02 23:43 ` prakash.sangappa
2018-05-03 8:57 ` Michal Hocko
2018-05-03 22:37 ` prakash.sangappa
2018-05-04 11:10 ` Michal Hocko
2018-05-03 18:03 ` Christopher Lameter
2018-05-03 22:39 ` prakash.sangappa
2018-05-04 11:12 ` Michal Hocko
2018-05-04 16:18 ` Prakash Sangappa
2018-05-10 7:42 ` Michal Hocko
2018-05-10 16:00 ` Prakash Sangappa
2018-05-11 6:39 ` Michal Hocko
2018-05-04 14:57 ` Christopher Lameter
2018-05-04 16:27 ` Prakash Sangappa
2018-05-07 14:47 ` Christopher Lameter
2018-05-07 22:50 ` prakash.sangappa
2018-05-08 12:53 ` Christopher Lameter
2018-09-12 23:02 Alexey Dobriyan
2018-09-13 22:17 ` prakash.sangappa
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