From: Peter Zijlstra <peterz@infradead.org>
To: Mel Gorman <mgorman@techsingularity.net>
Cc: SeongJae Park <sjpark@amazon.com>,
"Huang, Ying" <ying.huang@intel.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Ingo Molnar <mingo@redhat.com>, Mel Gorman <mgorman@suse.de>,
Rik van Riel <riel@surriel.com>,
Daniel Jordan <daniel.m.jordan@oracle.com>,
Tejun Heo <tj@kernel.org>, Dave Hansen <dave.hansen@intel.com>,
Tim Chen <tim.c.chen@intel.com>, Aubrey Li <aubrey.li@intel.com>
Subject: Re: Re: Re: [RFC] autonuma: Support to scan page table asynchronously
Date: Fri, 17 Apr 2020 14:21:48 +0200 [thread overview]
Message-ID: <20200417122148.GC20730@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20200417121629.GA3758@techsingularity.net>
On Fri, Apr 17, 2020 at 01:16:29PM +0100, Mel Gorman wrote:
> On Fri, Apr 17, 2020 at 12:21:29PM +0200, SeongJae Park wrote:
> > On Fri, 17 Apr 2020 12:04:17 +0200 Peter Zijlstra <peterz@infradead.org> wrote:
> >
> > > On Fri, Apr 17, 2020 at 09:05:08AM +0200, SeongJae Park wrote:
> > > > I think the main idea of DAMON[1] might be able to applied here. Have you
> > > > considered it?
> > > >
> > > > [1] https://lore.kernel.org/linux-mm/20200406130938.14066-1-sjpark@amazon.com/
> > >
> > > I've ignored that entire thing after you said the information it
> > > provides was already available through the PMU.
> >
> > Sorry if my answer made you confused. What I wanted to say was that the
> > fundamental access checking mechanism that DAMON depends on is PTE Accessed bit
> > for now, but it could be modified to use PMU or other features instead.
>
> I would not be inclined to lean towards either approach for NUMA
> balancing. Fiddling with the accessed bit can have consequences for page
> aging and residency -- fine for debugging a problem, not to fine for
> normal usage. I would expect the PMU approach would have high overhead
> as well as taking over a PMU counter that userspace debugging may expect
> to be available.
Oh, quite agreed; I was just saying I never saw the use of that whole
DAMON thing. AFAICT it's not actually solving a problem, just making
more.
next prev parent reply other threads:[~2020-04-17 12:21 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-14 8:19 [RFC] autonuma: Support to scan page table asynchronously Huang Ying
2020-04-14 12:06 ` Mel Gorman
2020-04-15 8:14 ` Huang, Ying
2020-04-17 7:05 ` SeongJae Park
2020-04-17 10:04 ` Peter Zijlstra
2020-04-17 10:21 ` SeongJae Park
2020-04-17 12:16 ` Mel Gorman
2020-04-17 12:21 ` Peter Zijlstra [this message]
2020-04-17 12:44 ` SeongJae Park
2020-04-17 14:46 ` Mel Gorman
2020-04-18 9:48 ` SeongJae Park
2020-04-20 2:32 ` Huang, Ying
2020-04-15 11:32 ` Peter Zijlstra
2020-04-16 1:24 ` Huang, Ying
2020-04-17 10:06 ` Peter Zijlstra
2020-04-20 3:26 ` Huang, Ying
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200417122148.GC20730@hirez.programming.kicks-ass.net \
--to=peterz@infradead.org \
--cc=aubrey.li@intel.com \
--cc=daniel.m.jordan@oracle.com \
--cc=dave.hansen@intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mgorman@suse.de \
--cc=mgorman@techsingularity.net \
--cc=mingo@redhat.com \
--cc=riel@surriel.com \
--cc=sjpark@amazon.com \
--cc=tim.c.chen@intel.com \
--cc=tj@kernel.org \
--cc=ying.huang@intel.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).