From: Shakeel Butt <shakeelb@google.com>
To: SeongJae Park <sjpark@amazon.com>
Cc: SeongJae Park <sjpark@amazon.de>,
Jonathan.Cameron@huawei.com,
Andrea Arcangeli <aarcange@redhat.com>,
acme@kernel.org, alexander.shishkin@linux.intel.com,
amit@kernel.org, benh@kernel.crashing.org,
brendan.d.gregg@gmail.com,
Brendan Higgins <brendanhiggins@google.com>,
Qian Cai <cai@lca.pw>, Colin Ian King <colin.king@canonical.com>,
Jonathan Corbet <corbet@lwn.net>,
David Hildenbrand <david@redhat.com>,
dwmw@amazon.com, "Du, Fan" <fan.du@intel.com>,
foersleo@amazon.de, Greg Thelen <gthelen@google.com>,
Ian Rogers <irogers@google.com>,
jolsa@redhat.com, "Kirill A. Shutemov" <kirill@shutemov.name>,
mark.rutland@arm.com, Mel Gorman <mgorman@suse.de>,
Minchan Kim <minchan@kernel.org>, Ingo Molnar <mingo@redhat.com>,
namhyung@kernel.org,
"Peter Zijlstra (Intel)" <peterz@infradead.org>,
Randy Dunlap <rdunlap@infradead.org>,
Rik van Riel <riel@surriel.com>,
David Rientjes <rientjes@google.com>,
Steven Rostedt <rostedt@goodmis.org>,
rppt@kernel.org, sblbir@amazon.com, shuah@kernel.org,
sj38.park@gmail.com, snu@amazon.de,
Vlastimil Babka <vbabka@suse.cz>,
Vladimir Davydov <vdavydov.dev@gmail.com>,
Yang Shi <yang.shi@linux.alibaba.com>,
Huang Ying <ying.huang@intel.com>,
zgf574564920@gmail.com, linux-damon@amazon.com,
Linux MM <linux-mm@kvack.org>,
linux-doc@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>
Subject: Re: [RFC v7 00/10] DAMON: Support Physical Memory Address Space Monitoring
Date: Thu, 20 Aug 2020 08:44:33 -0700 [thread overview]
Message-ID: <CALvZod7a=zr8VX3T2KOheUJ-THjGz=O+JBdcjw4iraN3m9jSJg@mail.gmail.com> (raw)
In-Reply-To: <20200820071052.24271-1-sjpark@amazon.com>
On Thu, Aug 20, 2020 at 12:11 AM SeongJae Park <sjpark@amazon.com> wrote:
>
> On Wed, 19 Aug 2020 18:21:44 -0700 Shakeel Butt <shakeelb@google.com> wrote:
>
> > On Tue, Aug 18, 2020 at 12:25 AM SeongJae Park <sjpark@amazon.com> wrote:
> > >
> > > From: SeongJae Park <sjpark@amazon.de>
> > >
> > > Changes from Previous Version
> > > =============================
> > >
> > > - Use 42 as the fake target id for paddr instead of -1
> > > - Fix a typo
> > >
> > > Introduction
> > > ============
> > >
> > > DAMON[1] programming interface users can extend DAMON for any address space by
> > > configuring the address-space specific low level primitives with appropriate
> > > ones including their own implementations. However, because the implementation
> > > for the virtual address space is only available now, the users should implement
> > > their own for other address spaces. Worse yet, the user space users who rely
> > > on the debugfs interface and user space tool, cannot implement their own.
> > >
> > > This patchset implements another reference implementation of the low level
> > > primitives for the physical memory address space. With this change, hence, the
> > > kernel space users can monitor both the virtual and the physical address spaces
> > > by simply changing the configuration in the runtime. Further, this patchset
> > > links the implementation to the debugfs interface and the user space tool for
> > > the user space users.
> > >
> > > Note that the implementation supports only the user memory, as same to the idle
> > > page access tracking feature.
> > >
> > > [1] https://lore.kernel.org/linux-mm/20200706115322.29598-1-sjpark@amazon.com/
> > >
> >
> > I am still struggling to find the benefit of this feature the way it
> > is implemented i.e. region based physical address space monitoring.
> > What exactly am I supposed to do for a given hot (or cold) physical
> > region? In a containerized world, that region can contain pages from
> > any cgroup. I can not really do anything about the accesses PHY-DAMON
> > provides me for a region.
>
> Technically speaking, this patchset introduces an implementation of DAMON's low
> level primitives for physical address space of LRU-listed pages. In other
> words, it is not designed for cgroups case.
So, this RFC is for a system running a single workload which comprises
multiple processes. Instead of registering each process with DAMON,
just monitor the whole physical memory, right?
Though I am still not sure how the output from DAMON can be used in
this case. DAMON told me a physical region is cold, how do I find out
processes that have mapped the pages in that region to do
process_madvise(PAGEOUT) on them?
next prev parent reply other threads:[~2020-08-20 15:44 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-18 7:24 [RFC v7 00/10] DAMON: Support Physical Memory Address Space Monitoring SeongJae Park
2020-08-18 7:24 ` [RFC v7 01/10] mm/damon/debugfs: Allow users to set initial monitoring target regions SeongJae Park
2020-08-18 7:24 ` [RFC v7 02/10] tools/damon: Support init target regions specification SeongJae Park
2020-08-18 7:24 ` [RFC v7 03/10] mm/damon-test: Add more unit tests for 'init_regions' SeongJae Park
2020-08-18 19:22 ` Brendan Higgins
2020-08-18 7:24 ` [RFC v7 04/10] selftests/damon/_chk_record: Do not check number of gaps SeongJae Park
2020-08-18 7:24 ` [RFC v7 05/10] Docs/admin-guide/mm/damon: Document 'init_regions' feature SeongJae Park
2020-08-18 7:24 ` [RFC v7 06/10] mm/damon: Implement callbacks for physical memory monitoring SeongJae Park
2020-08-20 0:26 ` Shakeel Butt
2020-08-20 7:16 ` SeongJae Park
2020-08-20 13:26 ` Shakeel Butt
2020-08-20 14:28 ` SeongJae Park
2020-08-28 8:11 ` Alkaid
2020-08-28 9:53 ` SeongJae Park
2020-08-28 11:39 ` SeongJae Park
2020-08-18 7:24 ` [RFC v7 07/10] mm/damon/debugfs: Support " SeongJae Park
2020-08-18 7:24 ` [RFC v7 08/10] tools/damon/record: " SeongJae Park
2020-08-18 7:25 ` [RFC v7 09/10] tools/damon/record: Support NUMA specific recording SeongJae Park
2020-08-18 7:25 ` [RFC v7 10/10] Docs/DAMON: Document physical memory monitoring support SeongJae Park
2020-08-20 1:21 ` [RFC v7 00/10] DAMON: Support Physical Memory Address Space Monitoring Shakeel Butt
2020-08-20 7:10 ` SeongJae Park
2020-08-20 15:44 ` Shakeel Butt [this message]
2020-08-20 17:33 ` SeongJae Park
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