From: Shakeel Butt <shakeelb@google.com>
To: SeongJae Park <sj38.park@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
SeongJae Park <sjpark@amazon.de>,
Jonathan.Cameron@huawei.com, acme@kernel.org,
alexander.shishkin@linux.intel.com, amit@kernel.org,
benh@kernel.crashing.org,
Brendan Higgins <brendanhiggins@google.com>,
Jonathan Corbet <corbet@lwn.net>,
David Hildenbrand <david@redhat.com>,
dwmw@amazon.com, Marco Elver <elver@google.com>,
"Du, Fan" <fan.du@intel.com>,
foersleo@amazon.de, greg@kroah.com,
Greg Thelen <gthelen@google.com>,
guoju.fgj@alibaba-inc.com, jgowans@amazon.com,
Mel Gorman <mgorman@suse.de>,
mheyne@amazon.de, Minchan Kim <minchan@kernel.org>,
Ingo Molnar <mingo@redhat.com>,
namhyung@kernel.org,
"Peter Zijlstra (Intel)" <peterz@infradead.org>,
Rik van Riel <riel@surriel.com>,
David Rientjes <rientjes@google.com>,
Steven Rostedt <rostedt@goodmis.org>,
Mike Rapoport <rppt@kernel.org>, Shuah Khan <shuah@kernel.org>,
sieberf@amazon.com, snu@zelle79.org,
Vlastimil Babka <vbabka@suse.cz>,
Vladimir Davydov <vdavydov.dev@gmail.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: [PATCH v31 05/13] mm/damon: Implement primitives for the virtual memory address spaces
Date: Wed, 30 Jun 2021 17:19:06 -0700 [thread overview]
Message-ID: <CALvZod5=Bbih1ryTz33NzDvaKojx=tAj7UF49Eo00B_19-L+fw@mail.gmail.com> (raw)
In-Reply-To: <CALvZod4zE812VjubFKfbTG_jF7-uX5kT48=XQ+2cYxnzsY9-fQ@mail.gmail.com>
On Wed, Jun 30, 2021 at 5:18 PM Shakeel Butt <shakeelb@google.com> wrote:
>
> On Mon, Jun 21, 2021 at 1:31 AM SeongJae Park <sj38.park@gmail.com> wrote:
> >
> > From: SeongJae Park <sjpark@amazon.de>
> >
> > This commit introduces a reference implementation of the address space
> > specific low level primitives for the virtual address space, so that
> > users of DAMON can easily monitor the data accesses on virtual address
> > spaces of specific processes by simply configuring the implementation to
> > be used by DAMON.
> >
> > The low level primitives for the fundamental access monitoring are
> > defined in two parts:
> >
> > 1. Identification of the monitoring target address range for the address
> > space.
> > 2. Access check of specific address range in the target space.
> >
> > The reference implementation for the virtual address space does the
> > works as below.
> >
> > PTE Accessed-bit Based Access Check
> > -----------------------------------
> >
> > The implementation uses PTE Accessed-bit for basic access checks. That
> > is, it clears the bit for the next sampling target page and checks
> > whether it is set again after one sampling period. This could disturb
> > the reclaim logic. DAMON uses ``PG_idle`` and ``PG_young`` page flags
> > to solve the conflict, as Idle page tracking does.
> >
> > VMA-based Target Address Range Construction
> > -------------------------------------------
> >
> > Only small parts in the super-huge virtual address space of the
> > processes are mapped to physical memory and accessed. Thus, tracking
> > the unmapped address regions is just wasteful. However, because DAMON
> > can deal with some level of noise using the adaptive regions adjustment
> > mechanism, tracking every mapping is not strictly required but could
> > even incur a high overhead in some cases. That said, too huge unmapped
> > areas inside the monitoring target should be removed to not take the
> > time for the adaptive mechanism.
> >
> > For the reason, this implementation converts the complex mappings to
> > three distinct regions that cover every mapped area of the address
> > space. Also, the two gaps between the three regions are the two biggest
> > unmapped areas in the given address space. The two biggest unmapped
> > areas would be the gap between the heap and the uppermost mmap()-ed
> > region, and the gap between the lowermost mmap()-ed region and the stack
> > in most of the cases. Because these gaps are exceptionally huge in
> > usual address spaces, excluding these will be sufficient to make a
> > reasonable trade-off. Below shows this in detail::
> >
> > <heap>
> > <BIG UNMAPPED REGION 1>
> > <uppermost mmap()-ed region>
> > (small mmap()-ed regions and munmap()-ed regions)
> > <lowermost mmap()-ed region>
> > <BIG UNMAPPED REGION 2>
> > <stack>
> >
> > Signed-off-by: SeongJae Park <sjpark@amazon.de>
> > Reviewed-by: Leonard Foerster <foersleo@amazon.de>
> > Reviewed-by: Fernand Sieber <sieberf@amazon.com>
>
> Acked-by: Shakeel Butt <shakeelb@google.com>
Ok that was by mistake. The ACK is for v32.
next prev parent reply other threads:[~2021-07-01 0:19 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-21 8:30 [PATCH v31 00/13] Introduce Data Access MONitor (DAMON) SeongJae Park
2021-06-21 8:30 ` [PATCH v31 01/13] mm: " SeongJae Park
2021-06-22 14:59 ` Shakeel Butt
2021-06-24 10:26 ` SeongJae Park
2021-06-24 14:34 ` Shakeel Butt
2021-06-21 8:30 ` [PATCH v31 02/13] mm/damon/core: Implement region-based sampling SeongJae Park
2021-06-22 14:59 ` Shakeel Butt
2021-06-21 8:30 ` [PATCH v31 03/13] mm/damon: Adaptively adjust regions SeongJae Park
2021-06-22 14:59 ` Shakeel Butt
2021-06-24 10:26 ` SeongJae Park
2021-06-21 8:30 ` [PATCH v31 04/13] mm/idle_page_tracking: Make PG_idle reusable SeongJae Park
2021-06-21 8:31 ` [PATCH v31 05/13] mm/damon: Implement primitives for the virtual memory address spaces SeongJae Park
2021-06-22 15:00 ` Shakeel Butt
2021-06-24 10:26 ` SeongJae Park
2021-06-24 14:42 ` Shakeel Butt
2021-06-24 15:21 ` SeongJae Park
2021-06-24 16:33 ` Shakeel Butt
2021-06-24 17:38 ` SeongJae Park
2021-07-01 0:18 ` Shakeel Butt
2021-07-01 0:19 ` Shakeel Butt [this message]
2021-06-21 8:31 ` [PATCH v31 06/13] mm/damon: Add a tracepoint SeongJae Park
2021-06-22 15:01 ` Shakeel Butt
2021-06-21 8:31 ` [PATCH v31 07/13] mm/damon: Implement a debugfs-based user space interface SeongJae Park
2021-06-22 18:12 ` Shakeel Butt
2021-06-24 10:26 ` SeongJae Park
2021-06-24 14:52 ` Shakeel Butt
2021-06-21 8:31 ` [PATCH v31 08/13] mm/damon/dbgfs: Export kdamond pid to the user space SeongJae Park
2021-06-22 18:23 ` Shakeel Butt
2021-06-24 10:26 ` SeongJae Park
2021-06-21 8:31 ` [PATCH v31 09/13] mm/damon/dbgfs: Support multiple contexts SeongJae Park
2021-06-21 8:31 ` [PATCH v31 10/13] Documentation: Add documents for DAMON SeongJae Park
2021-06-21 8:31 ` [PATCH v31 11/13] mm/damon: Add kunit tests SeongJae Park
2021-06-21 8:31 ` [PATCH v31 12/13] mm/damon: Add user space selftests SeongJae Park
2021-06-21 8:31 ` [PATCH v31 13/13] MAINTAINERS: Update for DAMON SeongJae Park
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='CALvZod5=Bbih1ryTz33NzDvaKojx=tAj7UF49Eo00B_19-L+fw@mail.gmail.com' \
--to=shakeelb@google.com \
--cc=Jonathan.Cameron@huawei.com \
--cc=acme@kernel.org \
--cc=akpm@linux-foundation.org \
--cc=alexander.shishkin@linux.intel.com \
--cc=amit@kernel.org \
--cc=benh@kernel.crashing.org \
--cc=brendanhiggins@google.com \
--cc=corbet@lwn.net \
--cc=david@redhat.com \
--cc=dwmw@amazon.com \
--cc=elver@google.com \
--cc=fan.du@intel.com \
--cc=foersleo@amazon.de \
--cc=greg@kroah.com \
--cc=gthelen@google.com \
--cc=guoju.fgj@alibaba-inc.com \
--cc=jgowans@amazon.com \
--cc=linux-damon@amazon.com \
--cc=linux-doc@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mgorman@suse.de \
--cc=mheyne@amazon.de \
--cc=minchan@kernel.org \
--cc=mingo@redhat.com \
--cc=namhyung@kernel.org \
--cc=peterz@infradead.org \
--cc=riel@surriel.com \
--cc=rientjes@google.com \
--cc=rostedt@goodmis.org \
--cc=rppt@kernel.org \
--cc=shuah@kernel.org \
--cc=sieberf@amazon.com \
--cc=sj38.park@gmail.com \
--cc=sjpark@amazon.de \
--cc=snu@zelle79.org \
--cc=vbabka@suse.cz \
--cc=vdavydov.dev@gmail.com \
--cc=zgf574564920@gmail.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).