From: Shakeel Butt <shakeelb@google.com>
To: SeongJae Park <sjpark@amazon.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
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, Marco Elver <elver@google.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 <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>,
Mike Rapoport <rppt@kernel.org>,
sblbir@amazon.com, Shuah Khan <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: [PATCH v22 07/18] mm/page_idle: Avoid interferences from concurrent users
Date: Wed, 25 Nov 2020 07:30:27 -0800 [thread overview]
Message-ID: <CALvZod7xhyp6yY_v6nyWp-yqHQUCtCBcxFXz=fSKOjS62HrG-A@mail.gmail.com> (raw)
In-Reply-To: <20201020085940.13875-8-sjpark@amazon.com>
On Tue, Oct 20, 2020 at 2:06 AM SeongJae Park <sjpark@amazon.com> wrote:
>
> From: SeongJae Park <sjpark@amazon.de>
>
> Concurrent Idle Page Tracking users can interfere each other because the
> interface doesn't provide a central rule for synchronization between the
> users. Users could implement their own synchronization rule, but even
> in that case, applications developed by different users would not know
> how to synchronize with others. To help this situation, this commit
> introduces a centralized synchronization infrastructure of Idle Page
> Tracking.
>
> In detail, this commit introduces a mutex lock for Idle Page Tracking,
> called 'page_idle_lock'. It is exposed to user space via a new bool
> sysfs file, '/sys/kernel/mm/page_idle/lock'. By writing to and reading
> from the file, users can hold/release and read status of the mutex.
> Writes to the Idle Page Tracking 'bitmap' file fails if the lock is not
> held, while reads of the file can be done regardless of the lock status.
>
> Note that users could still interfere each other if they abuse this
> locking rule. Nevertheless, this change will let them notice the rule.
>
> Signed-off-by: SeongJae Park <sjpark@amazon.de>
I don't think this is allowed. I mean returning to user space with
held mutex and other processes can unlock it. I don't think mutex is
what you need. Or more importantly is this really an issue?
next prev parent reply other threads:[~2020-11-25 15:30 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-20 8:59 [PATCH v22 00/18] Introduce Data Access MONitor (DAMON) SeongJae Park
2020-10-20 8:59 ` [PATCH v22 01/18] mm: " SeongJae Park
2020-11-25 15:29 ` Shakeel Butt
2020-11-26 11:51 ` SeongJae Park
2020-12-08 7:41 ` SeongJae Park
2020-10-20 8:59 ` [PATCH v22 02/18] mm/damon: Implement region based sampling SeongJae Park
2020-11-25 15:29 ` Shakeel Butt
2020-11-26 12:09 ` SeongJae Park
2020-10-20 8:59 ` [PATCH v22 03/18] mm/damon: Adaptively adjust regions SeongJae Park
2020-11-25 15:29 ` Shakeel Butt
2020-11-26 12:12 ` SeongJae Park
2020-10-20 8:59 ` [PATCH v22 04/18] mm/damon: Track dynamic monitoring target regions update SeongJae Park
2020-11-25 15:29 ` Shakeel Butt
2020-11-26 12:18 ` SeongJae Park
2020-10-20 8:59 ` [PATCH v22 05/18] mm/idle_page_tracking: Make PG_(idle|young) reusable SeongJae Park
2020-11-25 15:30 ` Shakeel Butt
2020-11-26 12:31 ` SeongJae Park
2020-10-20 8:59 ` [PATCH v22 06/18] mm/damon: Implement primitives for the virtual memory address spaces SeongJae Park
2020-11-25 15:30 ` Shakeel Butt
2020-11-26 13:34 ` SeongJae Park
2020-10-20 8:59 ` [PATCH v22 07/18] mm/page_idle: Avoid interferences from concurrent users SeongJae Park
2020-11-25 15:30 ` Shakeel Butt [this message]
2020-11-26 13:37 ` SeongJae Park
2020-10-20 8:59 ` [PATCH v22 08/18] mm/damon/primitives: Make coexistable with Idle Page Tracking SeongJae Park
2020-10-20 8:59 ` [PATCH v22 09/18] mm/damon: Add a tracepoint SeongJae Park
2020-10-20 8:59 ` [PATCH v22 10/18] mm/damon: Implement a debugfs-based user space interface SeongJae Park
2020-11-25 15:30 ` Shakeel Butt
2020-11-26 13:45 ` SeongJae Park
2020-10-20 8:59 ` [PATCH v22 11/18] mm/damon/dbgfs: Implement recording feature SeongJae Park
2020-10-20 8:59 ` [PATCH v22 12/18] mm/damon/dbgfs: Export kdamond pid to the user space SeongJae Park
2020-10-20 8:59 ` [PATCH v22 13/18] mm/damon/dbgfs: Support multiple contexts SeongJae Park
2020-10-20 8:59 ` [PATCH v22 14/18] tools: Introduce a minimal user-space tool for DAMON SeongJae Park
2020-10-20 8:59 ` [PATCH v22 15/18] Documentation: Add documents " SeongJae Park
2020-10-20 8:59 ` [PATCH v22 16/18] mm/damon: Add kunit tests SeongJae Park
2020-10-20 8:59 ` [PATCH v22 17/18] mm/damon: Add user space selftests SeongJae Park
2020-10-20 8:59 ` [PATCH v22 18/18] MAINTAINERS: Update for DAMON SeongJae Park
2020-11-11 16:41 ` [PATCH v22 00/18] Introduce Data Access MONitor (DAMON) SeongJae Park
2020-11-17 8:05 ` SeongJae Park
2020-11-17 14:30 ` SeongJae Park
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