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From: SeongJae Park <sjpark@amazon.com>
To: SeongJae Park <sj38.park@gmail.com>
Cc: Jonathan Cameron <Jonathan.Cameron@Huawei.com>,
	SeongJae Park <sjpark@amazon.com>, <akpm@linux-foundation.org>,
	SeongJae Park <sjpark@amazon.de>, <aarcange@redhat.com>,
	<yang.shi@linux.alibaba.com>, <acme@kernel.org>,
	<alexander.shishkin@linux.intel.com>, <amit@kernel.org>,
	<brendan.d.gregg@gmail.com>, <brendanhiggins@google.com>,
	<cai@lca.pw>, <colin.king@canonical.com>, <corbet@lwn.net>,
	<dwmw@amazon.com>, <jolsa@redhat.com>, <kirill@shutemov.name>,
	<mark.rutland@arm.com>, <mgorman@suse.de>, <minchan@kernel.org>,
	<mingo@redhat.com>, <namhyung@kernel.org>, <peterz@infradead.org>,
	<rdunlap@infradead.org>, <rientjes@google.com>,
	<rostedt@goodmis.org>, <shuah@kernel.org>, <vbabka@suse.cz>,
	<vdavydov.dev@gmail.com>, <linux-mm@kvack.org>,
	<linux-doc@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Subject: Re: Re: Re: [PATCH v6 02/14] mm/damon: Implement region based sampling
Date: Tue, 17 Mar 2020 12:32:05 +0100
Message-ID: <20200317113205.3617-1-sjpark@amazon.com> (raw)
In-Reply-To: <20200313201649.26646-1-sj38.park@gmail.com> (raw)

On Fri, 13 Mar 2020 21:16:49 +0100 SeongJae Park <sj38.park@gmail.com> wrote:

> On Fri, 13 Mar 2020 17:29:54 +0000 Jonathan Cameron <Jonathan.Cameron@Huawei.com> wrote:
> 
> > On Mon, 24 Feb 2020 13:30:35 +0100
> > SeongJae Park <sjpark@amazon.com> wrote:
> > 
> > > From: SeongJae Park <sjpark@amazon.de>
> > > 
> > > This commit implements DAMON's basic access check and region based
> > > sampling mechanisms.  This change would seems make no sense, mainly
> > > because it is only a part of the DAMON's logics.  Following two commits
> > > will make more sense.
> > > 
> [...]
> > 
> > Came across a minor issue inline.  kthread_run calls kthread_create.
> > That gives a potential sleep while atomic issue given the spin lock.
> > 
> > Can probably be fixed by preallocating the thread then starting it later.
> > 
> > Jonathan
> [...]
> > > +/*
> > > + * Start or stop the kdamond
> > > + *
> > > + * Returns 0 if success, negative error code otherwise.
> > > + */
> > > +static int damon_turn_kdamond(struct damon_ctx *ctx, bool on)
> > > +{
> > > +	spin_lock(&ctx->kdamond_lock);
> > > +	ctx->kdamond_stop = !on;
> > > +	if (!ctx->kdamond && on) {
> > > +		ctx->kdamond = kthread_run(kdamond_fn, ctx, "kdamond");
> > 
> > Can't do this under a spin lock.
> 
> Good catch!  And, agree to your suggestion.  I will fix this in that way!

I changed my mind.  I would like to simply use mutex instead of spinlock, as
khugepaged also does.  If you have different opinion, please let me know.


Thanks,
SeongJae Park

> 
> 
> Thanks,
> SeongJae Park


  reply index

Thread overview: 51+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-24 12:30 [PATCH v6 00/14] Introduce Data Access MONitor (DAMON) SeongJae Park
2020-02-24 12:30 ` [PATCH v6 01/14] mm: " SeongJae Park
2020-03-10  8:54   ` Jonathan Cameron
2020-03-10 11:50     ` SeongJae Park
2020-02-24 12:30 ` [PATCH v6 02/14] mm/damon: Implement region based sampling SeongJae Park
2020-03-10  8:57   ` Jonathan Cameron
2020-03-10 11:52     ` SeongJae Park
2020-03-10 15:55       ` Jonathan Cameron
2020-03-10 16:22         ` SeongJae Park
2020-03-10 17:39           ` Jonathan Cameron
2020-03-12  9:20             ` SeongJae Park
2020-03-13 17:29   ` Jonathan Cameron
2020-03-13 20:16     ` SeongJae Park
2020-03-17 11:32       ` SeongJae Park [this message]
2020-02-24 12:30 ` [PATCH v6 03/14] mm/damon: Adaptively adjust regions SeongJae Park
2020-03-10  8:57   ` Jonathan Cameron
2020-03-10 11:53     ` SeongJae Park
2020-02-24 12:30 ` [PATCH v6 04/14] mm/damon: Apply dynamic memory mapping changes SeongJae Park
2020-03-10  9:00   ` Jonathan Cameron
2020-03-10 11:53     ` SeongJae Park
2020-02-24 12:30 ` [PATCH v6 05/14] mm/damon: Implement callbacks SeongJae Park
2020-03-10  9:01   ` Jonathan Cameron
2020-03-10 11:55     ` SeongJae Park
2020-02-24 12:30 ` [PATCH v6 06/14] mm/damon: Implement access pattern recording SeongJae Park
2020-03-10  9:01   ` Jonathan Cameron
2020-03-10 11:55     ` SeongJae Park
2020-02-24 12:30 ` [PATCH v6 07/14] mm/damon: Implement kernel space API SeongJae Park
2020-03-10  9:01   ` Jonathan Cameron
2020-03-10 11:56     ` SeongJae Park
2020-02-24 12:30 ` [PATCH v6 08/14] mm/damon: Add debugfs interface SeongJae Park
2020-03-10  9:02   ` Jonathan Cameron
2020-03-10 11:56     ` SeongJae Park
2020-02-24 12:30 ` [PATCH v6 09/14] mm/damon: Add a tracepoint for result writing SeongJae Park
2020-03-10  9:03   ` Jonathan Cameron
2020-03-10 11:57     ` SeongJae Park
2020-02-24 12:30 ` [PATCH v6 10/14] tools: Add a minimal user-space tool for DAMON SeongJae Park
2020-02-24 12:30 ` [PATCH v6 11/14] Documentation/admin-guide/mm: Add a document " SeongJae Park
2020-03-10  9:03   ` Jonathan Cameron
2020-03-10 11:57     ` SeongJae Park
2020-02-24 12:30 ` [PATCH v6 12/14] mm/damon: Add kunit tests SeongJae Park
2020-02-24 12:30 ` [PATCH v6 13/14] mm/damon: Add user selftests SeongJae Park
2020-02-24 12:30 ` [PATCH v6 14/14] MAINTAINERS: Update for DAMON SeongJae Park
2020-03-02 11:35 ` [PATCH v6 00/14] Introduce Data Access MONitor (DAMON) SeongJae Park
2020-03-09 10:23   ` SeongJae Park
2020-03-10 17:21 ` Shakeel Butt
2020-03-12 10:07   ` SeongJae Park
2020-03-12 10:43     ` SeongJae Park
2020-03-18 19:52       ` Shakeel Butt
2020-03-19  9:03         ` SeongJae Park
2020-03-23 17:29           ` Shakeel Butt
2020-03-24  8:34             ` SeongJae Park

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