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From: SeongJae Park <sj38.park@gmail.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: SeongJae Park <sj38.park@gmail.com>,
	SeongJae Park <sjpark@amazon.de>,
	Jonathan.Cameron@Huawei.com, acme@kernel.org,
	alexander.shishkin@linux.intel.com, amit@kernel.org,
	benh@kernel.crashing.org, brendanhiggins@google.com,
	corbet@lwn.net, david@redhat.com, dwmw@amazon.com,
	elver@google.com, fan.du@intel.com, foersleo@amazon.de,
	greg@kroah.com, gthelen@google.com, guoju.fgj@alibaba-inc.com,
	jgowans@amazon.com, joe@perches.com, mgorman@suse.de,
	mheyne@amazon.de, minchan@kernel.org, mingo@redhat.com,
	namhyung@kernel.org, peterz@infradead.org, riel@surriel.com,
	rientjes@google.com, rostedt@goodmis.org, rppt@kernel.org,
	shakeelb@google.com, shuah@kernel.org, sieberf@amazon.com,
	snu@zelle79.org, vbabka@suse.cz, vdavydov.dev@gmail.com,
	zgf574564920@gmail.com, linux-damon@amazon.com,
	linux-mm@kvack.org, linux-doc@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v34 07/13] mm/damon: Implement a debugfs-based user space interface
Date: Fri,  6 Aug 2021 11:46:44 +0000	[thread overview]
Message-ID: <20210806114645.6777-1-sjpark@amazon.de> (raw)
In-Reply-To: <20210805174304.3c3d8c8ee971bc9ddf6988af@linux-foundation.org>

From: SeongJae Park <sjpark@amazon.de>

On Thu, 5 Aug 2021 17:43:04 -0700 Andrew Morton <akpm@linux-foundation.org> wrote:

> On Fri, 16 Jul 2021 08:14:43 +0000 SeongJae Park <sj38.park@gmail.com> wrote:
> 
> > From: SeongJae Park <sjpark@amazon.de>
> > 
> > DAMON is designed to be used by kernel space code such as the memory
> > management subsystems, and therefore it provides only kernel space API.
> > That said, letting the user space control DAMON could provide some
> > benefits to them.  For example, it will allow user space to analyze
> > their specific workloads and make their own special optimizations.
> > 
> > For such cases, this commit implements a simple DAMON application kernel
> > module, namely 'damon-dbgfs', which merely wraps the DAMON api and
> > exports those to the user space via the debugfs.
> > 
> > ...
> >
> > +static int __init damon_dbgfs_init(void)
> > +{
> > +	int rc;
> > +
> > +	dbgfs_ctxs = kmalloc(sizeof(*dbgfs_ctxs), GFP_KERNEL);
> > +	if (!dbgfs_ctxs) {
> > +		pr_err("%s: dbgfs ctxs alloc failed\n", __func__);
> > +		return -ENOMEM;
> > +	}
> > +	dbgfs_ctxs[0] = dbgfs_new_ctx();
> > +	if (!dbgfs_ctxs[0]) {
> > +		kfree(dbgfs_ctxs);
> > +		pr_err("%s: dbgfs ctx alloc failed\n", __func__);
> > +		return -ENOMEM;
> > +	}
> 
> checkpatch points out that the "alloc failed" messages are unneeded -
> kmalloc(GFP_KERNEL) will have already emitted a stack trace.  Is this
> fixup OK?

Yes, of course.  I also see you already kindly applied this in the -mm tree[1],
appreciate!

[1] https://www.ozlabs.org/~akpm/mmotm/broken-out/mm-damon-implement-a-debugfs-based-user-space-interface-fix.patch


Thanks,
SeongJae Park

[...]


  reply	other threads:[~2021-08-06 11:46 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-16  8:14 [PATCH v34 00/13] Introduce Data Access MONitor (DAMON) SeongJae Park
2021-07-16  8:14 ` [PATCH v34 01/13] mm: " SeongJae Park
2021-07-16  8:14 ` [PATCH v34 02/13] mm/damon/core: Implement region-based sampling SeongJae Park
2021-07-16  8:14 ` [PATCH v34 03/13] mm/damon: Adaptively adjust regions SeongJae Park
2021-07-16  8:14 ` [PATCH v34 04/13] mm/idle_page_tracking: Make PG_idle reusable SeongJae Park
2021-07-16  8:14 ` [PATCH v34 05/13] mm/damon: Implement primitives for the virtual memory address spaces SeongJae Park
2021-08-26 14:09   ` David Hildenbrand
2021-08-26 17:29     ` SeongJae Park
2021-08-26 21:42       ` David Hildenbrand
2021-08-27 11:06         ` SeongJae Park
2021-07-16  8:14 ` [PATCH v34 06/13] mm/damon: Add a tracepoint SeongJae Park
2021-07-16  8:14 ` [PATCH v34 07/13] mm/damon: Implement a debugfs-based user space interface SeongJae Park
2021-08-06  0:43   ` Andrew Morton
2021-08-06 11:46     ` SeongJae Park [this message]
2021-08-06  0:43   ` Andrew Morton
2021-08-06 11:47     ` SeongJae Park
2021-07-16  8:14 ` [PATCH v34 08/13] mm/damon/dbgfs: Export kdamond pid to the user space SeongJae Park
2021-07-16  8:14 ` [PATCH v34 09/13] mm/damon/dbgfs: Support multiple contexts SeongJae Park
2021-07-16  8:14 ` [PATCH v34 10/13] Documentation: Add documents for DAMON SeongJae Park
2021-07-16  8:14 ` [PATCH v34 11/13] mm/damon: Add kunit tests SeongJae Park
2021-07-16  8:14 ` [PATCH v34 12/13] mm/damon: Add user space selftests SeongJae Park
2021-07-16  8:14 ` [PATCH v34 13/13] MAINTAINERS: Update for DAMON SeongJae Park
2021-07-27 21:30 ` [PATCH v34 00/13] Introduce Data Access MONitor (DAMON) Shakeel Butt
2021-07-28  8:36   ` SeongJae Park
2021-08-02  8:24     ` SeongJae Park
2021-08-04  7:41       ` SeongJae Park
2021-08-06  0:03     ` Andrew Morton
2021-08-06 11:48       ` SeongJae Park
2021-08-09 14:07         ` SeongJae Park
2021-08-06  0:43 ` Andrew Morton
2021-08-06 11:48   ` SeongJae Park
2021-08-07 18:28     ` Andrew Morton

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