From: Sasha Levin <sasha.levin@oracle.com>
To: Joonsoo Kim <iamjoonsoo.kim@lge.com>,
Stefan Strogin <s.strogin@partner.samsung.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>,
Marek Szyprowski <m.szyprowski@samsung.com>,
Michal Nazarewicz <mina86@mina86.com>,
aneesh.kumar@linux.vnet.ibm.com,
Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
Dmitry Safonov <d.safonov@partner.samsung.com>,
Pintu Kumar <pintu.k@samsung.com>,
Weijie Yang <weijie.yang@samsung.com>,
Laura Abbott <lauraa@codeaurora.org>,
SeongJae Park <sj38.park@gmail.com>, Hui Zhu <zhuhui@xiaomi.com>,
Minchan Kim <minchan@kernel.org>,
Dyasly Sergey <s.dyasly@samsung.com>,
Vyacheslav Tyrtov <v.tyrtov@samsung.com>,
Aleksei Mateosian <a.mateosian@samsung.com>,
gregory.0xf0@gmail.com, gioh.kim@lge.com, pavel@ucw.cz,
stefan.strogin@gmail.com
Subject: Re: [PATCH v4 0/5] mm: cma: add some debug information for CMA
Date: Mon, 16 Mar 2015 21:54:18 -0400 [thread overview]
Message-ID: <5507894A.2080008@oracle.com> (raw)
In-Reply-To: <20150317014306.GB19483@js1304-P5Q-DELUXE>
On 03/16/2015 09:43 PM, Joonsoo Kim wrote:
> On Mon, Mar 16, 2015 at 07:06:55PM +0300, Stefan Strogin wrote:
>> > Hi all.
>> >
>> > Here is the fourth version of a patch set that adds some debugging facility for
>> > CMA.
>> >
>> > This patch set is based on next-20150316.
>> > It is also available on git:
>> > git://github.com/stefanstrogin/linux -b cmainfo-v4
>> >
>> > We want an interface to see a list of currently allocated CMA buffers and some
>> > useful information about them (like /proc/vmallocinfo but for physically
>> > contiguous buffers allocated with CMA).
>> >
>> > For example. We want a big (megabytes) CMA buffer to be allocated in runtime
>> > in default CMA region. If someone already uses CMA then the big allocation
>> > could fail. If it happened then with such an interface we could find who used
>> > CMA at the moment of failure, who caused fragmentation and so on. Ftrace also
>> > would be helpful here, but with ftrace we can see the whole history of
>> > allocations and releases, whereas with this patch set we can see a snapshot of
>> > CMA region with actual information about its allocations.
> Hello,
>
> Hmm... I still don't think that this is really helpful to find root
> cause of fragmentation. Think about following example.
>
> Assume 1024 MB CMA region.
>
> 128 MB allocation * 4
> 1 MB allocation
> 128 MB allocation
> 128 MB release * 4 (first 4)
> try 512 MB allocation
>
> With above sequences, fragmentation happens and 512 MB allocation would
> be failed. We can get information about 1 MB allocation and 128 MB one
> from the buffer list as you suggested, but, fragmentation are related
> to whole sequence of allocation/free history, not snapshot of allocation.
This is solvable by dumping task->comm in the tracepoint patch (1/5), right?
Thanks,
Sasha
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2015-03-17 1:54 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-03-16 16:06 [PATCH v4 0/5] mm: cma: add some debug information for CMA Stefan Strogin
2015-03-16 16:06 ` [PATCH v4 1/5] mm: cma: add trace events to debug physically-contiguous memory allocations Stefan Strogin
2015-03-16 20:49 ` Stefan Strogin
2015-03-16 23:47 ` Steven Rostedt
2015-03-19 20:18 ` Stefan Strogin
2015-03-19 20:34 ` Steven Rostedt
2015-03-20 10:46 ` Stefan Strogin
2015-03-20 14:31 ` Steven Rostedt
2015-03-17 7:40 ` Ingo Molnar
2015-03-19 20:22 ` Stefan Strogin
2015-03-23 14:04 ` Ingo Molnar
2015-03-16 16:06 ` [PATCH v4 2/5] mm: cma: add number of pages to debug message in cma_release() Stefan Strogin
2015-03-16 16:06 ` [PATCH v4 3/5] stacktrace: add seq_print_stack_trace() Stefan Strogin
2015-03-16 17:33 ` Michal Nazarewicz
2015-03-16 16:06 ` [PATCH v4 4/5] mm: cma: add list of currently allocated CMA buffers to debugfs Stefan Strogin
2015-03-16 17:51 ` Michal Nazarewicz
2015-03-16 16:09 ` [PATCH v4 5/5] mm: cma: add functions to get region pages counters Stefan Strogin
2015-03-17 1:43 ` [PATCH v4 0/5] mm: cma: add some debug information for CMA Joonsoo Kim
2015-03-17 1:54 ` Sasha Levin [this message]
2015-03-17 2:04 ` Joonsoo Kim
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=5507894A.2080008@oracle.com \
--to=sasha.levin@oracle.com \
--cc=a.mateosian@samsung.com \
--cc=akpm@linux-foundation.org \
--cc=aneesh.kumar@linux.vnet.ibm.com \
--cc=d.safonov@partner.samsung.com \
--cc=gioh.kim@lge.com \
--cc=gregory.0xf0@gmail.com \
--cc=iamjoonsoo.kim@lge.com \
--cc=lauraa@codeaurora.org \
--cc=laurent.pinchart@ideasonboard.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=m.szyprowski@samsung.com \
--cc=mina86@mina86.com \
--cc=minchan@kernel.org \
--cc=pavel@ucw.cz \
--cc=pintu.k@samsung.com \
--cc=s.dyasly@samsung.com \
--cc=s.strogin@partner.samsung.com \
--cc=sj38.park@gmail.com \
--cc=stefan.strogin@gmail.com \
--cc=v.tyrtov@samsung.com \
--cc=weijie.yang@samsung.com \
--cc=zhuhui@xiaomi.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).