Message-id: <551D3E73.9070405@partner.samsung.com>
Date: Thu, 02 Apr 2015 16:04:51 +0300
From: Stefan Strogin <s.strogin@partner.samsung.com>
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To: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
        Steven Rostedt <rostedt@goodmis.org>, Ingo Molnar <mingo@redhat.com>,
        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>,
        Sasha Levin <sasha.levin@oracle.com>,
        Dmitry Safonov <d.safonov@partner.samsung.com>,
        Pintu Kumar <pintu.k@samsung.com>,
        Laura Abbott <lauraa@codeaurora.org>,
        Dyasly Sergey <s.dyasly@samsung.com>,
        Vyacheslav Tyrtov <v.tyrtov@samsung.com>,
        Aleksei Mateosian <a.mateosian@samsung.com>, gioh.kim@lge.com,
        stefan.strogin@gmail.com
Subject: Re: [PATCH] mm: cma: add trace events for CMA allocations and freeings
References: <1427895103-9431-1-git-send-email-s.strogin@partner.samsung.com>
 <20150402073340.GA13158@js1304-P5Q-DELUXE>
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Hello Joonsoo,

On 02/04/15 10:33, Joonsoo Kim wrote:
> Hello,
> 
> On Wed, Apr 01, 2015 at 04:31:43PM +0300, Stefan Strogin wrote:
>> Add trace events for cma_alloc() and cma_release().
>>
>> The cma_alloc tracepoint is used both for successful and failed allocations,
>> in case of allocation failure pfn=-1UL is stored and printed.
>>
>> Signed-off-by: Stefan Strogin <stefan.strogin@gmail.com>
>> ---
>>
>> Took out from the patch set "mm: cma: add some debug information for CMA" v4
>> (http://thread.gmane.org/gmane.linux.kernel.mm/129903) because of probable
>> uselessness of the rest of the patches.
> 
> I think that patch 5/5 in previous submission is handy and
> simple to merge. Although we can calculate it by using bitmap,
> it would be good to get that information(used size and maxchunk size)
> directly.

Well, then I can send the patch 5/5 once more, this time singly.

> 
>> @@ -414,6 +416,8 @@ struct page *cma_alloc(struct cma *cma, unsigned int count, unsigned int align)
>>  		start = bitmap_no + mask + 1;
>>  	}
>>  
>> +	trace_cma_alloc(page ? pfn : -1UL, page, count);
>> +
> 
> I think that tracing align is also useful.
> Is there any reason not to include it?

In our case (DMA) alignment is easily calculated from the allocation
size and CONFIG_CMA_ALIGNMENT. But I think you're right, e.g. it may be
not so obvious on powerpc kvm? Anyway it won't be a shortcoming if we
trace 'align' too.

> 
> Thanks.

Thank you for the reply.
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