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Date: Wed, 18 Feb 2015 16:12:35 +0300
From: Safonov Dmitry <d.safonov@partner.samsung.com>
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To: Gioh Kim <gioh.kim@lge.com>,
        Stefan Strogin <s.strogin@partner.samsung.com>, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.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>,
        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>, gregory.0xf0@gmail.com,
        sasha.levin@oracle.com, pavel@ucw.cz, stefan.strogin@gmail.com
Subject: Re: [PATCH 2/4] mm: cma: add functions to get region pages counters
References: <cover.1423777850.git.s.strogin@partner.samsung.com>
 <c6a3312c9eb667f0f5330c313f328bc49f7addd9.1423777850.git.s.strogin@partner.samsung.com>
 <54DEFA03.6010308@lge.com>
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Hello,
On 02/14/2015 10:32 AM, Gioh Kim wrote:
> 2015-02-13 ???? 7:15?? Stefan Strogin ??(??) ?? ??:
>> From: Dmitry Safonov <d.safonov@partner.samsung.com>
>>
>> Here are two functions that provide interface to compute/get used size
>> and size of biggest free chunk in cma region.
> I usually just try to allocate memory, not check free size before try,
> becuase free size can be changed after I check it.
>
> Could you tell me why biggest free chunk size is necessary?
>
It may have changed after checking - at beginning of allocation
this information is completely useless as you mentioned, but
it may be very helpful after failed allocation to detect fragmentation
problem: i.e, you failed to alloc 20 Mb from 100 Mb CMA region
with 60 Mb free space, so you will know the reason.

-- 
Best regards,
Safonov Dmitry.

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