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Date: Wed, 18 May 2016 10:48:25 +0200
From: Michal Hocko <mhocko@kernel.org>
To: lunar12 lunartwix <lunartwix@gmail.com>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
        Joonsoo Kim <iamjoonsoo.kim@lge.com>, Minchan Kim <minchan@kernel.org>,
        Marek Szyprowski <m.szyprowski@samsung.com>
Subject: Re: malloc() size in CMA region seems to be aligned to CMA_ALIGNMENT
Message-ID: <20160518084824.GA21680@dhcp22.suse.cz>
References: <CA+a3UFfGxJajS3Lqkp8M4kaikTWHprUXbUvECYC9dojgazQ8pg@mail.gmail.com>
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[CC linux-mm and some usual suspects]

On Tue 17-05-16 23:37:55, lunar12 lunartwix wrote:
> A 4MB dma_alloc_coherent  in kernel after malloc(2*1024) 40 times in
> CMA region by user space will cause an error on our ARM 3.18 kernel
> platform with a 32MB CMA.
> 
> It seems that the malloc in CMA region will be aligned to
> CMA_ALIGNMENT everytime even if the requested malloc size is very
> small so the CMA region is not available after the malloc operations.
> 
> Is there any configuraiton that can change this behavior??
> 
> Thanks
> 
> Cheers
> Ken

-- 
Michal Hocko
SUSE Labs