From mboxrd@z Thu Jan 1 00:00:00 1970 From: js1304@gmail.com (Joonsoo Kim) Date: Fri, 30 Jan 2015 21:58:48 +0900 Subject: CMA related memory questions In-Reply-To: <54CAF9A4.1040606@samsung.com> References: <54CAF314.4070301@linaro.org> <54CAF9A4.1040606@samsung.com> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 2015-01-30 12:25 GMT+09:00 Heesub Shin : > > > On 01/30/2015 11:57 AM, Jun Nie wrote: >> >> On 2015?01?30? 10:36, Jun Nie wrote: >>> >>> Hi Marek & Arnd, >>> >>> Did you ever know issue that free CMA memory is high, but system is >>> hungry for memory and page cache is very low? I am enabling CMA in >>> Android on my board with 512MB memory and see FreeMem in /proc/meminfo >>> increase a lot with CMA comparing the reservation solution on boot. But >>> I find system is not borrowing memory from CMA pool when running 3dmark >>> (high webkit workload at start). Because the FreeMem size is high, but >>> cache size decreasing significantly to several MB during benchmark run, >>> I suppose system is trying to reclaim memory from pagecache for new >>> allocation. My question is that what API that page cache and webkit >>> related functionality are using to allocate memory. Maybe page cache >>> require memory that is not movable/reclaimable memory, where we may have >>> optimization to go thru dma_alloc_xxx to borrow CMA memory? I suppose >>> app level memory allocation shall be movable/reclaimable memory and can >>> borrow from CMA pool, but not sure whether the flag match the >>> movable/reclaimable memory and go thru the right path. Hello, Maybe, you experienced the problem what I tried to solve. CMA freepage allocation logic in mainline doesn't work well now since they are only allocated in fallback case. See below link for detailed explanation. https://lkml.org/lkml/2014/5/28/64 This problem can be solved by aggressive allocation approach in that link, but, there are too many issues left in CMA. So, I'm trying to implement ZONE_CMA now. Prototyping is nearly finished so I will send it soon. Thanks.