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SubjectRe: [Linaro-mm-sig] [PATCHv23 13/16] drivers: add Contiguous Memory Allocator
2012/2/23 Marek Szyprowski <>:
> The Contiguous Memory Allocator is a set of helper functions for DMA
> mapping framework that improves allocations of contiguous memory chunks.
> CMA grabs memory on system boot, marks it with MIGRATE_CMA migrate type
> and gives back to the system. Kernel is allowed to allocate only movable
> pages within CMA's managed memory so that it can be used for example for
> page cache when DMA mapping do not use it. On
> dma_alloc_from_contiguous() request such pages are migrated out of CMA
> area to free required contiguous block and fulfill the request. This
> allows to allocate large contiguous chunks of memory at any time
> assuming that there is enough free memory available in the system.
> This code is heavily based on earlier works by Michal Nazarewicz.
> Signed-off-by: Marek Szyprowski <>
> Signed-off-by: Kyungmin Park <>
> Signed-off-by: Michal Nazarewicz <>
> Acked-by: Arnd Bergmann <>
> Tested-by: Rob Clark <>
> Tested-by: Ohad Ben-Cohen <>
> Tested-by: Benjamin Gaignard <>
> Tested-by: Robert Nelson <>

if there is a /proc/cmainfo like /proc/slabinfo, it might be helpful
to people as we can see the usage of CMA clearly.


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