Andrey Volkov wrote: > Hello Jes and all > > I try to use your allocator (gen_pool_xxx), idea of which > is a cute nice thing. But current implementation of it is > inappropriate for a _device_ (aka onchip, like framebuffer) memory > allocation, by next reasons: > > 1) Device memory is expensive resource by access time and/or size cost. > So we couldn't use (usually) this memory for the free blocks lists. > 2) Device memory usually have special requirement of access to it > (alignment/special insn). So we couldn't use part of allocated > blocks for some control structures (this problem solved in your > implementation, it's common remark) > 3) Obvious (IMHO) workflow of mem. allocator look like: > - at startup time, driver allocate some big > (almost) static mem. chunk(s) for a control/data structures. > - during work of the device, driver allocate many small > mem. blocks with almost identical size. > such behavior lead to degeneration of buddy method and > transform it to the first/best fit method (with long seek > by the free node list). > 4) The simple binary buddy method is far away from perfect for a device > due to a big internal fragmentation. Especially for a > network/mfd devices, for which, size of allocated data very > often is not a power of 2. > > I start to modify your code to satisfy above demands, > but firstly I wish to know your, or somebody else, opinion. > > Especially I will very happy if somebody have and could > provide to all, some device specific memory usage statistics. >
Hi Andrey, FYI, on arch/ppc/lib/rheap.c theres an implementation of a remote heap. It is currently used for the management of freescale's CPM1 & CPM2 internal dual port RAM. Take a look, it might be what you have in mind. Regards Pantelis
