Hi Hans! On 29 March 2011 16:50, Hans Verkuil <hverk...@xs4all.nl> wrote: > On Tuesday, March 29, 2011 16:01:33 Willy POISSON wrote: >> Hi all, >> Following to the Warsaw mini-summit action point, I would like to open >> the thread to gather buffer pool & memory manager requirements. >> The list of requirement for buffer pool may contain: >> - Support physically contiguous and virtual memory
Only physical contigous allocator supported in hwmem as of today. >> - Support IPC, import/export handles (between >> processes/drivers/userland/etc) Supported in hwmem >> - Security(access rights in order to secure no one unauthorized is >> allowed to access buffers) Supported in hwmem >> - Cache flush management (by using setdomain and optimize when flushing >> is needed) Supported in hwmem >> - Pin/unpin in order to get the actual address to be able to do >> defragmentation Pin/unpin implemented but defragmentation not done...yet. It's more of a memory allocator feature and I know CMA took influence of this and added pin/unpin into CMA in order to be able to do defragmentation >> - Support pinning in user land in order to allow defragmentation while >> buffer is mmapped but not pined. >> - Both a user API and a Kernel API is needed for this module. (Kernel >> drivers needs to be able to resolve buffer handles as well from the memory >> manager module, and pin/unpin) Supported in hwmem >> - be able to support any platform specific allocator (Separate memory >> allocation from management as allocator is platform dependant) As Laurent pinpointed we have a tightly coupled physical contigous memory allocator in hwmem today. Plan is to separate this more clearly from the hwmem api's and also add a virtual memory allocator as well(This is not supported today). We have also tested as a quick prototype to use CMA as allocator. >> - Support multiple region domain (Allow to allocate from several memory >> domain ex: DDR1, DDR2, Embedded SRAM to make for ex bandwidth load balancing >> ...) Not supported in hwmem today. No problems to add separate regions(mapped to several ddr banks or whatever), although loadbalancing and similar will likely need some fancy hw in order to spread addresses across the regions efficiently. > > Thanks for your input, Willy! > > I have one question: do you know which of the points mentioned above are > implemented in actual existing code that ST-Ericsson uses? Ideally with links > to such code as well if available :-) > > That will help as a reference. > You can find the details of current hwmem in the linux-mm list. http://marc.info/?l=linux-mm&w=2&r=1&s=hwmem&q=b BR /Robert Fekete -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
