On Mon, 29 Jul 2013 13:27:12 +0200 Marek Szyprowski <m.szyprowski@xxxxxxxxxxx> wrote: > > You've gone to all this trouble to get a higher-order allocation so you'd > > have fewer segments, then you undo it all by splitting things apart into > > individual pages. Why? Clearly I'm missing something, this seems to > > defeat the purpose of the whole exercise? > > Individual zero-order pages are required to get them mapped to userspace in > mmap callback. Yeah, Ricardo explained that too. The right solution might be to fix that problem rather than work around it, but I can see why one might shy at that task! :) I do wonder, though, if an intermediate solution using huge pages might be the best approach? That would get the number of segments down pretty far, and using huge pages for buffers would reduce TLB pressure significantly if the CPU is working through the data at all. Meanwhile, inserting huge pages into the process's address space should work easily. Just a thought. jon -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
