On Wed, 22 Jan 2014 11:30:19 -0800 James Bottomley <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx> wrote: > But this, I think, is the fundamental point for debate. If we can pull > alignment and other tricks to solve 99% of the problem is there a need > for radical VM surgery? Is there anything coming down the pipe in the > future that may move the devices ahead of the tricks? I expect it would be relatively simple to get large blocksizes working on powerpc with 64k PAGE_SIZE. So before diving in and doing huge amounts of work, perhaps someone can do a proof-of-concept on powerpc (or ia64) with 64k blocksize. That way we'll at least have an understanding of what the potential gains will be. If the answer is "1.5%" then poof - go off and do something else. (And the gains on powerpc would be an upper bound - unlike powerpc, x86 still has to fiddle around with 16x as many pages and perhaps order-4 allocations(?)) -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>