On 07/20, Benjamin LaHaise wrote: > > On Mon, Jul 20, 2015 at 07:33:11PM +0200, Oleg Nesterov wrote: > > > > And if we accept the fact this memory is locked and if we properly account > > it, then may be we can just kill aio_migratepage(), aio_private_file(), and > > change aio_setup_ring() to simply use install_special_mapping(). This will > > greatly simplify the code. But let me remind that I know nothing about aio, > > so please don't take my thoughts seriously. > > No, you can't get rid of that code. The page migration is required when > CPUs/memory is offlined and data needs to be moved to another node. Of course, if we remove aio_migratepage() then aio can't be moved, > Similarly, support for mremap() is also required for container migration / > restoration. This is not the problem. And one of the reasons to move ->mremap() into vm_operations_struct was that install_special_mapping() can use it. > Given how small the amount of memory aio can pin I agree, but why should we worry about migration then? let this memory be unmovable, don't use GFP_RECLAIMABLE/MOVABLE, etc. But again, again, please ignore. This all is off-topic and my understanding is very limited. > it is unlikely that the accounting of > how much aio has pinned will make any real difference in the big picture. Agreed, but this can help to remove the system-wide aio-max-nr. Again, unpriviliged user can steal aio. Oleg. -- To unsubscribe from this list: send the line "unsubscribe linux-next" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
