On Thu 14-03-19 09:09:22, Oscar Salvador wrote: > On Wed, Mar 13, 2019 at 10:31:33AM -0400, Qian Cai wrote: > > Also, after calling the "useless" undo_isolate_page_range() here, it > > reaches the point of no returning by notifying MEM_OFFLINE. Those pages > > will be marked as MIGRATE_MOVABLE again once onlining. The only thing > > left to do is to decrease the number of isolated pageblocks zone > > counter which would make some paths of the page allocation slower that > > the above commit introduced. A memory block is usually at most 1GiB in > > size, so an "int" should be enough to represent the number of pageblocks > > in a block. Fix an incorrect comment along the way. > > Well, x86_64's memblocks can be up to 2GB depending on the memory we got. > Plus the fact that alloc_contig_range can be used to isolate 16GB-hugetlb > pages on powerpc, and that could be a lot of pageblocks. > > While an "int" could still hold, I think we should use "long" just to be > more future-proof. I would rather not touch that for now. If we really need to change the type then do it when it is really needed. I pressume more things would have to be changed anyway. -- Michal Hocko SUSE Labs
