On Wed 05-07-17 13:18:18, Balbir Singh wrote: > On Tue, Jul 4, 2017 at 10:51 PM, Michal Hocko <mhocko@xxxxxxxxxx> wrote: > > On Mon 03-07-17 17:14:14, Jérôme Glisse wrote: > >> HMM pages (private or public device pages) are ZONE_DEVICE page and > >> thus you can not use page->lru fields of those pages. This patch > >> re-arrange the uncharge to allow single page to be uncharge without > >> modifying the lru field of the struct page. > >> > >> There is no change to memcontrol logic, it is the same as it was > >> before this patch. > > > > What is the memcg semantic of the memory? Why is it even charged? AFAIR > > this is not a reclaimable memory. If yes how are we going to deal with > > memory limits? What should happen if go OOM? Does killing an process > > actually help to release that memory? Isn't it pinned by a device? > > > > For the patch itself. It is quite ugly but I haven't spotted anything > > obviously wrong with it. It is the memcg semantic with this class of > > memory which makes me worried. > > > > This is the HMM CDM case. Memory is normally malloc'd and then > migrated to ZONE_DEVICE or vice-versa. One of the things we did > discuss was seeing ZONE_DEVICE memory in user page tables. This doesn't answer any of the above questions though. -- Michal Hocko SUSE Labs -- 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>
