On Fri 07-04-17 10:57:43, Jerome Glisse wrote: > On Fri, Apr 07, 2017 at 04:45:04PM +0200, Michal Hocko wrote: > > On Fri 07-04-17 10:32:49, Jerome Glisse wrote: > > > On Fri, Apr 07, 2017 at 02:13:49PM +0200, Michal Hocko wrote: > > > > On Wed 05-04-17 16:40:11, Jérôme Glisse wrote: > > > > > When hotpluging memory we want more information on the type of memory. > > > > > This is to extend ZONE_DEVICE to support new type of memory other than > > > > > the persistent memory. Existing user of ZONE_DEVICE (persistent memory) > > > > > will be left un-modified. > > > > > > > > My current hotplug rework [1] is touching this path as well. It is not > > > > really clear from the chage why you are changing this and what are the > > > > further expectations of MEMORY_DEVICE_PERSISTENT. Infact I have replaced > > > > for_device with want__memblock [2]. I plan to repost shortly but I would > > > > like to understand your modifications more to reduce potential conflicts > > > > in the code. Why do you need to distinguish different types of memory > > > > anyway. > > > > > > > > [1] http://lkml.kernel.org/r/20170330115454.32154-1-mhocko@xxxxxxxxxx > > > > [2] the current patchset is in git://git.kernel.org/pub/scm/linux/kernel/git/mhocko/mm.git > > > > branch attempts/rewrite-mem_hotplug-WIP > > > > > > This is needed for UNADDRESSABLE memory type introduced in patch 3 and > > > the arch specific bits are in patch 4. Basicly for UNADDRESSABLE memory > > > i do not want the arch code to create a linear mapping for the range > > > being hotpluged. Adding memory_type in this patch allow to distinguish > > > between different type of ZONE_DEVICE. > > > > Why don't you use __add_pages directly then? > > That's a possibility, i wanted to keep the arch code in the loop in case > some arch wanted to do something specific. But it is unlikely to ever be > use outside x86 and i don't think we will want to do anything more than > skipping linear mapping. Hmm, I am looking closer and x86 stil updates max_pfn. Is this needed or you are guaranteed to not cross the max_pfn? > Note that however for CDM when doing it with ZONE_DEVICE (i am gonna > post an RFC for that) maybe the powerpc folks will want to know the > memory type ie what kind of ZONE_DEVICE this is. I don't think they need > it but i am not sure if there is anything specific needed for their > next gen power 9 in respect of device memory. Well, I really want to get rid of anything zone specific down the arch_add_memory. So whatever they want to do with zone they will have to do it after arch_add_memory. > Andrew if Michal think it is better to not use arch_add_memory directly > for my case than i can respin HMM patchset. Let me know. Well, I can drop https://git.kernel.org/pub/scm/linux/kernel/git/mhocko/mm.git/commit/?h=attempts/rewrite-mem_hotplug-WIP&id=bb1657d823a85bca045712467f517980650652ca and arch_add_memory can have memory type argument as you suggest. I am just trying to understand what are the expectations here. If you only care about x86 then it sounds a bit too much to tweak all arches. -- 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>
