On Wed, Apr 03, 2019 at 10:46:03AM +0200, Michal Hocko wrote: > On Thu 28-03-19 14:43:18, Oscar Salvador wrote: > > From: Michal Hocko <mhocko@xxxxxxxx> > > > > arch_add_memory, __add_pages take a want_memblock which controls whether > > the newly added memory should get the sysfs memblock user API (e.g. > > ZONE_DEVICE users do not want/need this interface). Some callers even > > want to control where do we allocate the memmap from by configuring > > altmap. > > > > Add a more generic hotplug context for arch_add_memory and __add_pages. > > struct mhp_restrictions contains flags which contains additional > > features to be enabled by the memory hotplug (MHP_MEMBLOCK_API > > currently) and altmap for alternative memmap allocator. > > > > Please note that the complete altmap propagation down to vmemmap code > > is still not done in this patch. It will be done in the follow up to > > reduce the churn here. > > > > This patch shouldn't introduce any functional change. > > Is there an agreement on the interface here? Or do we want to hide almap > behind some more general looking interface? If the former is true, can > we merge it as it touches a code that might cause merge conflicts later on > as multiple people are working on this area. Uhm, I think that the interface is fine for now. I thought about providing some callbacks to build the altmap layout, but I realized that it was overcomplicated and I would rather start easy. Maybe the naming could be changed to what David suggested, something like "mhp_options", which actually looks more generic and allows us to stuff more things into it should the need arise in the future. But that is something that can come afterwards I guess. But merging this now is not a bad idea taking into account that some people is working on the same area and merge conflicts arise easily. Otherwise re-working it every version is going to be a pita. -- Oscar Salvador SUSE L3
