On 10.12.19 11:04, Michal Hocko wrote: > On Mon 09-12-19 12:43:40, Dan Williams wrote: >> On Mon, Dec 9, 2019 at 12:24 PM Logan Gunthorpe <logang@xxxxxxxxxxxx> wrote: >>> >>> >>> >>> On 2019-12-09 12:23 p.m., David Hildenbrand wrote: >>>> On 09.12.19 20:13, Logan Gunthorpe wrote: > [...] >>>>> #ifdef CONFIG_MEMORY_HOTPLUG >>>>> -int arch_add_memory(int nid, u64 start, u64 size, >>>>> +int arch_add_memory(int nid, u64 start, u64 size, pgprot_t prot, >>>>> struct mhp_restrictions *restrictions) >>>> >>>> Can we fiddle that into "struct mhp_restrictions" instead? >>> >>> Yes, if that's what people want, it's pretty trivial to do. I chose not >>> to do it that way because it doesn't get passed down to add_pages() and >>> it's not really a "restriction". If I don't hear any objections, I will >>> do that for v2. >> >> +1 to storing this information alongside the altmap in that structure. >> However, I agree struct mhp_restrictions, with the MHP_MEMBLOCK_API >> flag now gone, has lost all of its "restrictions". How about dropping >> the 'flags' property and renaming the struct to 'struct >> mhp_modifiers'? > > Hmm, this email somehow didn't end up in my inbox so I have missed it > before replying. > > Well, mhp_modifiers makes some sense and it would reduce the API > proliferation but how do you expect the prot part to be handled? > I really do not want people to think about PAGE_KERNEL or which > protection to use because my experience tells that this will get copied > without much thinking or simply will break with some odd usecases. > So how exactly this would be used? I was thinking about exactly the same "issue". 1. default initialization via a function memhp_modifier_default_init(&modified); 2. a flag that unlocks the prot field (default:0). Without the flag, it is ignored. We can keep the current initialization then. Other ideas? -- Thanks, David / dhildenb
