On Thu, Nov 20, 2014 at 11:54:06AM -0800, Linus Torvalds wrote: > On Thu, Nov 20, 2014 at 2:19 AM, Mel Gorman <mgorman@xxxxxxx> wrote: > > This is a preparatory patch that introduces protnone helpers for automatic > > NUMA balancing. > > Oh, I hadn't noticed that you had renamed these things. It was > probably already true in your V1 version. > > I do *not* think that "pte_protnone_numa()" makes sense as a name. It > only confuses people to think that there is still/again something > NUMA-special about the PTE. The whole point of the protnone changes > was to make it really very very clear that from a hardware standpoint, > this is *exactly* about protnone, and nothing else. > > The fact that we then use protnone PTE's for numa faults is a VM > internal issue, it should *not* show up in the architecture page table > helpers. > > I'm not NAK'ing this name, but I really think it's a very important > part of the whole patch series - to stop the stupid confusion about > NUMA entries. As far as the page tables are concerned, this has > absolutely _zero_ to do with NUMA. > > We made that mistake once. We're fixing it. Let the naming *show* that > it's fixed, and this is "pte_protnone()". > > The places that use this for NUMA handling might have a comment or > something. But they'll be in the VM where this matters, not in the > architecture page table description files. The comment would be > something like "if the vma is accessible, but the PTE is marked > protnone, this is a autonuma entry". > I feared that people would eventually make the mistake of thinking that pte_protnone() would return true for PROT_NONE VMAs that do *not* have the page table bit set. I'll use the old name as you suggest and expand the comment. It'll be in v3. -- Mel Gorman 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>