On Wed, Aug 01, 2018 at 01:56:19PM -0700, Linus Torvalds wrote: > On Wed, Aug 1, 2018 at 1:52 PM Kirill A. Shutemov <kirill@xxxxxxxxxxxxx> wrote: > > > > Is there a reason why we pass vma to flush_tlb_range? > > Yes. It's even in that patch. > > The fact is, real MM users *have* a vma, and passing it in to the TLB > flushing is the right thing to do. That allows architectures that care > (mainly powerpc, I think) to notice that "hey, this range only had > execute permissions, so I only need to flush the ITLB". > > The people who use tlb_flush_range() any other way are doing an > arch-specific hack. It's not how tlb_flush_range() was defined, and > it's not how you can use it in general. Okay, I see. ARM, unicore32 and xtensa avoid iTLB flush for non-executable VMAs. > > > It's not obvious to me what information from VMA can be useful for an > > implementation. > > See the patch I sent, which had this as part of it: > > - * XXX fix me: flush_tlb_range() should take an mm > pointer instead of a > - * vma pointer. > + * flush_tlb_range() takes a vma instead of a mm pointer because > + * some architectures want the vm_flags for ITLB/DTLB flush. > > because I wanted to educate people about why the interface was what it > was, and the "fixme" was bogus shit. I didn't noticied this. Sorry. -- Kirill A. Shutemov
