Messages in this thread | | | Date | Thu, 6 Feb 2014 17:31:55 -0800 | Subject | Re: [RFC] de-asmify the x86-64 system call slowpath | From | Linus Torvalds <> |
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On Thu, Feb 6, 2014 at 2:24 PM, Kirill A. Shutemov <kirill@shutemov.name> wrote: > > If we want to reduce number of page fault with less overhead we probably > should concentrate on minor page fault -- populate pte around fault > address which already in page cache. It should cover scripting use-case > pretty well.
That's what my patch largely does. Except I screwed up and didn't use FAULT_FLAG_ALLOW_RETRY in fault_around().
Anyway, my patch kind of works, but I'm starting to hate it. I think I want to try to extend the "->fault()" interface to allow filemap_fault() to just fill in multiple pages.
We alread have that "vmf->page" thing, we could make it a small array easily. That would allow proper gang lookup, and much more efficient "fill in multiple entries in one go" in mm/memory.c.
> Heh! `man 3 mmap' actually suggests MAP_POPULATE | MAP_NONBLOCK. > What's the story beyond MAP_NONBLOCK?
It does nothing, afaik.
Linus
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