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Date: Thu, 6 Feb 2014 17:31:55 -0800 From: Linus Torvalds <torvalds@...ux-foundation.org> To: "Kirill A. Shutemov" <kirill@...temov.name> Cc: Peter Anvin <hpa@...or.com>, Ingo Molnar <mingo@...hat.com>, Thomas Gleixner <tglx@...utronix.de>, Peter Zijlstra <peterz@...radead.org>, "the arch/x86 maintainers" <x86@...nel.org>, Linux Kernel Mailing List <linux-kernel@...r.kernel.org>, Ning Qu <quning@...gle.com> Subject: Re: [RFC] de-asmify the x86-64 system call slowpath On Thu, Feb 6, 2014 at 2:24 PM, Kirill A. Shutemov <kirill@...temov.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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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