Subject: Re: [PATCH V4 0/2] mm: FAULT_AROUND_ORDER patchset performance data for powerpc

From: Andrew Morton <[email-masked]>
Date: Tue, 20 May 2014 00:32:01 -0700

On Tue, 20 May 2014 15:52:07 +0930 Rusty Russell <[email-masked]> wrote:

> "Kirill A. Shutemov" <[email-masked]> writes:
> > Andrew Morton wrote:
> >> On Mon, 19 May 2014 16:23:07 -0700 (PDT) Hugh Dickins <[email-masked]> wrote:
> >> 
> >> > Shouldn't FAULT_AROUND_ORDER and fault_around_order be changed to be
> >> > the order of the fault-around size in bytes, and fault_around_pages()
> >> > use 1UL << (fault_around_order - PAGE_SHIFT)
> >> 
> >> Yes.  And shame on me for missing it (this time!) at review.
> >> 
> >> There's still time to fix this.  Patches, please.
> >
> > Here it is. Made at 3.30 AM, build tested only.
> 
> Prefer on top of Maddy's patch which makes it always a variable, rather
> than CONFIG_DEBUG_FS.  It's got enough hair as it is.
> 

We're at 3.15-rc5 and this interface should be finalised for 3.16.  So
Kirrill's patch is pretty urgent and should come first.

Well.  It's only a debugfs interface at this stage so we are allowed to
change it later, but it's better not to.