[lkml]   [2008]   [Jan]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [PATCH] [0/31] Great change_page_attr patch series v2
On Tuesday 15 January 2008 10:11:44 Jan Beulich wrote:
> >>> Andi Kleen <> 14.01.08 23:16 >>>
> >
> >Lots of improvements to change_page_attr(). Make it a lot more
> >efficient and fix various bugs.
> >
> >Changes against earlier version
> >
> >- Fixed some complaints
> >- Improved self test suite
> >- Fixed more reference bugs
> >- Fix NX handling on 32bit
> >- Remove some useless code there
> >- Few other random fixes
> The one concept that I'm missing (but that I can easily produce a follow-up
> patch for, as I had this in my c_p_a() changes) is the tracking and adjusting
> of the reference protection for a large page range that got fully converted
> to another type (namely relevant for .rodata if it exceeds 2/4 Mb), allowing
> to use a large page mapping in this case even for non-default mappings.

Ah -- i got rid of that by changing the rodata code to not do this
except for the debugging case

CPA: Only unmap kernel init pages in text mapping when CONFIG_DEBUG_RODATA is set

Otherwise the kernel will likely always run with 4K pages instead of 2MB pages,
which is costly in terms of TLBs.

But you're right that would be an useful feature. But wouldn't it require
aligning rodata to 2MB in the vmlinux to be really effective?

> Apart from the other comments, the whole series
> Acked-by: Jan Beulich <>



 \ /
  Last update: 2008-01-15 11:13    [from the cache]
©2003-2014 Jasper Spaans. hosted at Digital Ocean