Messages in this thread | | | From | Andi Kleen <> | Subject | Re: [PATCH] [0/31] Great change_page_attr patch series v2 | Date | Tue, 15 Jan 2008 11:06:15 +0100 |
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On Tuesday 15 January 2008 10:11:44 Jan Beulich wrote: > >>> Andi Kleen <ak@suse.de> 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 checkpatch.pl 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 <jbeulich@novell.com>
Thanks.
-Andi
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