| Subject | Re: [PATCH 09/13] mm, powerpc: Move the RCU page-table freeing into generic code | From | Peter Zijlstra <> | Date | Fri, 09 Apr 2010 10:08:31 +0200 |
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On Fri, 2010-04-09 at 13:35 +1000, Nick Piggin wrote: > On Thu, Apr 08, 2010 at 09:17:46PM +0200, Peter Zijlstra wrote: > > Index: linux-2.6/include/asm-generic/tlb.h > > =================================================================== > > --- linux-2.6.orig/include/asm-generic/tlb.h > > +++ linux-2.6/include/asm-generic/tlb.h > > @@ -27,6 +27,49 @@ > > #define tlb_fast_mode(tlb) 1 > > #endif > > > > +#ifdef HAVE_ARCH_RCU_TABLE_FREE > > +/* > > + * Semi RCU freeing of the page directories. > > + * > > + * This is needed by some architectures to implement gup_fast(). > > Really? I see the comment in the powerpc code, but powerpc was already > using RCU before gup_fast(), and AFAIKS it is indeed using it so that > it can handle faults by getting the linux pte with find_linux_pte ?
Ah, see that is my ignorance of the powerpc mmu code, I've only been staring at this mmu_gather piece long enough to (hopefully) make it work.
If there is indeed more to it, then yes, that needs documenting.
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