From mboxrd@z Thu Jan  1 00:00:00 1970
From: Peter Zijlstra <peterz@infradead.org>
Subject: Re: [PATCH 07/13] powerpc: Preemptible mmu_gather
Date: Fri, 09 Apr 2010 11:22:06 +0200
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To: Nick Piggin <npiggin@suse.de>
Cc: Andrea Arcangeli <aarcange@redhat.com>, Avi Kivity <avi@redhat.com>, Thomas Gleixner <tglx@linutronix.de>, Rik van Riel <riel@redhat.com>, Ingo Molnar <mingo@elte.hu>, akpm@linux-foundation.org, Linus Torvalds <torvalds@linux-foundation.org>, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, Benjamin Herrenschmidt <benh@kernel.crashing.org>, David Miller <davem@davemloft.net>, Hugh Dickins <hugh.dickins@tiscali.co.uk>, Mel Gorman <mel@csn.ul.ie>

On Fri, 2010-04-09 at 18:46 +1000, Nick Piggin wrote:
> > struct mmu_page {
> >   struct page *page;
> > #ifdef HAVE_ARCH_TLB_VADDR
> >   unsigned long vaddr;
> > #endif
> > };
> 
> Well you could also have a per-arch struct for this, which they can
> fill in their own info with (I think powerpc takes the pte as well)

Ah, right you are.

Maybe something like:

#ifndef tlb_fill_page
struct mmu_page {
	struct page *page;
};

#define tlb_fill_page(tlb, pte, addr) do { } while (0)
#endif

Which can be used from the tlb_remove_tlb_entry() implementation to
gather both the pte and addr. The only complication seems to be that
tlb_remove_tlb_entry() and tlb_remove_page() aren't always matched.

Also, it looks like both power and sparc drive the pte/vaddr flush from
the pte_update/set_pte_at like functions. Which means its not synced to
the mmu_gather at all.

So I'm not at all sure its feasible to link these, but I'll keep it in
mind.