Re: [RFC][PATCH 4/6] arm, mm: Convert arm to generic tlb

On Wed, 2011-03-09 at 15:36 +0000, Catalin Marinas wrote:

On Wed, 2011-03-09 at 15:19 +0000, Peter Zijlstra wrote:

quoted

On Wed, 2011-03-09 at 15:16 +0000, Catalin Marinas wrote:

quoted

Hi Peter,

On 2 March 2011 17:59, Peter Zijlstra [off-list ref] wrote:

quoted

--- linux-2.6.orig/arch/arm/include/asm/tlb.h
+++ linux-2.6/arch/arm/include/asm/tlb.h

[...]

quoted

+__pte_free_tlb(struct mmu_gather *tlb, pgtable_t pte, unsigned long addr)
 {
       pgtable_page_dtor(pte);
-       tlb_add_flush(tlb, addr);
       tlb_remove_page(tlb, pte);
 }

I think we still need a tlb_track_range() call here. On the path to
pte_free_tlb() (for example shift_arg_pages ... free_pte_range) there
doesn't seem to be any code setting the tlb->start/end range. Did I
miss anything?

Patch 3 included:

-#define pte_free_tlb(tlb, ptep, address)                       \
-       do {                                                    \
-               tlb->need_flush = 1;                            \
-               __pte_free_tlb(tlb, ptep, address);             \
+#define pte_free_tlb(tlb, ptep, address)                                       \
+       do {                                                                    \
+               tlb->need_flush = 1;                                            \
+               tlb_track_range(tlb, address, pmd_addr_end(address, TASK_SIZE));\
+               __pte_free_tlb(tlb, ptep, address);                             \
        } while (0)

OK, so the range is tracked. The only issue is that for platforms with a
folded pmd the range end would go to TASK_SIZE. In this case
pgd_addr_end() would make more sense (or something like
PTRS_PER_PTE*PAGE_SIZE).

Urgh, so when pmds are folded pmd_addr_end() doesn't get to be the next
biggest thing?  PTRS_PER_PTE*PAGE_SIZE like things don't work since
there is no guarantee addr is at the beginning of the pmd.

Ok, will try and sort that out.

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