[IA64] 4-level page tables
This patch introduces 4-level page tables to ia64. I have run some benchmarks and found nothing interesting. Performance has consistently fallen within the noise range. It also introduces a config option (setting the default to 3 levels). The config option prevents having 4 level page tables with 64k base page size. Signed-off-by: Robin Holt <holt@sgi.com> Signed-off-by: Tony Luck <tony.luck@intel.com>
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zatwierdzone przez
Tony Luck

rodzic
d12eb7e11c
commit
837cd0bdf5
@@ -114,7 +114,7 @@ ENTRY(vhpt_miss)
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shl r21=r16,3 // shift bit 60 into sign bit
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shr.u r17=r16,61 // get the region number into r17
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;;
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shr r22=r21,3
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shr.u r22=r21,3
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#ifdef CONFIG_HUGETLB_PAGE
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extr.u r26=r25,2,6
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;;
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@@ -140,20 +140,34 @@ ENTRY(vhpt_miss)
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(p6) dep r17=r18,r19,3,(PAGE_SHIFT-3) // r17=PTA + IFA(33,42)*8
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(p7) dep r17=r18,r17,3,(PAGE_SHIFT-6) // r17=PTA + (((IFA(61,63) << 7) | IFA(33,39))*8)
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cmp.eq p7,p6=0,r21 // unused address bits all zeroes?
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shr.u r18=r22,PMD_SHIFT // shift L2 index into position
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#ifdef CONFIG_PGTABLE_4
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shr.u r28=r22,PUD_SHIFT // shift L2 index into position
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#else
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shr.u r18=r22,PMD_SHIFT // shift L3 index into position
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#endif
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;;
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ld8 r17=[r17] // fetch the L1 entry (may be 0)
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;;
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(p7) cmp.eq p6,p7=r17,r0 // was L1 entry NULL?
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dep r17=r18,r17,3,(PAGE_SHIFT-3) // compute address of L2 page table entry
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#ifdef CONFIG_PGTABLE_4
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dep r28=r28,r17,3,(PAGE_SHIFT-3) // compute address of L2 page table entry
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;;
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(p7) ld8 r20=[r17] // fetch the L2 entry (may be 0)
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shr.u r19=r22,PAGE_SHIFT // shift L3 index into position
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shr.u r18=r22,PMD_SHIFT // shift L3 index into position
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(p7) ld8 r29=[r28] // fetch the L2 entry (may be 0)
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;;
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(p7) cmp.eq.or.andcm p6,p7=r20,r0 // was L2 entry NULL?
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dep r21=r19,r20,3,(PAGE_SHIFT-3) // compute address of L3 page table entry
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(p7) cmp.eq.or.andcm p6,p7=r29,r0 // was L2 entry NULL?
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dep r17=r18,r29,3,(PAGE_SHIFT-3) // compute address of L3 page table entry
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#else
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dep r17=r18,r17,3,(PAGE_SHIFT-3) // compute address of L3 page table entry
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#endif
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;;
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(p7) ld8 r18=[r21] // read the L3 PTE
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(p7) ld8 r20=[r17] // fetch the L3 entry (may be 0)
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shr.u r19=r22,PAGE_SHIFT // shift L4 index into position
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;;
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(p7) cmp.eq.or.andcm p6,p7=r20,r0 // was L3 entry NULL?
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dep r21=r19,r20,3,(PAGE_SHIFT-3) // compute address of L4 page table entry
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;;
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(p7) ld8 r18=[r21] // read the L4 PTE
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mov r19=cr.isr // cr.isr bit 0 tells us if this is an insn miss
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;;
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(p7) tbit.z p6,p7=r18,_PAGE_P_BIT // page present bit cleared?
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@@ -192,14 +206,21 @@ ENTRY(vhpt_miss)
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* between reading the pagetable and the "itc". If so, flush the entry we
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* inserted and retry.
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*/
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ld8 r25=[r21] // read L3 PTE again
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ld8 r26=[r17] // read L2 entry again
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ld8 r25=[r21] // read L4 entry again
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ld8 r26=[r17] // read L3 PTE again
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#ifdef CONFIG_PGTABLE_4
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ld8 r18=[r28] // read L2 entry again
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#endif
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cmp.ne p6,p7=r0,r0
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;;
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cmp.ne p6,p7=r26,r20 // did L2 entry change
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cmp.ne.or.andcm p6,p7=r26,r20 // did L3 entry change
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#ifdef CONFIG_PGTABLE_4
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cmp.ne.or.andcm p6,p7=r29,r18 // did L4 PTE change
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#endif
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mov r27=PAGE_SHIFT<<2
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;;
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(p6) ptc.l r22,r27 // purge PTE page translation
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(p7) cmp.ne.or.andcm p6,p7=r25,r18 // did L3 PTE change
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(p7) cmp.ne.or.andcm p6,p7=r25,r18 // did L4 PTE change
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;;
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(p6) ptc.l r16,r27 // purge translation
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#endif
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@@ -432,18 +453,30 @@ ENTRY(nested_dtlb_miss)
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(p6) dep r17=r18,r19,3,(PAGE_SHIFT-3) // r17=PTA + IFA(33,42)*8
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(p7) dep r17=r18,r17,3,(PAGE_SHIFT-6) // r17=PTA + (((IFA(61,63) << 7) | IFA(33,39))*8)
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cmp.eq p7,p6=0,r21 // unused address bits all zeroes?
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shr.u r18=r22,PMD_SHIFT // shift L2 index into position
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#ifdef CONFIG_PGTABLE_4
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shr.u r18=r22,PUD_SHIFT // shift L2 index into position
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#else
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shr.u r18=r22,PMD_SHIFT // shift L3 index into position
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#endif
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;;
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ld8 r17=[r17] // fetch the L1 entry (may be 0)
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;;
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(p7) cmp.eq p6,p7=r17,r0 // was L1 entry NULL?
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dep r17=r18,r17,3,(PAGE_SHIFT-3) // compute address of L2 page table entry
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;;
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#ifdef CONFIG_PGTABLE_4
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(p7) ld8 r17=[r17] // fetch the L2 entry (may be 0)
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shr.u r19=r22,PAGE_SHIFT // shift L3 index into position
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shr.u r18=r22,PMD_SHIFT // shift L3 index into position
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;;
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(p7) cmp.eq.or.andcm p6,p7=r17,r0 // was L2 entry NULL?
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dep r17=r19,r17,3,(PAGE_SHIFT-3) // compute address of L3 page table entry
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dep r17=r18,r17,3,(PAGE_SHIFT-3) // compute address of L2 page table entry
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;;
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#endif
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(p7) ld8 r17=[r17] // fetch the L3 entry (may be 0)
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shr.u r19=r22,PAGE_SHIFT // shift L4 index into position
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;;
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(p7) cmp.eq.or.andcm p6,p7=r17,r0 // was L3 entry NULL?
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dep r17=r19,r17,3,(PAGE_SHIFT-3) // compute address of L4 page table entry
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(p6) br.cond.spnt page_fault
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mov b0=r30
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br.sptk.many b0 // return to continuation point
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