The patch titled
paravirt: pte clear not present
has been added to the -mm tree. Its filename is
paravirt-pte-clear-not-present.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: paravirt: pte clear not present
From: Zachary Amsden <zach@xxxxxxxxxx>
Change pte_clear_full to a more appropriately named pte_clear_not_present,
allowing optimizations when not-present mapping changes need not be reflected
in the hardware TLB for protected page table modes. There is also another
case that can use it in the fremap code.
Signed-off-by: Zachary Amsden <zach@xxxxxxxxxx>
Signed-off-by: Jeremy Fitzhardinge <jeremy@xxxxxxxxxxxxx>
Cc: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
include/asm-generic/pgtable.h | 9 +++++++--
mm/fremap.c | 2 +-
mm/memory.c | 2 +-
3 files changed, 9 insertions(+), 4 deletions(-)
diff -puN include/asm-generic/pgtable.h~paravirt-pte-clear-not-present include/asm-generic/pgtable.h
--- a/include/asm-generic/pgtable.h~paravirt-pte-clear-not-present
+++ a/include/asm-generic/pgtable.h
@@ -112,8 +112,13 @@ do { \
})
#endif
-#ifndef __HAVE_ARCH_PTE_CLEAR_FULL
-#define pte_clear_full(__mm, __address, __ptep, __full) \
+/*
+ * Some architectures may be able to avoid expensive synchronization
+ * primitives when modifications are made to PTE's which are already
+ * not present, or in the process of an address space destruction.
+ */
+#ifndef __HAVE_ARCH_PTE_CLEAR_NOT_PRESENT_FULL
+#define pte_clear_not_present_full(__mm, __address, __ptep, __full) \
do { \
pte_clear((__mm), (__address), (__ptep)); \
} while (0)
diff -puN mm/fremap.c~paravirt-pte-clear-not-present mm/fremap.c
--- a/mm/fremap.c~paravirt-pte-clear-not-present
+++ a/mm/fremap.c
@@ -39,7 +39,7 @@ static int zap_pte(struct mm_struct *mm,
} else {
if (!pte_file(pte))
free_swap_and_cache(pte_to_swp_entry(pte));
- pte_clear(mm, addr, ptep);
+ pte_clear_not_present_full(mm, addr, ptep, 0);
}
return !!page;
}
diff -puN mm/memory.c~paravirt-pte-clear-not-present mm/memory.c
--- a/mm/memory.c~paravirt-pte-clear-not-present
+++ a/mm/memory.c
@@ -690,7 +690,7 @@ static unsigned long zap_pte_range(struc
continue;
if (!pte_file(ptent))
free_swap_and_cache(pte_to_swp_entry(ptent));
- pte_clear_full(mm, addr, pte, tlb->fullmm);
+ pte_clear_not_present_full(mm, addr, pte, tlb->fullmm);
} while (pte++, addr += PAGE_SIZE, (addr != end && *zap_work > 0));
add_mm_rss(mm, file_rss, anon_rss);
_
Patches currently in -mm which might be from zach@xxxxxxxxxx are
split-i386-and-x86_64-ptraceh.patch
uml-use-ptrace-abih-instead-of-ptraceh.patch
x86-allow-a-kernel-to-not-be-in-ring-0.patch
x86-allow-a-kernel-to-not-be-in-ring-0-tidy.patch
x86-add-a-bootparameter-to-reserve-high-linear-address-space.patch
x86-trivial-pgtableh-__assembly__-move.patch
x86-trivial-move-of-__have-macros-in-i386-pagetable-headers.patch
x86-trivial-move-of-ptep_set_access_flags.patch
x86-remove-unused-include-from-efi_stubs.patch
paravirt-remove-read-hazard-from-cow.patch
paravirt-pte-clear-not-present.patch
paravirt-lazy-mmu-mode-hooks.patch
paravirt-combine-flush-accessed-dirty.patch
paravirt-kpte-flush.patch
paravirt-optimize-ptep-establish-for-pae.patch
paravirt-remove-set-pte-atomic.patch
paravirt-pae-compile-fix.patch
paravirt-update-pte-hook.patch
-
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