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authorZachary Amsden <zach@vmware.com>2006-09-30 23:29:31 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2006-10-01 00:39:33 -0700
commit9888a1cae3f859db38b9604e3df1c02177161bb0 (patch)
tree5954dc5e1a2dc1251a57a41aa15b7776a530f230
parent3dc907951446b9317b1887223caa4e083390de9f (diff)
[PATCH] paravirt: pte clear not present
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@vmware.com> Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
-rw-r--r--include/asm-generic/pgtable.h9
-rw-r--r--mm/fremap.c2
-rw-r--r--mm/memory.c2
3 files changed, 9 insertions, 4 deletions
diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h
index 349260cd86ed..78740716c9e7 100644
--- a/include/asm-generic/pgtable.h
+++ b/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 --git a/mm/fremap.c b/mm/fremap.c
index aa30618ec6b2..7a9d0f5d246d 100644
--- a/mm/fremap.c
+++ b/mm/fremap.c
@@ -39,7 +39,7 @@ static int zap_pte(struct mm_struct *mm, struct vm_area_struct *vma,
} 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 --git a/mm/memory.c b/mm/memory.c
index 7707187484cc..2e754621d333 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -690,7 +690,7 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb,
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);

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