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authorZachary Amsden <zach@vmware.com>2006-10-01 02:29:36 -0400
committerLinus Torvalds <torvalds@g5.osdl.org>2006-10-01 03:39:34 -0400
commitd6d861e3c963b4077c83e078e3e300c4b81f93e7 (patch)
tree842071ac905575aa0ea8bedd3a1ac5db29416bcf /include/asm-i386/pgtable-2level.h
parent23002d88be309a7c78db69363c9d933a29a3b0bb (diff)
[PATCH] paravirt: optimize ptep establish for pae
The ptep_establish macro is only used on user-level PTEs, for P->P mapping changes. Since these always happen under protection of the pagetable lock, the strong synchronization of a 64-bit cmpxchg is not needed, in fact, not even a lock prefix needs to be used. We can simply instead clear the P-bit, followed by a normal set. The write ordering is still important to avoid the possibility of the TLB snooping a partially written PTE and getting a bad mapping installed. Signed-off-by: Zachary Amsden <zach@vmware.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Jeremy Fitzhardinge <jeremy@xensource.com> Cc: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'include/asm-i386/pgtable-2level.h')
-rw-r--r--include/asm-i386/pgtable-2level.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/include/asm-i386/pgtable-2level.h b/include/asm-i386/pgtable-2level.h
index 201c86a6711e..8d8d3b9ecdb0 100644
--- a/include/asm-i386/pgtable-2level.h
+++ b/include/asm-i386/pgtable-2level.h
@@ -16,6 +16,7 @@
16#define set_pte(pteptr, pteval) (*(pteptr) = pteval) 16#define set_pte(pteptr, pteval) (*(pteptr) = pteval)
17#define set_pte_at(mm,addr,ptep,pteval) set_pte(ptep,pteval) 17#define set_pte_at(mm,addr,ptep,pteval) set_pte(ptep,pteval)
18#define set_pte_atomic(pteptr, pteval) set_pte(pteptr,pteval) 18#define set_pte_atomic(pteptr, pteval) set_pte(pteptr,pteval)
19#define set_pte_present(mm,addr,ptep,pteval) set_pte_at(mm,addr,ptep,pteval)
19#define set_pmd(pmdptr, pmdval) (*(pmdptr) = (pmdval)) 20#define set_pmd(pmdptr, pmdval) (*(pmdptr) = (pmdval))
20 21
21#define pte_clear(mm,addr,xp) do { set_pte_at(mm, addr, xp, __pte(0)); } while (0) 22#define pte_clear(mm,addr,xp) do { set_pte_at(mm, addr, xp, __pte(0)); } while (0)