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authorZachary Amsden <zach@vmware.com>2006-09-30 23:29:33 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2006-10-01 00:39:33 -0700
commit6606c3e0da5360799e07ae24b05080cc85c68e72 (patch)
tree5072acfc3b36e48ec84fe28805d160cbc9b28900 /mm/mremap.c
parent9888a1cae3f859db38b9604e3df1c02177161bb0 (diff)
downloadlinaro-lsk-6606c3e0da5360799e07ae24b05080cc85c68e72.tar.gz
[PATCH] paravirt: lazy mmu mode hooks.patch
Implement lazy MMU update hooks which are SMP safe for both direct and shadow page tables. The idea is that PTE updates and page invalidations while in lazy mode can be batched into a single hypercall. We use this in VMI for shadow page table synchronization, and it is a win. It also can be used by PPC and for direct page tables on Xen. For SMP, the enter / leave must happen under protection of the page table locks for page tables which are being modified. This is because otherwise, you end up with stale state in the batched hypercall, which other CPUs can race ahead of. Doing this under the protection of the locks guarantees the synchronization is correct, and also means that spurious faults which are generated during this window by remote CPUs are properly handled, as the page fault handler must re-check the PTE under protection of the same lock. 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>
Diffstat (limited to 'mm/mremap.c')
-rw-r--r--mm/mremap.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/mm/mremap.c b/mm/mremap.c
index 7c15cf3373a..9c769fa29f3 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -98,6 +98,7 @@ static void move_ptes(struct vm_area_struct *vma, pmd_t *old_pmd,
new_ptl = pte_lockptr(mm, new_pmd);
if (new_ptl != old_ptl)
spin_lock_nested(new_ptl, SINGLE_DEPTH_NESTING);
+ arch_enter_lazy_mmu_mode();
for (; old_addr < old_end; old_pte++, old_addr += PAGE_SIZE,
new_pte++, new_addr += PAGE_SIZE) {
@@ -109,6 +110,7 @@ static void move_ptes(struct vm_area_struct *vma, pmd_t *old_pmd,
set_pte_at(mm, new_addr, new_pte, pte);
}
+ arch_leave_lazy_mmu_mode();
if (new_ptl != old_ptl)
spin_unlock(new_ptl);
pte_unmap_nested(new_pte - 1);