diff options
| author | Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp> | 2012-03-21 15:49:39 +0100 |
|---|---|---|
| committer | Avi Kivity <avi@redhat.com> | 2012-04-08 15:08:25 +0200 |
| commit | 220f773a0013bf6fe2eefd9718ac7471f368fd8e (patch) | |
| tree | a4062100aff69a887a3636743fa407d440d7c512 | |
| parent | KVM: x86: add paging gcc optimization (diff) | |
| download | linux-220f773a0013bf6fe2eefd9718ac7471f368fd8e.tar.xz linux-220f773a0013bf6fe2eefd9718ac7471f368fd8e.zip | |
KVM: MMU: Make pte_list_desc fit cache lines well
We have PTE_LIST_EXT + 1 pointers in this structure and these 40/20
bytes do not fit cache lines well. Furthermore, some allocators may
use 64/32-byte objects for the pte_list_desc cache.
This patch solves this problem by changing PTE_LIST_EXT from 4 to 3.
For shadow paging, the new size is still large enough to hold both the
kernel and process mappings for usual anonymous pages. For file
mappings, there may be a slight change in the cache usage.
Note: with EPT/NPT we almost always have a single spte in each reverse
mapping and we will not see any change by this.
Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Signed-off-by: Avi Kivity <avi@redhat.com>
| -rw-r--r-- | arch/x86/kvm/mmu.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index dc5f2459db6c..3213348e3a93 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -135,8 +135,6 @@ module_param(dbg, bool, 0644); #define PT64_PERM_MASK (PT_PRESENT_MASK | PT_WRITABLE_MASK | PT_USER_MASK \ | PT64_NX_MASK) -#define PTE_LIST_EXT 4 - #define ACC_EXEC_MASK 1 #define ACC_WRITE_MASK PT_WRITABLE_MASK #define ACC_USER_MASK PT_USER_MASK @@ -151,6 +149,9 @@ module_param(dbg, bool, 0644); #define SHADOW_PT_INDEX(addr, level) PT64_INDEX(addr, level) +/* make pte_list_desc fit well in cache line */ +#define PTE_LIST_EXT 3 + struct pte_list_desc { u64 *sptes[PTE_LIST_EXT]; struct pte_list_desc *more; |