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| author | Anthony Yznaga <anthony.yznaga@oracle.com> | 2020-06-02 23:07:29 +0300 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2020-06-04 21:42:35 +0300 |
| commit | 4b44295538b421de2de8b5754472284fe2daa4e9 (patch) | |
| tree | 78817f473b4d571a80885ba9ae9aabc79fbef474 /arch/x86/kvm/x86.c | |
| parent | 5688fed649f15a232e75148afb0a28864046f44c (diff) | |
| download | linux-4b44295538b421de2de8b5754472284fe2daa4e9.tar.xz | |
KVM: x86: avoid unnecessary rmap walks when creating/moving slots
On large memory guests it has been observed that creating a memslot
for a very large range can take noticeable amount of time.
Investigation showed that the time is spent walking the rmaps to update
existing sptes to remove write access or set/clear dirty bits to support
dirty logging. These rmap walks are unnecessary when creating or moving
a memslot. A newly created memslot will not have any existing mappings,
and the existing mappings of a moved memslot will have been invalidated
and flushed. Any mappings established once the new/moved memslot becomes
visible will be set using the properties of the new slot.
Signed-off-by: Anthony Yznaga <anthony.yznaga@oracle.com>
Message-Id: <1591128450-11977-3-git-send-email-anthony.yznaga@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/x86.c')
| -rw-r--r-- | arch/x86/kvm/x86.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index e11e0494f833..f39bdd5fd7cf 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -10242,7 +10242,7 @@ void kvm_arch_commit_memory_region(struct kvm *kvm, * * FIXME: const-ify all uses of struct kvm_memory_slot. */ - if (change != KVM_MR_DELETE) + if (change == KVM_MR_FLAGS_ONLY) kvm_mmu_slot_apply_flags(kvm, (struct kvm_memory_slot *) new); /* Free the arrays associated with the old memslot. */ |