Messages in this thread Patch in this message | | | Date | Fri, 25 Mar 2022 23:31:25 +0000 | Subject | [PATCH] KVM: x86/mmu: Speed up slot_rmap_walk_next for sparsely populated rmaps | From | Vipin Sharma <> |
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Avoid calling handlers on empty rmap entries and skip to the next non empty rmap entry.
Empty rmap entries are noop in handlers.
Signed-off-by: Vipin Sharma <vipinsh@google.com> Suggested-by: Sean Christopherson <seanjc@google.com> Change-Id: I8abf0f4d82a2aae4c5d58b80bcc17ffc30785ffc --- arch/x86/kvm/mmu/mmu.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 51671cb34fb6..f296340803ba 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -1499,11 +1499,14 @@ static bool slot_rmap_walk_okay(struct slot_rmap_walk_iterator *iterator) return !!iterator->rmap; } -static void slot_rmap_walk_next(struct slot_rmap_walk_iterator *iterator) +static noinline void +slot_rmap_walk_next(struct slot_rmap_walk_iterator *iterator) { - if (++iterator->rmap <= iterator->end_rmap) { + while (++iterator->rmap <= iterator->end_rmap) { iterator->gfn += (1UL << KVM_HPAGE_GFN_SHIFT(iterator->level)); - return; + + if (iterator->rmap->val) + return; } if (++iterator->level > iterator->end_level) { base-commit: c9b8fecddb5bb4b67e351bbaeaa648a6f7456912 -- 2.35.1.1021.g381101b075-goog
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