From 6f9e5c1702319e048a90e06e31b957fbbcecbe07 Mon Sep 17 00:00:00 2001 From: Takuya Yoshikawa Date: Mon, 1 Nov 2010 14:36:09 +0900 Subject: [PATCH] KVM: use kmalloc() for small dirty bitmaps Currently we are using vmalloc() for all dirty bitmaps even if they are small enough, say less than K bytes. We use kmalloc() if dirty bitmap size is less than or equal to PAGE_SIZE so that we can avoid vmalloc area usage for VGA. This will also make the logging start/stop faster. Signed-off-by: Takuya Yoshikawa Signed-off-by: Marcelo Tosatti --- virt/kvm/kvm_main.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 27649fdaa007..9ce1079e8f89 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -449,7 +449,11 @@ static void kvm_destroy_dirty_bitmap(struct kvm_memory_slot *memslot) if (!memslot->dirty_bitmap) return; - vfree(memslot->dirty_bitmap_head); + if (2 * kvm_dirty_bitmap_bytes(memslot) > PAGE_SIZE) + vfree(memslot->dirty_bitmap_head); + else + kfree(memslot->dirty_bitmap_head); + memslot->dirty_bitmap = NULL; memslot->dirty_bitmap_head = NULL; } @@ -547,11 +551,14 @@ static int kvm_create_dirty_bitmap(struct kvm_memory_slot *memslot) { unsigned long dirty_bytes = 2 * kvm_dirty_bitmap_bytes(memslot); - memslot->dirty_bitmap = vmalloc(dirty_bytes); + if (dirty_bytes > PAGE_SIZE) + memslot->dirty_bitmap = vzalloc(dirty_bytes); + else + memslot->dirty_bitmap = kzalloc(dirty_bytes, GFP_KERNEL); + if (!memslot->dirty_bitmap) return -ENOMEM; - memset(memslot->dirty_bitmap, 0, dirty_bytes); memslot->dirty_bitmap_head = memslot->dirty_bitmap; return 0; } -- 2.30.2