I updated this one[3/3] only to use [vk]zalloc Changelog: I replaced ((vmalloc | kmalloc) + memset) with (vzalloc | kzalloc). Also, the patch description was updated.
vzalloc() was introduced recently, so this one may be better. BTW, I noticed that bitmaps are created/destroyed many times: logging stop/start frequently from qemu side? So even after the double buffering patch[2/3], this patch may have more performance gain than I expected. Takuya === 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 <[email protected]> --- virt/kvm/kvm_main.c | 13 ++++++++++--- 1 files changed, 10 insertions(+), 3 deletions(-) diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 8b28581..45d2cef 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; } -- 1.7.0.4 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
