On Mon, Apr 26, 2010 at 06:58:54PM +0900, Takuya Yoshikawa wrote: > Although we always allocate a new dirty bitmap in x86's get_dirty_log(), > it is only used as a zero-source of copy_to_user() and freed right after > that when memslot is clean. This patch uses clear_user() instead of doing > this unnecessary zero-source allocation. > > Performance improvement: as we can expect easily, the time needed to > allocate a bitmap is completely reduced. In my test, the improved ioctl > was about 4 to 10 times faster than the original one for clean slots. > Furthermore, the reduced allocations seem to produce good effects for > other cases too. Actually, I observed that the time for the ioctl was > more stable than the original one and the average time for dirty slots > was also reduced by some extent. > > Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@xxxxxxxxxxxxx> Looks good to me. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
