Messages in this thread | | | Date | Wed, 01 Feb 2012 20:12:31 +0900 | From | Takuya Yoshikawa <> | Subject | Re: [RFC][PATCH] srcu: Implement call_srcu() |
| |
(2012/02/01 20:01), Avi Kivity wrote: > On 02/01/2012 01:00 PM, Takuya Yoshikawa wrote:
>> How about just doing: >> >> take a spin_lock >> copy the entire (or some portions of) bitmap locally >> clear the bitmap >> unlock >> > > That means that vcpus dirtying memory also have to take that lock, and > spin while the bitmap is being copied. So kvm_vm_ioctl_get_dirty_log() > will become faster, at the expense of vcpus, which I think is a bad > tradeoff.
Almost every caller is already holding the mmu_lock.
Isn't it possible to make others hold the lock only for the case of marking to the bitmap? (I will check myself too.)
>> write protect the dirty pages based on the copied dirty data >> >> copy_to_user >> >> >> >> I can show you some performance numbers, this weekend, if you like. > > That'll be great, numbers are better than speculation. >
Yes, I already have some good numbers to show (and some patches).
Takuya
| |