Re: [RFC][PATCH] srcu: Implement call_srcu()
From: Avi Kivity
Date: Wed Feb 01 2012 - 06:02:02 EST
On 02/01/2012 01:00 PM, Takuya Yoshikawa wrote:
>> rcu_assign_pointer), and use atomic operations to copy and clear:
>> word = bitmap[i]
>> atomic_and(&bitmap[i], ~word)
> This kind of this was really slow IIRC.
> How about just doing:
> take a spin_lock
> copy the entire (or some portions of) bitmap locally
> clear the bitmap
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
> write protect the dirty pages based on the copied dirty data
> I can show you some performance numbers, this weekend, if you like.
That'll be great, numbers are better than speculation.
error compiling committee.c: too many arguments to function
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