Re: [PATCH] kvm_vm_ioctl_get_dirty_log doesn't need any, probably doesn't want any

[Avi Kivity <avi-atKUWr5tajBWk0Htik3J/w@public.gmane.org>]

Rusty Russell wrote:
> I'm not sure what "any" was for: some optimization which got trimmed,
> I imagine.  But neither "any" nor "i" are used later in the function,
> so I've excised it.
>
>   

Looks like it was used to guard kvm_mmu_slot_remove_write_access(); 
optimizing the case where the guest just leaves the screen alone (which 
it usually does, especially in benchmarks).

I'd rather reinstate that optimization.  See 
66d8a4e4d4bd470216028daabb9d887b73259c96 where the damage was done.

> Signed-off-by: Rusty Russell <rusty-8n+1lVoiYb80n/F98K4Iww@public.gmane.org>
>
> diff -r a17d7fe2b240 drivers/kvm/kvm_main.c
> --- a/drivers/kvm/kvm_main.c	Mon Jul 30 15:10:22 2007 +1000
> +++ b/drivers/kvm/kvm_main.c	Mon Jul 30 15:20:33 2007 +1000
> @@ -830,9 +830,7 @@ static int kvm_vm_ioctl_get_dirty_log(st
>  				      struct kvm_dirty_log *log)
>  {
>  	struct kvm_memory_slot *memslot;
> -	int r, i;
> -	int n;
> -	unsigned long any = 0;
> +	int r, n;
>  
>  	spin_lock(&kvm->lock);
>  
> @@ -851,11 +849,7 @@ static int kvm_vm_ioctl_get_dirty_log(st
>  	if (!memslot->dirty_bitmap)
>  		goto out;
>  
> -	n = ALIGN(memslot->npages, BITS_PER_LONG) / 8;
> -
> -	for (i = 0; !any && i < n/sizeof(long); ++i)
> -		any = memslot->dirty_bitmap[i];
> -
> +	n = BITS_TO_LONGS(memslot->npages) * sizeof(long);
>  	r = -EFAULT;
>  	if (copy_to_user(log->dirty_bitmap, memslot->dirty_bitmap, n))
>  		goto out;
>
>
>   


-- 
error compiling committee.c: too many arguments to function


-------------------------------------------------------------------------
This SF.net email is sponsored by: Splunk Inc.
Still grepping through log files to find problems?  Stop.
Now Search log events and configuration files using AJAX and a browser.
Download your FREE copy of Splunk now >>  http://get.splunk.com/