Re: [Xen-devel] [PATCH 2/2] xen/grant: introduce func gnttab_unmap_refs_async_wait_completion()

[David Vrabel <david.vrabel@citrix.com>]

On 30/03/15 01:03, Bob Liu wrote:
> 
> On 03/28/2015 08:44 AM, Konrad Rzeszutek Wilk wrote:
>> On Thu, Mar 26, 2015 at 04:32:45PM +0100, Roger Pau Monné wrote:
>>> El 26/03/15 a les 13.16, Bob Liu ha escrit:
>>>> There are several place using gnttab async unmap and wait for
>>>> completion, so move the common code to a function
>>>> gnttab_unmap_refs_async_wait_completion().
>>>>
>>>> Signed-off-by: Bob Liu <bob.liu@oracle.com>
>>>
>>> For the blkback parts:
>>>
>>> Acked-by: Roger Pau Monné <roger.pau@citrix.com>
>>>
>>> Although, as David already said, I think we should do better than BUG_ON
>>> on error.
>>
> 
> This patch only keeps the existing behaviour the same as before. I
> prefer to make new patches(based on this one) if want to change the
> behaviour.
> 
>> Have an 'stuck deferred pages' list and an timer to occasionally
>> flush them out? Something similar to 569ca5b3f94cd0b3295ec5943aa457cf4a4f6a3a
>> "xen/gnttab: add deferred freeing logic" ?
> 
> Sounds like a good idea.

If it failed the first time I don't see how it would succeed later.  No
one has actually hit this particular BUG_ON() so I would leave it as is.

David