Re: [PATCH 1/1] swiotlb: save io_tlb_used to local variable before leaving critical section

From: Dongli Zhang
Date: Mon Apr 15 2019 - 02:47:20 EST


As the patch to be fixed is still in Konrad's own tree, I will send the v2 for
the patch to be fixed, instead of an incremental fix.

Dongli Zhang

On 4/12/19 10:13 PM, Joe Jin wrote:
> I'm good to have this patch, which helps identify the cause of failure is
> fragmentation or it really been used up.
>
> On 4/12/19 4:38 AM, Dongli Zhang wrote:
>> When swiotlb is full, the kernel would print io_tlb_used. However, the
>> result might be inaccurate at that time because we have left the critical
>> section protected by spinlock.
>>
>> Therefore, we backup the io_tlb_used into local variable before leaving
>> critical section.
>>
>> Fixes: 83ca25948940 ("swiotlb: dump used and total slots when swiotlb buffer is full")
>> Suggested-by: HÃkon Bugge <haakon.bugge@xxxxxxxxxx>
>> Signed-off-by: Dongli Zhang <dongli.zhang@xxxxxxxxxx>
>
> Reviewed-by: Joe Jin <joe.jin@xxxxxxxxxx>
>
> Thanks,
> Joe
>