Re: [PATCH v4 1/3] iommu/iova: Add free_all_cpu_cached_iovas()

[Jean-Philippe Brucker]

On Thu, Dec 10, 2020 at 02:23:07AM +0800, John Garry wrote:
> Add a helper function to free the CPU rcache for all online CPUs.
> 
> There also exists a function of the same name in
> drivers/iommu/intel/iommu.c, but the parameters are different, and there
> should be no conflict.
> 
> Signed-off-by: John Garry <john.garry@xxxxxxxxxx>
> Tested-by: Xiang Chen <chenxiang66@xxxxxxxxxxxxx>
> Reviewed-by: Zhen Lei <thunder.leizhen@xxxxxxxxxx>

Reviewed-by: Jean-Philippe Brucker <jean-philippe@xxxxxxxxxx>

(unless we find a better solution for patch 3)

> ---
>  drivers/iommu/iova.c | 13 +++++++++----
>  1 file changed, 9 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/iommu/iova.c b/drivers/iommu/iova.c
> index f9c35852018d..cf1aacda2fe4 100644
> --- a/drivers/iommu/iova.c
> +++ b/drivers/iommu/iova.c
> @@ -238,6 +238,14 @@ static int __alloc_and_insert_iova_range(struct iova_domain *iovad,
>  	return -ENOMEM;
>  }
>  
> +static void free_all_cpu_cached_iovas(struct iova_domain *iovad)
> +{
> +	unsigned int cpu;
> +
> +	for_each_online_cpu(cpu)
> +		free_cpu_cached_iovas(cpu, iovad);
> +}
> +
>  static struct kmem_cache *iova_cache;
>  static unsigned int iova_cache_users;
>  static DEFINE_MUTEX(iova_cache_mutex);
> @@ -435,15 +443,12 @@ alloc_iova_fast(struct iova_domain *iovad, unsigned long size,
>  retry:
>  	new_iova = alloc_iova(iovad, size, limit_pfn, true);
>  	if (!new_iova) {
> -		unsigned int cpu;
> -
>  		if (!flush_rcache)
>  			return 0;
>  
>  		/* Try replenishing IOVAs by flushing rcache. */
>  		flush_rcache = false;
> -		for_each_online_cpu(cpu)
> -			free_cpu_cached_iovas(cpu, iovad);
> +		free_all_cpu_cached_iovas(iovad);
>  		free_global_cached_iovas(iovad);
>  		goto retry;
>  	}
> -- 
> 2.26.2
> 
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