linux-kernel - Re: [RESEND PATCH v3 1/4] iommu/iova: Add free_all_cpu_cached

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Date:   Wed, 9 Dec 2020 16:58:56 +0800
From:   "Leizhen (ThunderTown)" <thunder.leizhen@...wei.com>
To:     John Garry <john.garry@...wei.com>, <robin.murphy@....com>,
        <joro@...tes.org>, <will@...nel.org>
CC:     <linuxarm@...wei.com>, <linux-kernel@...r.kernel.org>,
        <iommu@...ts.linux-foundation.org>, <xiyou.wangcong@...il.com>
Subject: Re: [RESEND PATCH v3 1/4] iommu/iova: Add free_all_cpu_cached_iovas()

On 2020/11/17 18:25, 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@...wei.com>
> ---
>  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 30d969a4c5fd..81b7399dd5e8 100644
> --- a/drivers/iommu/iova.c
> +++ b/drivers/iommu/iova.c
> @@ -227,6 +227,14 @@ 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);
> @@ -422,15 +430,12 @@ 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);
>  		goto retry;
>  	}
>  

Reviewed-by: Zhen Lei <thunder.leizhen@...wei.com>

>