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Date:   Fri, 10 Sep 2021 16:23:20 -0700 (PDT)
From:   Stefano Stabellini <sstabellini@kernel.org>
To:     Jan Beulich <jbeulich@suse.com>
cc:     Juergen Gross <jgross@suse.com>,
        Boris Ostrovsky <boris.ostrovsky@oracle.com>,
        Stefano Stabellini <sstabellini@kernel.org>,
        lkml <linux-kernel@vger.kernel.org>,
        "xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>
Subject: Re: [PATCH 06/12] swiotlb-xen: limit init retries
In-Reply-To: <984fa426-2b7b-4b77-5ce8-766619575b7f@suse.com>
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References: <588b3e6d-2682-160c-468e-44ca4867a570@suse.com> <984fa426-2b7b-4b77-5ce8-766619575b7f@suse.com>
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On Tue, 7 Sep 2021, Jan Beulich wrote:
> Due to the use of max(1024, ...) there's no point retrying (and issuing
> bogus log messages) when the number of slabs is already no larger than
> this minimum value.
> 
> Signed-off-by: Jan Beulich <jbeulich@suse.com>

Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>


> --- a/drivers/xen/swiotlb-xen.c
> +++ b/drivers/xen/swiotlb-xen.c
> @@ -207,7 +207,7 @@ retry:
>  	swiotlb_set_max_segment(PAGE_SIZE);
>  	return 0;
>  error:
> -	if (repeat--) {
> +	if (nslabs > 1024 && repeat--) {
>  		/* Min is 2MB */
>  		nslabs = max(1024UL, ALIGN(nslabs >> 1, IO_TLB_SEGSIZE));
>  		bytes = nslabs << IO_TLB_SHIFT;
> @@ -243,7 +243,7 @@ retry:
>  	rc = xen_swiotlb_fixup(start, nslabs);
>  	if (rc) {
>  		memblock_free(__pa(start), PAGE_ALIGN(bytes));
> -		if (repeat--) {
> +		if (nslabs > 1024 && repeat--) {
>  			/* Min is 2MB */
>  			nslabs = max(1024UL, ALIGN(nslabs >> 1, IO_TLB_SEGSIZE));
>  			bytes = nslabs << IO_TLB_SHIFT;
>