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From: Zoltan Kiss <zoltan.kiss@citrix•com>
To: Ian Campbell <Ian.Campbell@citrix•com>,
	Konrad Rzeszutek Wilk <konrad.wilk@oracle•com>,
	David Vrabel <david.vrabel@citrix•com>
Cc: <wei.liu2@citrix•com>, <xen-devel@lists•xenproject.org>,
	<netdev@vger•kernel.org>, <linux-kernel@vger•kernel.org>,
	<jonathan.davies@citrix•com>
Subject: Re: [PATCH net-next v7 4/9] xen-netback: Introduce TX grant mapping
Date: Thu, 13 Mar 2014 12:34:32 +0000	[thread overview]
Message-ID: <5321A5D8.3060507@citrix.com> (raw)
In-Reply-To: <1394705874.25873.19.camel@kazak.uk.xensource.com>

On 13/03/14 10:17, Ian Campbell wrote:
> Pulling out this one comment for the attention on the core Xen/Linux
> maintainers.
>
> On Thu, 2014-03-06 at 21:48 +0000, Zoltan Kiss wrote:
> [...]
>> @@ -343,8 +347,26 @@ struct xenvif *xenvif_alloc(struct device *parent, domid_t domid,
>>   	vif->pending_prod = MAX_PENDING_REQS;
>>   	for (i = 0; i < MAX_PENDING_REQS; i++)
>>   		vif->pending_ring[i] = i;
>> -	for (i = 0; i < MAX_PENDING_REQS; i++)
>> -		vif->mmap_pages[i] = NULL;
>> +	spin_lock_init(&vif->callback_lock);
>> +	spin_lock_init(&vif->response_lock);
>> +	/* If ballooning is disabled, this will consume real memory, so you
>> +	 * better enable it. The long term solution would be to use just a
>> +	 * bunch of valid page descriptors, without dependency on ballooning
>> +	 */
>
> I wonder if we ought to enforce this via Kconfig? i.e. making
> CONFIG_XEN_BACKEND (or the individual backends) depend on BALLOON (or
> select?) or by making CONFIG_XEN_BALLOON non-optional etc.
I support this idea, but let's have other's views.
>
> IIRC David V was looking into a solution involving auto hotplugging a
> new region to use for this case, but then I guess
> CONFIG_XEN_BALLOON_MEMORY_HOTPLUG would equally need to be enabled.
Yes, if that happens in the near future, we shouldn't be bothered by the 
above right now.

>
>> +	err = alloc_xenballooned_pages(MAX_PENDING_REQS,
>> +				       vif->mmap_pages,
>> +				       false);
> [...]
>

  reply	other threads:[~2014-03-13 12:34 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-03-06 21:48 [PATCH net-next v7 0/9] xen-netback: TX grant mapping with SKBTX_DEV_ZEROCOPY instead of copy Zoltan Kiss
2014-03-06 21:48 ` [PATCH net-next v7 1/9] xen-netback: Use skb->cb for pending_idx Zoltan Kiss
2014-03-06 21:48 ` [PATCH net-next v7 2/9] xen-netback: Minor refactoring of netback code Zoltan Kiss
2014-03-06 21:48 ` [PATCH net-next v7 3/9] xen-netback: Handle foreign mapped pages on the guest RX path Zoltan Kiss
2014-03-06 21:48 ` [PATCH net-next v7 4/9] xen-netback: Introduce TX grant mapping Zoltan Kiss
2014-03-13 10:17   ` Ian Campbell
2014-03-13 12:34     ` Zoltan Kiss [this message]
2014-03-13 10:33   ` Ian Campbell
2014-03-13 10:56     ` [Xen-devel] " David Vrabel
2014-03-13 11:02       ` Ian Campbell
2014-03-13 11:09         ` David Vrabel
2014-03-13 11:13         ` Wei Liu
2014-03-13 13:17     ` Zoltan Kiss
2014-03-13 13:56       ` Ian Campbell
2014-03-13 17:43         ` Zoltan Kiss
2014-03-06 21:48 ` [PATCH net-next v7 5/9] xen-netback: Remove old TX grant copy definitons and fix indentations Zoltan Kiss
2014-03-06 21:48 ` [PATCH net-next v7 6/9] xen-netback: Add stat counters for zerocopy Zoltan Kiss
2014-03-06 21:48 ` [PATCH net-next v7 7/9] xen-netback: Handle guests with too many frags Zoltan Kiss
2014-03-06 21:48 ` [PATCH net-next v7 8/9] xen-netback: Timeout packets in RX path Zoltan Kiss
2014-03-13 10:39   ` Ian Campbell
2014-03-06 21:48 ` [PATCH net-next v7 9/9] xen-netback: Aggregate TX unmap operations Zoltan Kiss
2014-03-19 21:16   ` Zoltan Kiss
2014-03-20  9:53     ` Paul Durrant
2014-03-20 10:48     ` Wei Liu
2014-03-20 11:14       ` Paul Durrant
2014-03-20 12:38         ` Wei Liu
2014-03-20 16:11           ` Zoltan Kiss
2014-03-07 21:05 ` [PATCH net-next v7 0/9] xen-netback: TX grant mapping with SKBTX_DEV_ZEROCOPY instead of copy David Miller
2014-03-08 14:37   ` Zoltan Kiss
2014-03-08 23:57     ` David Miller
2014-03-10 10:15       ` Wei Liu
2014-03-12 15:40       ` Ian Campbell
2014-03-12 18:49         ` Zoltan Kiss
2014-03-13 10:43         ` Ian Campbell
2014-03-13 10:08 ` Ian Campbell
2014-03-13 18:23   ` Zoltan Kiss

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