From: David Vrabel <dvrabel@cantab•net>
To: Wei Liu <wei.liu2@citrix•com>,
xen-devel@lists•xen.org, netdev@vger•kernel.org
Cc: Ian Campbell <ian.campbell@citrix•com>,
annie.li@oracle•com, david.vrabel@citrix•com, jbeulich@suse•com,
Jason Luan <jianhai.luan@oracle•com>
Subject: Re: [Xen-devel] [PATCH net V2] xen-netback: use jiffies_64 value to calculate credit timeout
Date: Mon, 28 Oct 2013 11:53:38 +0000 [thread overview]
Message-ID: <526E5042.7080406@cantab.net> (raw)
In-Reply-To: <1382960117-13053-1-git-send-email-wei.liu2@citrix.com>
On 28/10/2013 11:35, Wei Liu wrote:
> time_after_eq() only works if the delta is < MAX_ULONG/2.
>
> For a 32bit Dom0, if netfront sends packets at a very low rate, the time
> between subsequent calls to tx_credit_exceeded() may exceed MAX_ULONG/2
> and the test for timer_after_eq() will be incorrect. Credit will not be
> replenished and the guest may become unable to send packets (e.g., if
> prior to the long gap, all credit was exhausted).
>
> Use jiffies_64 variant to mitigate this problem for 32bit Dom0.
Reviewed-by: David Vrabel <david.vrabel@citrix•com>
David
prev parent reply other threads:[~2013-10-28 11:53 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-10-28 11:35 [PATCH net V2] xen-netback: use jiffies_64 value to calculate credit timeout Wei Liu
2013-10-28 11:49 ` Jan Beulich
2013-10-28 12:01 ` Wei Liu
2013-10-28 11:53 ` David Vrabel [this message]
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