From: jianhai luan <jianhai.luan@oracle.com>
To: Wei Liu <wei.liu2@citrix.com>, David Laight <David.Laight@ACULAB.COM>
Cc: Jan Beulich <JBeulich@suse.com>, annie li <annie.li@oracle.com>,
david.vrabel@citrix.com, ian.campbell@citrix.com,
xen-devel@lists.xenproject.org, netdev@vger.kernel.org
Subject: Re: [Xen-devel] [PATCH net] xen-netback: add the scenario which now beyond the range time_after_eq().
Date: Wed, 23 Oct 2013 16:02:14 +0800 [thread overview]
Message-ID: <52678286.6000802@oracle.com> (raw)
In-Reply-To: <20131018112417.GA20185@zion.uk.xensource.com>
On 2013-10-18 19:24, Wei Liu wrote:
> On Fri, Oct 18, 2013 at 09:40:33AM +0100, David Laight wrote:
>>>> My understanding is this patch does not simply double the span, it is
>>>> just stricter than the original one. Please check my previous comments,
>>>> I paste it here.
>>> No, the code (on a 32-bit arch) just _can't_ handle jiffies differences
>>> beyond 2^32, no matter how cleverly you use the respective macros.
>>> All arithmetic there is done modulo 2^32.
>> I haven't followed this discussion very closely but it might be possible
>> to arrange that the 'incorrect lack of credit' only occurs for a few
>> seconds every time 'jiffies' wraps - instead of half of the time.
>> Then you'd have to be extremely unlucky to hit the timing window.
>>
> As I understand it, this is the idea of this patch -- to narrow down the
> timing window.
Jan, do you agree the idea or have better suggestion to me.
Thanks,
Jason
>
> Wei.
>
>> David
>>
>>
>>
>> --
>> To unsubscribe from this list: send the line "unsubscribe netdev" in
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next prev parent reply other threads:[~2013-10-23 8:02 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-10-16 17:22 [PATCH net] xen-netback: add the scenario which now beyond the range time_after_eq() Jason Luan
2013-10-17 8:26 ` [Xen-devel] " Jan Beulich
2013-10-17 9:02 ` jianhai luan
2013-10-17 9:04 ` jianhai luan
2013-10-17 9:15 ` David Vrabel
2013-10-17 10:19 ` jianhai luan
2013-10-17 10:31 ` David Vrabel
2013-10-17 13:59 ` jianhai luan
2013-10-17 14:06 ` Wei Liu
2013-10-17 15:23 ` jianhai luan
2013-10-17 15:25 ` David Vrabel
2013-10-17 15:41 ` jianhai luan
2013-10-18 6:48 ` annie li
2013-10-17 9:26 ` Jan Beulich
2013-10-17 9:59 ` jianhai luan
2013-10-17 16:38 ` annie li
2013-10-17 16:41 ` Wei Liu
2013-10-18 1:59 ` annie li
2013-10-18 7:43 ` Jan Beulich
2013-10-18 8:14 ` annie li
2013-10-18 8:26 ` Jan Beulich
2013-10-18 8:40 ` David Laight
2013-10-18 11:24 ` Wei Liu
2013-10-23 8:02 ` jianhai luan [this message]
2013-10-23 16:07 ` Jan Beulich
2013-10-24 10:04 ` David Laight
2013-10-24 11:34 ` jianhai luan
2013-10-18 8:55 ` annie li
2013-10-17 16:21 ` annie li
2013-10-18 7:41 ` Jan Beulich
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