2005-12-27 03:32:43

by jeff shia

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Subject: do we still need the jiffies wraparound functions ?

Hello,

Under the kernel 2.6.x,the jiffies is defined as u64.We cannot count
on it to overflow.
Do we still need the functions to solve this problem?

Thank you.


2005-12-27 04:02:37

by Tim Schmielau

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Subject: Re: do we still need the jiffies wraparound functions ?

On Tue, 27 Dec 2005, jeff shia wrote:

> Under the kernel 2.6.x,the jiffies is defined as u64.We cannot count
> on it to overflow.

Actually, no. jiffies is still defined as unsigned long, which reduces
overhead where 64 bit jiffies are not needed. Only jiffies_64 is an u64.

> Do we still need the functions to solve this problem?

Yes.

Tim

2005-12-27 04:05:06

by Dave Jones

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Subject: Re: do we still need the jiffies wraparound functions ?

On Tue, Dec 27, 2005 at 11:32:41AM +0800, jeff shia wrote:
> Hello,
>
> Under the kernel 2.6.x,the jiffies is defined as u64.We cannot count
> on it to overflow.

You can guarantee it will overflow within a few minutes of booting.
This is done deliberatly to catch jiffy-wrap bugs.

> Do we still need the functions to solve this problem?

yes.

Dave