lkml.org 
[lkml]   [2012]   [Apr]   [20]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
Subjectmsecs_to_jiffies() still returns values greater then MAX_JIFFY_OFFSET
Hi,

i'm new to the LKML and so i couldn't reply to the old mail from Mar
2011.

On 29 Mar 2011 there was already a disucssion about this issue:

http://lkml.org/lkml/2011/3/29/262

The problem still exists, as /kernel/time.c wasn't patched. I stumbled
upon this "bug" when i modified the ipset sourcecode that uses
msecs_to_jiffies() for timeout calculations.

When i call msecs_to_jiffies(2147483000) the return value is 2147483000
on my x86 32-Bit System with 1000Hz. When i call the function with
msecs_to_jiffies(2147484000) the return value is MAX_JIFFY_OFFSET what's
1073741822 on my system. That isn't the behaviour i expect from this
comment in time.c:

* - 'too large' values [that would result in larger than
* MAX_JIFFY_OFFSET values] mean 'infinite timeout' too.

So you can pass values greater then MAX_JIFFY_OFFSET up to INT_MAX in
this example although the limit should be at INT_MAX/2 for
MAX_JIFFY_OFFSET.

I'm not sure if the solution is to increase MAX_JIFFY_OFFSET or to catch
values between this gap. I also don't understand why the function
returns a unsigned long but is limited to integer. It could be nice to
increase the values that can be handled with this function.

Greetings

--
Andreas Herz


\
 
 \ /
  Last update: 2012-04-20 09:05    [W:0.029 / U:0.288 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site