* Question re: __mlog_cpu_guess in fs/ocfs2/cluster/masklog.h
@ 2006-05-22 23:45 Lee Revell
2006-05-23 15:27 ` Zach Brown
0 siblings, 1 reply; 4+ messages in thread
From: Lee Revell @ 2006-05-22 23:45 UTC (permalink / raw)
To: linux-kernel; +Cc: mark.fasheh, kurt.hackel
I am puzzled by this code and comment:
/*
* smp_processor_id() "helpfully" screams when called outside preemptible
* regions in current kernels. sles doesn't have the variants that don't
* scream. just do this instead of trying to guess which we're building
* against.. *sigh*.
*/
#define __mlog_cpu_guess ({ \
unsigned long _cpu = get_cpu(); \
put_cpu(); \
_cpu; \
})
First I think you mean "inside preemptible regions". Second, it screams
because it's a bug to call smp_processor_id() from preemptible code!
Am I missing something?
Lee
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: Question re: __mlog_cpu_guess in fs/ocfs2/cluster/masklog.h
2006-05-22 23:45 Question re: __mlog_cpu_guess in fs/ocfs2/cluster/masklog.h Lee Revell
@ 2006-05-23 15:27 ` Zach Brown
2006-05-23 16:34 ` Lee Revell
0 siblings, 1 reply; 4+ messages in thread
From: Zach Brown @ 2006-05-23 15:27 UTC (permalink / raw)
To: Lee Revell; +Cc: linux-kernel, mark.fasheh, kurt.hackel
> Am I missing something?
The comment isn't particularly coherent and can be gotten rid of. What
puzzles you about the code?
- z
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: Question re: __mlog_cpu_guess in fs/ocfs2/cluster/masklog.h
2006-05-23 15:27 ` Zach Brown
@ 2006-05-23 16:34 ` Lee Revell
2006-05-23 16:42 ` Zach Brown
0 siblings, 1 reply; 4+ messages in thread
From: Lee Revell @ 2006-05-23 16:34 UTC (permalink / raw)
To: Zach Brown; +Cc: linux-kernel, mark.fasheh, kurt.hackel
On Tue, 2006-05-23 at 08:27 -0700, Zach Brown wrote:
> > Am I missing something?
>
> The comment isn't particularly coherent and can be gotten rid of. What
> puzzles you about the code?
I was wondering how it could not be a bug to use smp_processor_id in
preemptible code, but I see that it's only used for debug output. Sorry
for the noise.
Lee
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: Question re: __mlog_cpu_guess in fs/ocfs2/cluster/masklog.h
2006-05-23 16:34 ` Lee Revell
@ 2006-05-23 16:42 ` Zach Brown
0 siblings, 0 replies; 4+ messages in thread
From: Zach Brown @ 2006-05-23 16:42 UTC (permalink / raw)
To: Lee Revell; +Cc: linux-kernel, mark.fasheh, kurt.hackel
> I was wondering how it could not be a bug to use smp_processor_id in
> preemptible code, but I see that it's only used for debug output. Sorry
> for the noise.
No problem, thanks for taking a look in the first place. We'll update
the comment to make it more explicit.
- z
^ permalink raw reply [flat|nested] 4+ messages in thread
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2006-05-22 23:45 Question re: __mlog_cpu_guess in fs/ocfs2/cluster/masklog.h Lee Revell
2006-05-23 15:27 ` Zach Brown
2006-05-23 16:34 ` Lee Revell
2006-05-23 16:42 ` Zach Brown
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