* 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
end of thread, other threads:[~2006-05-23 16:42 UTC | newest] Thread overview: 4+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 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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