whence CONFIG_PROVE_SPIN_LOCKING?

whence CONFIG_PROVE_SPIN_LOCKING?

[Robert P. J. Day]

$ grep -r PROVE_SPIN_LOCKING *
Documentation/irqflags-tracing.txt:CONFIG_TRACE_IRQFLAGS_SUPPORT is needed for CONFIG_PROVE_SPIN_LOCKING
kernel/spinlock.c:#ifdef CONFIG_PROVE_SPIN_LOCKING

rday
-- 
========================================================================
Robert P. J. Day
Linux Consulting, Training and Annoying Kernel Pedantry
Waterloo, Ontario, CANADA

http://fsdev.net/wiki/index.php?title=Main_Page
========================================================================

Re: whence CONFIG_PROVE_SPIN_LOCKING?

[Jiri Kosina]

On Sun, 18 Mar 2007, Robert P. J. Day wrote:

> $ grep -r PROVE_SPIN_LOCKING *
> Documentation/irqflags-tracing.txt:CONFIG_TRACE_IRQFLAGS_SUPPORT is needed for CONFIG_PROVE_SPIN_LOCKING
> kernel/spinlock.c:#ifdef CONFIG_PROVE_SPIN_LOCKING

This should almost certainly be CONFIG_PROVE_LOCKING ... ?

-- 
Jiri Kosina

Re: whence CONFIG_PROVE_SPIN_LOCKING?

[Robert P. J. Day]

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On Sun, 18 Mar 2007, Jiri Kosina wrote:

> On Sun, 18 Mar 2007, Robert P. J. Day wrote:
>
> > $ grep -r PROVE_SPIN_LOCKING *
> > Documentation/irqflags-tracing.txt:CONFIG_TRACE_IRQFLAGS_SUPPORT is needed for CONFIG_PROVE_SPIN_LOCKING
> > kernel/spinlock.c:#ifdef CONFIG_PROVE_SPIN_LOCKING
>
> This should almost certainly be CONFIG_PROVE_LOCKING ... ?

actually, no, i found this web page:

http://www.ussg.iu.edu/hypermail/linux/kernel/0606.0/0527.html

which refers to a number of related "PROVE" options.  what their
status is these days is not clear, but i'm just pointing out that
someone is testing the one above when it can't possibly be set
anywhere.

rday

p.s.  just FYI, i ran my "find dead CONFIG variables" script on the
entire tree and, as we speak, there are 316 preprocessor tests that
are testing variables of the form "CONFIG_whatever" for which that
option is not set anywhere in the tree.  (that is, 316 distinct
variables, not just 316 distinct tests.)  see the attached script and
feel free to run it from the top of the tree on your favourite
directory or sub-directory.

i'm not saying every one of those examples represents an error.  some
of those might be set in a makefile, etc.  but it's enlghtening to run
it anyway to see the output.

-- 
========================================================================
Robert P. J. Day
Linux Consulting, Training and Annoying Kernel Pedantry
Waterloo, Ontario, CANADA

http://fsdev.net/wiki/index.php?title=Main_Page
========================================================================

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Re: whence CONFIG_PROVE_SPIN_LOCKING?

[Denis Vlasenko]

Hi,

On Sunday 18 March 2007 22:06, Robert P. J. Day wrote:
> p.s.  just FYI, i ran my "find dead CONFIG variables" script on the
> entire tree and, as we speak, there are 316 preprocessor tests that
> are testing variables of the form "CONFIG_whatever" for which that
> option is not set anywhere in the tree.  (that is, 316 distinct
> variables, not just 316 distinct tests.)  see the attached script and
> feel free to run it from the top of the tree on your favourite
> directory or sub-directory.

In busybox project we adopted the usage of -Wundef
and we try to minimize usage of #ifdef CONFIG_xxx - each boolean
CONFIG_xxx option for busybox is accompanied with
ENABLE_xxx #define which is 1 or 0, never "undefined",
and we check it instead of CONFIG_xxx.

Because if -Wundef, gcc complains whenever we use #if
on undefined ENABLE_xxx.
--
vda