* [linux-kernel]Why there are so many struct rw_semaphore being defined?
@ 2007-07-04 9:07 jidong xiao
2007-07-04 9:15 ` Oliver Neukum
0 siblings, 1 reply; 3+ messages in thread
From: jidong xiao @ 2007-07-04 9:07 UTC (permalink / raw)
To: linux-kernel
I see struct rw_semaphore is defined in
include/linux/rwsem-spinlock.h,in the meanwhile, I also can find it in
include/asm-**/rwsem.h,for
example,include/asm-i386/rwsem.h,include/asm-x86_64/rwsem.h,why?which
one should be used?
Thanks
Jason Xiao
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [linux-kernel]Why there are so many struct rw_semaphore being defined?
2007-07-04 9:07 [linux-kernel]Why there are so many struct rw_semaphore being defined? jidong xiao
@ 2007-07-04 9:15 ` Oliver Neukum
2007-07-04 10:34 ` Stefan Richter
0 siblings, 1 reply; 3+ messages in thread
From: Oliver Neukum @ 2007-07-04 9:15 UTC (permalink / raw)
To: jidong xiao; +Cc: linux-kernel
Am Mittwoch, 4. Juli 2007 schrieb jidong xiao:
> I see struct rw_semaphore is defined in
> include/linux/rwsem-spinlock.h,in the meanwhile, I also can find it in
Quote:
#ifndef _LINUX_RWSEM_H
#error "please don't include linux/rwsem-spinlock.h directly, use linux/rwsem.h instead"
#endif
> include/asm-**/rwsem.h,for
> example,include/asm-i386/rwsem.h,include/asm-x86_64/rwsem.h,why?which
> one should be used?
This structure is so important to performance that some architectures
have version optimized to their features.
Regards
Oliver
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [linux-kernel]Why there are so many struct rw_semaphore being defined?
2007-07-04 9:15 ` Oliver Neukum
@ 2007-07-04 10:34 ` Stefan Richter
0 siblings, 0 replies; 3+ messages in thread
From: Stefan Richter @ 2007-07-04 10:34 UTC (permalink / raw)
To: Oliver Neukum; +Cc: jidong xiao, linux-kernel
Oliver Neukum wrote:
> Am Mittwoch, 4. Juli 2007 schrieb jidong xiao:
>> I see struct rw_semaphore is defined in
>> include/linux/rwsem-spinlock.h,in the meanwhile, I also can find it in
>
> Quote:
>
> #ifndef _LINUX_RWSEM_H
> #error "please don't include linux/rwsem-spinlock.h directly, use linux/rwsem.h instead"
> #endif
>
>> include/asm-**/rwsem.h,for
>> example,include/asm-i386/rwsem.h,include/asm-x86_64/rwsem.h,why?which
>> one should be used?
>
> This structure is so important to performance that some architectures
> have version optimized to their features.
...but of course we generally include linux/rwsem.h instead of
architecture-specific header files. linux/rwsem.h will transparently
pull in the optimized variants for us. (It's evident from the source.)
--
Stefan Richter
-=====-=-=== -=== --=--
http://arcgraph.de/sr/
^ permalink raw reply [flat|nested] 3+ messages in thread
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2007-07-04 9:07 [linux-kernel]Why there are so many struct rw_semaphore being defined? jidong xiao
2007-07-04 9:15 ` Oliver Neukum
2007-07-04 10:34 ` Stefan Richter
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