Messages in this thread | | | Date | Fri, 7 Jul 2006 22:25:10 -0700 (PDT) | From | Linus Torvalds <> | Subject | Re: [patch] spinlocks: remove 'volatile' |
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On Fri, 7 Jul 2006, Albert Cahalan wrote: > > Key thing being "language environment", meaning gcc.
No.
The key thing is "language environment", meaning THE HARDWARE.
> By the language spec, volatile is a low-performance way to > get the job done.
No.
"volatile" simply CANNOT get the job done. It fundamentally does _nothing_ for all the issues that are fundamental today: CPU memory ordering in SMP, special IO synchronization requirements for memory-mapped IO registers etc etc.
It's not that "volatile" is the "portable way". It's that "volatile" is fundamentally not sufficient for the job.
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