Messages in this thread | | | From | Andi Kleen <> | Subject | Re: [PATCH 7/8] i386: bitops: Kill needless usage of __asm__ __volatile__ | Date | Mon, 23 Jul 2007 18:18:00 +0200 |
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On Monday 23 July 2007 18:06:03 Satyam Sharma wrote: > From: Satyam Sharma <ssatyam@cse.iitk.ac.in> > > [7/8] i386: bitops: Kill needless usage of __asm__ __volatile__ > > Another oddity I noticed in this file. The semantics of __volatile__ > when used to qualify inline __asm__ are that the compiler will not > (1) elid, or, (2) reorder, or, (3) intersperse, our inline asm with > the rest of the generated code. > > However, we do not want these guarantees in the unlocked variants of the > bitops functions.
I thought so too and did a similar transformation while moving some string functions out of line. After that recent misadventure I would be very very careful with this.
Overall I'm sorry to say, but the risk:gain ratio of this patch is imho totally out of whack.
It took a long time to get bitops.h correct and as far as we know it is compiled correctly currently. You risk all at for very dubious improvements.
-Andi
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