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Adam J. Richter wrote: > > Your comment prompted me to look at > linux-2.5.2-pre11/include/asm-i386/spinlock.h, and I now believe that > the "lock; decb" that it uses for grabbing spinlocks will return an > incorrect success if 255 or more processors are waiting on the same > spinlock. I don't know if anybody has ever built a shared memory x86 > multiprocessor with 257 (not a typo) or more CPU's, but it's possible > to imagine. It's also possible to imagine this scenario happening > with even just one processor and a preemtable kernel. I believe that > the current preemtable kernel patch limits the number of preempted > processes to something like four or six, but that's just a temporary > limitation of the current version. > Linux specificially does not allow for more processors than there are bits in a long (32 or 64). Libc, however, since it counts processes, not CPUs, uses a 4-byte word. -hpa - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ | |||||||||
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