On Fri, Jan 11, 2008 at 04:58:28PM +0530, Nikanth Karthikesan wrote: > On Fri, 2008-01-11 at 12:12 +0100, Andi Kleen wrote: > > Nikanth Karthikesan <[EMAIL PROTECTED]> writes: > > > > > > Also the globals random_read_wakeup_thresh and > > > random_write_wakeup_thresh are not at all protected by any locks! Why > > > locks are not needed for these? > > > > Reading variables sizeof <= native word size (32bit or 64bit depending > > on architecture) is atomic by itself. This is not necessarily > > guaranteed in ISO-C or POSIX threads, but Linux can assume that. > > Yes, I found that by checking the implementation of atomic_read. > > But I didnt check the implementation of atomic_set before sending the > mail and assumed assigning to a variable may not be atomic on all arch, > and because of that, we may be reading a half-written, variable! But > assigning to an int is also atomic on all arch.
For completeness this both only applies to naturally aligned variables for portable code. -Andi -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
