* Paul E. McKenney <paul...@linux.vnet.ibm.com> wrote:
> + (*) The compiler is within its rights to reload a variable, for example,
> + in cases where high register pressure prevents the compiler from
> + keeping all data of interest in registers. The compiler might
> + therefore optimize the variable tmp out of our previous example:
> +
> + while (tmp = a)
> + do_something_with(tmp);
> +
> + This could result in the following code, which is perfectly safe in
> + single-threaded code, but can be fatal in concurrent code:
> +
> + while (a)
> + do_something_with(a);
> +
> + For example, the optimized version of this code could result in
> + passing a zero to do_something_with() in the case where the variable
> + a was modified by some other CPU between the "while" statement and
> + the call to do_something_with().
Nit: I guess references to variable names such as 'a' should be quoted
(same for 'tmp', 'b', etc):
For example, the optimized version of this code could result in
passing a zero to do_something_with() in the case where the variable
'a' was modified by some other CPU between the "while" statement and
the call to do_something_with().
which makes reading it less ambiguous and more fluid IMO. This
observation applies to the whole document as 'a' is used in many
places.
Thanks,
Ingo
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
