Re: [GIT PULL] RCU changes for v4.1

From: Linus Torvalds
Date: Tue Apr 14 2015 - 23:20:14 EST

On Tue, Apr 14, 2015 at 7:55 PM, Paul E. McKenney
<paulmck@xxxxxxxxxxxxxxxxxx> wrote:
> Does the (currently being tested) patch below fix things up? If not,
> please fill me in on the further error of my ways.

Looks ok.

That said, couldn't that last dummy gp_init_delay variable:

> +/* Delay in jiffies for grace-period initialization delays, debug only. */
> +static int gp_init_delay = CONFIG_RCU_TORTURE_TEST_SLOW_INIT_DELAY;
> module_param(gp_init_delay, int, 0644);
> +static const int gp_init_delay;
> +#endif /* #else #ifdef CONFIG_RCU_TORTURE_TEST_SLOW_INIT */

be just a

#define gp_init_delay 0

for the non-CONFIG_RCU_TORTURE_TEST_SLOW_INIT case, so that the code
that then does

+ if (gp_init_delay > 0 &&
+ !(rsp->gpnum % (rcu_num_nodes * PER_RCU_NODE_PERIOD)))

would just trivially compile away.

I guess the compiler *might* see a 'static const int' that is never
touched and realize it's always zero, but it's not obvious that will
be the case.


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