Re: [PATCH 3/3] blk-throttle: don't parse cgroup path if trace isn't enabled

From: Jeff Moyer
Date: Wed May 11 2016 - 09:47:18 EST


Steven Rostedt <rostedt@xxxxxxxxxxx> writes:

>> Do we want to return !!(bt->act_mask & BLK_TC_NOTIFY)?
>
> The return type is bool. I would think that gcc would be smart enough
> to make the conversion.
>
> To check, I compiled the following function:
>
> bool testbool(int x)
> {
> return x & 1<<3;
> }
>
> and the result was:
>
>
> 0000000000000000 <testbool>:
> 0: 55 push %rbp
> 1: 48 89 e5 mov %rsp,%rbp
> 4: 89 7d fc mov %edi,-0x4(%rbp)
> 7: 8b 45 fc mov -0x4(%rbp),%eax
> a: 83 e0 08 and $0x8,%eax
> d: 85 c0 test %eax,%eax
> f: 0f 95 c0 setne %al
> 12: 5d pop %rbp
> 13: c3 retq
>
> I get the same by adding !!(x & 1<<3)
>
> Looks like it does the conversion.

Cool, thanks!

-Jeff