From: Steven Rostedt <rostedt@goodmis.org>
To: Jeff Moyer <jmoyer@redhat.com>
Cc: Shaohua Li <shli@fb.com>, <linux-block@vger.kernel.org>,
<linux-kernel@vger.kernel.org>, <axboe@fb.com>,
<Kernel-team@fb.com>
Subject: Re: [PATCH 3/3] blk-throttle: don't parse cgroup path if trace isn't enabled
Date: Tue, 10 May 2016 19:33:45 -0400 [thread overview]
Message-ID: <20160510193345.6243a503@gandalf.local.home> (raw)
In-Reply-To: <x49a8jx7vww.fsf@segfault.boston.devel.redhat.com>
On Tue, 10 May 2016 11:52:15 -0400
Jeff Moyer <jmoyer@redhat.com> wrote:
> > +static inline bool blk_trace_note_message_enabled(struct request_queue *q)
> > +{
> > + struct blk_trace *bt = q->blk_trace;
> > + if (likely(!bt))
> > + return false;
> > + return bt->act_mask & BLK_TC_NOTIFY;
>
> 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.
-- Steve
next prev parent reply other threads:[~2016-05-10 23:33 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-10 0:22 [PATCH 1/3] blktrace: delete garbage for message trace Shaohua Li
2016-05-10 0:22 ` [PATCH 2/3] blktrace: add missed mask name Shaohua Li
2016-05-10 15:45 ` Jeff Moyer
2016-05-10 0:22 ` [PATCH 3/3] blk-throttle: don't parse cgroup path if trace isn't enabled Shaohua Li
2016-05-10 5:46 ` Simon Guo
2016-05-11 16:54 ` Shaohua Li
2016-05-10 15:52 ` Jeff Moyer
2016-05-10 23:33 ` Steven Rostedt [this message]
2016-05-11 13:47 ` Jeff Moyer
2016-05-11 0:20 ` Shaohua Li
2016-05-11 13:41 ` Jeff Moyer
2016-05-11 16:49 ` Shaohua Li
2016-05-10 14:31 ` [PATCH 1/3] blktrace: delete garbage for message trace Jeff Moyer
2016-05-10 14:46 ` Jens Axboe
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