From: Steven Rostedt <rostedt@goodmis.org>
To: Ingo Molnar <mingo@elte.hu>
Cc: LKML <linux-kernel@vger.kernel.org>
Subject: [RT] possible bug in trace_start_sched_wakeup
Date: Thu, 26 Jan 2006 20:57:02 -0500 [thread overview]
Message-ID: <1138327022.7814.8.camel@localhost.localdomain> (raw)
Ingo,
I've been agonizing over the latency code, and have a question about
__trace_start_sched_wakup.
Here we have:
void __trace_start_sched_wakeup(struct task_struct *p)
{
struct cpu_trace *tr;
int cpu;
if (trace_user_triggered || !wakeup_timing)
return;
spin_lock(&sch.trace_lock);
if (sch.task && (sch.task->prio >= p->prio))
goto out_unlock;
I don't get the sch.task->prio >= p->prio. Here the lower the number
the greater the priority. So this if statement is saying:
If sch.task is either NULL or if p is greater in priority than or equal
to the priority of sch.task then quit.
Then again later in trace_stop_sched_switched:
if (sch.task && (sch.task->prio >= p->prio))
sch.task = NULL;
Again, if p is a higher priority than sch.task we set sch.task to NULL??
What am I missing here?
Thanks,
-- Steve
next reply other threads:[~2006-01-27 1:57 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-01-27 1:57 Steven Rostedt [this message]
2006-01-27 4:38 ` [RT] possible bug in trace_start_sched_wakeup Steven Rostedt
2006-01-27 9:46 ` Ingo Molnar
2006-01-27 12:46 ` Steven Rostedt
2006-01-27 9:54 ` Ingo Molnar
2006-01-27 12:47 ` Steven Rostedt
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1138327022.7814.8.camel@localhost.localdomain \
--to=rostedt@goodmis.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@elte.hu \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).