From: Mike Travis <travis@sgi.com>
To: Ingo Molnar <mingo@elte.hu>
Cc: Rusty Russell <rusty@rustcorp.com.au>,
LKML <linux-kernel@vger.kernel.org>
Subject: tip/master merge problem?
Date: Wed, 31 Dec 2008 14:08:45 -0800 [thread overview]
Message-ID: <495BED6D.8040307@sgi.com> (raw)
Hi Ingo,
I found this code snippet in kernel/sched.c in the tip/master tree. It
appears to be a merge mistake: (cut and pasted - no tabs)
292 /*
293 * If this cpu is the one which updates jiffies, then
294 * give up the assignment and let it be taken by the
295 * cpu which runs the tick timer next, which might be
296 * this cpu as well. If we don't drop this here the
297 * jiffies might be stale and do_timer() never
298 * invoked.
299 */
300 if (cpu == tick_do_timer_cpu)
301 tick_do_timer_cpu = TICK_DO_TIMER_NONE;
302
303 if (delta_jiffies > 1)
304
305 /* Skip reprogram of event if its not changed */
306 if (ts->tick_stopped && ktime_equal(expires, dev->next_event))
307 goto out;
308
309 cpumask_set_cpu(cpu, nohz_cpu_mask);
I think the "Skip reprogram" was inserted into the middle of a previous
if-then statement.
git blames it on:
00147449 (Woodruff, Richard 2008-12-01 14:18:11 -0800 292) /*
00147449 (Woodruff, Richard 2008-12-01 14:18:11 -0800 293) * If this cpu is the one which updates jiffies, then
00147449 (Woodruff, Richard 2008-12-01 14:18:11 -0800 294) * give up the assignment and let it be taken by the
00147449 (Woodruff, Richard 2008-12-01 14:18:11 -0800 295) * cpu which runs the tick timer next, which might be
00147449 (Woodruff, Richard 2008-12-01 14:18:11 -0800 296) * this cpu as well. If we don't drop this here the
00147449 (Woodruff, Richard 2008-12-01 14:18:11 -0800 297) * jiffies might be stale and do_timer() never
00147449 (Woodruff, Richard 2008-12-01 14:18:11 -0800 298) * invoked.
00147449 (Woodruff, Richard 2008-12-01 14:18:11 -0800 299) */
00147449 (Woodruff, Richard 2008-12-01 14:18:11 -0800 300) if (cpu == tick_do_timer_cpu)
00147449 (Woodruff, Richard 2008-12-01 14:18:11 -0800 301) tick_do_timer_cpu = TICK_DO_TIMER_NONE;
00147449 (Woodruff, Richard 2008-12-01 14:18:11 -0800 302)
6ba9b346 (Ingo Molnar 2007-02-19 18:11:56 +0000 303) if (delta_jiffies > 1)
00147449 (Woodruff, Richard 2008-12-01 14:18:11 -0800 304)
00147449 (Woodruff, Richard 2008-12-01 14:18:11 -0800 305) /* Skip reprogram of event if its not changed */
00147449 (Woodruff, Richard 2008-12-01 14:18:11 -0800 306) if (ts->tick_stopped && ktime_equal(expires, dev->next_event))
00147449 (Woodruff, Richard 2008-12-01 14:18:11 -0800 307) goto out;
00147449 (Woodruff, Richard 2008-12-01 14:18:11 -0800 308)
6a7b3dc3 (Rusty Russell 2008-11-25 02:35:04 +1030 309) cpumask_set_cpu(cpu, nohz_cpu_mask);
I've Cc'd both interested parties.
Thanks,
Mike
next reply other threads:[~2008-12-31 22:08 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-12-31 22:08 Mike Travis [this message]
2009-01-02 16:06 ` tip/master merge problem? Ingo Molnar
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