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Message-ID: <20150206115051.GL23123@twins.programming.kicks-ass.net>
Date: Fri, 6 Feb 2015 12:50:51 +0100
From: Peter Zijlstra <peterz@...radead.org>
To: Bruno Prémont <bonbons@...ux-vserver.org>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>,
"Rafael J. Wysocki" <rjw@...ysocki.net>,
Ingo Molnar <mingo@...nel.org>,
Peter Hurley <peter@...leysoftware.com>,
Davidlohr Bueso <dave@...olabs.net>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
Thomas Gleixner <tglx@...utronix.de>,
Ilya Dryomov <ilya.dryomov@...tank.com>,
Mike Galbraith <umgwanakikbuti@...il.com>,
Oleg Nesterov <oleg@...hat.com>
Subject: Re: Linux 3.19-rc5
On Thu, Feb 05, 2015 at 10:14:36PM +0100, Bruno Prémont wrote:
> The loop is now replaced by a single WARN() trace - I guess expected:
> From my reading of the thread fixing pccardd/sched TASK_RUNNING usage/check
> is another issue left for the future.
Yeah, something like the below will make it go away -- under the
assumption that that comment is actually correct, I don't know, the
pcmcia people should probably write a better comment :/
Also, set_current_state(TASK_RUNNING) is almost always pointless, nobody
cares about that barrier, so make it go away.
---
drivers/pcmcia/cs.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/drivers/pcmcia/cs.c b/drivers/pcmcia/cs.c
index 5292db69c426..5678e161a17d 100644
--- a/drivers/pcmcia/cs.c
+++ b/drivers/pcmcia/cs.c
@@ -635,6 +635,12 @@ static int pccardd(void *__skt)
skt->sysfs_events = 0;
spin_unlock_irqrestore(&skt->thread_lock, flags);
+ /*
+ * Supposedly this is a rarely contended mutex and
+ * sleeping is therefore unlikely, the occasional
+ * extra loop iteration is harmless.
+ */
+ sched_annotate_sleep();
mutex_lock(&skt->skt_mutex);
if (events & SS_DETECT)
socket_detect_change(skt);
@@ -679,7 +685,7 @@ static int pccardd(void *__skt)
try_to_freeze();
}
/* make sure we are running before we exit */
- set_current_state(TASK_RUNNING);
+ __set_current_state(TASK_RUNNING);
/* shut down socket, if a device is still present */
if (skt->state & SOCKET_PRESENT) {
--
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