linux-kernel - [PATCH RESEND v2] rtsx_usb_ms: use schedule_timeout

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Date:	Tue, 03 May 2016 16:53:31 +0300
From:	Oleksandr Natalenko <oleksandr@...alenko.name>
To:	Andrew Morton <akpm@...ux-foundation.org>
Cc:	Oleg Nesterov <oleg@...hat.com>,
	Ben Hutchings <ben@...adent.org.uk>,
	Lee Jones <lee.jones@...aro.org>,
	Wolfram Sang <wsa@...-dreams.de>,
	Roger Tseng <rogerable@...ltek.com>,
	linux-kernel@...r.kernel.org
Subject: [PATCH RESEND v2] rtsx_usb_ms: use schedule_timeout_idle() in polling
 loop

First version of this patch has already been posted to LKML by Ben 
Hutchings
~6 months ago, but no further action were performed.

Original Ben's message goes below.

===
rtsx_usb_ms creates a task that mostly sleeps, but tasks in
uninterruptible sleep still contribute to the load average (for
bug-compatibility with Unix).  A load average of ~1 on a system that
should be idle is somewhat alarming.

Change the sleep to be interruptible, but still ignore signals.
===

v2 of this patch uses schedule_timeout_idle() instead of msleep() and
removes flush_signals() introduces in v1 of this patch as kthread 
ignores
all signals unless it does allow_signal().

References: https://bugs.debian.org/765717
Signed-off-by: Oleksandr Natalenko <oleksandr@...alenko.name>
---
  drivers/memstick/host/rtsx_usb_ms.c | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/memstick/host/rtsx_usb_ms.c 
b/drivers/memstick/host/rtsx_usb_ms.c
index 1105db2..d34bc35 100644
--- a/drivers/memstick/host/rtsx_usb_ms.c
+++ b/drivers/memstick/host/rtsx_usb_ms.c
@@ -706,7 +706,7 @@ poll_again:
  		if (host->eject)
  			break;

-		msleep(1000);
+		schedule_timeout_idle(HZ);
  	}

  	complete(&host->detect_ms_exit);
-- 
2.8.2