linux-kernel - [PATCH RESEND] rtsx_usb_ms: Use msleep

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Date:	Mon, 02 May 2016 23:17:41 +0300
From:	Oleksandr Natalenko <oleksandr@...alenko.name>
To:	Ben Hutchings <ben@...adent.org.uk>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	Lee Jones <lee.jones@...aro.org>,
	Wolfram Sang <wsa@...-dreams.de>,
	Roger Tseng <rogerable@...ltek.com>,
	linux-kernel@...r.kernel.org
Subject: [PATCH RESEND] rtsx_usb_ms: Use msleep_interruptible() in polling
 loop

This patch has already been posted to LKML by Ben Hutchings ~6 months
ago, but AFAIK no further action were performed. However, this patch
really fixes weird loadavg with RTS5129 card reader, so I would wonder
if this could be merged. AFAIK, it has been applied to some distros'
kernels, e.g., Ubuntu.

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.

A better fix might be to replace this loop with a delayed work item.

References: https://bugs.debian.org/765717
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
Signed-off-by: Oleksandr Natalenko <oleksandr@...alenko.name>
---
  drivers/memstick/host/rtsx_usb_ms.c | 3 ++-
  1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/memstick/host/rtsx_usb_ms.c 
b/drivers/memstick/host/rtsx_usb_ms.c
index 1105db2..645dede 100644
--- a/drivers/memstick/host/rtsx_usb_ms.c
+++ b/drivers/memstick/host/rtsx_usb_ms.c
@@ -706,7 +706,8 @@ poll_again:
  		if (host->eject)
  			break;

-		msleep(1000);
+		if (msleep_interruptible(1000))
+			flush_signals(current);
  	}

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