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

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Message-ID: <20151009071859.GL17172@x1>
Date:	Fri, 9 Oct 2015 08:18:59 +0100
From:	Lee Jones <lee.jones@...aro.org>
To:	Ben Hutchings <ben@...adent.org.uk>
Cc:	Maxim Levitsky <maximlevitsky@...il.com>,
	Roger Tseng <rogerable@...ltek.com>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH RESEND] rtsx_usb_ms: Use msleep_interruptible() in
 polling loop

On Thu, 08 Oct 2015, Ben Hutchings wrote:

> On Thu, 2015-10-08 at 08:19 +0100, Lee Jones wrote:
> > On Mon, 28 Sep 2015, Ben Hutchings wrote:
> > 
> > > 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>
> > 
> > Any chance you can use Git instead of Quilt?  Failing that, is there a
> > way to tell Quilt to supply a diffstat in the patch?
> 
> Why does it matter?

To this patch?  It probably doesn't.

In general?  It absolutely helps with patch review -- it's the second
thing I look at.  Diffstats are especially helpful if/when patches
cross subsystem boundaries or when multiple files a touched.  Until I
scroll down I have no idea if this is just a memstick patch (which I
can see at the bottom of my screen) or in fact amends 5 subsystems
and requires special handling.

> 'git am' is happy to apply it.  But in case it
> really does make a difference, I've attached the git-format-patch
> version.

I meant more 'from now on', rather than that patch being a special
case.  Ultimately it's your decision.  I just think it makes things
that little bit easier for the reviewer, as I'm sure you can
appreciate.

> > > ---
> > > --- 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);
> > 
> > 
> > 

> From 34dca6b208a1108a9499412f584468b31ee025e0 Mon Sep 17 00:00:00 2001
> From: Ben Hutchings <ben@...adent.org.uk>
> Date: Sun, 26 Oct 2014 03:39:42 +0000
> Subject: [PATCH] rtsx_usb_ms: Use msleep_interruptible() in polling loop
> 
> 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>
> ---
>  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);




-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
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