linux-kernel - Re: [PATCH] UBI: Replace yield() with cond

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Message-ID: <1336467723.23308.23.camel@sauron.fi.intel.com>
Date:	Tue, 08 May 2012 12:02:03 +0300
From:	Artem Bityutskiy <dedekind1@...il.com>
To:	Richard Weinberger <richard@....at>
Cc:	linux-mtd@...ts.infradead.org, dwmw2@...radead.org,
	linux-kernel@...r.kernel.org, peterz@...radead.org
Subject: Re: [PATCH] UBI: Replace yield() with cond_resched()

On Tue, 2012-05-08 at 10:26 +0200, Richard Weinberger wrote:
> The comment above yield()'s definition says:
>  * If you want to use yield() to wait for something, use wait_event().
>  * If you want to use yield() to be 'nice' for others, use cond_resched().
>  * If you still want to use yield(), do not!
> 
> The yield() usage of UBI really looks like the "be nice for others" case,
> so use cond_resched().
> 
> Signed-off-by: Richard Weinberger <richard@....at>
> CC: peterz@...radead.org

I guess we would better sleep for a couple of hundreds of milliseconds
instead.

The purpose was different. If we have I/O error, we hope it is a
transient failure. E.g., the HW is temporary unavailable because of an
internal issue. And with yield() we hoped to schedule away for longer
time than usual and let other processes which may affect that HW go
forward and do something.

But whole this thing does not have any solid real-case basis, just
something which looked sane to do to me.

Someone on the list also questioned the entire re-tries, but he did not
care enough to send a tested patch. But this is a separate and
independent issue.

-- 
Best Regards,
Artem Bityutskiy

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