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

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <4FA8FC83.7000503@nod.at>
Date:	Tue, 08 May 2012 12:59:15 +0200
From:	Richard Weinberger <richard@....at>
To:	dedekind1@...il.com
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()

Am 08.05.2012 11:02, schrieb Artem Bityutskiy:
> 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.

So, you'd prefer a msleep_interruptible(500) instead of yield() in this case?

> 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.

Okay, yield() is clearly the wrong choice here.
cond_resched() is better.

Thanks,
//richard


Download attachment "signature.asc" of type "application/pgp-signature" (491 bytes)