From: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
To: Kent Overstreet <kmo@daterainc.com>
Cc: Ben Hutchings <ben@decadent.org.uk>,
Thomas Gleixner <tglx@linutronix.de>,
linux-kernel@vger.kernel.org
Subject: Re: PREEMPT_RT vs bcache
Date: Wed, 7 Aug 2013 23:12:37 +0200 [thread overview]
Message-ID: <20130807211237.GM6104@pengutronix.de> (raw)
In-Reply-To: <20130807205357.GD11612@kmo-pixel>
On Wed, Aug 07, 2013 at 01:53:57PM -0700, Kent Overstreet wrote:
> On Wed, Aug 07, 2013 at 10:28:18PM +0200, Ben Hutchings wrote:
> > As Kent said back in 2011 (commit 84759c6d18c5), bcache needs
> > {down,up}_read_non_owner(). But these are not implemented by the -rt
> > patchset when PREEMPT_RT_FULL is enabled. Can they be added, or is
> > there a fundamental conflict here?
>
> You should be able to cherry pick
> 84759c6d18c5144432781ddca037d929ee9db8a5 (Revert "rw_semaphore: remove
> up/down_read_non_owner") - that went in when bcache was merged.
That doesn't help with PREEMPT_RT_FULL because include/linux/rwsem.h
looks like:
[ ... some includes ... ]
#ifdef CONFIG_PREEMPT_RT_FULL
#include <linux/rwsem_rt.h>
#else /* PREEMPT_RT_FULL */
[ ... vanilla content including definitions of {down,up}_read_non_owner]
#endif
So Ben's question was how (if at all) we should implement
{down,up}_read_non_owner for PREEMPT_RT_FULL.
Is it save to just use the vanilla implementation on RT?
Best regards
Uwe
--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | http://www.pengutronix.de/ |
next prev parent reply other threads:[~2013-08-07 21:12 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-07 20:28 PREEMPT_RT vs bcache Ben Hutchings
2013-08-07 20:53 ` Kent Overstreet
2013-08-07 21:08 ` Ben Hutchings
2013-08-07 21:09 ` Kent Overstreet
2013-08-07 21:12 ` Uwe Kleine-König [this message]
2013-08-08 7:26 ` Christoph Hellwig
2013-08-08 7:43 ` Kent Overstreet
2013-08-08 12:11 ` Christoph Hellwig
2013-09-12 15:01 ` Thomas Gleixner
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