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From: Yong Zhang <yong.zhang0@gmail.com>
To: Christoph Hellwig <hch@infradead.org>
Cc: Torben Hohn <torbenh@gmx.de>,
	linux-kernel@vger.kernel.org, Thomas Gleixner <tglx@tglx.de>
Subject: Re: [PATCH] RFC: abstract access to xtime_lock into a set of inline functions
Date: Fri, 21 Jan 2011 21:23:49 +0800	[thread overview]
Message-ID: <20110121132349.GB6051@zhy> (raw)
In-Reply-To: <20110120173029.GA26121@infradead.org>

On Thu, Jan 20, 2011 at 12:30:29PM -0500, Christoph Hellwig wrote:
> On Thu, Jan 20, 2011 at 06:14:08PM +0100, Torben Hohn wrote:
> > the -rt patches change the xtime_lock to a raw_seqlock_t
> > so a pretty huge portion of the patch deals with changing
> > the locking functions.
> > 
> > this commit uses inline functions, to hide the type
> > of the lock.
> 
> That's not how kernel code usually works.
> 
> > -	write_seqlock(&xtime_lock);
> > +	xtime_write_seqlock();
> >  	do_timer(1);
> > -	write_sequnlock(&xtime_lock);
> > +	xtime_write_sequnlock();
> 
> However there's a pretty clear pattern of taking xtime_lock, calling
> do_timer and then releasing.  A useful thing you could do is to rename
> do_timer to do_timer_locked and make do_timer take and release
> xtime_lock in one place.

How about adding raw_seqlock just like what we have done for
spinlock? Thus xtime_lock can be defined to raw_seqlock and
others can also benefit from the raw_seqlock like xtime_lock.

Thanks,
Yong

      parent reply	other threads:[~2011-01-21 13:24 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-01-20 17:14 [PATCH] RFC: abstract access to xtime_lock into a set of inline functions Torben Hohn
2011-01-20 17:30 ` Christoph Hellwig
2011-01-20 19:37   ` john stultz
2011-01-21 13:38     ` [PATCH] RFC: change do_timer() to take xtime lock, and provide do_timer_locked() Torben Hohn
2011-01-21 13:59       ` Thomas Gleixner
2011-01-21 13:57     ` [PATCH] RFC: abstract access to xtime_lock into a set of inline functions Thomas Gleixner
2011-01-21 13:23   ` Yong Zhang [this message]

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