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Date: Tue, 28 Feb 2017 22:28:20 +0900
From: Byungchul Park <byungchul.park@lge.com>
Subject: Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature
Message-ID: <20170228132820.GH3817@X58A-UD3R>
References: <1484745459-2055-1-git-send-email-byungchul.park@lge.com>
 <1484745459-2055-7-git-send-email-byungchul.park@lge.com>
 <20170228130513.GH5680@worktop>
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Sender: owner-linux-mm@kvack.org
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To: Peter Zijlstra <peterz@infradead.org>
Cc: mingo@kernel.org, tglx@linutronix.de, walken@google.com, boqun.feng@gmail.com, kirill@shutemov.name, linux-kernel@vger.kernel.org, linux-mm@kvack.org, iamjoonsoo.kim@lge.com, akpm@linux-foundation.org, npiggin@gmail.com, kernel-team@lge.com

On Tue, Feb 28, 2017 at 02:05:13PM +0100, Peter Zijlstra wrote:
> On Wed, Jan 18, 2017 at 10:17:32PM +0900, Byungchul Park wrote:
> > +#define MAX_XHLOCKS_NR 64UL
> 
> > +#ifdef CONFIG_LOCKDEP_CROSSRELEASE
> > +	if (tsk->xhlocks) {
> > +		void *tmp = tsk->xhlocks;
> > +		/* Disable crossrelease for current */
> > +		tsk->xhlocks = NULL;
> > +		vfree(tmp);
> > +	}
> > +#endif
> 
> > +#ifdef CONFIG_LOCKDEP_CROSSRELEASE
> > +	p->xhlock_idx = 0;
> > +	p->xhlock_idx_soft = 0;
> > +	p->xhlock_idx_hard = 0;
> > +	p->xhlock_idx_nmi = 0;
> > +	p->xhlocks = vzalloc(sizeof(struct hist_lock) * MAX_XHLOCKS_NR);
> 
> I don't think we need vmalloc for this now.

Really? When is a better time to do it?

I think the time creating a task is the best time to initialize it. No?

> 
> > +	p->work_id = 0;
> > +#endif
> 
> > +#ifdef CONFIG_LOCKDEP_CROSSRELEASE
> > +	if (p->xhlocks) {
> > +		void *tmp = p->xhlocks;
> > +		/* Diable crossrelease for current */
> > +		p->xhlocks = NULL;
> > +		vfree(tmp);
> > +	}
> > +#endif
> 
> Second instance of the same code, which would suggest using a function
> for this. Also, with a function you can loose the #ifdeffery.

Yes. It looks much better.

Thank you very much.

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