linux-kernel - Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

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Date:   Tue, 28 Feb 2017 14:05:13 +0100
From:   Peter Zijlstra <peterz@...radead.org>
To:     Byungchul Park <byungchul.park@....com>
Cc:     mingo@...nel.org, tglx@...utronix.de, walken@...gle.com,
        boqun.feng@...il.com, kirill@...temov.name,
        linux-kernel@...r.kernel.org, linux-mm@...ck.org,
        iamjoonsoo.kim@....com, akpm@...ux-foundation.org,
        npiggin@...il.com
Subject: Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

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.

> +	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.