linux-kernel - Re: [PATCH v2 4/4] futex: Avoid taking hb lock if nothing to wakeup

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: Windows password security audit tool. GUI, reports in PDF.

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

Message-ID: <20131210162411.GM12849@twins.programming.kicks-ass.net>
Date:	Tue, 10 Dec 2013 17:24:11 +0100
From:	Peter Zijlstra <peterz@...radead.org>
To:	Davidlohr Bueso <davidlohr@...com>
Cc:	linux-kernel@...r.kernel.org, mingo@...nel.org,
	dvhart@...ux.intel.com, tglx@...utronix.de,
	paulmck@...ux.vnet.ibm.com, efault@....de, jeffm@...e.com,
	torvalds@...ux-foundation.org, scott.norton@...com,
	tom.vaden@...com, aswin@...com, Waiman.Long@...com,
	jason.low2@...com
Subject: Re: [PATCH v2 4/4] futex: Avoid taking hb lock if nothing to wakeup

On Tue, Dec 03, 2013 at 01:45:27AM -0800, Davidlohr Bueso wrote:
> @@ -203,6 +221,9 @@ static const struct futex_q futex_q_init = {
>   * waiting on a futex.
>   */
>  struct futex_hash_bucket {
> +#ifdef CONFIG_SMP
> +	atomic_t waiters;
> +#endif
>  	spinlock_t lock;
>  	struct plist_head chain;
>  } ____cacheline_aligned_in_smp;

> @@ -2805,6 +2906,9 @@ static int __init futex_init(void)
>  	for (i = 0; i < futex_hashsize; i++) {
>  		plist_head_init(&futex_queues[i].chain);
>  		spin_lock_init(&futex_queues[i].lock);
> +#ifdef CONFIG_SMP
> +		atomic_set(&futex_queues[i].waiters, 0);
> +#endif
>  	}
>  
>  	return 0;

Just remove those two #ifdefs, its not like the data structure size
matters at this point.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/