linux-kernel - Re: [PATCH tip/core/rcu 08/23] rcu: Segregate rcu

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 for Android: free password hash cracker in your pocket

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

Date:	Sat, 1 Sep 2012 19:51:00 -0700
From:	Josh Triplett <josh@...htriplett.org>
To:	"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
Cc:	linux-kernel@...r.kernel.org, mingo@...e.hu, laijs@...fujitsu.com,
	dipankar@...ibm.com, akpm@...ux-foundation.org,
	mathieu.desnoyers@...ymtl.ca, niv@...ibm.com, tglx@...utronix.de,
	peterz@...radead.org, rostedt@...dmis.org, Valdis.Kletnieks@...edu,
	dhowells@...hat.com, eric.dumazet@...il.com, darren@...art.com,
	fweisbec@...il.com, sbw@....edu, patches@...aro.org,
	Dimitri Sivanich <sivanich@....com>
Subject: Re: [PATCH tip/core/rcu 08/23] rcu: Segregate rcu_state fields to
 improve cache locality

On Thu, Aug 30, 2012 at 11:18:23AM -0700, Paul E. McKenney wrote:
> From: Dimitri Sivanich <sivanich@....com>
> 
> The fields in the rcu_state structure that are protected by the
> root rcu_node structure's ->lock can share a cache line with the
> fields protected by ->onofflock.  This can result in excessive
> memory contention on large systems, so this commit applies
> ____cacheline_internodealigned_in_smp to the ->onofflock field in
> order to segregate them.
> 
> Signed-off-by: Dimitri Sivanich <sivanich@....com>
> Signed-off-by: Paul E. McKenney <paulmck@...ux.vnet.ibm.com>
> Tested-by: Dimitri Sivanich <sivanich@....com>

Reviewed-by: Josh Triplett <josh@...htriplett.org>

>  kernel/rcutree.h |    3 ++-
>  1 files changed, 2 insertions(+), 1 deletions(-)
> 
> diff --git a/kernel/rcutree.h b/kernel/rcutree.h
> index effb273..5d92b80 100644
> --- a/kernel/rcutree.h
> +++ b/kernel/rcutree.h
> @@ -394,7 +394,8 @@ struct rcu_state {
>  
>  	/* End of fields guarded by root rcu_node's lock. */
>  
> -	raw_spinlock_t onofflock;		/* exclude on/offline and */
> +	raw_spinlock_t onofflock ____cacheline_internodealigned_in_smp;
> +						/* exclude on/offline and */
>  						/*  starting new GP. */
>  	struct rcu_head *orphan_nxtlist;	/* Orphaned callbacks that */
>  						/*  need a grace period. */
> -- 
> 1.7.8
> 
--
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/