linux-kernel - Re: [PATCH] sched:Prefer numa hotness over cache hotness

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] [day] [month] [year] [list]

Message-ID: <20150611140129.GV19282@twins.programming.kicks-ass.net>
Date:	Thu, 11 Jun 2015 16:01:29 +0200
From:	Peter Zijlstra <peterz@...radead.org>
To:	Srikar Dronamraju <srikar@...ux.vnet.ibm.com>
Cc:	Ingo Molnar <mingo@...nel.org>, linux-kernel@...r.kernel.org,
	Rik van Riel <riel@...hat.com>, Mel Gorman <mgorman@...e.de>
Subject: Re: [PATCH] sched:Prefer numa hotness over cache hotness

On Wed, Jun 10, 2015 at 12:33:35PM +0530, Srikar Dronamraju wrote:
> The current load balancer may not try to prevent a task from moving out
> of a preferred node to a less preferred node. The reason for this being:
> 
> - Since sched features NUMA and NUMA_RESIST_LOWER are disabled by
>   default, migrate_degrades_locality() always returns false.
> 
> - Even if NUMA_RESIST_LOWER were to be enabled, if its cache hot,
>   migrate_degrades_locality() never gets called.
> 
> The above behaviour can mean that tasks can move out of their preferred
> node but they may be eventually be brought back to their preferred node
> by numa balancer (due to higher numa faults).
> 
> To avoid the above, this commit merges migrate_degrades_locality() and
> migrate_improves_locality(). It also replaces 3 sched features NUMA,
> NUMA_FAVOUR_HIGHER and NUMA_RESIST_LOWER by a single sched feature NUMA.
> 

Does not apply.
--
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/