From: Eric Dumazet <dada1@cosmosbay.com>
To: "Siddha, Suresh B" <suresh.b.siddha@intel.com>
Cc: Christoph Lameter <christoph@lameter.com>,
Andi Kleen <andi@firstfloor.org>,
Andrew Morton <akpm@linux-foundation.org>,
linux kernel <linux-kernel@vger.kernel.org>
Subject: Re: non-NUMA cache_free_alien() (was Re: [RFC] SLAB : NUMA cache_free_alien() very expensive because of virt_to_slab(objp); nodeid = slabp->nodeid;)
Date: Thu, 22 Mar 2007 23:56:37 +0100 [thread overview]
Message-ID: <460309A5.6070404@cosmosbay.com> (raw)
In-Reply-To: <20070322224045.GA3200@linux-os.sc.intel.com>
Siddha, Suresh B a écrit :
> On Thu, Mar 22, 2007 at 11:12:39PM +0100, Eric Dumazet wrote:
>> Siddha, Suresh B a écrit :
>>> + if (num_online_nodes() == 1)
>>> + use_alien_caches = 0;
>>> +
>> Unfortunatly this part is wrong.
>
> oops.
>
>> You should check num_possible_nodes(), or nr_node_ids (this one is cheaper,
>> its a variable instead of a function call)
>
> But that is based on compile time option, isn't it? Perhaps I need
> to use some other mechanism to find out the platform is not NUMA capable..
nr_node_ids is defined to 1 if you compile a non NUMA kernel.
If CONFIG_NUMA is on, then nr_node_ids is a variable, that is filled with the
maximum nodeid of possible node (+1). If your machine is not CPU hot plug
capable, and you have say one node, (one dual core processor for example),
then nr_node_ids will be set to 1
(see mm/page_alloc.c function setup_nr_node_ids() )
So this is OK for your need...
next prev parent reply other threads:[~2007-03-22 22:56 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-03-20 17:12 [RFC] SLAB : NUMA cache_free_alien() very expensive because of virt_to_slab(objp); nodeid = slabp->nodeid; Eric Dumazet
2007-03-20 19:54 ` Christoph Lameter
2007-03-20 21:32 ` Andi Kleen
2007-03-20 22:09 ` Eric Dumazet
2007-03-21 0:16 ` Christoph Lameter
2007-03-21 6:27 ` Eric Dumazet
2007-03-21 6:57 ` [PATCH] SLAB : Use num_possible_cpus() in enable_cpucache() Eric Dumazet
2007-03-21 7:21 ` [PATCH] SLAB : Dont allocate empty shared caches Eric Dumazet
2007-03-21 13:13 ` Pekka Enberg
2007-03-21 13:02 ` [PATCH] SLAB : Use num_possible_cpus() in enable_cpucache() Pekka Enberg
2007-03-21 18:45 ` Christoph Lameter
2007-03-21 7:03 ` [RFC] SLAB : NUMA cache_free_alien() very expensive because of virt_to_slab(objp); nodeid = slabp->nodeid; Christoph Lameter
2007-03-21 7:14 ` Eric Dumazet
2007-03-21 14:35 ` Christoph Lameter
2007-03-21 0:18 ` Christoph Lameter
2007-03-21 2:44 ` Andi Kleen
2007-03-21 3:10 ` Christoph Lameter
2007-03-22 21:28 ` non-NUMA cache_free_alien() (was Re: [RFC] SLAB : NUMA cache_free_alien() very expensive because of virt_to_slab(objp); nodeid = slabp->nodeid;) Siddha, Suresh B
2007-03-22 22:10 ` Christoph Lameter
2007-03-22 22:12 ` Eric Dumazet
2007-03-22 22:40 ` Siddha, Suresh B
2007-03-22 22:56 ` Eric Dumazet [this message]
2007-03-23 1:25 ` Christoph Lameter
2007-03-23 14:14 ` Andi Kleen
2007-03-23 14:12 ` Andi Kleen
2007-04-02 22:55 ` Siddha, Suresh B
2007-04-03 0:23 ` Christoph Lameter
2007-04-03 0:31 ` Siddha, Suresh B
2007-04-09 18:01 ` [patch 1/2] x86_64: set node_possible_map at runtime Siddha, Suresh B
2007-04-09 18:07 ` [patch 2/2] slab, x86_64: skip cache_free_alien() on non NUMA Siddha, Suresh B
2007-04-09 20:23 ` [patch 1/2] x86_64: set node_possible_map at runtime Andrew Morton
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