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From: Glauber Costa <glommer@parallels.com>
To: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>, Joonsoo Kim <js1304@gmail.com>,
	linux-mm@kvack.org, David Rientjes <rientjes@google.com>,
	elezegarcia@gmail.com
Subject: Re: CK2 [01/15] slab: Simplify bootstrap
Date: Mon, 22 Oct 2012 11:57:39 +0400	[thread overview]
Message-ID: <5084FC73.1030302@parallels.com> (raw)
In-Reply-To: <0000013a796a77f9-b0c5beb7-21e0-4e62-bc08-5b909617f678-000000@email.amazonses.com>

On 10/19/2012 06:25 PM, Christoph Lameter wrote:
> The nodelists field in kmem_cache is pointing to the first unused
> object in the array field when bootstrap is complete.
> 
> A problem with the current approach is that the statically sized
> kmem_cache structure use on boot can only contain NR_CPUS entries.
> If the number of nodes plus the number of cpus is greater then we
> would overwrite memory following the kmem_cache_boot definition.
> 
> Increase the size of the array field to ensure that also the node
> pointers fit into the array field.
> 
> Once we do that we no longer need the kmem_cache_nodelists
> array and we can then also use that structure elsewhere.

Fair.

One comment:

>  /*
> + * The memory after the last cpu cache pointer is used for the
> + * the nodelists pointer.
> + */
> +static void setup_nodelists_pointer(struct kmem_cache *s)
> +{
> +	s->nodelists = (struct kmem_list3 **)&s->array[nr_cpu_ids];
> +}
> +
> +/*
>   * Initialisation.  Called after the page allocator have been initialised and
>   * before smp_init().
>   */
> @@ -1590,13 +1597,15 @@ void __init kmem_cache_init(void)
>  	int node;
>  
>  	kmem_cache = &kmem_cache_boot;
> +	setup_nodelists_pointer(kmem_cache);
>  
>  	if (num_possible_nodes() == 1)
>  		use_alien_caches = 0;
>  
> +
>  	for (i = 0; i < NUM_INIT_LISTS; i++) {
>  		kmem_list3_init(&initkmem_list3[i]);
> -		if (i < MAX_NUMNODES)
> +		if (i < nr_node_ids)
>  			kmem_cache->nodelists[i] = NULL;
>  	}

With nodelists being part of kmem_cache, and kmem_cache being allocated
with kmem_cache_zalloc, it seems to me that you can actually just get
rid of the inner loop instead of patching it. But this is orthogonal to
this patch...

So:

Acked-by: Glauber Costa <glommer@parallels.com>

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  reply	other threads:[~2012-10-22  7:57 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20121019142254.724806786@linux.com>
2012-10-19 14:25 ` CK2 [02/15] create common functions for boot slab creation Christoph Lameter
2012-10-20 15:57   ` JoonSoo Kim
2012-10-19 14:25 ` CK2 [01/15] slab: Simplify bootstrap Christoph Lameter
2012-10-22  7:57   ` Glauber Costa [this message]
2012-10-23 20:45     ` Christoph Lameter
2012-10-19 14:32 ` CK2 [14/15] stat: Use size_t for sizes instead of unsigned Christoph Lameter
2012-10-22  8:42   ` Glauber Costa
2012-10-19 14:32 ` CK2 [05/15] Common alignment code Christoph Lameter
2012-10-19 14:32 ` CK2 [12/15] Common definition for the array of kmalloc caches Christoph Lameter
2012-10-19 14:42 ` CK2 [15/15] Common Kmalloc cache determination Christoph Lameter
2012-10-20 16:20   ` JoonSoo Kim
2012-10-23 20:40     ` Christoph Lameter
2012-10-19 14:42 ` CK2 [13/15] Common function to create the kmalloc array Christoph Lameter
2012-10-22  9:51   ` Glauber Costa
2012-10-19 14:42 ` CK2 [04/15] slab: Use the new create_boot_cache function to simplify bootstrap Christoph Lameter
2012-10-20 16:01   ` JoonSoo Kim
2012-10-22  8:09   ` Glauber Costa
2012-10-23 21:40     ` Christoph Lameter
2012-10-19 14:45 ` CK2 [08/15] slab: Use common kmalloc_index/kmalloc_size functions Christoph Lameter
2012-10-20 16:12   ` JoonSoo Kim
2012-10-23 20:39     ` Christoph Lameter
2012-10-24 17:47       ` JoonSoo Kim
2012-10-19 14:49 ` CK2 [09/15] slab: Common name for the per node structures Christoph Lameter
2012-10-20 16:14   ` JoonSoo Kim
2012-10-23 20:39     ` Christoph Lameter
2012-10-22  8:32   ` Glauber Costa
2012-10-19 14:51 ` CK2 [06/15] Move kmalloc related function defs Christoph Lameter
2012-10-22  8:11   ` Glauber Costa
2012-10-19 14:51 ` CK2 [03/15] slub: Use a statically allocated kmem_cache boot structure for bootstrap Christoph Lameter
2012-10-19 14:51 ` CK2 [07/15] Common kmalloc slab index determination Christoph Lameter
2012-10-22  9:45   ` Glauber Costa
2012-10-23 20:48     ` Christoph Lameter
2012-10-19 14:51 ` CK2 [10/15] slab: rename nodelists to node Christoph Lameter
2012-10-22  8:34   ` Glauber Costa
2012-10-19 14:58 ` CK2 [11/15] Common constants for kmalloc boundaries Christoph Lameter
     [not found] <20120928191715.368450474@linux.com>
2012-09-28 19:18 ` CK2 [01/15] slab: Simplify bootstrap Christoph Lameter

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