On Fri, Nov 09, 2018 at 12:48:06PM -0800, Andrew Morton wrote:
>On Thu, 8 Nov 2018 09:12:04 +0800 Wei Yang <richard.weiyang@xxxxxxxxx> wrote:
>
>> for_each_zone_zonelist() iterates the zonelist one by one, which means
>> it will iterate on zones on the same node. While get_partial_node()
>> checks available slab on node base instead of zone.
>>
>> This patch skip a node in case get_partial_node() fails to acquire slab
>> on that node.
>
>This is rather hard to follow.
>
>I *think* the patch is a performance optimization: prevent
>get_any_partial() from checking a node which get_partial_node() has
>already looked at?
You are right :-)
>
>Could we please have a more complete changelog?
Hmm... I would like to.
But I am not sure which part makes you hard to follow. If you would like
to tell me the pain point, I am glad to think about how to make it more
obvious.
>
>> --- a/mm/slub.c
>> +++ b/mm/slub.c
>> @@ -1873,7 +1873,7 @@ static void *get_partial_node(struct kmem_cache *s, struct kmem_cache_node *n,
>> * Get a page from somewhere. Search in increasing NUMA distances.
>> */
>> static void *get_any_partial(struct kmem_cache *s, gfp_t flags,
>> - struct kmem_cache_cpu *c)
>> + struct kmem_cache_cpu *c, int except)
>> {
>> #ifdef CONFIG_NUMA
>> struct zonelist *zonelist;
>> @@ -1882,6 +1882,9 @@ static void *get_any_partial(struct kmem_cache *s, gfp_t flags,
>> enum zone_type high_zoneidx = gfp_zone(flags);
>> void *object;
>> unsigned int cpuset_mems_cookie;
>> + nodemask_t nmask = node_states[N_MEMORY];
>> +
>> + node_clear(except, nmask);
>
>And please add a comment describing what's happening here and why it is
>done. Adding a sentence to the block comment over get_any_partial()
>would be suitable.
>
Sure, I would address this in next spin.
--
Wei Yang
Help you, Help me
