From: JoonSoo Kim <js1304@gmail.com>
To: Glauber Costa <glommer@parallels.com>
Cc: Christoph Lameter <cl@linux.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Pekka Enberg <penberg@kernel.org>,
David Rientjes <rientjes@google.com>
Subject: Re: [PATCH 2/2] slab: move kmem_cache_free to common code
Date: Tue, 23 Oct 2012 09:48:19 +0900 [thread overview]
Message-ID: <CAAmzW4PJkDbLJBKZ1zPNDw+dHPcgzX_25tMw3rWoX0ybpXACSQ@mail.gmail.com> (raw)
In-Reply-To: <508561E0.5000406@parallels.com>
Hello, Glauber.
2012/10/23 Glauber Costa <glommer@parallels.com>:
> On 10/22/2012 06:45 PM, Christoph Lameter wrote:
>> On Mon, 22 Oct 2012, Glauber Costa wrote:
>>
>>> + * kmem_cache_free - Deallocate an object
>>> + * @cachep: The cache the allocation was from.
>>> + * @objp: The previously allocated object.
>>> + *
>>> + * Free an object which was previously allocated from this
>>> + * cache.
>>> + */
>>> +void kmem_cache_free(struct kmem_cache *s, void *x)
>>> +{
>>> + __kmem_cache_free(s, x);
>>> + trace_kmem_cache_free(_RET_IP_, x);
>>> +}
>>> +EXPORT_SYMBOL(kmem_cache_free);
>>> +
>>
>> This results in an additional indirection if tracing is off. Wonder if
>> there is a performance impact?
>>
> if tracing is on, you mean?
>
> Tracing already incurs overhead, not sure how much a function call would
> add to the tracing overhead.
>
> I would not be concerned with this, but I can measure, if you have any
> specific workload in mind.
With this patch, kmem_cache_free() invokes __kmem_cache_free(),
that is, it add one more "call instruction" than before.
I think that Christoph's comment means above fact.
Thanks.
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next prev parent reply other threads:[~2012-10-23 0:48 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-22 14:05 [PATCH 0/2] move kmem_cache_free to common code Glauber Costa
2012-10-22 14:05 ` [PATCH 1/2] slab: commonize slab_cache field in struct page Glauber Costa
2012-10-22 14:44 ` Christoph Lameter
2012-10-24 8:58 ` Pekka Enberg
2012-10-22 14:05 ` [PATCH 2/2] slab: move kmem_cache_free to common code Glauber Costa
2012-10-22 14:45 ` Christoph Lameter
2012-10-22 15:10 ` Glauber Costa
2012-10-23 0:48 ` JoonSoo Kim [this message]
2012-10-23 8:07 ` Glauber Costa
2012-10-23 10:52 ` Glauber Costa
2012-10-23 15:43 ` JoonSoo Kim
2012-10-24 8:31 ` Glauber Costa
2012-10-24 13:39 ` Glauber Costa
2012-10-23 14:12 ` Christoph Lameter
2012-10-23 14:15 ` Glauber Costa
2012-10-23 14:34 ` Christoph Lameter
2012-10-23 18:16 ` Christoph Lameter
2012-10-24 8:56 ` Pekka Enberg
2012-10-24 10:03 ` Glauber Costa
2012-10-24 8:56 ` Pekka Enberg
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