From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx175.postini.com [74.125.245.175]) by kanga.kvack.org (Postfix) with SMTP id 9D5BC6B009D for ; Mon, 22 Oct 2012 20:48:20 -0400 (EDT) Received: by mail-ob0-f169.google.com with SMTP id va7so3693540obc.14 for ; Mon, 22 Oct 2012 17:48:19 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <508561E0.5000406@parallels.com> References: <1350914737-4097-1-git-send-email-glommer@parallels.com> <1350914737-4097-3-git-send-email-glommer@parallels.com> <0000013a88eff593-50da3bb8-3294-41db-9c32-4e890ef6940a-000000@email.amazonses.com> <508561E0.5000406@parallels.com> Date: Tue, 23 Oct 2012 09:48:19 +0900 Message-ID: Subject: Re: [PATCH 2/2] slab: move kmem_cache_free to common code From: JoonSoo Kim Content-Type: text/plain; charset=ISO-8859-1 Sender: owner-linux-mm@kvack.org List-ID: To: Glauber Costa Cc: Christoph Lameter , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Pekka Enberg , David Rientjes Hello, Glauber. 2012/10/23 Glauber Costa : > 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. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org