Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935639AbYBTQio (ORCPT ); Wed, 20 Feb 2008 11:38:44 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S934467AbYBTQ2H (ORCPT ); Wed, 20 Feb 2008 11:28:07 -0500 Received: from viefep18-int.chello.at ([213.46.255.22]:59041 "EHLO viefep19-int.chello.at" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S934461AbYBTQ2C (ORCPT ); Wed, 20 Feb 2008 11:28:02 -0500 Message-ID: <47BC54FB.2050508@trash.net> Date: Wed, 20 Feb 2008 17:27:39 +0100 From: Patrick McHardy User-Agent: Mozilla-Thunderbird 2.0.0.6 (X11/20071008) MIME-Version: 1.0 To: Jan Engelhardt CC: =?ISO-8859-15?Q?Ilpo_J=E4rvinen?= , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, David Miller , Arnaldo Carvalho de Melo Subject: Re: [RFC PATCH 3/8] [NET]: uninline dev_alloc_skb, de-bloats a lot References: <1203515238-22848-1-git-send-email-ilpo.jarvinen@helsinki.fi> <1203515238-22848-2-git-send-email-ilpo.jarvinen@helsinki.fi> <1203515238-22848-3-git-send-email-ilpo.jarvinen@helsinki.fi> <1203515238-22848-4-git-send-email-ilpo.jarvinen@helsinki.fi> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1121 Lines: 31 Jan Engelhardt wrote: > On Feb 20 2008 15:47, Ilpo J?rvinen wrote: >> -23668 392 funcs, 104 +, 23772 -, diff: -23668 --- dev_alloc_skb >> >> -static inline struct sk_buff *dev_alloc_skb(unsigned int length) >> -{ >> - return __dev_alloc_skb(length, GFP_ATOMIC); >> -} >> +extern struct sk_buff *dev_alloc_skb(unsigned int length); > > Striking. How can this even happen? A callsite which calls > > dev_alloc_skb(n) > > is just equivalent to > > __dev_alloc_skb(n, GFP_ATOMIC); > > which means there's like 4 (or 8 if it's long) bytes more on the > stack. For a worst case, count in another 8 bytes for push and pop or mov on > the stack. But that still does not add up to 23 kb. __dev_alloc_skb() is also an inline function which performs some extra work. Which raises the question - if dev_alloc_skb() is uninlined, shouldn't __dev_alloc_skb() be uninline as well? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/