From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx121.postini.com [74.125.245.121]) by kanga.kvack.org (Postfix) with SMTP id EBFE06B0044 for ; Wed, 26 Sep 2012 18:43:46 -0400 (EDT) Date: Wed, 26 Sep 2012 15:43:45 -0700 From: Andrew Morton Subject: Re: [PATCH v3 2/9] rbtree: add __rb_change_child() helper function Message-Id: <20120926154345.52cb9f33.akpm@linux-foundation.org> In-Reply-To: <506382E3.3020102@att.net> References: <1345500331-10546-1-git-send-email-walken@google.com> <1345500331-10546-3-git-send-email-walken@google.com> <20120820151710.eeed9bcf.akpm@linux-foundation.org> <506382E3.3020102@att.net> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Daniel Santos Cc: Daniel Santos , Michel Lespinasse , riel@redhat.com, peterz@infradead.org, aarcange@redhat.com, dwmw2@infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, torvalds@linux-foundation.org On Wed, 26 Sep 2012 17:34:11 -0500 Daniel Santos wrote: > Sorry to resurrect the dead here, but I'm playing catch-up and this > looks important. > > On 08/20/2012 05:17 PM, Andrew Morton wrote: > > I'm inclined to agree with Peter here - "inline" is now a vague, > > pathetic and useless thing. The problem is that the reader just > > doesn't *know* whether or not the writer really wanted it to be > > inlined. > > > > If we have carefully made a decision to inline a function, we should > > (now) use __always_inline. > Are we all aware here that __always_inline (a.k.a. > "__attribute__((always_inline))") just means "inline even when not > optimizing"? This appears to be a very common misunderstanding (unless > the gcc docs are wrong, see > http://gcc.gnu.org/onlinedocs/gcc/Function-Attributes.html#index-g_t_0040code_007bflatten_007d-function-attribute-2512). > > If you want to *force* gcc to inline a function (when inlining is > enabled), you can currently only do it from the calling function by > adding the |flatten attribute to it, which I have proposed adding here: > https://lkml.org/lkml/2012/9/25/643. > > Thus, all of the __always_inline markings we have in the kernel only > affect unoptimized builds (and maybe -O1?). If we need this feature > (and I think it would be darned handy!) we'll have to work on gcc to get it. When I replace the four __always_inline's in fs/namei.c with "inline", namei.o's .text shrinks 2kbytes (gcc-4.4.4), so __always_inline does allear to be doing what we think it does? -- 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