From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Morton Subject: Re: [PATCH 1/4] compiler.h: introduce unused_expression() macro Date: Fri, 27 Apr 2012 14:53:02 -0700 Message-ID: <20120427145302.64f50e5c.akpm@linux-foundation.org> References: <20120425112623.26927.43229.stgit@zurg> <20120426152909.b1e653bf.akpm@linux-foundation.org> <4F9A6CFA.8040805@openvz.org> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: Received: from mail.linuxfoundation.org ([140.211.169.12]:58481 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753059Ab2D0VxE (ORCPT ); Fri, 27 Apr 2012 17:53:04 -0400 In-Reply-To: <4F9A6CFA.8040805@openvz.org> Sender: linux-arch-owner@vger.kernel.org List-ID: To: Konstantin Khlebnikov Cc: Linus Torvalds , "linux-kernel@vger.kernel.org" , "linux-arch@vger.kernel.org" On Fri, 27 Apr 2012 13:55:06 +0400 Konstantin Khlebnikov wrote: > Andrew Morton wrote: > > On Wed, 25 Apr 2012 15:26:23 +0400 > > Konstantin Khlebnikov wrote: > > for example VM_BUG_ON(!PageCompound(page) || !PageHead(page)); in > do_huge_pmd_wp_page() generates 114 bytes. > > But they mostly disappears if I replace it with > -VM_BUG_ON(!PageCompound(page) || !PageHead(page)); > +VM_BUG_ON(!PageCompound(page)); > +VM_BUG_ON(!PageHead(page)); > weird... > > add/remove: 0/0 grow/shrink: 7/97 up/down: 135/-1784 (-1649) OK, thanks. I'm inclined to apply the patchset as-is. If the apparently mythical use of side-effects in VM_BUG_ON() really exist then we deserve everything which happens to us as a result ;) Please update the changelogs so they cover all the points which have been discussed, add my little code comment then send out a v2, being sure to cc everyone who has been involved in the discussion?