Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758588Ab2FZQxG (ORCPT ); Tue, 26 Jun 2012 12:53:06 -0400 Received: from one.firstfloor.org ([213.235.205.2]:39241 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757731Ab2FZQxF (ORCPT ); Tue, 26 Jun 2012 12:53:05 -0400 Date: Tue, 26 Jun 2012 18:52:58 +0200 From: Andi Kleen To: Mel Gorman Cc: Rafael Aquini , linux-mm@kvack.org, Rik van Riel , Andi Kleen , "Michael S. Tsirkin" , linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org Subject: Re: [PATCH 1/4] mm: introduce compaction and migration for virtio ballooned pages Message-ID: <20120626165258.GY11413@one.firstfloor.org> References: <7f83427b3894af7969c67acc0f27ab5aa68b4279.1340665087.git.aquini@redhat.com> <20120626101729.GF8103@csn.ul.ie> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120626101729.GF8103@csn.ul.ie> User-Agent: Mutt/1.4.2.2i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 755 Lines: 18 > > What shocked me actually is that VM_BUG_ON code is executed on > !CONFIG_DEBUG_VM builds and has been since 2.6.36 due to commit [4e60c86bd: > gcc-4.6: mm: fix unused but set warnings]. I thought the whole point of > VM_BUG_ON was to avoid expensive and usually unnecessary checks. Andi, > was this deliberate? The idea was that the compiler optimizes it away anyways. I'm not fully sure what putback_balloon_page does, but if it just tests a bit (without non variable test_bit) it should be ok. -Andi -- 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/