Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760892Ab2BNO7y (ORCPT ); Tue, 14 Feb 2012 09:59:54 -0500 Received: from gw.danplanet.com ([50.43.125.66]:35302 "EHLO mail.danplanet.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751007Ab2BNO7x (ORCPT ); Tue, 14 Feb 2012 09:59:53 -0500 From: Dan Smith To: David Rientjes Cc: akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] Ensure that walk_page_range()'s start and end are page-aligned References: <1328902796-30389-1-git-send-email-danms@us.ibm.com> <87zkcm23az.fsf@caffeine.danplanet.com> Date: Tue, 14 Feb 2012 06:59:51 -0800 In-Reply-To: (David Rientjes's message of "Mon, 13 Feb 2012 13:55:31 -0800 (PST)") Message-ID: <87pqdh1mvs.fsf@caffeine.danplanet.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 939 Lines: 23 DR> That's not a precedent, there's a big difference between the DR> performance of gup_fast(), where we can't spare an additional DR> compare and branch, and walk_page_range(). VM_BUG_ON() is typically DR> used in situations where a debug kernel has been built, including DR> CONFIG_DEBUG_VM, and the check helps to isolate a problem that would DR> be otherwise difficult to find. Okay, fair enough. I was trying to stay in line with the other conventions, knowing that the check would only be done with CONFIG_DEBUG_VM enabled. I'd rather just make it always do the check in walk_page_range(). Does that sound reasonable? -- Dan Smith IBM Linux Technology Center email: danms@us.ibm.com -- 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/