From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751999AbaHDJZb (ORCPT ); Mon, 4 Aug 2014 05:25:31 -0400 Received: from smtp.codeaurora.org ([198.145.11.231]:48112 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751599AbaHDJZa (ORCPT ); Mon, 4 Aug 2014 05:25:30 -0400 Message-ID: <53DF5184.1040501@codeaurora.org> Date: Mon, 04 Aug 2014 14:55:24 +0530 From: Chintan Pandya User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.24) Gecko/20111108 Thunderbird/3.1.16 MIME-Version: 1.0 To: Andrew Morton CC: David Rientjes , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH v2] mm: BUG when __kmap_atomic_idx equals KM_TYPE_NR References: <1406787871-2951-1-git-send-email-cpandya@codeaurora.org> <53DA0C5A.3010409@codeaurora.org> <20140731154540.441ab79ff32ae5c10f64bcbd@linux-foundation.org> In-Reply-To: <20140731154540.441ab79ff32ae5c10f64bcbd@linux-foundation.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 08/01/2014 04:15 AM, Andrew Morton wrote: > On Thu, 31 Jul 2014 14:58:58 +0530 Chintan Pandya wrote: > >>> >>> I think Andrew's comment earlier was referring to the changelog only and >>> not the patch, which looked correct. >> >> I think Andrew asked for a BUG case details also to justify the >> overhead. But we have never encountered that BUG case. Present patch is >> only logical fix to the code. However, in the fast path, if such >> overhead is allowed, I can move BUG_ON out of any debug configs. >> Otherwise, as per Andrew's suggestion, I will convert DEBUG_HIGHMEM into >> DEBUG_VM which is used more frequently. > > The v1 patch added a small amount of overhead to kmap_atomic() for what > is evidently a very small benefit. > > Yes, I suggest we remove CONFIG_DEBUG_HIGHMEM from the kernel entirely > and switch all CONFIG_DEBUG_HIGHMEM sites to use CONFIG_DEBUG_VM. That way > the BUG_ON which you believe is useful will be tested by more people > more often. Ping!! Anything open for me to do here ? -- Chintan Pandya QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, hosted by The Linux Foundation