Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759430AbYARAr6 (ORCPT ); Thu, 17 Jan 2008 19:47:58 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757349AbYARArt (ORCPT ); Thu, 17 Jan 2008 19:47:49 -0500 Received: from waste.org ([66.93.16.53]:55749 "EHLO waste.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757332AbYARArs (ORCPT ); Thu, 17 Jan 2008 19:47:48 -0500 Subject: Re: 2.6.24-rc8-mm1: powerpc oopses From: Matt Mackall To: Andrew Morton Cc: m.kozlowski@tuxland.pl, linux-kernel@vger.kernel.org, paulus@samba.org, linuxppc-dev@ozlabs.org In-Reply-To: <20080117162913.0323c517.akpm@linux-foundation.org> References: <20080117023514.9df393cf.akpm@linux-foundation.org> <200801172315.28129.m.kozlowski@tuxland.pl> <20080117145105.ad968ea6.akpm@linux-foundation.org> <1200613194.3839.22.camel@cinder.waste.org> <20080117160513.3456b4eb.akpm@linux-foundation.org> <1200615168.3839.26.camel@cinder.waste.org> <20080117162913.0323c517.akpm@linux-foundation.org> Content-Type: text/plain Date: Thu, 17 Jan 2008 18:47:17 -0600 Message-Id: <1200617237.3839.32.camel@cinder.waste.org> Mime-Version: 1.0 X-Mailer: Evolution 2.12.2 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1400 Lines: 52 On Thu, 2008-01-17 at 16:29 -0800, Andrew Morton wrote: > Do we need `offset' at all? Looks like no. I wonder if there's a good argument for adding a pte_offset_val() which would let us do: pteval = pte_offset_val(pmd, addr); and shrink the map/unmap window and overhead here and possibly elsewhere? Anyway, updated but still untested patch now with revealing comment: diff -r 5595adaea70f fs/proc/task_mmu.c --- a/fs/proc/task_mmu.c Thu Jan 17 13:26:54 2008 -0600 +++ b/fs/proc/task_mmu.c Thu Jan 17 18:45:57 2008 -0600 @@ -584,18 +585,19 @@ pte_t *pte; int err = 0; - pte = pte_offset_map(pmd, addr); - for (; addr != end; pte++, addr += PAGE_SIZE) { + for (; addr != end; addr += PAGE_SIZE) { u64 pfn = PM_NOT_PRESENT; + pte = pte_offset_map(pmd, addr); if (is_swap_pte(*pte)) pfn = swap_pte_to_pagemap_entry(*pte); else if (pte_present(*pte)) pfn = pte_pfn(*pte); + /* unmap so we're not in atomic when we copy to userspace */ + pte_unmap(pte); err = add_to_pagemap(addr, pfn, pm); if (err) return err; } - pte_unmap(pte - 1); cond_resched(); -- Mathematics is the supreme nostalgia of our time. -- 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/