From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EC3FDC3F2D2 for ; Fri, 6 Mar 2020 00:28:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CBA7620870 for ; Fri, 6 Mar 2020 00:28:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727264AbgCFA2D (ORCPT ); Thu, 5 Mar 2020 19:28:03 -0500 Received: from ozlabs.org ([203.11.71.1]:38271 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727178AbgCFA1y (ORCPT ); Thu, 5 Mar 2020 19:27:54 -0500 Received: by ozlabs.org (Postfix, from userid 1034) id 48YT3X0KXSz9sPJ; Fri, 6 Mar 2020 11:27:51 +1100 (AEDT) X-powerpc-patch-notification: thanks X-powerpc-patch-commit: 6453f9ed9d4e4b4cdf201bf34bf460c436bf50ea In-Reply-To: <03c97f0f6b3790d164822563be80f2fd4713a955.1581932480.git.christophe.leroy@c-s.fr> To: Christophe Leroy , Benjamin Herrenschmidt , Paul Mackerras From: Michael Ellerman Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] powerpc/mm: Don't kmap_atomic() in pte_offset_map() on PPC32 Message-Id: <48YT3X0KXSz9sPJ@ozlabs.org> Date: Fri, 6 Mar 2020 11:27:51 +1100 (AEDT) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2020-02-17 at 09:41:35 UTC, Christophe Leroy wrote: > On PPC32, pte_offset_map() does a kmap_atomic() in order to support > page tables allocated in high memory, just like ARM and x86/32. > > But since at least 2008 and commit 8054a3428fbe ("powerpc: Remove dead > CONFIG_HIGHPTE"), page tables are never allocated in high memory. > > When the page is in low mem, kmap_atomic() just returns the page > address but still disable preemption and pagefault. And it is > not an inlined function, so we suffer function call for no reason. > > Make pte_offset_map() the same as pte_offset_kernel() and make > pte_unmap() void, in the same way as PPC64 which doesn't have HIGHMEM. > > Signed-off-by: Christophe Leroy Applied to powerpc next, thanks. https://git.kernel.org/powerpc/c/6453f9ed9d4e4b4cdf201bf34bf460c436bf50ea cheers