From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qt1-f198.google.com (mail-qt1-f198.google.com [209.85.160.198]) by kanga.kvack.org (Postfix) with ESMTP id 153296B744D for ; Wed, 5 Dec 2018 07:29:15 -0500 (EST) Received: by mail-qt1-f198.google.com with SMTP id j5so20273707qtk.11 for ; Wed, 05 Dec 2018 04:29:15 -0800 (PST) Received: from mx1.redhat.com (mx1.redhat.com. [209.132.183.28]) by mx.google.com with ESMTPS id o14si4989795qtb.200.2018.12.05.04.29.14 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 05 Dec 2018 04:29:14 -0800 (PST) From: David Hildenbrand Subject: [PATCH RFC 0/7] mm: PG_reserved cleanups and documentation Date: Wed, 5 Dec 2018 13:28:44 +0100 Message-Id: <20181205122851.5891-1-david@redhat.com> Sender: owner-linux-mm@kvack.org List-ID: To: linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-m68k@lists.linux-m68k.org, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, linux-mediatek@lists.infradead.org, David Hildenbrand , Albert Ou , Alexander Duyck , Andrew Morton , Anthony Yznaga , Arnd Bergmann , Benjamin Herrenschmidt , Bhupesh Sharma , Catalin Marinas , Christophe Leroy , Dan Williams , Dave Kleikamp , David Airlie , Geert Uytterhoeven , Greg Kroah-Hartman , Heiko Carstens , James Morse , Kees Cook , Marc Zyngier , Mark Rutland , Martin Schwidefsky , Matthew Wilcox , Michael Ellerman , Michal Hocko , Michal Hocko , Mike Rapoport , Miles Chen , Palmer Dabbelt , Paul Mackerras , Pavel Tatashin , Souptick Joarder , Stephen Rothwell , Tobias Klauser , Vasily Gorbik , Will Deacon I was recently going over all users of PG_reserved. Short story: it is difficult and sometimes not really clear if setting/checking for PG_reserved is only a relict from the past. Easy to break things. I had way more cleanups in this series inititally, but some architectures take PG_reserved as a way to apply a different caching strategy (for MMIO pages). So I decided to only include the most obvious changes (that are less likely to break something). So let's see if the documentation update for PG_reserved I crafted actually covers most cases or if there is plenty more. Most notably, for device memory we can hopefully soon stop setting it PG_reserved I only briefly tested this on s390x. David Hildenbrand (7): agp: efficeon: no need to set PG_reserved on GATT tables s390/vdso: don't clear PG_reserved powerpc/vdso: don't clear PG_reserved riscv/vdso: don't clear PG_reserved m68k/mm: use __ClearPageReserved() arm64: kexec: no need to ClearPageReserved() mm: better document PG_reserved arch/arm64/kernel/machine_kexec.c | 1 - arch/m68k/mm/memory.c | 2 +- arch/powerpc/kernel/vdso.c | 2 -- arch/riscv/kernel/vdso.c | 1 - arch/s390/kernel/vdso.c | 2 -- drivers/char/agp/efficeon-agp.c | 2 -- include/linux/page-flags.h | 18 ++++++++++++++++-- 7 files changed, 17 insertions(+), 11 deletions(-) -- 2.17.2