Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756851Ab0LPRiV (ORCPT ); Thu, 16 Dec 2010 12:38:21 -0500 Received: from g6t0187.atlanta.hp.com ([15.193.32.64]:15685 "EHLO g6t0187.atlanta.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756243Ab0LPRiT (ORCPT ); Thu, 16 Dec 2010 12:38:19 -0500 Subject: [PATCH 0/9] PCI: revert to allocating bottom-up, avoid E820 areas To: Jesse Barnes , Len Brown From: Bjorn Helgaas Cc: linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org, "H. Peter Anvin" , Thomas Gleixner , Linus Torvalds , Ingo Molnar , Adam Belay Date: Thu, 16 Dec 2010 10:38:15 -0700 Message-ID: <20101216173614.8185.19462.stgit@bob.kio> User-Agent: StGit/0.15 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3631 Lines: 74 [This is 2.6.37 material] In 2.6.34 and later, we automatically use "pci=use_crs" on recent (2008 or newer) machines, which means we assign PCI resources from the host bridge windows described by ACPI _CRS. In many cases, _CRS claims the windows are bigger than they really are, e.g., they may overlap system memory, ROM, or other ACPI devices. Linux allocates PCI memory bottom-up, ignores most ACPI devices, and does an incomplete job of avoiding E820 reserved areas, which caused problems like https://bugzilla.kernel.org/show_bug.cgi?id=16228 . As far as I can tell, Windows deals with this situation by removing all ACPI resources and allocating the remaining space top-down. I tried to make Linux allocate top-down as well, but since we don't have a good mechanism for avoiding the ACPI devices that clutter the top of memory, we tripped over several of those, which resulted in these regressions: https://bugzilla.kernel.org/show_bug.cgi?id=23132 (Dell 1545) https://bugzilla.kernel.org/show_bug.cgi?id=23332 (HP nx6325) https://bugzilla.kernel.org/show_bug.cgi?id=23542 (HP 2530p) https://bugzilla.kernel.org/show_bug.cgi?id=23802 (PCI / TPM conflict) So I think the best band-aid for now is to revert to bottom-up allocation and do a better job of avoiding E820 reserved areas. Obviously, it's not complete because we could still trip over ACPI devices (as in 23802), but that's a problem we've always had and it's not as likely if we go bottom-up. Patches 1-5 of this series are straight reverts ("git revert -n") of these patches which were merged in 2.6.37-rc1: 82e3e76 PCI: fix pci_bus_alloc_resource() hang, prefer positive decode 1af3c2e x86: allocate space within a region top-down dc9887d x86/PCI: allocate space from the end of a region, not the beginning b126b47 PCI: allocate bus resources from the top down e7f8567 resources: support allocating space within a region from the top down Patches 6-9 add the ability to avoid E820 regions and the top 2MB below 4GB. The last patch (avoid top 2MB) is not strictly necessary in that it doesn't fix any current issues I'm aware of. Bjorn --- Bjorn Helgaas (9): Revert "PCI: fix pci_bus_alloc_resource() hang, prefer positive decode" Revert "x86: allocate space within a region top-down" Revert "x86/PCI: allocate space from the end of a region, not the beginning" Revert "PCI: allocate bus resources from the top down" Revert "resources: support allocating space within a region from the top down" resources: add arch hook for preventing allocation in reserved areas x86: avoid low BIOS area when allocating address space x86: avoid E820 regions when allocating address space x86: avoid high BIOS area when allocating address space Documentation/kernel-parameters.txt | 5 -- arch/x86/include/asm/e820.h | 3 + arch/x86/kernel/Makefile | 1 arch/x86/kernel/resource.c | 48 ++++++++++++++++ arch/x86/kernel/setup.c | 1 arch/x86/pci/i386.c | 18 ++---- drivers/pci/bus.c | 81 ++------------------------- include/linux/ioport.h | 2 - kernel/resource.c | 104 +++-------------------------------- 9 files changed, 73 insertions(+), 190 deletions(-) create mode 100644 arch/x86/kernel/resource.c -- 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/