Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759375AbZDRWqt (ORCPT ); Sat, 18 Apr 2009 18:46:49 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753872AbZDRWqk (ORCPT ); Sat, 18 Apr 2009 18:46:40 -0400 Received: from hera.kernel.org ([140.211.167.34]:55028 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752388AbZDRWqj (ORCPT ); Sat, 18 Apr 2009 18:46:39 -0400 Message-ID: <49EA57C4.1000603@kernel.org> Date: Sat, 18 Apr 2009 15:44:20 -0700 From: Yinghai Lu User-Agent: Thunderbird 2.0.0.19 (X11/20081227) MIME-Version: 1.0 To: Linus Torvalds CC: Ingo Molnar , Jesse Barnes , "H. Peter Anvin" , Andrew Morton , Thomas Gleixner , "linux-kernel@vger.kernel.org" , linux-pci@vger.kernel.org, yannick.roehlly@free.fr Subject: Re: [PATCH] x86/pci: make pci_mem_start to be aligned only -v4 References: <49E00E9F.8030605@kernel.org> <49E4F6D6.6030709@kernel.org> <49E4F71F.10107@kernel.org> <49E52A7A.4070607@kernel.org> <49E52D3F.1090206@kernel.org> <20090416093152.6605612d@hobbes> <20090416165640.GA13927@elte.hu> <49E76864.9060309@kernel.org> <20090416172803.GB16618@elte.hu> <49E7916C.7050701@kernel.org> <49E99054.6050208@kernel.org> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5477 Lines: 158 Linus Torvalds wrote: > > On Sat, 18 Apr 2009, Yinghai Lu wrote: >> except need to change >>> + reserve_region_with_split(&iomem_resource, start, end, "RAM buffer"); >> ==> > + reserve_region_with_split(&iomem_resource, start, end - 1, "RAM buffer"); > > Yes, I sent out a later email pointing that out. > >> it will make sure dynmical allocating code will not use those range. >> >> and could make e820_setup_gap much simple. > > ACK. In fact: > >> Index: linux-2.6/arch/x86/kernel/e820.c >> =================================================================== >> --- linux-2.6.orig/arch/x86/kernel/e820.c >> +++ linux-2.6/arch/x86/kernel/e820.c >> @@ -635,14 +635,12 @@ __init void e820_setup_gap(void) >> #endif >> >> /* >> - * See how much we want to round up: start off with >> - * rounding to the next 1MB area. >> + * e820_reserve_resources_late will protect stolen RAM >> + * so just round it to 1M >> */ >> round = 0x100000; >> - while ((gapsize >> 4) > round) >> - round += round; >> - /* Fun with two's complement */ >> - pci_mem_start = (gapstart + round) & -round; >> + >> + pci_mem_start = roundup(gapstart, round); > > You can just remove "round" entirely. It's no longer a variable, it's just > an odd way of saying 1M ;) > >> Ingo, can you put those two patches in tip? > > I would suggest that we first change "reserve_region_with_split()" to not > recurse into the region. > > That function isn't used by anything else (we ended up using > "expand_to_fit()" instead in the one place that migth have used it), and > now th eone caller we do have would not want the recursion - if there > already exists a resource at the top level, we want to just avoid it. > > This - again TOTALLY UNTESTED - patch removes the "recurse into conflicts" > code. Comments? Testing? > > Linus > --- > kernel/resource.c | 46 ++++++++++++---------------------------------- > 1 files changed, 12 insertions(+), 34 deletions(-) > > diff --git a/kernel/resource.c b/kernel/resource.c > index fd5d7d5..ac5f3a3 100644 > --- a/kernel/resource.c > +++ b/kernel/resource.c > @@ -533,43 +533,21 @@ static void __init __reserve_region_with_split(struct resource *root, > res->end = end; > res->flags = IORESOURCE_BUSY; > > - for (;;) { > - conflict = __request_resource(parent, res); > - if (!conflict) > - break; > - if (conflict != parent) { > - parent = conflict; > - if (!(conflict->flags & IORESOURCE_BUSY)) > - continue; > - } > - > - /* Uhhuh, that didn't work out.. */ > - kfree(res); > - res = NULL; > - break; > - } > - > - if (!res) { > - /* failed, split and try again */ > - > - /* conflict covered whole area */ > - if (conflict->start <= start && conflict->end >= end) > - return; > + conflict = __request_resource(parent, res); > + if (!conflict) > + return; > > - if (conflict->start > start) > - __reserve_region_with_split(root, start, conflict->start-1, name); > - if (!(conflict->flags & IORESOURCE_BUSY)) { > - resource_size_t common_start, common_end; > + /* failed, split and try again */ > + kfree(res); > > - common_start = max(conflict->start, start); > - common_end = min(conflict->end, end); > - if (common_start < common_end) > - __reserve_region_with_split(root, common_start, common_end, name); > - } > - if (conflict->end < end) > - __reserve_region_with_split(root, conflict->end+1, end, name); > - } > + /* conflict covered whole area */ > + if (conflict->start <= start && conflict->end >= end) > + return; > > + if (conflict->start > start) > + __reserve_region_with_split(root, start, conflict->start-1, name); > + if (conflict->end < end) > + __reserve_region_with_split(root, conflict->end+1, end, name); > } > > void __init reserve_region_with_split(struct resource *root, with [ 0.000000] BIOS-provided physical RAM map: [ 0.000000] BIOS-e820: 0000000000000100 - 0000000000097400 (usable) [ 0.000000] BIOS-e820: 0000000000097400 - 00000000000a0000 (reserved) [ 0.000000] BIOS-e820: 0000000000100000 - 00000000b7fa0000 (usable) [ 0.000000] BIOS-e820: 00000000b7fae000 - 00000000b7fb0000 (usable) [ 0.000000] BIOS-e820: 00000000b7fb0000 - 00000000b7fbe000 (ACPI data) [ 0.000000] BIOS-e820: 00000000b7fbe000 - 00000000b7ff0000 (ACPI NVS) [ 0.000000] BIOS-e820: 00000000b7ff0000 - 00000000b8000000 (reserved) [ 0.000000] BIOS-e820: 00000000e0000000 - 00000000f0000000 (reserved) [ 0.000000] BIOS-e820: 00000000fec00000 - 00000000fec01000 (reserved) [ 0.000000] BIOS-e820: 00000000fee00000 - 00000000fef00000 (reserved) [ 0.000000] BIOS-e820: 00000000ff700000 - 0000000100000000 (reserved) [ 0.000000] BIOS-e820: 0000000100000000 - 0000002048000000 (usable) got 00000100-000973ff : System RAM 00097400-0009ffff : reserved 000a0000-000bffff : PCI Bus #00 000c0000-000cffff : pnp 00:0c 000e0000-000fffff : pnp 00:0c 00100000-b7f9ffff : System RAM 00200000-00c68f6b : Kernel code 00c68f6c-01332f7f : Kernel data 015a6000-01fcaa57 : Kernel bss 20000000-23ffffff : GART b7fa0000-b7fadfff : RAM buffer b7fae000-b7faffff : System RAM b7fb0000-b7fbdfff : ACPI Tables b7fbe000-b7feffff : ACPI Non-volatile Storage b7ff0000-b7ffffff : reserved ... 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