From: Yinghai Lu <yinghai@kernel.org>
To: Linus Torvalds <torvalds@linux-foundation.org>,
Steven Newbury <steve@snewbury.org.uk>,
"H. Peter Anvin" <hpa@zytor.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>,
Andrew Morton <akpm@linux-foundation.org>,
linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 02/11] PCI: Try to allocate mem64 above 4G at first
Date: Wed, 23 May 2012 11:40:46 -0700 [thread overview]
Message-ID: <CAE9FiQX=ECg5BmKm7B2ua_rZ6bOsceeHNsfFQRWBbNZx+8sBfw@mail.gmail.com> (raw)
In-Reply-To: <CAE9FiQXx_x9M5ncLk4DyL8heYQTcsHZt2JofFMjPfUd4mympeA@mail.gmail.com>
On Wed, May 23, 2012 at 10:30 AM, Yinghai Lu <yinghai@kernel.org> wrote:
> On Wed, May 23, 2012 at 8:57 AM, Linus Torvalds
> <torvalds@linux-foundation.org> wrote:
>> On Tue, May 22, 2012 at 11:34 PM, Yinghai Lu <yinghai@kernel.org> wrote:
>>> and will fall back to below 4g if it can not find any above 4g.
>>
>> Has this been tested on 32-bit machines without PAE? There might be
>> things that just happen to work because their allocations were always
>> done bottom-up.
>
> Good point. that problem should be addressed at first before this patch.
Just checked code for 32bit machines without PAE.
when X86_PAE is not set, phys_addr_t aka resource_size_t will be 32bit.
so in drivers/pci/bus.c::pci_bus_alloc_resource_fit()
will have bottom to 0.
resource_size_t bottom = PCIBIOS_MAX_MEM_32 + 1ULL;
also in arch/x86/kernel/setup.c::setup_arch()
iomem_resource.end = (1ULL << boot_cpu_data.x86_phys_bits) - 1;
will have iomem_resource.end to 0xffffffff
when X86_PAE is set, but CPU does not support PAE.
phys_addr_t aka resource_size_t will be 32bit.
so in drivers/pci/bus.c::pci_bus_alloc_resource_fit()
will have bottom to 4g.
resource_size_t bottom = PCIBIOS_MAX_MEM_32 + 1ULL;
but
in arch/x86/kernel/setup.c::setup_arch()
iomem_resource.end = (1ULL << boot_cpu_data.x86_phys_bits) - 1;
will have iomem_resource.end to 0xffffffff, because x86_phys_bits is 32 when PAE
is not detected in arch/x86/kernel/cpu/common.c::get_cpu_cap.
that mean first try will fail, so it will go to second try with bottom to 0.
so both case are safe with this patch.
Thanks
Yinghai
next prev parent reply other threads:[~2012-05-23 18:40 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-23 6:34 [PATCH 00/11] PCI: resource allocation related Yinghai Lu
2012-05-23 6:34 ` [PATCH 01/11] PCI: Should add children device res to fail list Yinghai Lu
2012-05-23 6:34 ` [PATCH 02/11] PCI: Try to allocate mem64 above 4G at first Yinghai Lu
2012-05-23 15:57 ` Linus Torvalds
2012-05-23 17:30 ` Yinghai Lu
2012-05-23 18:40 ` Yinghai Lu [this message]
2012-05-25 4:36 ` Bjorn Helgaas
2012-05-25 17:53 ` Yinghai Lu
2012-05-25 18:39 ` Yinghai Lu
2012-05-25 19:37 ` Bjorn Helgaas
2012-05-25 20:18 ` H. Peter Anvin
2012-05-25 20:19 ` Yinghai Lu
2012-05-25 21:55 ` Bjorn Helgaas
2012-05-25 21:58 ` H. Peter Anvin
2012-05-25 22:14 ` Bjorn Helgaas
2012-05-25 23:10 ` Yinghai Lu
2012-05-26 0:12 ` Bjorn Helgaas
2012-05-26 15:01 ` Bjorn Helgaas
2012-05-29 17:56 ` Yinghai Lu
2012-05-29 17:55 ` Yinghai Lu
2012-05-29 17:57 ` H. Peter Anvin
2012-05-29 18:17 ` Yinghai Lu
2012-05-29 19:03 ` H. Peter Anvin
2012-05-29 20:46 ` Yinghai Lu
2012-05-29 20:50 ` H. Peter Anvin
2012-06-01 23:30 ` Yinghai Lu
2012-06-04 1:05 ` Bjorn Helgaas
2012-06-05 2:37 ` Yinghai Lu
2012-06-05 4:50 ` Bjorn Helgaas
2012-06-05 5:04 ` Yinghai Lu
2012-06-06 9:44 ` Steven Newbury
2012-06-06 16:18 ` Bjorn Helgaas
[not found] ` <CAGLnvc_ejMWiiubVMo7DLz5ZVn1iMbf67FB4H7crRCCTRRqt2A@mail.gmail.com>
2012-07-04 3:00 ` joeyli
2012-05-29 20:53 ` David Miller
2012-05-29 19:23 ` Bjorn Helgaas
2012-05-29 20:40 ` Yinghai Lu
2012-05-29 23:24 ` Bjorn Helgaas
2012-05-29 23:27 ` Bjorn Helgaas
2012-05-29 23:33 ` Yinghai Lu
2012-05-29 23:47 ` Bjorn Helgaas
2012-05-30 7:40 ` Steven Newbury
2012-05-30 16:27 ` Bjorn Helgaas
2012-05-30 16:30 ` H. Peter Anvin
2012-05-30 16:33 ` Linus Torvalds
2012-05-23 6:34 ` [PATCH 03/11] intel-gtt: Read 64bit for gmar_bus_addr Yinghai Lu
2012-05-23 7:21 ` Dave Airlie
2012-05-23 7:44 ` Daniel Vetter
2012-05-23 6:34 ` [PATCH 04/11] PCI: Make sure assign same align with large size resource at first Yinghai Lu
2012-05-23 6:34 ` [PATCH 05/11] resources: Split out __allocate_resource() Yinghai Lu
2012-05-23 6:34 ` [PATCH 06/11] resource: make find_resource could return just fit resource Yinghai Lu
2012-05-23 6:34 ` [PATCH 07/11] PCI: Don't allocate small resource in big empty space Yinghai Lu
2012-05-23 6:34 ` [PATCH 08/11] resource: only return range with needed align Yinghai Lu
2012-05-23 6:34 ` [PATCH 09/11] PCI: Add is_pci_iov_resource_idx() Yinghai Lu
2012-05-23 6:34 ` [PATCH 10/11] PCI: Sort unassigned resources with correct alignment Yinghai Lu
2012-05-23 6:34 ` [PATCH 11/11] PCI: Treat ROM resource as optional during assigning Yinghai Lu
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