[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-Id: <1426115422-1823-2-git-send-email-mcgrof@do-not-panic.com>
Date: Wed, 11 Mar 2015 16:10:21 -0700
From: "Luis R. Rodriguez" <mcgrof@...not-panic.com>
To: rientjes@...gle.com, bhelgaas@...gle.com, mingo@...hat.com,
tglx@...utronix.de, hpa@...or.com, pure.logic@...us-software.ie,
jgross@...e.com, luto@...capital.net, andy.shevchenko@...il.com,
thomas.petazzoni@...e-electrons.com, JBeulich@...e.com, bp@...e.de
Cc: linux-kernel@...r.kernel.org, linux-pci@...r.kernel.org,
x86@...nel.org, "Luis R. Rodriguez" <mcgrof@...e.com>,
Ingo Molnar <mingo@...nel.org>
Subject: [PATCH v1 1/2] x86: kconfig: remove X86_UP_IOAPIC
From: "Luis R. Rodriguez" <mcgrof@...e.com>
X86_UP_IOAPIC is a way so that 32-bit UP systems can enable
X86_IOAPIC. X86_UP_IOAPIC is only as a visible user option if
you are on a 32-bit system but have X86_UP_APIC enabled. X86_UP_APIC
will be enabled by force if you have PCI_MSI on 32-bit systems
now, X86_UP_APIC will now only be user selectable if you didn't
have PCI_MSI enabled and are also not on a X86_32_NON_STANDARD
system. Bryan's original patch (refactored commit log in commit
38a1dfda) [0] describes that Intel CE, Intel MID and Intel Quark
are all 32-bit uniprocessor systems with IO-APICs, the code change
however only *re-enabled* UP_IOAPIC as an *option* when PCI_MSI
was enabled, but given that:
1) enabling X86_IOAPIC is the real end goal here
2) enabling X86_IOAPIC only increases the kernel only by 12064 bytes (~12 KiB)
3) enabling X86_IOAPIC will in no way slow down your kernel
Let's make a compromise for 32-bit systems and always enable X86_IOAPIC
when X86_UP_IOAPIC is enabled as 32-bit systems are not in a state
of flux and the price for the size is small with no performance impact.
Using:
export ARCH=i386
make allnoconfig
--> Enabling PCI_MSI
make localyesconfig
With X86_IO_APIC:
mcgrof@...on ~/linux-next (git::master)$ du -b arch/x86/boot/bzImage
734608 arch/x86/boot/bzImage
Without X86_IO_APIC:
mcgrof@...on ~/linux-next (git::master)$ du -b arch/x86/boot/bzImage
722544 arch/x86/boot/bzImage
[0] https://lkml.org/lkml/2015/1/22/718
Cc: David Rientjes <rientjes@...gle.com>
Cc: Bjorn Helgaas <bhelgaas@...gle.com>
Cc: Bryan O'Donoghue <pure.logic@...us-software.ie>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Andy Shevchenko <andy.shevchenko@...il.com>
Cc: Thomas Petazzoni <thomas.petazzoni@...e-electrons.com>
Cc: Ingo Molnar <mingo@...nel.org>
Cc: Borislav Petkov <bp@...e.de>
Cc: H. Peter Anvin <hpa@...or.com>
Cc: Jan Beulich <JBeulich@...e.com>
Cc: Juergen Gross <jgross@...e.com>
Cc: linux-pci@...r.kernel.org
Cc: x86@...nel.org
Signed-off-by: Luis R. Rodriguez <mcgrof@...e.com>
---
arch/x86/Kconfig | 15 ++-------------
1 file changed, 2 insertions(+), 13 deletions(-)
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 110f6ae..b17a8ea 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -899,6 +899,7 @@ config X86_UP_APIC
bool "Local APIC support on uniprocessors" if !PCI_MSI
default PCI_MSI
depends on X86_32 && !SMP && !X86_32_NON_STANDARD
+ select X86_IO_APIC
---help---
A local APIC (Advanced Programmable Interrupt Controller) is an
integrated interrupt controller in the CPU. If you have a single-CPU
@@ -909,18 +910,6 @@ config X86_UP_APIC
performance counters), and the NMI watchdog which detects hard
lockups.
-config X86_UP_IOAPIC
- bool "IO-APIC support on uniprocessors"
- depends on X86_UP_APIC
- ---help---
- An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
- SMP-capable replacement for PC-style interrupt controllers. Most
- SMP systems and many recent uniprocessor systems have one.
-
- If you have a single-CPU system with an IO-APIC, you can say Y here
- to use it. If you say Y here even though your machine doesn't have
- an IO-APIC, then the kernel will still run with no slowdown at all.
-
config X86_LOCAL_APIC
def_bool y
depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
@@ -928,7 +917,7 @@ config X86_LOCAL_APIC
config X86_IO_APIC
def_bool y
- depends on X86_LOCAL_APIC || X86_UP_IOAPIC
+ depends on X86_LOCAL_APIC
select IRQ_DOMAIN
config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
--
2.3.2.209.gd67f9d5.dirty
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists