linux/arch/x86
Suresh Siddha 97943390b0 x86, irq: Don't block IRQ0_VECTOR..IRQ15_VECTOR's on all cpu's
Currently IRQ0..IRQ15 are assigned to IRQ0_VECTOR..IRQ15_VECTOR's on
all the cpu's.

If these IRQ's are handled by legacy pic controller, then the kernel
handles them only on cpu 0. So there is no need to block this vector
space on all cpu's.

Similarly if these IRQ's are handled by IO-APIC, then the IRQ affinity
will determine on which cpu's we need allocate the vector resource for
that particular IRQ. This can be done dynamically and here also there
is no need to block 16 vectors for IRQ0..IRQ15 on all cpu's.

Fix this by initially assigning IRQ0..IRQ15 to IRQ0_VECTOR..IRQ15_VECTOR's only
on cpu 0. If the legacy controllers like pic handles these irq's, then
this configuration will be fixed. If more modern controllers like IO-APIC
handle these IRQ's, then we start with this configuration and as IRQ's
migrate, vectors (/and cpu's) associated with these IRQ's change dynamically.

This will freeup the block of 16 vectors on other cpu's which don't handle
IRQ0..IRQ15, which can now be used for other IRQ's that the particular cpu
handle.

[ hpa: this also an architectural cleanup for future legacy-PIC-free
  configurations. ]
[ hpa: fixed typo NR_LEGACY_IRQS -> NR_IRQS_LEGACY ]

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
LKML-Reference: <1263932453.2814.52.camel@sbs-t61.sc.intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2010-01-19 13:40:29 -08:00
..
boot Merge branch 'for-33' of git://repo.or.cz/linux-kbuild 2009-12-17 07:23:42 -08:00
configs tracing: Rename FTRACE_SYSCALLS for tracepoints 2009-08-26 00:17:35 +02:00
crypto Merge git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6 2009-12-01 15:16:22 +08:00
ia32 Unify sys_mmap* 2009-12-11 06:44:29 -05:00
include/asm x86, irq: Don't block IRQ0_VECTOR..IRQ15_VECTOR's on all cpu's 2010-01-19 13:40:29 -08:00
kernel x86, irq: Don't block IRQ0_VECTOR..IRQ15_VECTOR's on all cpu's 2010-01-19 13:40:29 -08:00
kvm Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu 2009-12-14 09:58:24 -08:00
lguest lguest: move panic notifier registration to its expected place. 2009-09-23 22:26:44 +09:30
lib Merge branch 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-12-19 09:48:14 -08:00
math-emu
mm Merge branch 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-12-19 09:48:14 -08:00
oprofile perf events, x86/stacktrace: Make stack walking optional 2009-12-17 09:56:19 +01:00
pci x86/PCI: claim SR-IOV BARs in pcibios_allocate_resource 2009-12-04 16:00:17 -08:00
power hw-breakpoints: Rewrite the hw-breakpoints layer on top of perf events 2009-11-08 15:34:42 +01:00
tools Merge branch 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-12-19 09:48:14 -08:00
vdso sysctl x86: Remove dead binary sysctl support 2009-11-12 02:05:04 -08:00
video
xen locking: Convert raw_spinlock to arch_spinlock 2009-12-14 23:55:32 +01:00
Kbuild
Kconfig hw-breakpoints: Fix hardware breakpoints -> perf events dependency 2009-12-18 13:11:51 +01:00
Kconfig.cpu Merge branch 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-12-08 13:27:33 -08:00
Kconfig.debug Merge branch 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-12-11 20:47:30 -08:00
Makefile Merge branch 'perf/core' into perf/probes 2009-11-17 10:17:47 +01:00
Makefile_32.cpu Merge branch 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-12-08 13:38:11 -08:00