linux/arch/mips
Alex Smith 4ace6139bf MIPS: SMP: Don't increment irq_count multiple times for call function IPIs
The majority of SMP platforms handle their IPIs through do_IRQ()
which calls irq_{enter/exit}(). When a call function IPI is received,
smp_call_function_interrupt() is called which also calls
irq_{enter,exit}(), meaning irq_count is raised twice.

When tick broadcasting is used (which is implemented via a call
function IPI), this incorrectly causes all CPU idle time on the core
receiving broadcast ticks to be accounted as time spent servicing
IRQs, as account_process_tick() will account as such if irq_count is
greater than 1. This results in 100% CPU usage being reported on a
core which receives its ticks via broadcast.

This patch removes the SMP smp_call_function_interrupt() wrapper which
calls irq_{enter,exit}(). Platforms which handle their IPIs through
do_IRQ() now call generic_smp_call_function_interrupt() directly to
avoid incrementing irq_count a second time. Platforms which don't
(loongson, sgi-ip27, sibyte) call generic_smp_call_function_interrupt()
wrapped in irq_{enter,exit}().

Signed-off-by: Alex Smith <alex.smith@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10770/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2015-08-03 09:25:12 +02:00
..
alchemy MIPS: Alchemy: Remove unneeded cast removing const 2015-06-21 21:53:46 +02:00
ar7
ath25 Merge branch 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2015-07-01 15:19:35 -07:00
ath79 MIPS: Add basic support for the TL-WR1043ND version 1 2015-06-21 21:54:10 +02:00
bcm47xx MIPS: BCM47xx: Simplify handling SPROM revisions 2015-06-21 22:19:59 +02:00
bcm63xx
bmips MIPS: BMIPS: Accept UHI interface for passing a dtb 2015-06-21 21:54:17 +02:00
boot MIPS: Malta: Basic DT plumbing 2015-06-21 21:54:29 +02:00
cavium-octeon MIPS: SMP: Don't increment irq_count multiple times for call function IPIs 2015-08-03 09:25:12 +02:00
cobalt MIPS: Cobalt Don't use module_init in non-modular MTD registration. 2015-06-21 22:14:30 +02:00
configs MIPS: Loongson: Naming style cleanup and rework 2015-06-21 21:53:59 +02:00
dec
emma
fw
include MIPS: SMP: Don't increment irq_count multiple times for call function IPIs 2015-08-03 09:25:12 +02:00
jazz
jz4740 MIPS: ingenic: Initial MIPS Creator CI20 support 2015-06-21 21:53:28 +02:00
kernel MIPS: SMP: Don't increment irq_count multiple times for call function IPIs 2015-08-03 09:25:12 +02:00
kvm The bulk of the changes here is for x86. And for once it's not 2015-06-24 09:36:49 -07:00
lantiq MIPS: SMP: Don't increment irq_count multiple times for call function IPIs 2015-08-03 09:25:12 +02:00
lasat
lib
loongson32 MIPS: Loongson: Naming style cleanup and rework 2015-06-21 21:53:59 +02:00
loongson64 MIPS: SMP: Don't increment irq_count multiple times for call function IPIs 2015-08-03 09:25:12 +02:00
math-emu MIPS: Fix erroneous JR emulation for MIPS R6 2015-07-09 11:11:43 +02:00
mm MIPS: Partially disable RIXI support. 2015-08-03 09:25:11 +02:00
mti-malta MIPS: SMP: Don't increment irq_count multiple times for call function IPIs 2015-08-03 09:25:12 +02:00
mti-sead3
net MIPS: BPF: Introduce BPF ASM helpers 2015-06-21 21:54:25 +02:00
netlogic MIPS: SMP: Don't increment irq_count multiple times for call function IPIs 2015-08-03 09:25:12 +02:00
oprofile
paravirt MIPS: SMP: Don't increment irq_count multiple times for call function IPIs 2015-08-03 09:25:12 +02:00
pci Merge branch 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2015-07-01 15:19:35 -07:00
pistachio MIPS: Pistachio: Support CDMM & Fast Debug Channel 2015-07-10 11:02:20 +02:00
pmcs-msp71xx MIPS: SMP: Don't increment irq_count multiple times for call function IPIs 2015-08-03 09:25:12 +02:00
pnx833x
power
ralink Merge branch 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2015-07-01 15:19:35 -07:00
rb532
sgi-ip22
sgi-ip27 MIPS: SMP: Don't increment irq_count multiple times for call function IPIs 2015-08-03 09:25:12 +02:00
sgi-ip32
sibyte MIPS: SMP: Don't increment irq_count multiple times for call function IPIs 2015-08-03 09:25:12 +02:00
sni
txx9
vr41xx
Kbuild
Kbuild.platforms MIPS: Loongson: Naming style cleanup and rework 2015-06-21 21:53:59 +02:00
Kconfig MIPS: SB1: Remove support for Pass 1 parts. 2015-07-14 21:47:34 +02:00
Kconfig.debug
Makefile MIPS: SB1: Remove support for Pass 1 parts. 2015-07-14 21:47:34 +02:00