Revision c8bc5e39ac110acc88e41dd45d3f99956686f074 authored by Linus Torvalds on 27 March 2012, 22:55:54 UTC, committed by Linus Torvalds on 27 March 2012, 22:55:54 UTC
Pull "ARM: Non-critical bug fixes" from Ardn Bergmann: "Simple bug fixes that were not considered important enough for inclusion into 3.3. One bug fix was originally intended for 3.3 but accidentally got missed, but is not marked stable because it should only get backported once later fixes also make it into v3.4. Signed-off-by: Arnd Bergmann <arnd@arndb.de>" * tag 'fixes-non-critical' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: (66 commits) iomux-mx25.h slew rate adjusted for LCD __LD pins ARM: davinci: DA850: move da850_register_pm to .init.text ARM: davinci: cpufreq: fix compiler warning ARM: OMAP2+: Fix build for omap4 only builds with missing include of linux/bug.h ARM: OMAP2+: Fix section warnings for hsmmc_init_one ARM: OMAP2+: Fix build issues with missing include of linux/bug.h ARM: OMAP2+: gpmc-smsc911x: only register regulator for first instance ARM: OMAP3+: PM: VP: fix integer truncation error ARM: OMAP2+: PM: fix wakeupgen warning when hotplug disabled ARM: OMAP2+: PM: fix section mismatch with omap2_init_processor_devices() ARM: OMAP2: Fix section warning for n8x0 when CONFIG_MMC_OMAP is not set ARM: OMAP2+: Fix omap24xx_io_desc warning if SoC subtypes are not selected ARM: OMAP1: Fix section mismatch for omap1_init_early() ARM: OMAP1: Fix typo in lcd_dma.c ARM: OMAP: mailbox: trivial whitespace fix ARM: OMAP: Remove definition cpu_is_omap4430() ARM: OMAP2+: included some headers twice ARM: OMAP: clock.c: included linux/debugfs.h twice ARM: OMAP: don't build hwspinlock in vain ARM: OMAP2+: ads7846_init: put gpio_pendown into pdata if it's provided ...
IRQ-affinity.txt
ChangeLog:
Started by Ingo Molnar <mingo@redhat.com>
Update by Max Krasnyansky <maxk@qualcomm.com>
SMP IRQ affinity
/proc/irq/IRQ#/smp_affinity and /proc/irq/IRQ#/smp_affinity_list specify
which target CPUs are permitted for a given IRQ source. It's a bitmask
(smp_affinity) or cpu list (smp_affinity_list) of allowed CPUs. It's not
allowed to turn off all CPUs, and if an IRQ controller does not support
IRQ affinity then the value will not change from the default of all cpus.
/proc/irq/default_smp_affinity specifies default affinity mask that applies
to all non-active IRQs. Once IRQ is allocated/activated its affinity bitmask
will be set to the default mask. It can then be changed as described above.
Default mask is 0xffffffff.
Here is an example of restricting IRQ44 (eth1) to CPU0-3 then restricting
it to CPU4-7 (this is an 8-CPU SMP box):
[root@moon 44]# cd /proc/irq/44
[root@moon 44]# cat smp_affinity
ffffffff
[root@moon 44]# echo 0f > smp_affinity
[root@moon 44]# cat smp_affinity
0000000f
[root@moon 44]# ping -f h
PING hell (195.4.7.3): 56 data bytes
...
--- hell ping statistics ---
6029 packets transmitted, 6027 packets received, 0% packet loss
round-trip min/avg/max = 0.1/0.1/0.4 ms
[root@moon 44]# cat /proc/interrupts | grep 'CPU\|44:'
CPU0 CPU1 CPU2 CPU3 CPU4 CPU5 CPU6 CPU7
44: 1068 1785 1785 1783 0 0 0 0 IO-APIC-level eth1
As can be seen from the line above IRQ44 was delivered only to the first four
processors (0-3).
Now lets restrict that IRQ to CPU(4-7).
[root@moon 44]# echo f0 > smp_affinity
[root@moon 44]# cat smp_affinity
000000f0
[root@moon 44]# ping -f h
PING hell (195.4.7.3): 56 data bytes
..
--- hell ping statistics ---
2779 packets transmitted, 2777 packets received, 0% packet loss
round-trip min/avg/max = 0.1/0.5/585.4 ms
[root@moon 44]# cat /proc/interrupts | 'CPU\|44:'
CPU0 CPU1 CPU2 CPU3 CPU4 CPU5 CPU6 CPU7
44: 1068 1785 1785 1783 1784 1069 1070 1069 IO-APIC-level eth1
This time around IRQ44 was delivered only to the last four processors.
i.e counters for the CPU0-3 did not change.
Here is an example of limiting that same irq (44) to cpus 1024 to 1031:
[root@moon 44]# echo 1024-1031 > smp_affinity
[root@moon 44]# cat smp_affinity
1024-1031
Note that to do this with a bitmask would require 32 bitmasks of zero
to follow the pertinent one.
Computing file changes ...
