linux-toradex.git/kernel/irq, branch v2.6.38-rc4

genirq: Prevent irq storm on migration

2011-02-02T21:15:08+00:00

move_native_irq() masks and unmasks the interrupt line
unconditionally, but the interrupt line might be masked due to a
threaded oneshot handler in progress. Unmasking the line in that case
can lead to interrupt storms. Observed on PREEMPT_RT.

Originally-from: Ingo Molnar 
Signed-off-by: Thomas Gleixner 
Cc: stable@kernel.org

genirq: Remove __do_IRQ

2011-01-21T10:55:31+00:00

All architectures are finally converted. Remove the cruft.

Signed-off-by: Thomas Gleixner 
Cc: Richard Henderson 
Cc: Mike Frysinger 
Cc: David Howells 
Cc: Tony Luck 
Cc: Greg Ungerer 
Cc: Michal Simek 
Acked-by: David Howells 
Cc: Kyle McMartin 
Acked-by: Benjamin Herrenschmidt 
Cc: Chen Liqin 
Cc: "David S. Miller" 
Cc: Chris Metcalf 
Cc: Jeff Dike

irq: use per_cpu kstat_irqs

2011-01-14T01:32:31+00:00

Use modern per_cpu API to increment {soft|hard}irq counters, and use
per_cpu allocation for (struct irq_desc)->kstats_irq instead of an array.

This gives better SMP/NUMA locality and saves few instructions per irq.

With small nr_cpuids values (8 for example), kstats_irq was a small array
(less than L1_CACHE_BYTES), potentially source of false sharing.

In the !CONFIG_SPARSE_IRQ case, remove the huge, NUMA/cache unfriendly
kstat_irqs_all[NR_IRQS][NR_CPUS] array.

Note: we still populate kstats_irq for all possible irqs in
early_irq_init().  We probably could use on-demand allocations.  (Code
included in alloc_descs()).  Problem is not all IRQS are used with a prior
alloc_descs() call.

kstat_irqs_this_cpu() is not used anymore, remove it.

Signed-off-by: Eric Dumazet 
Reviewed-by: Christoph Lameter 
Cc: Ingo Molnar 
Cc: Andi Kleen 
Cc: Tejun Heo 
Cc: Thomas Gleixner 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

sched: Constify function scope static struct sched_param usage

2011-01-07T14:55:45+00:00

Function-scope statics are discouraged because they are
easily overlooked and can cause subtle bugs/races due to
their global (non-SMP safe) nature.

Linus noticed that we did this for sched_param - at minimum
make the const.

Suggested-by: Linus Torvalds 
Signed-off-by: Peter Zijlstra 
LKML-Reference: Message-ID: 
Signed-off-by: Ingo Molnar

Merge branch 'linus' into sched/core

2010-12-08T19:15:29+00:00

Merge reason: we want to queue up dependent cleanup

Signed-off-by: Ingo Molnar

genirq: Fix incorrect proc spurious output

2010-12-01T07:44:26+00:00

Since commit a1afb637(switch /proc/irq/*/spurious to seq_file) all
/proc/irq/XX/spurious files show the information of irq 0.

Current irq_spurious_proc_open() passes on NULL as the 3rd argument,
which is used as an IRQ number in irq_spurious_proc_show(), to the
single_open(). Because of this, all the /proc/irq/XX/spurious file
shows IRQ 0 information regardless of the IRQ number.

To fix the problem, irq_spurious_proc_open() must pass on the
appropreate data (IRQ number) to single_open().

Signed-off-by: Kenji Kaneshige 
Reviewed-by: Yong Zhang 
LKML-Reference: <4CF4B778.90604@jp.fujitsu.com>
Cc: stable@kernel.org [2.6.33+]
Signed-off-by: Thomas Gleixner

Merge commit 'v2.6.37-rc2' into sched/core

2010-11-18T12:22:26+00:00

Merge reason: Move to a .37-rc base.

Signed-off-by: Ingo Molnar

Merge branches 'irq-core-for-linus' and 'core-locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

2010-11-01T00:40:24+00:00

* 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  genirq: Fix up irq_node() for irq_data changes.
  genirq: Add single IRQ reservation helper
  genirq: Warn if enable_irq is called before irq is set up

* 'core-locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  semaphore: Remove mutex emulation
  staging: Final semaphore cleanup
  jbd2: Convert jbd2_slab_create_sem to mutex
  hpfs: Convert sbi->hpfs_creation_de to mutex

Fix up trivial change/delete conflicts with deleted 'dream' drivers
(drivers/staging/dream/camera/{mt9d112.c,mt9p012_fox.c,mt9t013.c,s5k3e2fx.c})

/proc/stat: fix scalability of irq sum of all cpu

2010-10-28T01:03:13+00:00

In /proc/stat, the number of per-IRQ event is shown by making a sum each
irq's events on all cpus.  But we can make use of kstat_irqs().

kstat_irqs() do the same calculation, If !CONFIG_GENERIC_HARDIRQ,
it's not a big cost. (Both of the number of cpus and irqs are small.)

If a system is very big and CONFIG_GENERIC_HARDIRQ, it does

	for_each_irq()
		for_each_cpu()
			- look up a radix tree
			- read desc->irq_stat[cpu]
This seems not efficient. This patch adds kstat_irqs() for
CONFIG_GENRIC_HARDIRQ and change the calculation as

	for_each_irq()
		look up radix tree
		for_each_cpu()
			- read desc->irq_stat[cpu]

This reduces cost.

A test on (4096cpusp, 256 nodes, 4592 irqs) host (by Jack Steiner)

%time cat /proc/stat > /dev/null

Before Patch:	 2.459 sec
After Patch :	  .561 sec

[akpm@linux-foundation.org: unexport kstat_irqs, coding-style tweaks]
[akpm@linux-foundation.org: fix unused variable 'per_irq_sum']
Signed-off-by: KAMEZAWA Hiroyuki 
Tested-by: Jack Steiner 
Acked-by: Jack Steiner 
Cc: Yinghai Lu 
Cc: Ingo Molnar 
Cc: Thomas Gleixner 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

sched: Make sched_param argument static in sched_setscheduler() callers

2010-10-23T15:56:48+00:00

Andrew Morton pointed out almost all sched_setscheduler() callers are
using fixed parameters and can be converted to static.  It reduces runtime
memory use a little.

Signed-off-by: KOSAKI Motohiro 
Reported-by: Andrew Morton 
Acked-by: James Morris 
Cc: Ingo Molnar 
Cc: Steven Rostedt 
Signed-off-by: Andrew Morton 
Signed-off-by: Thomas Gleixner 
Signed-off-by: Ingo Molnar