21 Oct, 2010
1 commit
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With the addition of trace_softirq_raise() the softirq tracepoint got
even more convoluted. Why the tracepoints take two pointers to assign
an integer is beyond my comprehension.But adding an extra case which treats the first pointer as an unsigned
long when the second pointer is NULL including the back and forth
type casting is just horrible.Convert the softirq tracepoints to take a single unsigned int argument
for the softirq vector number and fix the call sites.Signed-off-by: Thomas Gleixner
LKML-Reference:
Acked-by: Peter Zijlstra
Acked-by: mathieu.desnoyers@efficios.com
Cc: Frederic Weisbecker
Cc: Steven Rostedt
05 Jun, 2010
1 commit
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The commit 80b5184cc537718122e036afe7e62d202b70d077 ("kernel/: convert cpu
notifier to return encapsulate errno value") changed the return value of
cpu notifier callbacks.Those callbacks don't return NOTIFY_BAD on failures anymore. But there
are a few callbacks which are called directly at init time and checking
the return value.I forgot to change BUG_ON checking by the direct callers in the commit.
Signed-off-by: Akinobu Mita
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
28 May, 2010
1 commit
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By the previous modification, the cpu notifier can return encapsulate
errno value. This converts the cpu notifiers for kernel/*.cSigned-off-by: Akinobu Mita
Cc: Ingo Molnar
Cc: Peter Zijlstra
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
11 May, 2010
1 commit
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The addition of preemptible RCU to treercu resulted in a bit of
confusion and inefficiency surrounding the handling of context switches
for RCU-sched and for RCU-preempt. For RCU-sched, a context switch
is a quiescent state, pure and simple, just like it always has been.
For RCU-preempt, a context switch is in no way a quiescent state, but
special handling is required when a task blocks in an RCU read-side
critical section.However, the callout from the scheduler and the outer loop in ksoftirqd
still calls something named rcu_sched_qs(), whose name is no longer
accurate. Furthermore, when rcu_check_callbacks() notes an RCU-sched
quiescent state, it ends up unnecessarily (though harmlessly, aside
from the performance hit) enqueuing the current task if it happens to
be running in an RCU-preempt read-side critical section. This not only
increases the maximum latency of scheduler_tick(), it also needlessly
increases the overhead of the next outermost rcu_read_unlock() invocation.This patch addresses this situation by separating the notion of RCU's
context-switch handling from that of RCU-sched's quiescent states.
The context-switch handling is covered by rcu_note_context_switch() in
general and by rcu_preempt_note_context_switch() for preemptible RCU.
This permits rcu_sched_qs() to handle quiescent states and only quiescent
states. It also reduces the maximum latency of scheduler_tick(), though
probably by much less than a microsecond. Finally, it means that tasks
within preemptible-RCU read-side critical sections avoid incurring the
overhead of queuing unless there really is a context switch.Suggested-by: Lai Jiangshan
Acked-by: Lai Jiangshan
Signed-off-by: Paul E. McKenney
Cc: Ingo Molnar
Cc: Peter Zijlstra
04 Feb, 2010
1 commit
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hrtimers callbacks are always done from hardirq context, either the
jiffy tick interrupt or the hrtimer device interrupt.[ there is currently one exception that can still call a hrtimer
callback from softirq, but even in that case this will still
work correctly. ]Reported-by: Wei Yongjun
Signed-off-by: Peter Zijlstra
Cc: Yury Polyanskiy
Tested-by: Wei Yongjun
Acked-by: David S. Miller
LKML-Reference:
Signed-off-by: Thomas Gleixner
15 Dec, 2009
1 commit
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* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu: (34 commits)
m68k: rename global variable vmalloc_end to m68k_vmalloc_end
percpu: add missing per_cpu_ptr_to_phys() definition for UP
percpu: Fix kdump failure if booted with percpu_alloc=page
percpu: make misc percpu symbols unique
percpu: make percpu symbols in ia64 unique
percpu: make percpu symbols in powerpc unique
percpu: make percpu symbols in x86 unique
percpu: make percpu symbols in xen unique
percpu: make percpu symbols in cpufreq unique
percpu: make percpu symbols in oprofile unique
percpu: make percpu symbols in tracer unique
percpu: make percpu symbols under kernel/ and mm/ unique
percpu: remove some sparse warnings
percpu: make alloc_percpu() handle array types
vmalloc: fix use of non-existent percpu variable in put_cpu_var()
this_cpu: Use this_cpu_xx in trace_functions_graph.c
this_cpu: Use this_cpu_xx for ftrace
this_cpu: Use this_cpu_xx in nmi handling
this_cpu: Use this_cpu operations in RCU
this_cpu: Use this_cpu ops for VM statistics
...Fix up trivial (famous last words) global per-cpu naming conflicts in
arch/x86/kvm/svm.c
mm/slab.c
02 Nov, 2009
1 commit
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Currently, rcu_irq_exit() is invoked only for CONFIG_NO_HZ,
while rcu_irq_enter() is invoked unconditionally. This patch
moves rcu_irq_exit() out from under CONFIG_NO_HZ so that the
calls are balanced.This patch has no effect on the behavior of the kernel because
both rcu_irq_enter() and rcu_irq_exit() are empty for
!CONFIG_NO_HZ, but the code is easier to understand if the calls
are obviously balanced in all cases.Signed-off-by: Lai Jiangshan
Signed-off-by: Paul E. McKenney
Cc: dipankar@in.ibm.com
Cc: mathieu.desnoyers@polymtl.ca
Cc: josh@joshtriplett.org
Cc: dvhltc@us.ibm.com
Cc: niv@us.ibm.com
Cc: peterz@infradead.org
Cc: rostedt@goodmis.org
Cc: Valdis.Kletnieks@vt.edu
Cc: dhowells@redhat.com
LKML-Reference:
Signed-off-by: Ingo Molnar
29 Oct, 2009
1 commit
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This patch updates percpu related symbols under kernel/ and mm/ such
that percpu symbols are unique and don't clash with local symbols.
This serves two purposes of decreasing the possibility of global
percpu symbol collision and allowing dropping per_cpu__ prefix from
percpu symbols.* kernel/lockdep.c: s/lock_stats/cpu_lock_stats/
* kernel/sched.c: s/init_rq_rt/init_rt_rq_var/ (any better idea?)
s/sched_group_cpus/sched_groups/* kernel/softirq.c: s/ksoftirqd/run_ksoftirqd/a
* kernel/softlockup.c: s/(*)_timestamp/softlockup_\1_ts/
s/watchdog_task/softlockup_watchdog/
s/timestamp/ts/ for local variables* kernel/time/timer_stats: s/lookup_lock/tstats_lookup_lock/
* mm/slab.c: s/reap_work/slab_reap_work/
s/reap_node/slab_reap_node/* mm/vmstat.c: local variable changed to avoid collision with vmstat_work
Partly based on Rusty Russell's "alloc_percpu: rename percpu vars
which cause name clashes" patch.Signed-off-by: Tejun Heo
Acked-by: (slab/vmstat) Christoph Lameter
Reviewed-by: Christoph Lameter
Cc: Rusty Russell
Cc: Ingo Molnar
Cc: Thomas Gleixner
Cc: Andrew Morton
Cc: Nick Piggin
18 Sep, 2009
1 commit
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With BLOCK_IOPOLL_SOFTIRQ added, softirq_to_name[] and
show_softirq_name() needs to be updated.Signed-off-by: Li Zefan
LKML-Reference:
Signed-off-by: Steven Rostedt
23 Aug, 2009
1 commit
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Make RCU-sched, RCU-bh, and RCU-preempt be underlying
implementations, with "RCU" defined in terms of one of the
three. Update the outdated rcu_qsctr_inc() names, as these
functions no longer increment anything.Signed-off-by: Paul E. McKenney
Cc: laijs@cn.fujitsu.com
Cc: dipankar@in.ibm.com
Cc: akpm@linux-foundation.org
Cc: mathieu.desnoyers@polymtl.ca
Cc: josht@linux.vnet.ibm.com
Cc: dvhltc@us.ibm.com
Cc: niv@us.ibm.com
Cc: peterz@infradead.org
Cc: rostedt@goodmis.org
LKML-Reference:
Signed-off-by: Ingo Molnar
22 Jul, 2009
1 commit
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commit ca109491f (hrtimer: removing all ur callback modes) moved all
hrtimer callbacks into hard interrupt context when high resolution
timers are active. That breaks code which relied on the assumption
that the callback happens in softirq context.Provide a generic infrastructure which combines tasklets and hrtimers
together to provide an in-softirq hrtimer experience.Signed-off-by: Peter Zijlstra
Cc: torvalds@linux-foundation.org
Cc: kaber@trash.net
Cc: David Miller
LKML-Reference:
Signed-off-by: Thomas Gleixner
19 Jun, 2009
1 commit
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Statistics for softirq doesn't exist.
It will be helpful like statistics for interrupts.
This patch introduces counting the number of softirq,
which will be exported in /proc/softirqs.When softirq handler consumes much CPU time,
/proc/stat is like the following.$ while :; do cat /proc/stat | head -n1 ; sleep 10 ; done
cpu 88 0 408 739665 583 28 2 0 0
cpu 450 0 1090 740970 594 28 1294 0 0
^^^^
softirqIn such a situation,
/proc/softirqs shows us which softirq handler is invoked.
We can see the increase rate of softirqs.$ cat /proc/softirqs
CPU0 CPU1 CPU2 CPU3
HI 0 0 0 0
TIMER 462850 462805 462782 462718
NET_TX 0 0 0 365
NET_RX 2472 2 2 40
BLOCK 0 0 381 1164
TASKLET 0 0 0 224
SCHED 462654 462689 462698 462427
RCU 3046 2423 3367 3173$ cat /proc/softirqs
CPU0 CPU1 CPU2 CPU3
HI 0 0 0 0
TIMER 463361 465077 465056 464991
NET_TX 53 0 1 365
NET_RX 3757 2 2 40
BLOCK 0 0 398 1170
TASKLET 0 0 0 224
SCHED 463074 464318 464612 463330
RCU 3505 2948 3947 3673When CPU TIME of softirq is high,
the rates of increase is the following.
TIMER : 220/sec : CPU1-3
NET_TX : 5/sec : CPU0
NET_RX : 120/sec : CPU0
SCHED : 40-200/sec : all CPU
RCU : 45-58/sec : all CPUThe rates of increase in an idle mode is the following.
TIMER : 250/sec
SCHED : 250/sec
RCU : 2/secIt seems many softirqs for receiving packets and rcu are invoked. This
gives us help for checking system.Signed-off-by: Keika Kobayashi
Reviewed-by: Hiroshi Shimamoto
Reviewed-by: KOSAKI Motohiro
Cc: Ingo Molnar
Cc: Eric Dumazet
Cc: Alexey Dobriyan
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
13 Jun, 2009
1 commit
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Rationale: kmemcheck needs to be able to schedule a tasklet without
touching any dynamically allocated memory _at_ _all_ (since that would
lead to a recursive page fault). This tasklet is used for writing the
error reports to the kernel log.The new scheduling function avoids touching any other tasklets by
inserting the new tasklist as the head of the "tasklet_hi" list instead
of on the tail.Also don't wake up the softirq thread lest the scheduler access some
tracked memory and we go down with a recursive page fault.In this case, we'd better just wait for the maximum time of 1/HZ for the
message to appear.Signed-off-by: Vegard Nossum
11 Jun, 2009
1 commit
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* 'tracing-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (244 commits)
Revert "x86, bts: reenable ptrace branch trace support"
tracing: do not translate event helper macros in print format
ftrace/documentation: fix typo in function grapher name
tracing/events: convert block trace points to TRACE_EVENT(), fix !CONFIG_BLOCK
tracing: add protection around module events unload
tracing: add trace_seq_vprint interface
tracing: fix the block trace points print size
tracing/events: convert block trace points to TRACE_EVENT()
ring-buffer: fix ret in rb_add_time_stamp
ring-buffer: pass in lockdep class key for reader_lock
tracing: add annotation to what type of stack trace is recorded
tracing: fix multiple use of __print_flags and __print_symbolic
tracing/events: fix output format of user stack
tracing/events: fix output format of kernel stack
tracing/trace_stack: fix the number of entries in the header
ring-buffer: discard timestamps that are at the start of the buffer
ring-buffer: try to discard unneeded timestamps
ring-buffer: fix bug in ring_buffer_discard_commit
ftrace: do not profile functions when disabled
tracing: make trace pipe recognize latency format flag
...
07 May, 2009
1 commit
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Merge reason: tracing/core was on a .30-rc1 base and was missing out on
on a handful of tracing fixes present in .30-rc5-almost.Signed-off-by: Ingo Molnar
29 Apr, 2009
1 commit
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"tracing: create automated trace defines" causes this compile error on s390,
as reported by Sachin Sant against linux-next:kernel/built-in.o: In function `__do_softirq':
(.text+0x1c680): undefined reference to `__tracepoint_softirq_entry'This happens because the definitions of the softirq tracepoints were moved
from kernel/softirq.c to kernel/irq/handle.c. Since s390 doesn't support
generic hardirqs handle.c doesn't get compiled and the definitions are
missing.So move the tracepoints to softirq.c again.
[ Impact: fix build failure on s390 ]
Reported-by: Sachin Sant
Signed-off-by: Heiko Carstens
Cc: Steven Rostedt
Cc: fweisbec@gmail.com
LKML-Reference:
Signed-off-by: Ingo Molnar
28 Apr, 2009
1 commit
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This simplifies the node awareness of the code. All our allocators
only deal with a NUMA node ID locality not with CPU ids anyway - so
there's no need to maintain (and transform) a CPU id all across the
IRq layer.v2: keep move_irq_desc related
[ Impact: cleanup, prepare IRQ code to be NUMA-aware ]
Signed-off-by: Yinghai Lu
Cc: Andrew Morton
Cc: Suresh Siddha
Cc: "Eric W. Biederman"
Cc: Rusty Russell
Cc: Jeremy Fitzhardinge
LKML-Reference:
Signed-off-by: Ingo Molnar
17 Apr, 2009
1 commit
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Fix sparse warning in kernel/softirq.c.
warning: do-while statement is not a compound statement
Signed-off-by: H Hartley Sweeten
LKML-Reference:
Signed-off-by: Ingo Molnar
15 Apr, 2009
2 commits
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Impact: clean up
Create a sub directory in include/trace called events to keep the
trace point headers in their own separate directory. Only headers that
declare trace points should be defined in this directory.Cc: Peter Zijlstra
Cc: Thomas Gleixner
Cc: Neil Horman
Cc: Zhao Lei
Cc: Eduard - Gabriel Munteanu
Cc: Pekka Enberg
Signed-off-by: Steven Rostedt -
This patch lowers the number of places a developer must modify to add
new tracepoints. The current method to add a new tracepoint
into an existing system is to write the trace point macro in the
trace header with one of the macros TRACE_EVENT, TRACE_FORMAT or
DECLARE_TRACE, then they must add the same named item into the C file
with the macro DEFINE_TRACE(name) and then add the trace point.This change cuts out the needing to add the DEFINE_TRACE(name).
Every file that uses the tracepoint must still include the trace/.h
file, but the one C file must also add a define before the including
of that file.#define CREATE_TRACE_POINTS
#includeThis will cause the trace/mytrace.h file to also produce the C code
necessary to implement the trace point.Note, if more than one trace/.h is used to create the C code
it is best to list them all together.#define CREATE_TRACE_POINTS
#include
#include
#includeThanks to Mathieu Desnoyers and Christoph Hellwig for coming up with
the cleaner solution of the define above the includes over my first
design to have the C code include a "special" header.This patch converts sched, irq and lockdep and skb to use this new
method.Cc: Peter Zijlstra
Cc: Thomas Gleixner
Cc: Neil Horman
Cc: Zhao Lei
Cc: Eduard - Gabriel Munteanu
Cc: Pekka Enberg
Signed-off-by: Steven Rostedt
07 Apr, 2009
1 commit
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* 'locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
lockdep: add stack dumps to asserts
hrtimer: fix rq->lock inversion (again)
06 Apr, 2009
1 commit
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* 'tracing-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (413 commits)
tracing, net: fix net tree and tracing tree merge interaction
tracing, powerpc: fix powerpc tree and tracing tree interaction
ring-buffer: do not remove reader page from list on ring buffer free
function-graph: allow unregistering twice
trace: make argument 'mem' of trace_seq_putmem() const
tracing: add missing 'extern' keywords to trace_output.h
tracing: provide trace_seq_reserve()
blktrace: print out BLK_TN_MESSAGE properly
blktrace: extract duplidate code
blktrace: fix memory leak when freeing struct blk_io_trace
blktrace: fix blk_probes_ref chaos
blktrace: make classic output more classic
blktrace: fix off-by-one bug
blktrace: fix the original blktrace
blktrace: fix a race when creating blk_tree_root in debugfs
blktrace: fix timestamp in binary output
tracing, Text Edit Lock: cleanup
tracing: filter fix for TRACE_EVENT_FORMAT events
ftrace: Using FTRACE_WARN_ON() to check "freed record" in ftrace_release()
x86: kretprobe-booster interrupt emulation code fix
...Fix up trivial conflicts in
arch/parisc/include/asm/ftrace.h
include/linux/memory.h
kernel/extable.c
kernel/module.c
04 Apr, 2009
1 commit
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* 'ipi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
s390: remove arch specific smp_send_stop()
panic: clean up kernel/panic.c
panic, smp: provide smp_send_stop() wrapper on UP too
panic: decrease oops_in_progress only after having done the panic
generic-ipi: eliminate WARN_ON()s during oops/panic
generic-ipi: cleanups
generic-ipi: remove CSD_FLAG_WAIT
generic-ipi: remove kmalloc()
generic IPI: simplify barriers and locking
31 Mar, 2009
2 commits
-
It appears I inadvertly introduced rq->lock recursion to the
hrtimer_start() path when I delegated running already expired
timers to softirq context.This patch fixes it by introducing a __hrtimer_start_range_ns()
method that will not use raise_softirq_irqoff() but
__raise_softirq_irqoff() which avoids the wakeup.It then also changes schedule() to check for pending softirqs and
do the wakeup then, I'm not quite sure I like this last bit, nor
am I convinced its really needed.Signed-off-by: Peter Zijlstra
Cc: Peter Zijlstra
Cc: paulus@samba.org
LKML-Reference:
Signed-off-by: Ingo Molnar -
Conflicts:
lib/Kconfig.debug
28 Mar, 2009
1 commit
-
Conflicts:
arch/parisc/kernel/irq.c
arch/x86/include/asm/fixmap_64.h
arch/x86/include/asm/setup.h
kernel/irq/handle.cSemantic merge:
arch/x86/include/asm/fixmap.hSigned-off-by: Ingo Molnar
13 Mar, 2009
7 commits
-
Impact: clean up
It is redundant to have 'SOFTIRQ' in the softirq names.
Reported-by: Andrew Morton
Signed-off-by: Steven Rostedt -
Introduce softirq entry/exit tracepoints. These are useful for
augmenting existing tracers, and to figure out softirq frequencies and
timings.[
s/irq_softirq_/softirq_/ for trace point names and
Fixed printf format in TRACE_FORMAT macro
- Steven Rostedt
]LKML-Reference:
Signed-off-by: Jason Baron
Signed-off-by: Steven Rostedt -
Create a 'softirq_to_name' array, which is indexed by softirq #, so
that we can easily convert between the softirq index # and its name, in
order to get more meaningful output messages.LKML-Reference:
Signed-off-by: Jason Baron
Signed-off-by: Steven Rostedt -
Impact: cleanup
The naming clashes with upcoming softirq tracepoints, so rename the
APIs to lockdep_*().Requested-by: Steven Rostedt
Signed-off-by: Ingo Molnar
10 Mar, 2009
2 commits
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…6/urgent', 'linus' and 'core/percpu' into x86/core
06 Mar, 2009
1 commit
-
Conflicts:
arch/x86/Kconfig
block/blktrace.c
kernel/irq/handle.cSemantic conflict:
kernel/trace/blktrace.cSigned-off-by: Ingo Molnar
05 Mar, 2009
1 commit
-
If a machine is flooded by network frames, a cpu can loop
100% of its time inside ksoftirqd() without calling schedule().
This can delay RCU grace period to insane values.Adding rcu_qsctr_inc() call in ksoftirqd() solves this problem.
Paul: "This regression was a result of the recent change from
"schedule()" to "cond_resched()", which got rid of that quiescent
state in the common case where a reschedule is not needed".Signed-off-by: Eric Dumazet
Reviewed-by: Paul E. McKenney
Signed-off-by: Andrew Morton
Signed-off-by: Ingo Molnar
25 Feb, 2009
1 commit
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Oleg noticed that we don't strictly need CSD_FLAG_WAIT, rework
the code so that we can use CSD_FLAG_LOCK for both purposes.Signed-off-by: Peter Zijlstra
Cc: Oleg Nesterov
Cc: Linus Torvalds
Cc: Nick Piggin
Cc: Jens Axboe
Cc: "Paul E. McKenney"
Cc: Rusty Russell
Signed-off-by: Ingo Molnar
23 Jan, 2009
1 commit
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Impact: fix to preempt trace triggering lockdep check_flag failure
In local_bh_disable, the use of add_preempt_count causes the
preempt tracer to start recording the time preemption is off.
But because it already modified the preempt_count to show
softirqs disabled, and before it called the lockdep code to
handle this, it causes a state that lockdep can not handle.The preempt tracer will reset the ring buffer on start of a trace,
and the ring buffer reset code does a spin_lock_irqsave. This
calls into lockdep and lockdep will fail when it detects the
invalid state of having softirqs disabled but the internal
current->softirqs_enabled is still set.The fix is to manually add the SOFTIRQ_OFFSET to preempt count
and call the preempt tracer code outside the lockdep critical
area.Thanks to Peter Zijlstra for suggesting this solution.
Signed-off-by: Steven Rostedt
Signed-off-by: Ingo Molnar
13 Jan, 2009
1 commit
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Impact: save RAM with large NR_CPUS, get smaller nr_irqs
Signed-off-by: Yinghai Lu
Signed-off-by: Mike Travis