A recent commit introduced a preemption warning for
perf_clock(), use raw_smp_processor_id() to avoid this, it
really doesn't matter which cpu we use here.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1267198583.22519.684.camel@laptop>
Cc: <stable@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
On platforms like dual socket quad-core platform, the scheduler load
balancer is not detecting the load imbalances in certain scenarios. This
is leading to scenarios like where one socket is completely busy (with
all the 4 cores running with 4 tasks) and leaving another socket
completely idle. This causes performance issues as those 4 tasks share
the memory controller, last-level cache bandwidth etc. Also we won't be
taking advantage of turbo-mode as much as we would like, etc.
Some of the comparisons in the scheduler load balancing code are
comparing the "weighted cpu load that is scaled wrt sched_group's
cpu_power" with the "weighted average load per task that is not scaled
wrt sched_group's cpu_power". While this has probably been broken for a
longer time (for multi socket numa nodes etc), the problem got aggrevated
via this recent change:
|
| commit f93e65c186
| Author: Peter Zijlstra <a.p.zijlstra@chello.nl>
| Date: Tue Sep 1 10:34:32 2009 +0200
|
| sched: Restore __cpu_power to a straight sum of power
|
Also with this change, the sched group cpu power alone no longer reflects
the group capacity that is needed to implement MC, MT performance
(default) and power-savings (user-selectable) policies.
We need to use the computed group capacity (sgs.group_capacity, that is
computed using the SD_PREFER_SIBLING logic in update_sd_lb_stats()) to
find out if the group with the max load is above its capacity and how
much load to move etc.
Reported-by: Ma Ling <ling.ma@intel.com>
Initial-Analysis-by: Zhang, Yanmin <yanmin_zhang@linux.intel.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
[ -v2: build fix ]
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: <stable@kernel.org> # [2.6.32.x, 2.6.33.x]
LKML-Reference: <1266970432.11588.22.camel@sbs-t61.sc.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Since the cpu argument to hw_perf_group_sched_in() is always
smp_processor_id(), simplify the code a little by removing this argument
and using the current cpu where needed.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: David Miller <davem@davemloft.net>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <1265890918.5396.3.camel@laptop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This patch adds correct AMD NorthBridge event scheduling.
NB events are events measuring L3 cache, Hypertransport traffic. They are
identified by an event code >= 0xe0. They measure events on the
Northbride which is shared by all cores on a package. NB events are
counted on a shared set of counters. When a NB event is programmed in a
counter, the data actually comes from a shared counter. Thus, access to
those counters needs to be synchronized.
We implement the synchronization such that no two cores can be measuring
NB events using the same counters. Thus, we maintain a per-NB allocation
table. The available slot is propagated using the event_constraint
structure.
Signed-off-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <4b703957.0702d00a.6bf2.7b7d@mx.google.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
In certain situations, the kernel may need to stop and start the same
event rapidly. The current PMU callbacks do not distinguish between stop
and release (i.e., stop + free the resource). Thus, a counter may be
released, then it will be immediately re-acquired. Event scheduling will
again take place with no guarantee to assign the same counter. On some
processors, this may event yield to failure to assign the event back due
to competion between cores.
This patch is adding a new pair of callback to stop and restart a counter
without actually release the underlying counter resource. On stop, the
counter is stopped, its values saved and that's it. On start, the value
is reloaded and counter is restarted (on x86, actual restart is delayed
until perf_enable()).
Signed-off-by: Stephane Eranian <eranian@google.com>
[ added fallback to ->enable/->disable for all other PMUs
fixed x86_pmu_start() to call x86_pmu.enable()
merged __x86_pmu_disable into x86_pmu_stop() ]
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <4b703875.0a04d00a.7896.ffffb824@mx.google.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
DaveM reported that currently perf interprets the pgoff value reported by
the MMAP events as a byte range, but the kernel reports it as a page
offset.
Since its broken (and unusable) anyway, change the kernel behaviour (ABI)
to report bytes indeed, avoiding the need for userspace to deal with
PAGE_SIZE things.
Reported-by: David Miller <davem@davemloft.net>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Introduce kprobes jump optimization arch-independent parts.
Kprobes uses breakpoint instruction for interrupting execution
flow, on some architectures, it can be replaced by a jump
instruction and interruption emulation code. This gains kprobs'
performance drastically.
To enable this feature, set CONFIG_OPTPROBES=y (default y if the
arch supports OPTPROBE).
Changes in v9:
- Fix a bug to optimize probe when enabling.
- Check nearby probes can be optimize/unoptimize when disarming/arming
kprobes, instead of registering/unregistering. This will help
kprobe-tracer because most of probes on it are usually disabled.
Changes in v6:
- Cleanup coding style for readability.
- Add comments around get/put_online_cpus().
Changes in v5:
- Use get_online_cpus()/put_online_cpus() for avoiding text_mutex
deadlock.
Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: systemtap <systemtap@sources.redhat.com>
Cc: DLE <dle-develop@lists.sourceforge.net>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Anders Kaseorg <andersk@ksplice.com>
Cc: Tim Abbott <tabbott@ksplice.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Mathieu Desnoyers <compudj@krystal.dyndns.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
LKML-Reference: <20100225133407.6725.81992.stgit@localhost6.localdomain6>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Discard freeing field->type since it is not necessary.
Reviewed-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Wenji Huang <wenji.huang@oracle.com>
LKML-Reference: <1266997226-6833-5-git-send-email-wenji.huang@oracle.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The "cpu" variable is declared at the start of the function and
also within a branch, with the exact same initialization.
Remove the local variable of the same name in the branch.
Signed-off-by: Wenji Huang <wenji.huang@oracle.com>
LKML-Reference: <1266997226-6833-3-git-send-email-wenji.huang@oracle.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The power tracer has been converted to power trace events.
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <4B84D50E.4070806@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
GCC 4.5 introduces behavior that forces the alignment of structures to
use the largest possible value. The default value is 32 bytes, so if
some structures are defined with a 4-byte alignment and others aren't
declared with an alignment constraint at all - it will align at 32-bytes.
For things like the ftrace events, this results in a non-standard array.
When initializing the ftrace subsystem, we traverse the _ftrace_events
section and call the initialization callback for each event. When the
structures are misaligned, we could be treating another part of the
structure (or the zeroed out space between them) as a function pointer.
This patch forces the alignment for all the ftrace_event_call structures
to 4 bytes.
Without this patch, the kernel fails to boot very early when built with
gcc 4.5.
It's trivial to check the alignment of the members of the array, so it
might be worthwhile to add something to the build system to do that
automatically. Unfortunately, that only covers this case. I've asked one
of the gcc developers about adding a warning when this condition is seen.
Cc: stable@kernel.org
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
LKML-Reference: <4B85770B.6010901@suse.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Under TREE_PREEMPT_RCU, print_other_cpu_stall() invokes
rcu_print_task_stall() with the root rcu_node structure's ->lock
held, and rcu_print_task_stall() acquires that same lock for
self-deadlock. Fix this by removing the lock acquisition from
rcu_print_task_stall(), and making all callers acquire the lock
instead.
Tested-by: John Kacur <jkacur@redhat.com>
Tested-by: Thomas Gleixner <tglx@linutronix.de>
Located-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: laijs@cn.fujitsu.com
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: <1266887105-1528-19-git-send-email-paulmck@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The C standard does not specify the result of an operation that
overflows a signed integer, so such operations need to be
avoided. This patch changes the type of several fields from
"long" to "unsigned long" and adjusts operations as needed.
ULONG_CMP_GE() and ULONG_CMP_LT() macros are introduced to do
the modular comparisons that are appropriate given that overflow
is an expected event.
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: laijs@cn.fujitsu.com
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: <1266887105-1528-17-git-send-email-paulmck@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Currently, rcu_needs_cpu() simply checks whether the current CPU
has an outstanding RCU callback, which means that the last CPU
to go into dyntick-idle mode might wait a few ticks for the
relevant grace periods to complete. However, if all the other
CPUs are in dyntick-idle mode, and if this CPU is in a quiescent
state (which it is for RCU-bh and RCU-sched any time that we are
considering going into dyntick-idle mode), then the grace period
is instantly complete.
This patch therefore repeatedly invokes the RCU grace-period
machinery in order to force any needed grace periods to complete
quickly. It does so a limited number of times in order to
prevent starvation by an RCU callback function that might pass
itself to call_rcu().
However, if any CPU other than the current one is not in
dyntick-idle mode, fall back to simply checking (with fix to bug
noted by Lai Jiangshan). Also, take advantage of last
grace-period forcing, the opportunity to do so noted by Steve
Rostedt. And apply simplified #ifdef condition suggested by
Frederic Weisbecker.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: laijs@cn.fujitsu.com
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: <1266887105-1528-15-git-send-email-paulmck@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Inspection is proving insufficient to catch all RCU misuses,
which is understandable given that rcu_dereference() might be
protected by any of four different flavors of RCU (RCU, RCU-bh,
RCU-sched, and SRCU), and might also/instead be protected by any
of a number of locking primitives. It is therefore time to
enlist the aid of lockdep.
This set of patches is inspired by earlier work by Peter
Zijlstra and Thomas Gleixner, and takes the following approach:
o Set up separate lockdep classes for RCU, RCU-bh, and RCU-sched.
o Set up separate lockdep classes for each instance of SRCU.
o Create primitives that check for being in an RCU read-side
critical section. These return exact answers if lockdep is
fully enabled, but if unsure, report being in an RCU read-side
critical section. (We want to avoid false positives!)
The primitives are:
For RCU: rcu_read_lock_held(void)
For RCU-bh: rcu_read_lock_bh_held(void)
For RCU-sched: rcu_read_lock_sched_held(void)
For SRCU: srcu_read_lock_held(struct srcu_struct *sp)
o Add rcu_dereference_check(), which takes a second argument
in which one places a boolean expression based on the above
primitives and/or lockdep_is_held().
o A new kernel configuration parameter, CONFIG_PROVE_RCU, enables
rcu_dereference_check(). This depends on CONFIG_PROVE_LOCKING,
and should be quite helpful during the transition period while
CONFIG_PROVE_RCU-unaware patches are in flight.
The existing rcu_dereference() primitive does no checking, but
upcoming patches will change that.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: laijs@cn.fujitsu.com
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: <1266887105-1528-1-git-send-email-paulmck@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Return -EINVAL for the bad size and for unrecognized NT_* type in
ptrace_regset() instead of -EIO.
Also update the comments for this ptrace interface with more clarifications.
Requested-by: Roland McGrath <roland@redhat.com>
Requested-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
LKML-Reference: <20100222225240.397523600@sbs-t61.sc.intel.com>
Acked-by: Roland McGrath <roland@redhat.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
find_task_by_vpid() is not safe without rcu_read_lock(). 2.6.33-rc7 got
RCU protection for sys_setpriority() but missed it for sys_getpriority().
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: "Paul E. McKenney" <paulmck@us.ibm.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Introduce run-time PM callbacks for the PCI bus type. Make the new
callbacks work in analogy with the existing system sleep PM
callbacks, so that the drivers already converted to struct dev_pm_ops
can use their suspend and resume routines for run-time PM without
modifications.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Useful for freeing a portion of the resource tree, e.g. when trying to
reallocate resources more efficiently.
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Now that we return the new resource start position, there is no
need to update "struct resource" inside the align function.
Therefore, mark the struct resource as const.
Cc: Bjorn Helgaas <bjorn.helgaas@hp.com>
Cc: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
As suggested by Linus, align functions should return the start
of a resource, not void. An update of "res->start" is no longer
necessary.
Cc: Bjorn Helgaas <bjorn.helgaas@hp.com>
Cc: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Make remaining netlink policies as const.
Fixup coding style where needed.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Use radix_tree irq_desc_tree instead of irq_desc_ptrs.
-v2: according to Eric and cyrill to use radix_tree_lookup_slot and
radix_tree_replace_slot
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
LKML-Reference: <1265793639-15071-32-git-send-email-yinghai@kernel.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Add replace_irq_desc() instead of poking at the array directly.
-v2: remove unneeded boundary check in replace_irq_desc
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
LKML-Reference: <1265793639-15071-31-git-send-email-yinghai@kernel.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
mem_init is moved early already.
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
LKML-Reference: <1265793639-15071-29-git-send-email-yinghai@kernel.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
x86/mm is on 32-rc4 and missing the spinlock namespace changes which
are needed for further commits into this topic.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
KPROBES_EVENT actually depends on the regs and stack access API
(b1cf540f) and not on x86.
So introduce a new config option which architectures can select if
they have the API implemented and switch x86.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Acked-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
LKML-Reference: <20100210162517.GB6933@osiris.boeblingen.de.ibm.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Most implementations of arch_syscall_addr() are the same, so create a
default version in common code and move the one piece that differs (the
syscall table) to asm/syscall.h. New arch ports don't have to waste
time copying & pasting this simple function.
The s390/sparc versions need to be different, so document why.
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Acked-by: David S. Miller <davem@davemloft.net>
Acked-by: Paul Mundt <lethal@linux-sh.org>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <1264498803-17278-1-git-send-email-vapier@gentoo.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
setscheduler() saves task->sched_class outside of the rq->lock held
region for a check after the setscheduler changes have become
effective. That might result in checking a stale value.
rtmutex_setprio() has the same problem, though it is protected by
p->pi_lock against setscheduler(), but for correctness sake (and to
avoid bad examples) it needs to be fixed as well.
Retrieve task->sched_class inside of the rq->lock held region.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: stable@kernel.org
This makes the range reservation feature available to other
architectures.
-v2: add get_max_mapped, max_pfn_mapped only defined in x86...
to fix PPC compiling
-v3: according to hpa, add CONFIG_HAVE_EARLY_RES
-v4: fix typo about EARLY_RES in config
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
LKML-Reference: <4B7B5723.4070009@kernel.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Add __percpu sparse annotations to core subsystems.
These annotations are to make sparse consider percpu variables to be
in a different address space and warn if accessed without going
through percpu accessors. This patch doesn't affect normal builds.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Christoph Lameter <cl@linux-foundation.org>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: linux-mm@kvack.org
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Dipankar Sarma <dipankar@in.ibm.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Eric Biederman <ebiederm@xmission.com>
This patch fixes following sparse warnings:
include/linux/kfifo.h:127:25: warning: Using plain integer as NULL pointer
kernel/kfifo.c:83:21: warning: Using plain integer as NULL pointer
Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Acked-by: Stefani Seibold <stefani@seibold.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
After kfifo rework it's no longer possible to reliably know if kfifo is
usable, since after kfifo_free(), kfifo_initialized() would still return
true. The correct behaviour is needed for at least FHCI USB driver.
This patch fixes the issue by resetting the kfifo to zero values (the
same approach is used in kfifo_alloc() if allocation failed).
Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Acked-by: Stefani Seibold <stefani@seibold.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Conflicts: kernel/sched.c
Necessary due to the urgent fixes which conflict with the code move
from sched.c to sched_fair.c
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Thomas found that due to ttwu() changing a task's cpu without holding
the rq->lock, task_rq_lock() might end up locking the wrong rq.
Avoid this by serializing against TASK_WAKING.
Reported-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1266241712.15770.420.camel@laptop>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Fix a SMT scheduler performance regression that is leading to a scenario
where SMT threads in one core are completely idle while both the SMT threads
in another core (on the same socket) are busy.
This is caused by this commit (with the problematic code highlighted)
commit bdb94aa5db
Author: Peter Zijlstra <a.p.zijlstra@chello.nl>
Date: Tue Sep 1 10:34:38 2009 +0200
sched: Try to deal with low capacity
@@ -4203,15 +4223,18 @@ find_busiest_queue()
...
for_each_cpu(i, sched_group_cpus(group)) {
+ unsigned long power = power_of(i);
...
- wl = weighted_cpuload(i);
+ wl = weighted_cpuload(i) * SCHED_LOAD_SCALE;
+ wl /= power;
- if (rq->nr_running == 1 && wl > imbalance)
+ if (capacity && rq->nr_running == 1 && wl > imbalance)
continue;
On a SMT system, power of the HT logical cpu will be 589 and
the scheduler load imbalance (for scenarios like the one mentioned above)
can be approximately 1024 (SCHED_LOAD_SCALE). The above change of scaling
the weighted load with the power will result in "wl > imbalance" and
ultimately resulting in find_busiest_queue() return NULL, causing
load_balance() to think that the load is well balanced. But infact
one of the tasks can be moved to the idle core for optimal performance.
We don't need to use the weighted load (wl) scaled by the cpu power to
compare with imabalance. In that condition, we already know there is only a
single task "rq->nr_running == 1" and the comparison between imbalance,
wl is to make sure that we select the correct priority thread which matches
imbalance. So we really need to compare the imabalnce with the original
weighted load of the cpu and not the scaled load.
But in other conditions where we want the most hammered(busiest) cpu, we can
use scaled load to ensure that we consider the cpu power in addition to the
actual load on that cpu, so that we can move the load away from the
guy that is getting most hammered with respect to the actual capacity,
as compared with the rest of the cpu's in that busiest group.
Fix it.
Reported-by: Ma Ling <ling.ma@intel.com>
Initial-Analysis-by: Zhang, Yanmin <yanmin_zhang@linux.intel.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1266023662.2808.118.camel@sbs-t61.sc.intel.com>
Cc: stable@kernel.org [2.6.32.x]
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
perf top: Fix help text alignment
perf: Fix hypervisor sample reporting
perf: Make bp_len type to u64 generic across the arch
Since mcount function can be called from everywhere,
it should be blacklisted. Moreover, the "mcount" symbol
is a special symbol name. So, it is better to put it in
the generic blacklist.
Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: systemtap <systemtap@sources.redhat.com>
Cc: DLE <dle-develop@lists.sourceforge.net>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <20100205062433.3745.36726.stgit@dhcp-100-2-132.bos.redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Commit 22e19085 ("Honour event state for aux stream data")
introduced a bug where we would drop FORK events.
The thing is that we deliver FORK events to the child process'
event, which at that time will be PERF_EVENT_STATE_INACTIVE
because the child won't be scheduled in (we're in the middle of
fork).
Solve this twice, change the event state filter to exclude only
disabled (STATE_OFF) or worse, and deliver FORK events to the
current (parent).
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Anton Blanchard <anton@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
LKML-Reference: <1266142324.5273.411.camel@laptop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Trying to add a probe like:
echo p:myprobe 0x10000 > /sys/kernel/debug/tracing/kprobe_events
will fail since the wrong pointer is passed to strict_strtoul
when trying to convert the address to an unsigned long.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Acked-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <20100210162346.GA6933@osiris.boeblingen.de.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Generic support for PTRACE_GETREGSET/PTRACE_SETREGSET commands which
export the regsets supported by each architecture using the correponding
NT_* types. These NT_* types are already part of the userland ABI, used
in representing the architecture specific register sets as different NOTES
in an ELF core file.
'addr' parameter for the ptrace system call encode the REGSET type (using
the corresppnding NT_* type) and the 'data' parameter points to the
struct iovec having the user buffer and the length of that buffer.
struct iovec iov = { buf, len};
ret = ptrace(PTRACE_GETREGSET/PTRACE_SETREGSET, pid, NT_XXX_TYPE, &iov);
On successful completion, iov.len will be updated by the kernel specifying
how much the kernel has written/read to/from the user's iov.buf.
x86 extended state registers are primarily exported using this interface.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
LKML-Reference: <20100211195614.886724710@sbs-t61.sc.intel.com>
Acked-by: Hongjiu Lu <hjl.tools@gmail.com>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
I don't see why we can only clear all functions from the filter.
After patching:
# echo sys_open > set_graph_function
# echo sys_close >> set_graph_function
# cat set_graph_function
sys_open
sys_close
# echo '!sys_close' >> set_graph_function
# cat set_graph_function
sys_open
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <4B726388.2000408@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
So make interface more consistent with early_res.
Later we can share some code with early_res.
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
LKML-Reference: <1265793639-15071-10-git-send-email-yinghai@kernel.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
We have almost the same code for mtrr cleanup and amd_bus checkup, and
this code will also be used in replacing bootmem with early_res,
so try to move them together and reuse it from different parts.
Also rename update_range to subtract_range as that is what the
function is actually doing.
-v2: update comments as Christoph requested
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
LKML-Reference: <1265793639-15071-4-git-send-email-yinghai@kernel.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Keep chip_data in create_irq_nr and destroy_irq.
When two drivers are setting up MSI-X at the same time via
pci_enable_msix() there is a race. See this dmesg excerpt:
[ 85.170610] ixgbe 0000:02:00.1: irq 97 for MSI/MSI-X
[ 85.170611] alloc irq_desc for 99 on node -1
[ 85.170613] igb 0000:08:00.1: irq 98 for MSI/MSI-X
[ 85.170614] alloc kstat_irqs on node -1
[ 85.170616] alloc irq_2_iommu on node -1
[ 85.170617] alloc irq_desc for 100 on node -1
[ 85.170619] alloc kstat_irqs on node -1
[ 85.170621] alloc irq_2_iommu on node -1
[ 85.170625] ixgbe 0000:02:00.1: irq 99 for MSI/MSI-X
[ 85.170626] alloc irq_desc for 101 on node -1
[ 85.170628] igb 0000:08:00.1: irq 100 for MSI/MSI-X
[ 85.170630] alloc kstat_irqs on node -1
[ 85.170631] alloc irq_2_iommu on node -1
[ 85.170635] alloc irq_desc for 102 on node -1
[ 85.170636] alloc kstat_irqs on node -1
[ 85.170639] alloc irq_2_iommu on node -1
[ 85.170646] BUG: unable to handle kernel NULL pointer dereference
at 0000000000000088
As you can see igb and ixgbe are both alternating on create_irq_nr()
via pci_enable_msix() in their probe function.
ixgbe: While looping through irq_desc_ptrs[] via create_irq_nr() ixgbe
choses irq_desc_ptrs[102] and exits the loop, drops vector_lock and
calls dynamic_irq_init. Then it sets irq_desc_ptrs[102]->chip_data =
NULL via dynamic_irq_init().
igb: Grabs the vector_lock now and starts looping over irq_desc_ptrs[]
via create_irq_nr(). It gets to irq_desc_ptrs[102] and does this:
cfg_new = irq_desc_ptrs[102]->chip_data;
if (cfg_new->vector != 0)
continue;
This hits the NULL deref.
Another possible race exists via pci_disable_msix() in a driver or in
the number of error paths that call free_msi_irqs():
destroy_irq()
dynamic_irq_cleanup() which sets desc->chip_data = NULL
...race window...
desc->chip_data = cfg;
Remove the save and restore code for cfg in create_irq_nr() and
destroy_irq() and take the desc->lock when checking the irq_cfg.
Reported-and-analyzed-by: Brandon Philips <bphilips@suse.de>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
LKML-Reference: <1265793639-15071-3-git-send-email-yinghai@kernel.org>
Signed-off-by: Brandon Phililps <bphilips@suse.de>
Cc: stable@kernel.org
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Export getboottime and monotonic_to_bootbased in order to let them
could be used by following patch.
Cc: stable@kernel.org
Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
kthread_create_on_cpu doesn't exist so update a comment in
kthread.c to reflect this.
Signed-off-by: Anton Blanchard <anton@samba.org>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20100209040740.GB3702@kryten>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
kthread_create_on_cpu doesn't exist so update a comment in kthread.c to reflect
this.
Signed-off-by: Anton Blanchard <anton@samba.org>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
When CONFIG_VIRT_CPU_ACCOUNTING and CONFIG_CGROUP_CPUACCT are
enabled we can call cpuacct_update_stats with values much larger
than percpu_counter_batch. This means the call to
percpu_counter_add will always add to the global count which is
protected by a spinlock and we end up with a global spinlock in
the scheduler.
Based on an idea by KOSAKI Motohiro, this patch scales the batch
value by cputime_one_jiffy such that we have the same batch
limit as we would if CONFIG_VIRT_CPU_ACCOUNTING was disabled.
His patch did this once at boot but that initialisation happened
too early on PowerPC (before time_init) and it was never updated
at runtime as a result of a hotplug cpu add/remove.
This patch instead scales percpu_counter_batch by
cputime_one_jiffy at runtime, which keeps the batch correct even
after cpu hotplug operations. We cap it at INT_MAX in case of
overflow.
For architectures that do not support
CONFIG_VIRT_CPU_ACCOUNTING, cputime_one_jiffy is the constant 1
and gcc is smart enough to optimise min(s32
percpu_counter_batch, INT_MAX) to just percpu_counter_batch at
least on x86 and PowerPC. So there is no need to add an #ifdef.
On a 64 thread PowerPC box with CONFIG_VIRT_CPU_ACCOUNTING and
CONFIG_CGROUP_CPUACCT enabled, a context switch microbenchmark
is 234x faster and almost matches a CONFIG_CGROUP_CPUACCT
disabled kernel:
CONFIG_CGROUP_CPUACCT disabled: 16906698 ctx switches/sec
CONFIG_CGROUP_CPUACCT enabled: 61720 ctx switches/sec
CONFIG_CGROUP_CPUACCT + patch: 16663217 ctx switches/sec
Tested with:
wget http://ozlabs.org/~anton/junkcode/context_switch.c
make context_switch
for i in `seq 0 63`; do taskset -c $i ./context_switch & done
vmstat 1
Signed-off-by: Anton Blanchard <anton@samba.org>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Tested-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
On UP:
kernel/sched.c: In function 'wake_up_new_task':
kernel/sched.c:2631: warning: unused variable 'cpu'
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Add a clocksource suspend callback. This callback can be used by the
clocksource driver to shutdown and perform any kind of late suspend
activities even though the clocksource driver itself is a non-sysdev
driver.
One example where this is useful is to fix the sh_cmt.c platform driver
that today suspends using the platform bus and shuts down the clocksource
too early.
With this callback in place the sh_cmt driver will suspend using the
clocksource and clockevent hooks and leave the platform device pm
callbacks unused.
Signed-off-by: Magnus Damm <damm@opensource.se>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: john stultz <johnstul@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Pass the clocksource as an argument to the clocksource resume callback.
Needed so we can point out which CMT channel the sh_cmt.c driver shall
resume.
Signed-off-by: Magnus Damm <damm@opensource.se>
Cc: john stultz <johnstul@us.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Some misspelled occurences of 'octet' and some comments were also fixed
as I was on it.
Signed-off-by: Daniel Mack <daniel@caiaq.de>
Cc: Jiri Kosina <trivial@kernel.org>
Cc: Joe Perches <joe@perches.com>
Cc: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Some comments misspell "should" or "shouldn't"; this fixes them. No code changes.
Signed-off-by: Adam Buchbinder <adam.buchbinder@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Since mcount function can be called from everywhere,
it should be blacklisted. Moreover, the "mcount" symbol
is a special symbol name. So, it is better to put it in
the generic blacklist.
Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: systemtap <systemtap@sources.redhat.com>
Cc: DLE <dle-develop@lists.sourceforge.net>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <20100205062433.3745.36726.stgit@dhcp-100-2-132.bos.redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
futex: Handle futex value corruption gracefully
futex: Handle user space corruption gracefully
futex_lock_pi() key refcnt fix
softlockup: Add sched_clock_tick() to avoid kernel warning on kgdb resume
Some comments misspell "invocation"; this fixes them. No code
changes.
Signed-off-by: Adam Buchbinder <adam.buchbinder@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Some comments misspell "truly"; this fixes them. No code changes.
Signed-off-by: Adam Buchbinder <adam.buchbinder@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Pretty much all of the calls do perf_disable/perf_enable cycles, pull
that out to cut back on hardware programming.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
It's a duplicate of tg->rt_se[cpu] and the only usage is
sched_rt_rq_dequeue() and sched_rt_rq_enqueue(). After the
first patch to those two function. rt_se can be removed.
Signed-off-by: Yong Zhang <yong.zhang0@gmail.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <2674af741001282258q38781619u653ca4a7dd267347@mail.gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This is the first step to remove rt_rq member rt_se because it have the
same meaning with tg->rt_se[cpu]. And the latter style is also used by
the fair scheduling class.
Signed-off-by: Yong Zhang <yong.zhang0@gmail.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <2674af741001282257r28c97a92o9f90cf16fe8d3d84@mail.gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Remove record freezing. Because kprobes never puts probe on
ftrace's mcount call anymore, it doesn't need ftrace to check
whether kprobes on it.
Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: systemtap <systemtap@sources.redhat.com>
Cc: DLE <dle-develop@lists.sourceforge.net>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: przemyslaw@pawelczyk.it
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <20100202214925.4694.73469.stgit@dhcp-100-2-132.bos.redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Check whether the address of new probe is already reserved by
ftrace or alternatives (on x86) when registering new probe.
If reserved, it returns an error and not register the probe.
Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: systemtap <systemtap@sources.redhat.com>
Cc: DLE <dle-develop@lists.sourceforge.net>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: przemyslaw@pawelczyk.it
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: Mathieu Desnoyers <compudj@krystal.dyndns.org>
Cc: Jason Baron <jbaron@redhat.com>
LKML-Reference: <20100202214918.4694.94179.stgit@dhcp-100-2-132.bos.redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Introducing *_text_reserved functions for checking the text
address range is partially reserved or not. This patch provides
checking routines for x86 smp alternatives and dynamic ftrace.
Since both functions modify fixed pieces of kernel text, they
should reserve and protect those from other dynamic text
modifier, like kprobes.
This will also be extended when introducing other subsystems
which modify fixed pieces of kernel text. Dynamic text modifiers
should avoid those.
Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: systemtap <systemtap@sources.redhat.com>
Cc: DLE <dle-develop@lists.sourceforge.net>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: przemyslaw@pawelczyk.it
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: Mathieu Desnoyers <compudj@krystal.dyndns.org>
Cc: Jason Baron <jbaron@redhat.com>
LKML-Reference: <20100202214911.4694.16587.stgit@dhcp-100-2-132.bos.redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Disable kprobe booster when CONFIG_PREEMPT=y at this time,
because it can't ensure that all kernel threads preempted on
kprobe's boosted slot run out from the slot even using
freeze_processes().
The booster on preemptive kernel will be resumed if
synchronize_tasks() or something like that is introduced.
Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: systemtap <systemtap@sources.redhat.com>
Cc: DLE <dle-develop@lists.sourceforge.net>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: Mathieu Desnoyers <compudj@krystal.dyndns.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <20100202214904.4694.24330.stgit@dhcp-100-2-132.bos.redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Right now the syslog "type" action are just raw numbers which makes
the source difficult to follow. This patch replaces the raw numbers
with defined constants for some level of sanity.
Signed-off-by: Kees Cook <kees.cook@canonical.com>
Acked-by: John Johansen <john.johansen@canonical.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
This allows the LSM to distinguish between syslog functions originating
from /proc/kmsg access and direct syscalls. By default, the commoncaps
will now no longer require CAP_SYS_ADMIN to read an opened /proc/kmsg
file descriptor. For example the kernel syslog reader can now drop
privileges after opening /proc/kmsg, instead of staying privileged with
CAP_SYS_ADMIN. MAC systems that implement security_syslog have unchanged
behavior.
Signed-off-by: Kees Cook <kees.cook@canonical.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Acked-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: James Morris <jmorris@namei.org>
Change 'bp_len' type to __u64 to make it work across archs as
the s390 architecture watch point length can be upto 2^64.
reference:
http://lkml.org/lkml/2010/1/25/212
This is an ABI change that is not backward compatible with
the previous hardware breakpoint info layout integrated in this
development cycle, a rebuilt of perf tools is necessary for
versions based on 2.6.33-rc1 - 2.6.33-rc6 to work with a
kernel based on this patch.
Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: "K. Prasad" <prasad@linux.vnet.ibm.com>
Cc: Maneesh Soni <maneesh@in.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin <schwidefsky@de.ibm.com>
LKML-Reference: <20100130045518.GA20776@in.ibm.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
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 <yjwei@cn.fujitsu.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Yury Polyanskiy <ypolyans@princeton.edu>
Tested-by: Wei Yongjun <yjwei@cn.fujitsu.com>
Acked-by: David S. Miller <davem@davemloft.net>
LKML-Reference: <1265120401.24455.306.camel@laptop>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
The WARN_ON in lookup_pi_state which complains about a mismatch
between pi_state->owner->pid and the pid which we retrieved from the
user space futex is completely bogus.
The code just emits the warning and then continues despite the fact
that it detected an inconsistent state of the futex. A conveniant way
for user space to spam the syslog.
Replace the WARN_ON by a consistency check. If the values do not match
return -EINVAL and let user space deal with the mess it created.
This also fixes the missing task_pid_vnr() when we compare the
pi_state->owner pid with the futex value.
Reported-by: Jermome Marchand <jmarchan@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Darren Hart <dvhltc@us.ibm.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: <stable@kernel.org>
If the owner of a PI futex dies we fix up the pi_state and set
pi_state->owner to NULL. When a malicious or just sloppy programmed
user space application sets the futex value to 0 e.g. by calling
pthread_mutex_init(), then the futex can be acquired again. A new
waiter manages to enqueue itself on the pi_state w/o damage, but on
unlock the kernel dereferences pi_state->owner and oopses.
Prevent this by checking pi_state->owner in the unlock path. If
pi_state->owner is not current we know that user space manipulated the
futex value. Ignore the mess and return -EINVAL.
This catches the above case and also the case where a task hijacks the
futex by setting the tid value and then tries to unlock it.
Reported-by: Jermome Marchand <jmarchan@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Darren Hart <dvhltc@us.ibm.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: <stable@kernel.org>
This fixes a futex key reference count bug in futex_lock_pi(),
where a key's reference count is incremented twice but decremented
only once, causing the backing object to not be released.
If the futex is created in a temporary file in an ext3 file system,
this bug causes the file's inode to become an "undead" orphan,
which causes an oops from a BUG_ON() in ext3_put_super() when the
file system is unmounted. glibc's test suite is known to trigger this,
see <http://bugzilla.kernel.org/show_bug.cgi?id=14256>.
The bug is a regression from 2.6.28-git3, namely Peter Zijlstra's
38d47c1b70 "[PATCH] futex: rely on
get_user_pages() for shared futexes". That commit made get_futex_key()
also increment the reference count of the futex key, and updated its
callers to decrement the key's reference count before returning.
Unfortunately the normal exit path in futex_lock_pi() wasn't corrected:
the reference count is incremented by get_futex_key() and queue_lock(),
but the normal exit path only decrements once, via unqueue_me_pi().
The fix is to put_futex_key() after unqueue_me_pi(), since 2.6.31
this is easily done by 'goto out_put_key' rather than 'goto out'.
Signed-off-by: Mikael Pettersson <mikpe@it.uu.se>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Darren Hart <dvhltc@us.ibm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: <stable@kernel.org>
In cgroup_create(), if alloc_css_id() returns failure, the errno is not
propagated to userspace, so mkdir will fail silently.
To trigger this bug, we mount blkio (or memory subsystem), and create more
then 65534 cgroups. (The number of cgroups is limited to 65535 if a
subsystem has use_id == 1)
# mount -t cgroup -o blkio xxx /mnt
# for ((i = 0; i < 65534; i++)); do mkdir /mnt/$i; done
# mkdir /mnt/65534
(should return ENOSPC)
#
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Acked-by: Paul Menage <menage@google.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix kfifo kernel-doc warnings:
Warning(kernel/kfifo.c:361): No description found for parameter 'total'
Warning(kernel/kfifo.c:402): bad line: @ @lenout: pointer to output variable with copied data
Warning(kernel/kfifo.c:412): No description found for parameter 'lenout'
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Stefani Seibold <stefani@seibold.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Free memory allocated using kmem_cache_zalloc using kmem_cache_free rather
than kfree.
The semantic patch that makes this change is as follows:
(http://coccinelle.lip6.fr/)
// <smpl>
@@
expression x,E,c;
@@
x = \(kmem_cache_alloc\|kmem_cache_zalloc\|kmem_cache_alloc_node\)(c,...)
... when != x = E
when != &x
?-kfree(x)
+kmem_cache_free(c,x)
// </smpl>
Signed-off-by: Julia Lawall <julia@diku.dk>
Acked-by: David Howells <dhowells@redhat.com>
Cc: James Morris <jmorris@namei.org>
Cc: Steve Dickson <steved@redhat.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: James Morris <jmorris@namei.org>
When we cat <debugfs>/tracing/stack_trace, we may cause circular lock:
sys_read()
t_start()
arch_spin_lock(&max_stack_lock);
t_show()
seq_printf(), vsnprintf() .... /* they are all trace-able,
when they are traced, max_stack_lock may be required again. */
The following script can trigger this circular dead lock very easy:
#!/bin/bash
echo 1 > /proc/sys/kernel/stack_tracer_enabled
mount -t debugfs xxx /mnt > /dev/null 2>&1
(
# make check_stack() zealous to require max_stack_lock
for ((; ;))
{
echo 1 > /mnt/tracing/stack_max_size
}
) &
for ((; ;))
{
cat /mnt/tracing/stack_trace > /dev/null
}
To fix this bug, we increase the percpu trace_active before
require the lock.
Reported-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
LKML-Reference: <4B67D4F9.9080905@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Commit f492e12ef0 ("sched: Remove
load_balance_newidle()") removed the only user of this function,
so remove it too.
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1265019219.24455.128.camel@laptop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
No change in functionality.
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
LKML-Reference: <1264938810-4173-1-git-send-email-akinobu.mita@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Use __weak instead of __attribute__((weak)).
Cc: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
It's based on walk_system_ram_range(), for archs that don't have
their own page_is_ram().
The static verions in MIPS and SCORE are also made global.
v4: prefer plain 1 instead of PAGE_IS_RAM (H. Peter Anvin)
v3: add comment (KAMEZAWA Hiroyuki)
"AFAIK, this "System RAM" information has been used for kdump to
grab valid memory area and seems good for the kernel itself."
v2: add PAGE_IS_RAM macro (Américo Wang)
Cc: Chen Liqin <liqin.chen@sunplusct.com>
Cc: Lennox Wu <lennox.wu@gmail.com>
Cc: Américo Wang <xiyou.wangcong@gmail.com>
Cc: linux-mips@linux-mips.org
Cc: Yinghai Lu <yinghai@kernel.org>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
LKML-Reference: <20100122081619.GA6431@localhost>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
* 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
perf, hw_breakpoint, kgdb: Do not take mutex for kernel debugger
x86, hw_breakpoints, kgdb: Fix kgdb to use hw_breakpoint API
hw_breakpoints: Release the bp slot if arch_validate_hwbkpt_settings() fails.
perf: Ignore perf.data.old
perf report: Fix segmentation fault when running with '-g none'
* 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
sched: Correct printk whitespace in warning from cpu down task check
sched: Fix incorrect sanity check
sched: Fix fork vs hotplug vs cpuset namespaces
When CONFIG_HAVE_UNSTABLE_SCHED_CLOCK is set, sched_clock() gets
the time from hardware such as the TSC on x86. In this
configuration kgdb will report a softlock warning message on
resuming or detaching from a debug session.
Sequence of events in the problem case:
1) "cpu sched clock" and "hardware time" are at 100 sec prior
to a call to kgdb_handle_exception()
2) Debugger waits in kgdb_handle_exception() for 80 sec and on
exit the following is called ... touch_softlockup_watchdog() -->
__raw_get_cpu_var(touch_timestamp) = 0;
3) "cpu sched clock" = 100s (it was not updated, because the
interrupt was disabled in kgdb) but the "hardware time" = 180 sec
4) The first timer interrupt after resuming from
kgdb_handle_exception updates the watchdog from the "cpu sched clock"
update_process_times() { ... run_local_timers() -->
softlockup_tick() --> check (touch_timestamp == 0) (it is "YES"
here, we have set "touch_timestamp = 0" at kgdb) -->
__touch_softlockup_watchdog() ***(A)--> reset "touch_timestamp"
to "get_timestamp()" (Here, the "touch_timestamp" will still be
set to 100s.) ...
scheduler_tick() ***(B)--> sched_clock_tick() (update "cpu sched
clock" to "hardware time" = 180s) ... }
5) The Second timer interrupt handler appears to have a large
jump and trips the softlockup warning.
update_process_times() { ... run_local_timers() -->
softlockup_tick() --> "cpu sched clock" - "touch_timestamp" =
180s-100s > 60s --> printk "soft lockup error messages" ... }
note: ***(A) reset "touch_timestamp" to
"get_timestamp(this_cpu)"
Why is "touch_timestamp" 100 sec, instead of 180 sec?
When CONFIG_HAVE_UNSTABLE_SCHED_CLOCK is set, the call trace of
get_timestamp() is:
get_timestamp(this_cpu)
-->cpu_clock(this_cpu)
-->sched_clock_cpu(this_cpu)
-->__update_sched_clock(sched_clock_data, now)
The __update_sched_clock() function uses the GTOD tick value to
create a window to normalize the "now" values. So if "now"
value is too big for sched_clock_data, it will be ignored.
The fix is to invoke sched_clock_tick() to update "cpu sched
clock" in order to recover from this state. This is done by
introducing the function touch_softlockup_watchdog_sync(). This
allows kgdb to request that the sched clock is updated when the
watchdog thread runs the first time after a resume from kgdb.
[yong.zhang0@gmail.com: Use per cpu instead of an array]
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Signed-off-by: Dongdong Deng <Dongdong.Deng@windriver.com>
Cc: kgdb-bugreport@lists.sourceforge.net
Cc: peterz@infradead.org
LKML-Reference: <1264631124-4837-2-git-send-email-jason.wessel@windriver.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This patch fixes the regression in functionality where the
kernel debugger and the perf API do not nicely share hw
breakpoint reservations.
The kernel debugger cannot use any mutex_lock() calls because it
can start the kernel running from an invalid context.
A mutex free version of the reservation API needed to get
created for the kernel debugger to safely update hw breakpoint
reservations.
The possibility for a breakpoint reservation to be concurrently
processed at the time that kgdb interrupts the system is
improbable. Should this corner case occur the end user is
warned, and the kernel debugger will prohibit updating the
hardware breakpoint reservations.
Any time the kernel debugger reserves a hardware breakpoint it
will be a system wide reservation.
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: kgdb-bugreport@lists.sourceforge.net
Cc: K.Prasad <prasad@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: torvalds@linux-foundation.org
LKML-Reference: <1264719883-7285-3-git-send-email-jason.wessel@windriver.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
In the 2.6.33 kernel, the hw_breakpoint API is now used for the
performance event counters. The hw_breakpoint_handler() now
consumes the hw breakpoints that were previously set by kgdb
arch specific code. In order for kgdb to work in conjunction
with this core API change, kgdb must use some of the low level
functions of the hw_breakpoint API to install, uninstall, and
deal with hw breakpoint reservations.
The kgdb core required a change to call kgdb_disable_hw_debug
anytime a slave cpu enters kgdb_wait() in order to keep all the
hw breakpoints in sync as well as to prevent hitting a hw
breakpoint while kgdb is active.
During the architecture specific initialization of kgdb, it will
pre-allocate 4 disabled (struct perf event **) structures. Kgdb
will use these to manage the capabilities for the 4 hw
breakpoint registers, per cpu. Right now the hw_breakpoint API
does not have a way to ask how many breakpoints are available,
on each CPU so it is possible that the install of a breakpoint
might fail when kgdb restores the system to the run state. The
intent of this patch is to first get the basic functionality of
hw breakpoints working and leave it to the person debugging the
kernel to understand what hw breakpoints are in use and what
restrictions have been imposed as a result. Breakpoint
constraints will be dealt with in a future patch.
While atomic, the x86 specific kgdb code will call
arch_uninstall_hw_breakpoint() and arch_install_hw_breakpoint()
to manage the cpu specific hw breakpoints.
The net result of these changes allow kgdb to use the same pool
of hw_breakpoints that are used by the perf event API, but
neither knows about future reservations for the available hw
breakpoint slots.
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: kgdb-bugreport@lists.sourceforge.net
Cc: K.Prasad <prasad@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: torvalds@linux-foundation.org
LKML-Reference: <1264719883-7285-2-git-send-email-jason.wessel@windriver.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
ntp.c doesn't need to access timekeeping internals directly, so change
xtime references to use the get_seconds() timekeeping interface.
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Cc: richard@rsk.demon.co.uk
LKML-Reference: <1264738844-21935-1-git-send-email-johnstul@us.ibm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Make time_esterror and time_maxerror static as no one uses them
outside of ntp.c
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Cc: richard@rsk.demon.co.uk
LKML-Reference: <1264719761.3437.47.camel@localhost.localdomain>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
One problem with frequency driven counters is that we cannot
predict the rate at which they trigger, therefore we have to
start them at period=1, this causes a ramp up effect. However,
if we fail to propagate the stable state on fork each new child
will have to ramp up again. This can lead to significant
artifacts in sample data.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: eranian@google.com
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <1264752266.4283.2121.camel@laptop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The return values of the kprobe's tracing functions are meaningless,
lets remove these.
Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Acked-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
LKML-Reference: <4B60E9A3.2040505@cn.fujitsu.com>
[fweisbec@gmail: whitespace fixes, drop useless void returns in end
of functions]
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Introduce ftrace_perf_buf_prepare() and ftrace_perf_buf_submit() to
gather the common code that operates on raw events sampling buffer.
This cleans up redundant code between regular trace events, syscall
events and kprobe events.
Changelog v1->v2:
- Rename function name as per Masami and Frederic's suggestion
- Add __kprobes for ftrace_perf_buf_prepare() and make
ftrace_perf_buf_submit() inline as per Masami's suggestion
- Export ftrace_perf_buf_prepare since modules will use it
Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Acked-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
LKML-Reference: <4B60E92D.9000808@cn.fujitsu.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
In the function graph tracer, a calling function is to be traced
only when it is enabled through the set_graph_function file,
or when it is nested in an enabled function.
Current code uses TSK_TRACE_FL_GRAPH to test whether it is nested
or not. Looking at the code, we can get this:
(trace->depth > 0) <==> (TSK_TRACE_FL_GRAPH is set)
trace->depth is more explicit to tell that it is nested.
So we use trace->depth directly and simplify the code.
No functionality is changed.
TSK_TRACE_FL_GRAPH is not removed yet, it is left for future usage.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <4B4DB0B6.7040607@cn.fujitsu.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
On a given architecture, when hardware breakpoint registration fails
due to un-supported access type (read/write/execute), we lose the bp
slot since register_perf_hw_breakpoint() does not release the bp slot
on failure.
Hence, any subsequent hardware breakpoint registration starts failing
with 'no space left on device' error.
This patch introduces error handling in register_perf_hw_breakpoint()
function and releases bp slot on error.
Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: K. Prasad <prasad@linux.vnet.ibm.com>
Cc: Maneesh Soni <maneesh@in.ibm.com>
LKML-Reference: <20100121125516.GA32521@in.ibm.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Due to an incorrect line break the output currently contains tabs.
Also remove trailing space.
The actual output that logcheck sent me looked like this:
Task events/1 (pid = 10) is on cpu 1^I^I^I^I(state = 1, flags = 84208040)
After this patch it becomes:
Task events/1 (pid = 10) is on cpu 1 (state = 1, flags = 84208040)
Signed-off-by: Frans Pop <elendilplanet.nl>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <201001251456.34996.elendil@planet.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
We moved to migrate on wakeup, which means that sleeping tasks could
still be present on offline cpus. Amend the check to only test running
tasks.
Reported-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
There was a bug in the old period code that caused intel_pmu_enable_all()
or native_write_msr_safe() to show up quite high in the profiles.
In staring at that code it made my head hurt, so I rewrote it in a
hopefully simpler fashion. Its now fully symetric between tick and
overflow driven adjustments and uses less data to boot.
The only complication is that it basically wants to do a u128 division.
The code approximates that in a rather simple truncate until it fits
fashion, taking care to balance the terms while truncating.
This version does not generate that sampling artefact.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Cc: <stable@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Lockdep has found the real bug, but the output doesn't look right to me:
> =========================================================
> [ INFO: possible irq lock inversion dependency detected ]
> 2.6.33-rc5 #77
> ---------------------------------------------------------
> emacs/1609 just changed the state of lock:
> (&(&tty->ctrl_lock)->rlock){+.....}, at: [<ffffffff8127c648>] tty_fasync+0xe8/0x190
> but this lock took another, HARDIRQ-unsafe lock in the past:
> (&(&sighand->siglock)->rlock){-.....}
"HARDIRQ-unsafe" and "this lock took another" looks wrong, afaics.
> ... key at: [<ffffffff81c054a4>] __key.46539+0x0/0x8
> ... acquired at:
> [<ffffffff81089af6>] __lock_acquire+0x1056/0x15a0
> [<ffffffff8108a0df>] lock_acquire+0x9f/0x120
> [<ffffffff81423012>] _raw_spin_lock_irqsave+0x52/0x90
> [<ffffffff8127c1be>] __proc_set_tty+0x3e/0x150
> [<ffffffff8127e01d>] tty_open+0x51d/0x5e0
The stack-trace shows that this lock (ctrl_lock) was taken under
->siglock (which is hopefully irq-safe).
This is a clear typo in check_usage_backwards() where we tell the print a
fancy routine we're forwards.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20100126181641.GA10460@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Update the graph tracer examples to cover the new frame pointer semantics
(in terms of passing it along). Move the HAVE_FUNCTION_GRAPH_FP_TEST docs
out of the Kconfig, into the right place, and expand on the details.
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
LKML-Reference: <1264165967-18938-1-git-send-email-vapier@gentoo.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
If the iterator comes to an empty page for some reason, or if
the page is emptied by a consuming read. The iterator code currently
does not check if the iterator is pass the contents, and may
return a false entry.
This patch adds a check to the ring buffer iterator to test if the
current page has been completely read and sets the iterator to the
next page if necessary.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Usually reads of the ring buffer is performed by a single task.
There are two types of reads from the ring buffer.
One is a consuming read which will consume the entry that was read
and the next read will be the entry that follows.
The other is an iterator that will let the user read the contents of
the ring buffer without modifying it. When an iterator is allocated,
writes to the ring buffer are disabled to protect the iterator.
The problem exists when consuming reads happen while an iterator is
allocated. Specifically, the kind of read that swaps out an entire
page (used by splice) and replaces it with a new read. If the iterator
is on the page that is swapped out, then the next read may read
from this swapped out page and return garbage.
This patch adds a check when reading the iterator to make sure that
the iterator contents are still valid. If a consuming read has taken
place, the iterator is reset.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
commit 0f8e8ef7 (clocksource: Simplify clocksource watchdog resume
logic) introduced a potential kgdb dead lock. When the kernel is
stopped by kgdb inside code which holds watchdog_lock then kgdb dead
locks in clocksource_resume_watchdog().
clocksource_resume_watchdog() is called from kbdg via
clocksource_touch_watchdog() to avoid that the clock source watchdog
marks TSC unstable after the kernel has been stopped.
Solve this by replacing spin_lock with a spin_trylock and just return
in case the lock is held. Not resetting the watchdog might result in
TSC becoming marked unstable, but that's an acceptable penalty for
using kgdb.
The timekeeping is anyway easily screwed up by kgdb when the system
uses either jiffies or a clock source which wraps in short intervals
(e.g. pm_timer wraps about every 4.6s), so we really do not have to
worry about that occasional TSC marked unstable side effect.
The second caller of clocksource_resume_watchdog() is
clocksource_resume(). The trylock is safe here as well because the
system is UP at this point, interrupts are disabled and nothing else
can hold watchdog_lock().
Reported-by: Jason Wessel <jason.wessel@windriver.com>
LKML-Reference: <1264480000-6997-4-git-send-email-jason.wessel@windriver.com>
Cc: kgdb-bugreport@lists.sourceforge.net
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: John Stultz <johnstul@us.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
If the contents of the ftrace ring buffer gets corrupted and the trace
file is read, it could create a kernel oops (usualy just killing the user
task thread). This is caused by the checking of the pid in the buffer.
If the pid is negative, it still references the cmdline cache array,
which could point to an invalid address.
The simple fix is to test for negative PIDs.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
clockevent: Don't remove broadcast device when cpu is dead
* git://git.infradead.org/~dwmw2/mtd-2.6.33:
mtd: tests: fix read, speed and stress tests on NOR flash
mtd: Really add ARM pismo support
kmsg_dump: Dump on crash_kexec as well
rtmutex_set_prio() is used to implement priority inheritance for
futexes. When a task is deboosted it gets enqueued at the tail of its
RT priority list. This is violating the POSIX scheduling semantics:
rt priority list X contains two runnable tasks A and B
task A runs with priority X and holds mutex M
task C preempts A and is blocked on mutex M
-> task A is boosted to priority of task C (Y)
task A unlocks the mutex M and deboosts itself
-> A is dequeued from rt priority list Y
-> A is enqueued to the tail of rt priority list X
task C schedules away
task B runs
This is wrong as task A did not schedule away and therefor violates
the POSIX scheduling semantics.
Enqueue the task to the head of the priority list instead.
Reported-by: Mathias Weber <mathias.weber.mw1@roche.com>
Reported-by: Carsten Emde <cbe@osadl.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Tested-by: Carsten Emde <cbe@osadl.org>
Tested-by: Mathias Weber <mathias.weber.mw1@roche.com>
LKML-Reference: <20100120171629.809074113@linutronix.de>
The ability of enqueueing a task to the head of a SCHED_FIFO priority
list is required to fix some violations of POSIX scheduling policy.
Implement the functionality in sched_rt.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Tested-by: Carsten Emde <cbe@osadl.org>
Tested-by: Mathias Weber <mathias.weber.mw1@roche.com>
LKML-Reference: <20100120171629.772169931@linutronix.de>
The ability of enqueueing a task to the head of a SCHED_FIFO priority
list is required to fix some violations of POSIX scheduling policy.
Extend the related functions with a "head" argument.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Tested-by: Carsten Emde <cbe@osadl.org>
Tested-by: Mathias Weber <mathias.weber.mw1@roche.com>
LKML-Reference: <20100120171629.734886007@linutronix.de>
There are a number of issues:
1) TASK_WAKING vs cgroup_clone (cpusets)
copy_process():
sched_fork()
child->state = TASK_WAKING; /* waiting for wake_up_new_task() */
if (current->nsproxy != p->nsproxy)
ns_cgroup_clone()
cgroup_clone()
mutex_lock(inode->i_mutex)
mutex_lock(cgroup_mutex)
cgroup_attach_task()
ss->can_attach()
ss->attach() [ -> cpuset_attach() ]
cpuset_attach_task()
set_cpus_allowed_ptr();
while (child->state == TASK_WAKING)
cpu_relax();
will deadlock the system.
2) cgroup_clone (cpusets) vs copy_process
So even if the above would work we still have:
copy_process():
if (current->nsproxy != p->nsproxy)
ns_cgroup_clone()
cgroup_clone()
mutex_lock(inode->i_mutex)
mutex_lock(cgroup_mutex)
cgroup_attach_task()
ss->can_attach()
ss->attach() [ -> cpuset_attach() ]
cpuset_attach_task()
set_cpus_allowed_ptr();
...
p->cpus_allowed = current->cpus_allowed
over-writing the modified cpus_allowed.
3) fork() vs hotplug
if we unplug the child's cpu after the sanity check when the child
gets attached to the task_list but before wake_up_new_task() shit
will meet with fan.
Solve all these issues by moving fork cpu selection into
wake_up_new_task().
Reported-by: Serge E. Hallyn <serue@us.ibm.com>
Tested-by: Serge E. Hallyn <serue@us.ibm.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1264106190.4283.1314.camel@laptop>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
perf: x86: Add support for the ANY bit
perf: Change the is_software_event() definition
perf: Honour event state for aux stream data
perf: Fix perf_event_do_pending() fallback callsite
perf kmem: Print usage help for unknown commands
perf kmem: Increase "Hit" column length
hw-breakpoints, perf: Fix broken mmiotrace due to dr6 by reference change
perf timechart: Use tid not pid for COMM change
Anton reported that perf record kept receiving events even after calling
ioctl(PERF_EVENT_IOC_DISABLE). It turns out that FORK,COMM and MMAP
events didn't respect the disabled state and kept flowing in.
Reported-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Tested-by: Anton Blanchard <anton@samba.org>
LKML-Reference: <1263459187.4244.265.camel@laptop>
CC: stable@kernel.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Paul questioned the context in which we should call
perf_event_do_pending(). After looking at that I found that it should be
called from IRQ context these days, however the fallback call-site is
placed in softirq context. Ammend this by placing the callback in the IRQ
timer path.
Reported-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1263374859.4244.192.camel@laptop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Remove the USER_SCHED feature. It has been scheduled to be removed in
2.6.34 as per http://marc.info/?l=linux-kernel&m=125728479022976&w=2
Signed-off-by: Dhaval Giani <dhaval.giani@gmail.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1263990378.24844.3.camel@localhost>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
We want to update the sched_group_powers when balance_cpu == this_cpu.
Currently the group powers are updated only if the balance_cpu is the
first CPU in the local group. But balance_cpu = this_cpu could also be
the first idle cpu in the group. Hence fix the place where the group
powers are updated.
Signed-off-by: Gautham R Shenoy <ego@in.ibm.com>
Signed-off-by: Joel Schopp <jschopp@austin.ibm.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1264017764.5717.127.camel@jschopp-laptop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Since all load_balance() callers will have !NULL balance parameters we
can now assume so and remove a few checks.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The two functions: load_balance{,_newidle}() are very similar, with the
following differences:
- rq->lock usage
- sb->balance_interval updates
- *balance check
So remove the load_balance_newidle() call with load_balance(.idle =
CPU_NEWLY_IDLE), explicitly unlock the rq->lock before calling (would be
done by double_lock_balance() anyway), and ignore the other differences
for now.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
load_balance() and load_balance_newidle() look remarkably similar, one
key point they differ in is the condition on when to active balance.
So split out that logic into a separate function.
One side effect is that previously load_balance_newidle() used to fail
and return -1 under these conditions, whereas now it doesn't. I've not
yet fully figured out the whole -1 return case for either
load_balance{,_newidle}().
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Since load-balancing can hold rq->locks for quite a long while, allow
breaking out early when there is lock contention.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Move code around to get rid of fwd declarations.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Again, since we only iterate the fair class, remove the abstraction.
Since this is the last user of the rq_iterator, remove all that too.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Since we only ever iterate the fair class, do away with this abstraction.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Take out the sched_class methods for load-balancing.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Straight fwd code movement.
Since non of the load-balance abstractions are used anymore, do away with
them and simplify the code some. In preparation move the code around.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Assume A->B schedule is processing, if B have acquired BKL before and it
need reschedule this time. Then on B's context, it will go to
need_resched_nonpreemptible for reschedule. But at this time, prev and
switch_count are related to A. It's wrong and will lead to incorrect
scheduler statistics.
Signed-off-by: Yong Zhang <yong.zhang0@gmail.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <2674af741001102238w7b0ddcadref00d345e2181d11@mail.gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
SD_PREFER_SIBLING is set at the CPU domain level if power saving isn't
enabled, leading to many cache misses on large machines as we traverse
looking for an idle shared cache to wake to. Change the enabler of
select_idle_sibling() to SD_SHARE_PKG_RESOURCES, and enable same at the
sibling domain level.
Reported-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1262612696.15495.15.camel@marge.simson.net>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Marc reported that the BUG_ON in clockevents_notify() triggers on his
system. This happens because the kernel tries to remove an active
clock event device (used for broadcasting) from the device list.
The handling of devices which can be used as per cpu device and as a
global broadcast device is suboptimal.
The simplest solution for now (and for stable) is to check whether the
device is used as global broadcast device, but this needs to be
revisited.
[ tglx: restored the cpuweight check and massaged the changelog ]
Reported-by: Marc Dionne <marc.c.dionne@gmail.com>
Tested-by: Marc Dionne <marc.c.dionne@gmail.com>
Signed-off-by: Xiaotian Feng <dfeng@redhat.com>
LKML-Reference: <1262834564-13033-1-git-send-email-dfeng@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@kernel.org
The smp ipi data is passed around and given write access by
other cpus and should be separated from per-cpu data consumed by
this cpu.
Looking for hot lines, I saw call_function_data shared with
tick_cpu_sched.
Signed-off-by: Milton Miller <miltonm@bga.com>
Acked-by: Anton Blanchard <anton@samba.org>
Acked-by: Jens Axboe <jens.axboe@oracle.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: : Nick Piggin <npiggin@suse.de>
LKML-Reference: <20100118020051.GR12666@kryten>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
When a task gets scheduled in. We don't touch the cpu bound events
so the priority order becomes:
cpu pinned, cpu flexible, task pinned, task flexible.
So schedule out cpu flexibles when a new task context gets in
and correctly order the groups to schedule in:
task pinned, cpu flexible, task flexible.
Cpu pinned groups don't need to be touched at this time.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
We don't need to schedule in/out pinned events on task tick,
now that pinned and flexible groups can be scheduled separately.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
Tune the scheduling helpers so that we can choose to schedule either
pinned and/or flexible groups from a context.
And while at it, refactor a bit the naming of these helpers to make
these more consistent and flexible.
There is no (intended) change in scheduling behaviour in this
patch.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
__perf_event_sched_out doesn't need to be globally available, make
it static.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
Update kprobe tracing self test for new syntax (it supports
deleting individual probes, and drops $argN support)
and behavior change (new probes are disabled in default).
This selftest includes the following checks:
- Adding function-entry probe and return probe with arguments.
- Enabling these probes.
- Deleting it individually.
Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: systemtap <systemtap@sources.redhat.com>
Cc: DLE <dle-develop@lists.sourceforge.net>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <20100114051211.7814.29436.stgit@localhost6.localdomain6>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
kernel/sched: don't expose local functions
The get_rr_interval_* functions are all class methods of
struct sched_class. They are not exported so make them
static.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Peter Zijlstra <peterz@infradead.org>
LKML-Reference: <201001132021.53253.hartleys@visionengravers.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Each time we save a function entry from the function graph
tracer, we check if the trace array is set, which is wasteful
because it is set anyway before we start the tracer. All we need
is to ensure we have good read and write orderings. When we set
the trace array, we just need to guarantee it to be visible
before starting tracing.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
LKML-Reference: <1263453795-7496-1-git-send-regression-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* 'tracing-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
tracing/filters: Add comment for match callbacks
tracing/filters: Fix MATCH_FULL filter matching for PTR_STRING
tracing/filters: Fix MATCH_MIDDLE_ONLY filter matching
lib: Introduce strnstr()
tracing/filters: Fix MATCH_END_ONLY filter matching
tracing/filters: Fix MATCH_FRONT_ONLY filter matching
ftrace: Fix MATCH_END_ONLY function filter
tracing/x86: Derive arch from bits argument in recordmcount.pl
ring-buffer: Add rb_list_head() wrapper around new reader page next field
ring-buffer: Wrap a list.next reference with rb_list_head()
The change in acpi_cpufreq to use smp_call_function_any causes a warning
when it is called since the function erroneously passes the cpu id to
cpumask_of_node rather than the node that the cpu is on. Fix this.
cpumask_of_node(3): node > nr_node_ids(1)
Pid: 1, comm: swapper Not tainted 2.6.33-rc3-00097-g2c1f189 #223
Call Trace:
[<ffffffff81028bb3>] cpumask_of_node+0x23/0x58
[<ffffffff81061f51>] smp_call_function_any+0x65/0xfa
[<ffffffff810160d1>] ? do_drv_read+0x0/0x2f
[<ffffffff81015fba>] get_cur_val+0xb0/0x102
[<ffffffff81016080>] get_cur_freq_on_cpu+0x74/0xc5
[<ffffffff810168a7>] acpi_cpufreq_cpu_init+0x417/0x515
[<ffffffff81562ce9>] ? __down_write+0xb/0xd
[<ffffffff8148055e>] cpufreq_add_dev+0x278/0x922
Signed-off-by: David John <davidjon@xenontk.org>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
On my first try using them I missed that the fifos need to be power of
two, resulting in a runtime bug. Document that requirement everywhere
(and fix one grammar bug)
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Stefani Seibold <stefani@seibold.net>
Cc: Roland Dreier <rdreier@cisco.com>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Andy Walls <awalls@radix.net>
Cc: Vikram Dhillon <dhillonv10@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In some upcoming code it's useful to peek into a FIFO without permanentely
removing data. This patch implements a new kfifo_out_peek() to do this.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Stefani Seibold <stefani@seibold.net>
Cc: Roland Dreier <rdreier@cisco.com>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Andy Walls <awalls@radix.net>
Cc: Vikram Dhillon <dhillonv10@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Right now for kfifo_*_user it's not easily possible to distingush between
a user copy failing and the FIFO not containing enough data. The problem
is that both conditions are multiplexed into the same return code.
Avoid this by moving the "copy length" into a separate output parameter
and only return 0/-EFAULT in the main return value.
I didn't fully adapt the weird "record" variants, those seem
to be unused anyways and were rather messy (should they be just removed?)
I would appreciate some double checking if I did all the conversions
correctly.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Cc: Stefani Seibold <stefani@seibold.net>
Cc: Roland Dreier <rdreier@cisco.com>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Andy Walls <awalls@radix.net>
Cc: Vikram Dhillon <dhillonv10@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The pointers to user buffers are currently unsigned char *, which requires
a lot of casting in the caller for any non-char typed buffers. Use void *
instead.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Stefani Seibold <stefani@seibold.net>
Cc: Roland Dreier <rdreier@cisco.com>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Andy Walls <awalls@radix.net>
Cc: Vikram Dhillon <dhillonv10@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Before scheduling an event group, we first check if a group can go
on. We first check if the group is made of software only events
first, in which case it is enough to know if the group can be
scheduled in.
For that purpose, we iterate through the whole group, which is
wasteful as we could do this check when we add/delete an event to
a group.
So we create a group_flags field in perf event that can host
characteristics from a group of events, starting with a first
PERF_GROUP_SOFTWARE flag that reduces the check on the fast path.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
This is more proper that doing it through a list_for_each_entry()
that breaks after the first entry.
v2: Don't rotate pinned groups as its not needed to time share
them.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
Split-up struct perf_event_context::group_list into pinned_groups
and flexible_groups (non-pinned).
This first appears to be useless as it duplicates various loops around
the group list handlings.
But it scales better in the fast-path in perf_sched_in(). We don't
anymore iterate twice through the entire list to separate pinned and
non-pinned scheduling. Instead we interate through two distinct lists.
The another desired effect is that it makes easier to define distinct
scheduling rules on both.
Changes in v2:
- Respectively rename pinned_grp_list and
volatile_grp_list into pinned_groups and flexible_groups as per
Ingo suggestion.
- Various cleanups
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
We should be clear on 2 things:
- the length parameter of a match callback includes
tailing '\0'.
- the string to be searched might not be NULL-terminated.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <4B4E8770.7000608@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
MATCH_FULL matching for PTR_STRING is not working correctly:
# echo 'func == vt' > events/bkl/lock_kernel/filter
# echo 1 > events/bkl/lock_kernel/enable
...
# cat trace
Xorg-1484 [000] 1973.392586: lock_kernel: ... func=vt_ioctl()
gpm-1402 [001] 1974.027740: lock_kernel: ... func=vt_ioctl()
We should pass to regex.match(..., len) the length (including '\0')
of the source string instead of the length of the pattern string.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <4B4E8763.5070707@cn.fujitsu.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The @str might not be NULL-terminated if it's of type
DYN_STRING or STATIC_STRING, so we should use strnstr()
instead of strstr().
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <4B4E8753.2000102@cn.fujitsu.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
For '*foo' pattern, we should allow any string ending with
'foo', but event filtering incorrectly disallows strings
like bar_foo_foo:
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <4B4E8735.6070604@cn.fujitsu.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
MATCH_FRONT_ONLY actually is a full matching:
# ./perf record -R -f -a -e lock:lock_acquire \
--filter 'name ~rcu_*' sleep 1
# ./perf trace
(no output)
We should pass the length of the pattern string to strncmp().
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <4B4E8721.5090301@cn.fujitsu.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
perf_event_task_sched_in() expects interrupts to be disabled,
but on architectures with __ARCH_WANT_INTERRUPTS_ON_CTXSW
defined, this isn't true. If this is defined, disable irqs
around the call in finish_task_switch().
Signed-off-by: Jamie Iles <jamie.iles@picochip.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King - ARM Linux <linux@arm.linux.org.uk>
LKML-Reference: <1262964453-27370-1-git-send-email-jamie.iles@picochip.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Drop function argument access syntax, because the function
arguments depend on not only architecture but also
compile-options and function API. And now, we have perf-probe
for finding register/memory assigned to each argument.
Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: systemtap <systemtap@sources.redhat.com>
Cc: DLE <dle-develop@lists.sourceforge.net>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Roland McGrath <roland@redhat.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Michael Neuling <mikey@neuling.org>
Cc: linuxppc-dev@ozlabs.org
LKML-Reference: <20100105224648.19431.52309.stgit@dhcp-100-2-132.bos.redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Currently, futexes have two problem:
A) The current futex code doesn't handle private file mappings properly.
get_futex_key() uses PageAnon() to distinguish file and
anon, which can cause the following bad scenario:
1) thread-A call futex(private-mapping, FUTEX_WAIT), it
sleeps on file mapping object.
2) thread-B writes a variable and it makes it cow.
3) thread-B calls futex(private-mapping, FUTEX_WAKE), it
wakes up blocked thread on the anonymous page. (but it's nothing)
B) Current futex code doesn't handle zero page properly.
Read mode get_user_pages() can return zero page, but current
futex code doesn't handle it at all. Then, zero page makes
infinite loop internally.
The solution is to use write mode get_user_page() always for
page lookup. It prevents the lookup of both file page of private
mappings and zero page.
Performance concerns:
Probaly very little, because glibc always initialize variables
for futex before to call futex(). It means glibc users never see
the overhead of this patch.
Compatibility concerns:
This patch has few compatibility issues. After this patch,
FUTEX_WAIT require writable access to futex variables (read-only
mappings makes EFAULT). But practically it's not a problem,
glibc always initalizes variables for futexes explicitly - nobody
uses read-only mappings.
Reported-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Darren Hart <dvhltc@us.ibm.com>
Cc: <stable@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Ulrich Drepper <drepper@gmail.com>
LKML-Reference: <20100105162633.45A2.A69D9226@jp.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Previously, each level of the rcu_node hierarchy had the same
rather unimaginative name: "&rcu_node_class[i]". This makes
lockdep diagnostics involving these lockdep classes less helpful
than would be nice. This patch fixes this by giving each level
of the rcu_node hierarchy a distinct name: "rcu_node_level_0",
"rcu_node_level_1", and so on. This version of the patch
includes improved diagnostics suggested by Josh Triplett and
Peter Zijlstra.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: laijs@cn.fujitsu.com
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: <12626498421830-git-send-email->
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The rcu_process_dyntick() function checks twice for the end of
the current grace period. However, it holds the current
rcu_node structure's ->lock field throughout, and doesn't get to
the second call to rcu_gp_in_progress() unless there is at least
one CPU corresponding to this rcu_node structure that has not
yet checked in for the current grace period, which would prevent
the current grace period from ending. So the current grace
period cannot have ended, and the second check is redundant, so
remove it.
Also, given that this function is used even with !CONFIG_NO_HZ,
its name is quite misleading. Change from rcu_process_dyntick()
to force_qs_rnp().
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: laijs@cn.fujitsu.com
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: <1262646550562-git-send-email->
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The comparisons of rsp->gpnum nad rsp->completed in
rcu_process_dyntick() and force_quiescent_state() can be
replaced by the much more clear rcu_gp_in_progress() predicate
function. After doing this, it becomes clear that the
RCU_SAVE_COMPLETED leg of the force_quiescent_state() function's
switch statement is almost completely a no-op. A small change
to the RCU_SAVE_DYNTICK leg renders it a complete no-op, after
which it can be removed. Doing so also eliminates the forcenow
local variable from force_quiescent_state().
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: laijs@cn.fujitsu.com
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: <12626465501781-git-send-email->
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Because a new grace period cannot start while we are executing
within the force_quiescent_state() function's switch statement,
if any test within that switch statement or within any function
called from that switch statement shows that the current grace
period has ended, we can safely re-do that test any time before
we leave the switch statement. This means that we no longer
need a return value from rcu_process_dyntick(), as we can simply
invoke rcu_gp_in_progress() to check whether the old grace
period has finished -- there is no longer any need to worry
about whether or not a new grace period has been started.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: laijs@cn.fujitsu.com
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: <12626465501857-git-send-email->
Signed-off-by: Ingo Molnar <mingo@elte.hu>
