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2012-03-05hung_task: fix the broken rcu_lock_break() logicOleg Nesterov
check_hung_uninterruptible_tasks()->rcu_lock_break() introduced by "softlockup: check all tasks in hung_task" commit ce9dbe24 looks absolutely wrong. - rcu_lock_break() does put_task_struct(). If the task has exited it is not safe to even read its ->state, nothing protects this task_struct. - The TASK_DEAD checks are wrong too. Contrary to the comment, we can't use it to check if the task was unhashed. It can be unhashed without TASK_DEAD, or it can be valid with TASK_DEAD. For example, an autoreaping task can do release_task(current) long before it sets TASK_DEAD in do_exit(). Or, a zombie task can have ->state == TASK_DEAD but release_task() was not called, and in this case we must not break the loop. Change this code to check pid_alive() instead, and do this before we drop the reference to the task_struct. Note: while_each_thread() under rcu_read_lock() is not really safe, it can livelock. This will be fixed later, but fortunately in this case the "max_count" logic saves us anyway. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Mandeep Singh Baines <msb@google.com> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-05vfork: kill PF_STARTINGOleg Nesterov
Previously it was (ab)used by utrace. Then it was wrongly used by the scheduler code. Currently it is not used, kill it before it finds the new erroneous user. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-05coredump_wait: don't call complete_vfork_done()Oleg Nesterov
Now that CLONE_VFORK is killable, coredump_wait() no longer needs complete_vfork_done(). zap_threads() should find and kill all tasks with the same ->mm, this includes our parent if ->vfork_done is set. mm_release() becomes the only caller, unexport complete_vfork_done(). Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-05vfork: make it killableOleg Nesterov
Make vfork() killable. Change do_fork(CLONE_VFORK) to do wait_for_completion_killable(). If it fails we do not return to the user-mode and never touch the memory shared with our child. However, in this case we should clear child->vfork_done before return, we use task_lock() in do_fork()->wait_for_vfork_done() and complete_vfork_done() to serialize with each other. Note: now that we use task_lock() we don't really need completion, we could turn task->vfork_done into "task_struct *wake_up_me" but this needs some complications. NOTE: this and the next patches do not affect in-kernel users of CLONE_VFORK, kernel threads run with all signals ignored including SIGKILL/SIGSTOP. However this is obviously the user-visible change. Not only a fatal signal can kill the vforking parent, a sub-thread can do execve or exit_group() and kill the thread sleeping in vfork(). Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-05vfork: introduce complete_vfork_done()Oleg Nesterov
No functional changes. Move the clear-and-complete-vfork_done code into the new trivial helper, complete_vfork_done(). Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-05kprobes: return proper error code from register_kprobe()Prashanth Nageshappa
register_kprobe() aborts if the address of the new request falls in a prohibited area (such as ftrace pouch, __kprobes annotated functions, non-kernel text addresses, jump label text). We however don't return the right error on this abort, resulting in a silent failure - incorrect adding/reporting of kprobes ('perf probe do_fork+18' or 'perf probe mcount' for instance). In V2 we are incorporating Masami Hiramatsu's feedback. This patch fixes it by returning -EINVAL upon failure. While we are here, rename the label used for exit to be more appropriate. Signed-off-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Signed-off-by: Prashanth K Nageshappa <prashanth@linux.vnet.ibm.com> Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Jason Baron <jbaron@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-05kmsg_dump: don't run on non-error paths by defaultMatthew Garrett
Since commit 04c6862c055f ("kmsg_dump: add kmsg_dump() calls to the reboot, halt, poweroff and emergency_restart paths"), kmsg_dump() gets run on normal paths including poweroff and reboot. This is less than ideal given pstore implementations that can only represent single backtraces, since a reboot may overwrite a stored oops before it's been picked up by userspace. In addition, some pstore backends may have low performance and provide a significant delay in reboot as a result. This patch adds a printk.always_kmsg_dump kernel parameter (which can also be changed from userspace). Without it, the code will only be run on failure paths rather than on normal paths. The option can be enabled in environments where there's a desire to attempt to audit whether or not a reboot was cleanly requested or not. Signed-off-by: Matthew Garrett <mjg@redhat.com> Acked-by: Seiji Aguchi <seiji.aguchi@hds.com> Cc: Seiji Aguchi <seiji.aguchi@hds.com> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Marco Stornelli <marco.stornelli@gmail.com> Cc: Artem Bityutskiy <Artem.Bityutskiy@nokia.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Don Zickus <dzickus@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-05perf: Add callback to flush branch_stack on context switchStephane Eranian
With branch stack sampling, it is possible to filter by priv levels. In system-wide mode, that means it is possible to capture only user level branches. The builtin SW LBR filter needs to disassemble code based on LBR captured addresses. For that, it needs to know the task the addresses are associated with. Because of context switches, the content of the branch stack buffer may contain addresses from different tasks. We need a callback on context switch to either flush the branch stack or save it. This patch adds a new callback in struct pmu which is called during context switches. The callback is called only when necessary. That is when a system-wide context has, at least, one event which uses PERF_SAMPLE_BRANCH_STACK. The callback is never called for per-thread context. In this version, the Intel x86 code simply flushes (resets) the LBR on context switches (fills it with zeroes). Those zeroed branches are then filtered out by the SW filter. Signed-off-by: Stephane Eranian <eranian@google.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1328826068-11713-11-git-send-email-eranian@google.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-03-05perf: Disable PERF_SAMPLE_BRANCH_* when not supportedStephane Eranian
PERF_SAMPLE_BRANCH_* is disabled for: - SW events (sw counters, tracepoints) - HW breakpoints - ALL but Intel x86 architecture - AMD64 processors Signed-off-by: Stephane Eranian <eranian@google.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1328826068-11713-10-git-send-email-eranian@google.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-03-05perf: Add generic taken branch sampling supportStephane Eranian
This patch adds the ability to sample taken branches to the perf_event interface. The ability to capture taken branches is very useful for all sorts of analysis. For instance, basic block profiling, call counts, statistical call graph. This new capability requires hardware assist and as such may not be available on all HW platforms. On Intel x86 it is implemented on top of the Last Branch Record (LBR) facility. To enable taken branches sampling, the PERF_SAMPLE_BRANCH_STACK bit must be set in attr->sample_type. Sampled taken branches may be filtered by type and/or priv levels. The patch adds a new field, called branch_sample_type, to the perf_event_attr structure. It contains a bitmask of filters to apply to the sampled taken branches. Filters may be implemented in HW. If the HW filter does not exist or is not good enough, some arch may also implement a SW filter. The following generic filters are currently defined: - PERF_SAMPLE_USER only branches whose targets are at the user level - PERF_SAMPLE_KERNEL only branches whose targets are at the kernel level - PERF_SAMPLE_HV only branches whose targets are at the hypervisor level - PERF_SAMPLE_ANY any type of branches (subject to priv levels filters) - PERF_SAMPLE_ANY_CALL any call branches (may incl. syscall on some arch) - PERF_SAMPLE_ANY_RET any return branches (may incl. syscall returns on some arch) - PERF_SAMPLE_IND_CALL indirect call branches Obviously filter may be combined. The priv level bits are optional. If not provided, the priv level of the associated event are used. It is possible to collect branches at a priv level different from the associated event. Use of kernel, hv priv levels is subject to permissions and availability (hv). The number of taken branch records present in each sample may vary based on HW, the type of sampled branches, the executed code. Therefore each sample contains the number of taken branches it contains. Signed-off-by: Stephane Eranian <eranian@google.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1328826068-11713-2-git-send-email-eranian@google.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-03-05Merge branch 'perf/urgent' into perf/coreIngo Molnar
Conflicts: tools/perf/builtin-record.c tools/perf/builtin-top.c tools/perf/perf.h tools/perf/util/top.h Merge reason: resolve these cherry-picking conflicts. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-03-04Merge branch 'pm-qos'Rafael J. Wysocki
* pm-qos: PM / QoS: unconditionally build the feature PM / QoS: Simplify PM QoS expansion/merge
2012-03-04Merge branch 'pm-sleep'Rafael J. Wysocki
* pm-sleep: PM / Freezer: Remove references to TIF_FREEZE in comments PM / Sleep: Add more wakeup source initialization routines PM / Hibernate: Enable usermodehelpers in hibernate() error path PM / Sleep: Make __pm_stay_awake() delete wakeup source timers PM / Sleep: Fix race conditions related to wakeup source timer function PM / Sleep: Fix possible infinite loop during wakeup source destruction PM / Hibernate: print physical addresses consistently with other parts of kernel PM: Add comment describing relationships between PM callbacks to pm.h PM / Sleep: Drop suspend_stats_update() PM / Sleep: Make enter_state() in kernel/power/suspend.c static PM / Sleep: Unify kerneldoc comments in kernel/power/suspend.c PM / Sleep: Remove unnecessary label from suspend_freeze_processes() PM / Sleep: Do not check wakeup too often in try_to_freeze_tasks() PM / Sleep: Initialize wakeup source locks in wakeup_source_add() PM / Hibernate: Refactor and simplify freezer_test_done PM / Hibernate: Thaw kernel threads in hibernation_snapshot() in error/test path PM / Freezer / Docs: Document the beauty of freeze/thaw semantics PM / Suspend: Avoid code duplication in suspend statistics update PM / Sleep: Introduce generic callbacks for new device PM phases PM / Sleep: Introduce "late suspend" and "early resume" of devices
2012-03-04PM / Freezer: Remove references to TIF_FREEZE in commentsMarcos Paulo de Souza
This patch removes all the references in the code about the TIF_FREEZE flag removed by commit a3201227f803ad7fd43180c5195dbe5a2bf998aa freezer: make freezing() test freeze conditions in effect instead of TIF_FREEZE There still are some references to TIF_FREEZE in Documentation/power/freezing-of-tasks.txt, but it looks like that documentation needs more thorough work to reflect how the new freezer works, and hence merely removing the references to TIF_FREEZE won't really help. So I have not touched that part in this patch. Suggested-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Signed-off-by: Marcos Paulo de Souza <marcos.mage@gmail.com> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2012-03-04PM / Hibernate: Enable usermodehelpers in hibernate() error pathSrivatsa S. Bhat
If create_basic_memory_bitmaps() fails, usermodehelpers are not re-enabled before returning. Fix this. And while at it, reword the goto labels so that they look more meaningful. Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Cc: stable@vger.kernel.org Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2012-03-02Merge branches 'core-urgent-for-linus', 'perf-urgent-for-linus' and ↵Linus Torvalds
'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pulling latest branches from Ingo: * 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: memblock: Fix size aligning of memblock_alloc_base_nid() * 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: perf probe: Ensure offset provided is not greater than function length without DWARF info too perf tools: Ensure comm string is properly terminated perf probe: Ensure offset provided is not greater than function length perf evlist: Return first evsel for non-sample event on old kernel perf/hwbp: Fix a possible memory leak * 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: CPU hotplug, cpusets, suspend: Don't touch cpusets during suspend/resume
2012-03-02sched: Clean up parameter passing of proc_sched_autogroup_set_nice()Hiroshi Shimamoto
Pass nice as a value to proc_sched_autogroup_set_nice(). No side effect is expected, and the variable err will be overwritten with the return value. Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/4F45FBB7.5090607@ct.jp.nec.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-03-02Block: use a freezable workqueue for disk-event pollingAlan Stern
This patch (as1519) fixes a bug in the block layer's disk-events polling. The polling is done by a work routine queued on the system_nrt_wq workqueue. Since that workqueue isn't freezable, the polling continues even in the middle of a system sleep transition. Obviously, polling a suspended drive for media changes and such isn't a good thing to do; in the case of USB mass-storage devices it can lead to real problems requiring device resets and even re-enumeration. The patch fixes things by creating a new system-wide, non-reentrant, freezable workqueue and using it for disk-events polling. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> CC: <stable@kernel.org> Acked-by: Tejun Heo <tj@kernel.org> Acked-by: Rafael J. Wysocki <rjw@sisk.pl> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-03-01tracing: Keep NMI watchdog from triggering when dumping traceSteven Rostedt
As ftrace_dump() (called by ftrace_dump_on_oops) disables interrupts as it dumps its output to the console, it can keep interrupts disabled for long periods of time. This is likely to trigger the NMI watchdog, and it can disrupt the output of critical data. Add a touch_nmi_watchdog() to each event that is written to the screen to keep the NMI watchdog from affecting the output. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2012-03-01sched: Ditch per cgroup task lists for load-balancingPeter Zijlstra
Per cgroup load-balance has numerous problems, chief amongst them that there is no real sane order in them. So stop pretending it makes sense and enqueue all tasks on a single list. This also allows us to more easily fix the fwd progress issue uncovered by the lock-break stuff. Rotate the list on failure to migreate and limit the total iterations to nr_running (which with releasing the lock isn't strictly accurate but close enough). Also add a filter that skips very light tasks on the first attempt around the list, this attempts to avoid shooting whole cgroups around without affecting over balance. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: pjt@google.com Link: http://lkml.kernel.org/n/tip-tx8yqydc7eimgq7i4rkc3a4g@git.kernel.org Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-03-01sched: Rename load-balancing fieldsPeter Zijlstra
s/env->this_/env->dst_/g s/env->busiest_/env->src_/g s/pull_task/move_task/g Makes everything clearer. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: pjt@google.com Link: http://lkml.kernel.org/n/tip-0yvgms8t8x962drpvl0fu0kk@git.kernel.org Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-03-01sched: Move load-balancing arguments into helper structPeter Zijlstra
Passing large sets of similar arguments all around the load-balancer gets tiresom when you want to modify something. Stick them all in a helper structure and pass the structure around. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: pjt@google.com Link: http://lkml.kernel.org/n/tip-5slqz0vhsdzewrfk9eza1aon@git.kernel.org Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-03-01sched/rt: Do not submit new work when PI-blockedThomas Gleixner
When we are PI-blocked then we want to get things done ASAP. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/n/tip-vw8et3445km5b8mpihf4trae@git.kernel.org Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-03-01sched/rt: Prevent idle task boostingThomas Gleixner
Idle task boosting is a nono in general. There is one exception, when PREEMPT_RT and NOHZ is active: The idle task calls get_next_timer_interrupt() and holds the timer wheel base->lock on the CPU and another CPU wants to access the timer (probably to cancel it). We can safely ignore the boosting request, as the idle CPU runs this code with interrupts disabled and will complete the lock protected section without being interrupted. So there is no real need to boost. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/n/tip-755rvsosz7sdzot12a3gbha6@git.kernel.org Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-03-01sched/wait: Add __wake_up_all_locked() APIThomas Gleixner
For code which protects the waitqueue itself with another lock it makes no sense to acquire the waitqueue lock for wakeup all. Provide __wake_up_all_locked(). This is an optimization on the vanilla kernel (to be used by the PCI code) and an important semantic distinction on -rt. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/n/tip-ux6m4b8jonb9inx8xafh77ds@git.kernel.org Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-03-01sched/rt: Document scheduler related skip-resched-check sitesThomas Gleixner
Create a distinction between scheduler related preempt_enable_no_resched() calls and the nearly one hundred other places in the kernel that do not want to reschedule, for one reason or another. This distinction matters for -rt, where the scheduler and the non-scheduler preempt models (and checks) are different. For upstream it's purely documentational. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/n/tip-gs88fvx2mdv5psnzxnv575ke@git.kernel.org Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-03-01sched/rt: Use schedule_preempt_disabled()Thomas Gleixner
Coccinelle based conversion. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/n/tip-24swm5zut3h9c4a6s46x8rws@git.kernel.org Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-03-01sched/rt: Add schedule_preempt_disabled()Thomas Gleixner
Add helper to get rid of the ever repeating: preempt_enable_no_resched(); schedule(); preempt_disable(); patterns. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/n/tip-wxx7btox7coby6ifv5vzhzgp@git.kernel.org Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-03-01sched/rt: Do not throttle when PI boostingPeter Zijlstra
When a runqueue has rt_runtime_us = 0 then the only way it can accumulate rt_time is via PI boosting. That causes the runqueue to be throttled and replenishing does not change anything due to rt_runtime_us = 0. So avoid that situation by clearing rt_time and skip the throttling alltogether. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> [ Changelog ] Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/n/tip-7x70cypsotjb4jvcor3edctk@git.kernel.org Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-03-01sched/rt: Keep period timer ticking when rt throttling is activePeter Zijlstra
When a runqueue is throttled we cannot disable the period timer because that timer is the only way to undo the throttling. We got stale throttling entries when a rq was throttled and then the global sysctl was disabled, which stopped the timer. Signed-off-by: Peter Zijlstra <peterz@infradead.org> [ Added changelog ] Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/n/tip-nuj34q52p6ro7szapuz84i0v@git.kernel.org Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-03-01Merge branch 'linus' into sched/coreIngo Molnar
Merge reason: we'll queue up dependent patches. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-02-28includecheck: delete any duplicate instances of module.hPaul Gortmaker
Different tree maintainers picked up independently generated trivial compile fixes based on linux-next testing, resulting in some cases where a file would have got more than one addition of module.h once everything was all merged together. Delete any duplicates so includecheck isn't complaining about anything related to module.h/export.h changes. Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2012-02-28static keys: Inline the static_key_enabled() functionJason Baron
In the jump label enabled case, calling static_key_enabled() results in a function call. The function returns the results of a compare, so it really doesn't need the overhead of a full function call. Let's make it 'static inline' for both the jump label enabled and disabled cases. Signed-off-by: Jason Baron <jbaron@redhat.com> Cc: a.p.zijlstra@chello.nl Cc: rostedt@goodmis.org Cc: mathieu.desnoyers@polymtl.ca Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/201202281849.q1SIn1p2023270@int-mx10.intmail.prod.int.phx2.redhat.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-02-28Merge branch 'perf/jump-labels' into perf/coreIngo Molnar
Merge reason: After much naming discussion, there seems to be consensus now - queue it up for v3.4. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-02-28Merge branch 'rcu/next' of ↵Ingo Molnar
git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu The major features of this series are: - making RCU more aggressive about entering dyntick-idle mode in order to improve energy efficiency - converting a few more call_rcu()s to kfree_rcu()s - applying a number of rcutree fixes and cleanups to rcutiny - removing CONFIG_SMP #ifdefs from treercu - allowing RCU CPU stall times to be set via sysfs - adding CPU-stall capability to rcutorture - adding more RCU-abuse diagnostics - updating documentation - fixing yet more issues located by the still-ongoing top-to-bottom inspection of RCU, this time with a special focus on the CPU-hotplug code path. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-02-28perf/hwbp: Fix a possible memory leakNamhyung Kim
If kzalloc() for TYPE_DATA failed on a given cpu, previous chunk of TYPE_INST will be leaked. Fix it. Thanks to Peter Zijlstra for suggesting this better solution. It should work as long as the initial value of the region is all 0's and that's the case of static (per-cpu) memory allocation. Signed-off-by: Namhyung Kim <namhyung.kim@lge.com> Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Link: http://lkml.kernel.org/r/1330391978-28070-1-git-send-email-namhyung.kim@lge.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-02-27Merge branch 'sched-urgent-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip * 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched/events: Revert trace_sched_stat_sleeptime()
2012-02-27Merge branch 'irq-urgent-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip * 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: genirq: Handle pending irqs in irq_startup() genirq: Unmask oneshot irqs when thread was not woken
2012-02-27tracing: Do not select FRAME_POINTER on PPCGerlando Falauto
On PowerPC, FUNCTION_TRACER selects FRAME_POINTER, even though the architecture does not support it. This causes the following warning: warning: (LOCKDEP && FAULT_INJECTION_STACKTRACE_FILTER && LATENCYTOP && FUNCTION_TRACER && KMEMCHECK) selects FRAME_POINTER which has unmet direct dependencies (DEBUG_KERNEL && (CRIS || M68K || FRV || UML || AVR32 || SUPERH || BLACKFIN || MN10300) || ARCH_WANT_FRAME_POINTERS) So remove the warning by adding the extra condition "if !PPC" to FUNCTION_TRACER for FRAME_POINTER selection Link: http://lkml.kernel.org/r/1330330101-8618-1-git-send-email-gerlando.falauto@keymile.com Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> Signed-off-by: Gerlando Falauto <gerlando.falauto@keymile.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2012-02-27CPU hotplug, cpusets, suspend: Don't touch cpusets during suspend/resumeSrivatsa S. Bhat
Currently, during CPU hotplug, the cpuset callbacks modify the cpusets to reflect the state of the system, and this handling is asymmetric. That is, upon CPU offline, that CPU is removed from all cpusets. However when it comes back online, it is put back only to the root cpuset. This gives rise to a significant problem during suspend/resume. During suspend, we offline all non-boot cpus and during resume we online them back. Which means, after a resume, all cpusets (except the root cpuset) will be restricted to just one single CPU (the boot cpu). But the whole point of suspend/resume is to restore the system to a state which is as close as possible to how it was before suspend. So to fix this, don't touch cpusets during suspend/resume. That is, modify the cpuset-related CPU hotplug callback to just ignore CPU hotplug when it is initiated as part of the suspend/resume sequence. Reported-by: Prashanth Nageshappa <prashanth@linux.vnet.ibm.com> Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/4F460D7B.1020703@linux.vnet.ibm.com Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-02-24epoll: introduce POLLFREE to flush ->signalfd_wqh before kfree()Oleg Nesterov
This patch is intentionally incomplete to simplify the review. It ignores ep_unregister_pollwait() which plays with the same wqh. See the next change. epoll assumes that the EPOLL_CTL_ADD'ed file controls everything f_op->poll() needs. In particular it assumes that the wait queue can't go away until eventpoll_release(). This is not true in case of signalfd, the task which does EPOLL_CTL_ADD uses its ->sighand which is not connected to the file. This patch adds the special event, POLLFREE, currently only for epoll. It expects that init_poll_funcptr()'ed hook should do the necessary cleanup. Perhaps it should be defined as EPOLLFREE in eventpoll. __cleanup_sighand() is changed to do wake_up_poll(POLLFREE) if ->signalfd_wqh is not empty, we add the new signalfd_cleanup() helper. ep_poll_callback(POLLFREE) simply does list_del_init(task_list). This make this poll entry inconsistent, but we don't care. If you share epoll fd which contains our sigfd with another process you should blame yourself. signalfd is "really special". I simply do not know how we can define the "right" semantics if it used with epoll. The main problem is, epoll calls signalfd_poll() once to establish the connection with the wait queue, after that signalfd_poll(NULL) returns the different/inconsistent results depending on who does EPOLL_CTL_MOD/signalfd_read/etc. IOW: apart from sigmask, signalfd has nothing to do with the file, it works with the current thread. In short: this patch is the hack which tries to fix the symptoms. It also assumes that nobody can take tasklist_lock under epoll locks, this seems to be true. Note: - we do not have wake_up_all_poll() but wake_up_poll() is fine, poll/epoll doesn't use WQ_FLAG_EXCLUSIVE. - signalfd_cleanup() uses POLLHUP along with POLLFREE, we need a couple of simple changes in eventpoll.c to make sure it can't be "lost". Reported-by: Maxime Bizon <mbizon@freebox.fr> Cc: <stable@kernel.org> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-02-24irq_domain/mips: Allow irq_domain on MIPSGrant Likely
This patch makes IRQ_DOMAIN usable on MIPS. It uses an ugly workaround to preserve current behaviour so that MIPS has time to add irq_domain registration to the irq controller drivers. The workaround will be removed in Linux v3.6 Signed-off-by: Grant Likely <grant.likely@secretlab.ca> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Rob Herring <rob.herring@calxeda.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-mips@linux-mips.org
2012-02-24static keys: Introduce 'struct static_key', static_key_true()/false() and ↵Ingo Molnar
static_key_slow_[inc|dec]() So here's a boot tested patch on top of Jason's series that does all the cleanups I talked about and turns jump labels into a more intuitive to use facility. It should also address the various misconceptions and confusions that surround jump labels. Typical usage scenarios: #include <linux/static_key.h> struct static_key key = STATIC_KEY_INIT_TRUE; if (static_key_false(&key)) do unlikely code else do likely code Or: if (static_key_true(&key)) do likely code else do unlikely code The static key is modified via: static_key_slow_inc(&key); ... static_key_slow_dec(&key); The 'slow' prefix makes it abundantly clear that this is an expensive operation. I've updated all in-kernel code to use this everywhere. Note that I (intentionally) have not pushed through the rename blindly through to the lowest levels: the actual jump-label patching arch facility should be named like that, so we want to decouple jump labels from the static-key facility a bit. On non-jump-label enabled architectures static keys default to likely()/unlikely() branches. Signed-off-by: Ingo Molnar <mingo@elte.hu> Acked-by: Jason Baron <jbaron@redhat.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> Cc: a.p.zijlstra@chello.nl Cc: mathieu.desnoyers@efficios.com Cc: davem@davemloft.net Cc: ddaney.cavm@gmail.com Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/20120222085809.GA26397@elte.hu Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-02-22tracing/ring-buffer: Only have tracing_on disable tracing buffersSteven Rostedt
As the ring-buffer code is being used by other facilities in the kernel, having tracing_on file disable *all* buffers is not a desired affect. It should only disable the ftrace buffers that are being used. Move the code into the trace.c file and use the buffer disabling for tracing_on() and tracing_off(). This way only the ftrace buffers will be affected by them and other kernel utilities will not be confused to why their output suddenly stopped. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2012-02-22sched: Make initial SCHED_RR timeslace DEF_TIMESLICEHiroshi Shimamoto
Current the initial SCHED_RR timeslice of init_task is HZ, which means 1s, and is not same as the default SCHED_RR timeslice DEF_TIMESLICE. Change that initial timeslice to the DEF_TIMESLICE. Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com> [ s/DEF_TIMESLICE/RR_TIMESLICE/g ] Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/4F3C9995.3010800@ct.jp.nec.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-02-22sched: Remove rcu_read_lock/unlock() from select_idle_sibling()Nikunj A. Dadhania
select_idle_sibling() is called from select_task_rq_fair(), which already has the RCU read lock held. Signed-off-by: Nikunj A. Dadhania <nikunj@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/20120217030409.11748.12491.stgit@abhimanyu Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-02-22sched/events: Revert trace_sched_stat_sleeptime()Peter Zijlstra
Commit 1ac9bc69 ("sched/tracing: Add a new tracepoint for sleeptime") added a new sched:sched_stat_sleeptime tracepoint. It's broken: the first sample we get on a task might be bad because of a stale sleep_start value that wasn't reset at the last task switch because the tracepoint was not active. It also breaks the existing schedstat samples due to the side effects of: - se->statistics.sleep_start = 0; ... - se->statistics.block_start = 0; Nor do I see means to fix it without adding overhead to the scheduler fast path, which I'm not willing to for the sake of redundant instrumentation. Most importantly, sleep time information can already be constructed by tracing context switches and wakeups, and taking the timestamp difference between the schedule-out, the wakeup and the schedule-in. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Andrew Vagin <avagin@openvz.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Link: http://lkml.kernel.org/n/tip-pc4c9qhl8q6vg3bs4j6k0rbd@git.kernel.org Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-02-22jump label: Fix compiler warningJason Baron
While cross-compiling on sparc64, I found: kernel/jump_label.c: In function 'jump_label_update': kernel/jump_label.c:447:40: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast] Fix by casting to 'unsigned long'. Signed-off-by: Jason Baron <jbaron@redhat.com> Cc: rostedt@goodmis.org Cc: mathieu.desnoyers@efficios.com Cc: davem@davemloft.net Cc: ddaney.cavm@gmail.com Cc: a.p.zijlstra@chello.nl Link: http://lkml.kernel.org/r/08026cbc6df80619cae833ef1ebbbc43efab69ab.1329851692.git.jbaron@redhat.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-02-22jump label: Add a WARN() if jump label key count goes negativeJason Baron
The count on a jump label key should never go negative. Add a WARN() to check for this condition. Signed-off-by: Jason Baron <jbaron@redhat.com> Cc: Gleb Natapov <gleb@redhat.com> Cc: rostedt@goodmis.org Cc: mathieu.desnoyers@efficios.com Cc: davem@davemloft.net Cc: ddaney.cavm@gmail.com Cc: a.p.zijlstra@chello.nl Link: http://lkml.kernel.org/r/3c68556121be4d1920417a3fe367da1ec38246b4.1329851692.git.jbaron@redhat.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-02-21rcu: Stop spurious warnings from synchronize_sched_expeditedHugh Dickins
synchronize_sched_expedited() is spamming CONFIG_DEBUG_PREEMPT=y users with an unintended warning from the cpu_is_offline() check: use raw_smp_processor_id() instead of smp_processor_id() there. Because the warning is under a get_online_cpus(), it is not possible for any CPUs to go offline, though it is quite possible that the task might migrate between the raw_smp_processor_id() and the check of cpu_is_offline(). This is not a problem because the task cannot migrate from an offline CPU to an online one or vice versa. The point of the check is to verify that synchronize_sched_expedited() is not called from an offline CPU, for example, from a CPU_DYING notifier, or, more important, from an outgoing CPU making its way from its CPU_DYING notifiers to the idle loop. Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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