linux/kernel/kthread.c, branch v2.6.28

Merge branch 'tracing-v28-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

2008-10-20T20:35:07Z

* 'tracing-v28-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (131 commits) tracing/fastboot: improve help text tracing/stacktrace: improve help text tracing/fastboot: fix initcalls disposition in bootgraph.pl tracing/fastboot: fix bootgraph.pl initcall name regexp tracing/fastboot: fix issues and improve output of bootgraph.pl tracepoints: synchronize unregister static inline tracepoints: tracepoint_synchronize_unregister() ftrace: make ftrace_test_p6nop disassembler-friendly markers: fix synchronize marker unregister static inline tracing/fastboot: add better resolution to initcall debug/tracing trace: add build-time check to avoid overrunning hex buffer ftrace: fix hex output mode of ftrace tracing/fastboot: fix initcalls disposition in bootgraph.pl tracing/fastboot: fix printk format typo in boot tracer ftrace: return an error when setting a nonexistent tracer ftrace: make some tracers reentrant ring-buffer: make reentrant ring-buffer: move page indexes into page headers tracing/fastboot: only trace non-module initcalls ftrace: move pc counter in irqtrace ... Manually fix conflicts: - init/main.c: initcall tracing - kernel/module.c: verbose level vs tracepoints - scripts/bootgraph.pl: fallout from cherry-picking commits.

kthread_bind: use wait_task_inactive(TASK_UNINTERRUPTIBLE)

2008-10-20T15:52:39Z

Now that wait_task_inactive(task, state) checks task->state == state, we can simplify the code and make this debugging check more robust. Signed-off-by: Oleg Nesterov Cc: Roland McGrath Cc: Ingo Molnar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

tracing, sched: LTTng instrumentation - scheduler

2008-10-14T08:30:52Z

Instrument the scheduler activity (sched_switch, migration, wakeups, wait for a task, signal delivery) and process/thread creation/destruction (fork, exit, kthread stop). Actually, kthread creation is not instrumented in this patch because it is architecture dependent. It allows to connect tracers such as ftrace which detects scheduling latencies, good/bad scheduler decisions. Tools like LTTng can export this scheduler information along with instrumentation of the rest of the kernel activity to perform post-mortem analysis on the scheduler activity. About the performance impact of tracepoints (which is comparable to markers), even without immediate values optimizations, tests done by Hideo Aoki on ia64 show no regression. His test case was using hackbench on a kernel where scheduler instrumentation (about 5 events in code scheduler code) was added. See the "Tracepoints" patch header for performance result detail. Changelog : - Change instrumentation location and parameter to match ftrace instrumentation, previously done with kernel markers. [ mingo@elte.hu: conflict resolutions ] Signed-off-by: Mathieu Desnoyers Acked-by: 'Peter Zijlstra' Signed-off-by: Ingo Molnar

tracehook: wait_task_inactive

2008-07-26T19:00:09Z

This extends wait_task_inactive() with a new argument so it can be used in a "soft" mode where it will check for the task changing state unexpectedly and back off. There is no change to existing callers. This lays the groundwork to allow robust, noninvasive tracing that can try to sample a blocked thread but back off safely if it wakes up. Signed-off-by: Roland McGrath Cc: Oleg Nesterov Reviewed-by: Ingo Molnar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

kthread: reduce stack pressure in create_kthread and kthreadd

2008-07-18T16:46:58Z

* Replace: set_cpus_allowed(..., CPU_MASK_ALL) with: set_cpus_allowed_ptr(..., CPU_MASK_ALL_PTR) to remove excessive stack requirements when NR_CPUS=4096. Signed-off-by: Mike Travis Cc: Andrew Morton Signed-off-by: Ingo Molnar

Freezer: Introduce PF_FREEZER_NOSIG

2008-07-16T21:27:03Z

The freezer currently attempts to distinguish kernel threads from user space tasks by checking if their mm pointer is unset and it does not send fake signals to kernel threads. However, there are kernel threads, mostly related to networking, that behave like user space tasks and may want to be sent a fake signal to be frozen. Introduce the new process flag PF_FREEZER_NOSIG that will be set by default for all kernel threads and make the freezer only send fake signals to the tasks having PF_FREEZER_NOSIG unset. Provide the set_freezable_with_signal() function to be called by the kernel threads that want to be sent a fake signal for freezing. This patch should not change the freezer's observable behavior. Signed-off-by: Rafael J. Wysocki Signed-off-by: Andi Kleen Acked-by: Pavel Machek Signed-off-by: Len Brown

sched: prevent bound kthreads from changing cpus_allowed

2008-06-10T10:26:16Z

Kthreads that have called kthread_bind() are bound to specific cpus, so other tasks should not be able to change their cpus_allowed from under them. Otherwise, it is possible to move kthreads, such as the migration or software watchdog threads, so they are not allowed access to the cpu they work on. Cc: Peter Zijlstra Cc: Paul Menage Cc: Paul Jackson Signed-off-by: David Rientjes Signed-off-by: Ingo Molnar

Deprecate find_task_by_pid()

2008-04-30T15:29:48Z

There are some places that are known to operate on tasks' global pids only: * the rest_init() call (called on boot) * the kgdb's getthread * the create_kthread() (since the kthread is run in init ns) So use the find_task_by_pid_ns(..., &init_pid_ns) there and schedule the find_task_by_pid for removal. [sukadev@us.ibm.com: Fix warning in kernel/pid.c] Signed-off-by: Pavel Emelyanov Cc: "Eric W. Biederman" Signed-off-by: Sukadev Bhattiprolu Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

kthread: call wake_up_process() without the lock being held

2008-04-29T15:06:04Z

From the POV of synchronization, there should be no need to call wake_up_process() with the 'kthread_create_lock' being held. Signed-off-by: Dmitry Adamushko Cc: Nick Piggin Cc: Ingo Molnar Cc: Rusty Russell Cc: "Paul E. McKenney" Cc: Peter Zijlstra Cc: Andy Whitcroft Cc: Oleg Nesterov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Merge branch 'semaphore' of git://git.kernel.org/pub/scm/linux/kernel/git/willy/misc

2008-04-21T22:41:27Z

* 'semaphore' of git://git.kernel.org/pub/scm/linux/kernel/git/willy/misc: Deprecate the asm/semaphore.h files in feature-removal-schedule. Convert asm/semaphore.h users to linux/semaphore.h security: Remove unnecessary inclusions of asm/semaphore.h lib: Remove unnecessary inclusions of asm/semaphore.h kernel: Remove unnecessary inclusions of asm/semaphore.h include: Remove unnecessary inclusions of asm/semaphore.h fs: Remove unnecessary inclusions of asm/semaphore.h drivers: Remove unnecessary inclusions of asm/semaphore.h net: Remove unnecessary inclusions of asm/semaphore.h arch: Remove unnecessary inclusions of asm/semaphore.h