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2011-11-23freezer: kill unused set_freezable_with_signal()Tejun Heo1-1/+1
There's no in-kernel user of set_freezable_with_signal() left. Mixing TIF_SIGPENDING with kernel threads can lead to nasty corner cases as kernel threads never travel signal delivery path on their own. e.g. the current implementation is buggy in the cancelation path of __thaw_task(). It calls recalc_sigpending_and_wake() in an attempt to clear TIF_SIGPENDING but the function never clears it regardless of sigpending state. This means that signallable freezable kthreads may continue executing with !freezing() && stuck TIF_SIGPENDING, which can be troublesome. This patch removes set_freezable_with_signal() along with PF_FREEZER_NOSIG and recalc_sigpending*() calls in freezer. User tasks get TIF_SIGPENDING, kernel tasks get woken up and the spurious sigpending is dealt with in the usual signal delivery path. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Oleg Nesterov <oleg@redhat.com>
2011-11-22freezer: implement and use kthread_freezable_should_stop()Tejun Heo1-0/+25
Writeback and thinkpad_acpi have been using thaw_process() to prevent deadlock between the freezer and kthread_stop(); unfortunately, this is inherently racy - nothing prevents freezing from happening between thaw_process() and kthread_stop(). This patch implements kthread_freezable_should_stop() which enters refrigerator if necessary but is guaranteed to return if kthread_stop() is invoked. Both thaw_process() users are converted to use the new function. Note that this deadlock condition exists for many of freezable kthreads. They need to be converted to use the new should_stop or freezable workqueue. Tested with synthetic test case. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Henrique de Moraes Holschuh <ibm-acpi@hmh.eng.br> Cc: Jens Axboe <axboe@kernel.dk> Cc: Oleg Nesterov <oleg@redhat.com>
2011-10-31kernel: Map most files to use export.h instead of module.hPaul Gortmaker1-1/+1
The changed files were only including linux/module.h for the EXPORT_SYMBOL infrastructure, and nothing else. Revector them onto the isolated export header for faster compile times. Nothing to see here but a whole lot of instances of: -#include <linux/module.h> +#include <linux/export.h> This commit is only changing the kernel dir; next targets will probably be mm, fs, the arch dirs, etc. Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-05-28cpuset: Fix cpuset_cpus_allowed_fallback(), don't update tsk->rt.nr_cpus_allowedKOSAKI Motohiro1-2/+2
The rule is, we have to update tsk->rt.nr_cpus_allowed if we change tsk->cpus_allowed. Otherwise RT scheduler may confuse. Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/4DD4B3FA.5060901@jp.fujitsu.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-03-31Fix common misspellingsLucas De Marchi1-1/+1
Fixes generated by 'codespell' and manually reviewed. Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
2011-03-23kthread: NUMA aware kthread_create_on_node()Eric Dumazet1-6/+25
All kthreads being created from a single helper task, they all use memory from a single node for their kernel stack and task struct. This patch suite creates kthread_create_on_node(), adding a 'cpu' parameter to parameters already used by kthread_create(). This parameter serves in allocating memory for the new kthread on its memory node if possible. Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Acked-by: David S. Miller <davem@davemloft.net> Reviewed-by: Andi Kleen <ak@linux.intel.com> Acked-by: Rusty Russell <rusty@rustcorp.com.au> Cc: Tejun Heo <tj@kernel.org> Cc: Tony Luck <tony.luck@intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: David Howells <dhowells@redhat.com> Cc: <linux-arch@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-07sched: Constify function scope static struct sched_param usagePeter Zijlstra1-1/+1
Function-scope statics are discouraged because they are easily overlooked and can cause subtle bugs/races due to their global (non-SMP safe) nature. Linus noticed that we did this for sched_param - at minimum make the const. Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: Message-ID: <AANLkTinotRxScOHEb0HgFgSpGPkq_6jKTv5CfvnQM=ee@mail.gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-01-05Merge commit 'v2.6.37' into sched/coreIngo Molnar1-0/+11
Merge reason: Merge the final .37 tree. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-12-22kthread_work: make lockdep happyYong Zhang1-0/+11
spinlock in kthread_worker and wait_queue_head in kthread_work both should be lockdep sensible, so change the interface to make it suiltable for CONFIG_LOCKDEP. tj: comment update Reported-by: Nicolas <nicolas.mailhot@laposte.net> Signed-off-by: Yong Zhang <yong.zhang0@gmail.com> Signed-off-by: Andy Walls <awalls@md.metrocast.net> Tested-by: Andy Walls <awalls@md.metrocast.net> Cc: Tejun Heo <tj@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Tejun Heo <tj@kernel.org>
2010-10-23sched: Make sched_param argument static in sched_setscheduler() callersKOSAKI Motohiro1-1/+1
Andrew Morton pointed out almost all sched_setscheduler() callers are using fixed parameters and can be converted to static. It reduces runtime memory use a little. Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Reported-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: James Morris <jmorris@namei.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-06-29kthread: implement kthread_data()Tejun Heo1-0/+15
Implement kthread_data() which takes @task pointing to a kthread and returns @data specified when creating the kthread. The caller is responsible for ensuring the validity of @task when calling this function. Signed-off-by: Tejun Heo <tj@kernel.org>
2010-06-29kthread: implement kthread_workerTejun Heo1-0/+149
Implement simple work processor for kthread. This is to ease using kthread. Single thread workqueue used to be used for things like this but workqueue won't guarantee fixed kthread association anymore to enable worker sharing. This can be used in cases where specific kthread association is necessary, for example, when it should have RT priority or be assigned to certain cgroup. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org>
2010-03-25cpuset: fix the problem that cpuset_mem_spread_node() returns an offline nodeMiao Xie1-1/+1
cpuset_mem_spread_node() returns an offline node, and causes an oops. This patch fixes it by initializing task->mems_allowed to node_states[N_HIGH_MEMORY], and updating task->mems_allowed when doing memory hotplug. Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Acked-by: David Rientjes <rientjes@google.com> Reported-by: Nick Piggin <npiggin@suse.de> Tested-by: Nick Piggin <npiggin@suse.de> Cc: Paul Menage <menage@google.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-02-09kthread, sched: Remove reference to kthread_create_on_cpuAnton Blanchard1-1/+1
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>
2009-12-16sched: Move kthread_bind() back to kthread.cPeter Zijlstra1-0/+23
Since kthread_bind() lost its dependencies on sched.c, move it back where it came from. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Galbraith <efault@gmx.de> LKML-Reference: <20091216170518.039524041@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-11-03sched: Fix kthread_bind() by moving the body of kthread_bind() to sched.cMike Galbraith1-23/+0
Eric Paris reported that commit f685ceacab07d3f6c236f04803e2f2f0dbcc5afb causes boot time PREEMPT_DEBUG complaints. [ 4.590699] BUG: using smp_processor_id() in preemptible [00000000] code: rmmod/1314 [ 4.593043] caller is task_hot+0x86/0xd0 Since kthread_bind() messes with scheduler internals, move the body to sched.c, and lock the runqueue. Reported-by: Eric Paris <eparis@redhat.com> Signed-off-by: Mike Galbraith <efault@gmx.de> Tested-by: Eric Paris <eparis@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1256813310.7574.3.camel@marge.simson.net> [ v2: fix !SMP build and clean up ] Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-09-09sched: Keep kthreads at default priorityMike Galbraith1-4/+0
Removes kthread/workqueue priority boost, they increase worst-case desktop latencies. Signed-off-by: Mike Galbraith <efault@gmx.de> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1252486344.28645.18.camel@marge.simson.net> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-07-27update the comment in kthread_stop()Oleg Nesterov1-4/+6
Commit 63706172f332fd3f6e7458ebfb35fa6de9c21dc5 ("kthreads: rework kthread_stop()") removed the limitation that the thread function mysr not call do_exit() itself, but forgot to update the comment. Since that commit it is OK to use kthread_stop() even if kthread can exit itself. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-19kthreads: rework kthread_stop()Oleg Nesterov1-41/+28
Based on Eric's patch which in turn was based on my patch. kthread_stop() has the nasty problems: - it runs unpredictably long with the global semaphore held. - it deadlocks if kthread itself does kthread_stop() before it obeys the kthread_should_stop() request. - it is not useable if kthread exits on its own, see for example the ugly "wait_to_die:" hack in migration_thread() - it is not possible to just tell kthread it should stop, we must always wait for its exit. With this patch kthread() allocates all neccesary data (struct kthread) on its own stack, globals kthread_stop_xxx are deleted. ->vfork_done is used as a pointer into "struct kthread", this means kthread_stop() can easily wait for kthread's exit. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Christoph Hellwig <hch@lst.de> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Vitaliy Gusev <vgusev@openvz.org Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-19kthreads: simplify the startup synchronizationOleg Nesterov1-7/+4
We use two completions two create the kernel thread, this is a bit ugly. kthread() wakes up create_kthread() via ->started, then create_kthread() wakes up the caller kthread_create() via ->done. But kthread() does not need to wait for kthread(), it can just return. Instead kthread() itself can wake up the caller of kthread_create(). Kill kthread_create_info->started, ->done is enough. This improves the scalability a bit and sijmplifies the code. The only problem if kernel_thread() fails, in that case create_kthread() must do complete(&create->done). Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Christoph Hellwig <hch@lst.de> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Vitaliy Gusev <vgusev@openvz.org Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-17cpuset,mm: update tasks' mems_allowed in timeMiao Xie1-0/+2
Fix allocating page cache/slab object on the unallowed node when memory spread is set by updating tasks' mems_allowed after its cpuset's mems is changed. In order to update tasks' mems_allowed in time, we must modify the code of memory policy. Because the memory policy is applied in the process's context originally. After applying this patch, one task directly manipulates anothers mems_allowed, and we use alloc_lock in the task_struct to protect mems_allowed and memory policy of the task. But in the fast path, we didn't use lock to protect them, because adding a lock may lead to performance regression. But if we don't add a lock,the task might see no nodes when changing cpuset's mems_allowed to some non-overlapping set. In order to avoid it, we set all new allowed nodes, then clear newly disallowed ones. [lee.schermerhorn@hp.com: The rework of mpol_new() to extract the adjusting of the node mask to apply cpuset and mpol flags "context" breaks set_mempolicy() and mbind() with MPOL_PREFERRED and a NULL nodemask--i.e., explicit local allocation. Fix this by adding the check for MPOL_PREFERRED and empty node mask to mpol_new_mpolicy(). Remove the now unneeded 'nodes = NULL' from mpol_new(). Note that mpol_new_mempolicy() is always called with a non-NULL 'nodes' parameter now that it has been removed from mpol_new(). Therefore, we don't need to test nodes for NULL before testing it for 'empty'. However, just to be extra paranoid, add a VM_BUG_ON() to verify this assumption.] [lee.schermerhorn@hp.com: I don't think the function name 'mpol_new_mempolicy' is descriptive enough to differentiate it from mpol_new(). This function applies cpuset set context, usually constraining nodes to those allowed by the cpuset. However, when the 'RELATIVE_NODES flag is set, it also translates the nodes. So I settled on 'mpol_set_nodemask()', because the comment block for mpol_new() mentions that we need to call this function to "set nodes". Some additional minor line length, whitespace and typo cleanup.] Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Paul Menage <menage@google.com> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: Yasunori Goto <y-goto@jp.fujitsu.com> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-15tracing/events: move trace point headers into include/trace/eventsSteven Rostedt1-1/+1
Impact: clean up Create a sub directory in include/trace called events to keep the trace point headers in their own separate directory. Only headers that declare trace points should be defined in this directory. Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Neil Horman <nhorman@tuxdriver.com> Cc: Zhao Lei <zhaolei@cn.fujitsu.com> Cc: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-04-14tracing: create automated trace definesSteven Rostedt1-3/+0
This patch lowers the number of places a developer must modify to add new tracepoints. The current method to add a new tracepoint into an existing system is to write the trace point macro in the trace header with one of the macros TRACE_EVENT, TRACE_FORMAT or DECLARE_TRACE, then they must add the same named item into the C file with the macro DEFINE_TRACE(name) and then add the trace point. This change cuts out the needing to add the DEFINE_TRACE(name). Every file that uses the tracepoint must still include the trace/<type>.h file, but the one C file must also add a define before the including of that file. #define CREATE_TRACE_POINTS #include <trace/mytrace.h> This will cause the trace/mytrace.h file to also produce the C code necessary to implement the trace point. Note, if more than one trace/<type>.h is used to create the C code it is best to list them all together. #define CREATE_TRACE_POINTS #include <trace/foo.h> #include <trace/bar.h> #include <trace/fido.h> Thanks to Mathieu Desnoyers and Christoph Hellwig for coming up with the cleaner solution of the define above the includes over my first design to have the C code include a "special" header. This patch converts sched, irq and lockdep and skb to use this new method. Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Neil Horman <nhorman@tuxdriver.com> Cc: Zhao Lei <zhaolei@cn.fujitsu.com> Cc: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-04-09kthread: move sched-realeted initialization from kthreadd contextOleg Nesterov1-11/+11
kthreadd is the single thread which implements ths "create" request, move sched_setscheduler/etc from create_kthread() to kthread_create() to improve the scalability. We should be careful with sched_setscheduler(), use _nochek helper. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Christoph Hellwig <hch@lst.de> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: Vitaliy Gusev <vgusev@openvz.org Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2009-04-09kthread: Don't looking for a task in create_kthread() #2Vitaliy Gusev1-3/+1
Remove the unnecessary find_task_by_pid_ns(). kthread() can just use "current" to get the same result. Signed-off-by: Vitaliy Gusev <vgusev@openvz.org> Acked-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2009-03-30cpumask: remove dangerous CPU_MASK_ALL_PTR, &CPU_MASK_ALLRusty Russell1-2/+2
Impact: cleanup (Thanks to Al Viro for reminding me of this, via Ingo) CPU_MASK_ALL is the (deprecated) "all bits set" cpumask, defined as so: #define CPU_MASK_ALL (cpumask_t) { { ... } } Taking the address of such a temporary is questionable at best, unfortunately 321a8e9d (cpumask: add CPU_MASK_ALL_PTR macro) added CPU_MASK_ALL_PTR: #define CPU_MASK_ALL_PTR (&CPU_MASK_ALL) Which formalizes this practice. One day gcc could bite us over this usage (though we seem to have gotten away with it so far). So replace everywhere which used &CPU_MASK_ALL or CPU_MASK_ALL_PTR with the modern "cpu_all_mask" (a real const struct cpumask *). Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Acked-by: Ingo Molnar <mingo@elte.hu> Reported-by: Al Viro <viro@zeniv.linux.org.uk> Cc: Mike Travis <travis@sgi.com>
2008-11-16tracepoints: add DECLARE_TRACE() and DEFINE_TRACE()Mathieu Desnoyers1-0/+3
Impact: API *CHANGE*. Must update all tracepoint users. Add DEFINE_TRACE() to tracepoints to let them declare the tracepoint structure in a single spot for all the kernel. It helps reducing memory consumption, especially when declaring a lot of tracepoints, e.g. for kmalloc tracing. *API CHANGE WARNING*: now, DECLARE_TRACE() must be used in headers for tracepoint declarations rather than DEFINE_TRACE(). This is the sane way to do it. The name previously used was misleading. Updates scheduler instrumentation to follow this API change. Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-21Merge branch 'tracing-v28-for-linus' of ↵Linus Torvalds1-0/+5
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * '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.
2008-10-20kthread_bind: use wait_task_inactive(TASK_UNINTERRUPTIBLE)Oleg Nesterov1-3/+2
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 <oleg@tv-sign.ru> Cc: Roland McGrath <roland@redhat.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>
2008-10-14tracing, sched: LTTng instrumentation - schedulerMathieu Desnoyers1-0/+5
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 <mathieu.desnoyers@polymtl.ca> Acked-by: 'Peter Zijlstra' <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-07-26tracehook: wait_task_inactiveRoland McGrath1-1/+1
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 <roland@redhat.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Reviewed-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-18kthread: reduce stack pressure in create_kthread and kthreaddMike Travis1-2/+2
* 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 <travis@sgi.com> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-07-17Freezer: Introduce PF_FREEZER_NOSIGRafael J. Wysocki1-1/+1
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 <rjw@sisk.pl> Signed-off-by: Andi Kleen <ak@linux.intel.com> Acked-by: Pavel Machek <pavel@suse.cz> Signed-off-by: Len Brown <len.brown@intel.com>
2008-06-10sched: prevent bound kthreads from changing cpus_allowedDavid Rientjes1-0/+1
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 <peterz@infradead.org> Cc: Paul Menage <menage@google.com> Cc: Paul Jackson <pj@sgi.com> Signed-off-by: David Rientjes <rientjes@google.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-04-30Deprecate find_task_by_pid()Pavel Emelyanov1-1/+1
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 <xemul@openvz.org> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Sukadev Bhattiprolu <sukadev@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-29kthread: call wake_up_process() without the lock being heldDmitry Adamushko1-1/+1
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 <dmitry.adamushko@gmail.com> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: Ingo Molnar <mingo@elte.hu> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Andy Whitcroft <apw@shadowen.org> Cc: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-22Merge branch 'semaphore' of ↵Linus Torvalds1-1/+0
git://git.kernel.org/pub/scm/linux/kernel/git/willy/misc * '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
2008-04-19sched: fix cpus_allowed settingsGregory Haskins1-0/+1
Signed-off-by: Gregory Haskins <ghaskins@novell.com> Acked-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-04-19kernel: Remove unnecessary inclusions of asm/semaphore.hMatthew Wilcox1-1/+0
None of these files use any of the functionality promised by asm/semaphore.h. Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
2008-01-25sched: fix, always create kernel threads with normal priorityMichal Schmidt1-1/+11
Ensure that the kernel threads are created with the usual nice level and affinity even if kthreadd's properties were changed from the default by root. Signed-off-by: Michal Schmidt <mschmidt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2007-08-01kthread: silence bogus section mismatch warningSatyam Sharma1-10/+2
WARNING: kernel/built-in.o(.text+0x16910): Section mismatch: reference to .init.text: (between 'kthreadd' and 'init_waitqueue_head') comes because kernel/kthread.c:kthreadd() is not __init but calls kthreadd_setup() which is __init. But this is ok, because kthreadd_setup() is only ever called at init time, and then kthreadd() proceeds into its "for (;;)" loop. We could mark kthreadd __init_refok, but kthreadd_setup() with just one callsite and 4 lines in it (it's been that small since 10ab825bdef8df51) doesn't need to be a separate function at all -- so let's just move those four lines at beginning of kthreadd() itself. Signed-off-by: Satyam Sharma <ssatyam@cse.iitk.ac.in> Acked-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-16mm: fix improper .init-type section referencesJan Beulich1-1/+1
.. which modpost started warning about. Signed-off-by: Jan Beulich <jbeulich@novell.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-24freezer: fix kthread_create vs freezer theoretical raceOleg Nesterov1-2/+5
kthread() sleeps in TASK_INTERRUPTIBLE state waiting for the first wakeup. In theory, this wakeup may come from freeze_process()->signal_wake_up(), so the task can disappear even before kthread_create() sets its ->comm. Change kthread() to use TASK_UNINTERRUPTIBLE. [akpm@linux-foundation.org: s/BUG_ON/WARN_ON+recover] Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Acked-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Cc: Gautham R Shenoy <ego@in.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-09change kernel threads to ignore signals instead of blocking themOleg Nesterov1-14/+3
Currently kernel threads use sigprocmask(SIG_BLOCK) to protect against signals. This doesn't prevent the signal delivery, this only blocks signal_wake_up(). Every "killall -33 kthreadd" means a "struct siginfo" leak. Change kthreadd_setup() to set all handlers to SIG_IGN instead of blocking them (make a new helper ignore_signals() for that). If the kernel thread needs some signal, it should use allow_signal() anyway, and in that case it should not use CLONE_SIGHAND. Note that we can't change daemonize() (should die!) in the same way, because it can be used along with CLONE_SIGHAND. This means that allow_signal() still should unblock the signal to work correctly with daemonize()ed threads. However, disallow_signal() doesn't block the signal any longer but ignores it. NOTE: with or without this patch the kernel threads are not protected from handle_stop_signal(), this seems harmless, but not good. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Acked-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-09kthread: don't depend on work queuesEric W. Biederman1-56/+68
Currently there is a circular reference between work queue initialization and kthread initialization. This prevents the kthread infrastructure from initializing until after work queues have been initialized. We want the properties of tasks created with kthread_create to be as close as possible to the init_task and to not be contaminated by user processes. The later we start our kthreadd that creates these tasks the harder it is to avoid contamination from user processes and the more of a mess we have to clean up because the defaults have changed on us. So this patch modifies the kthread support to not use work queues but to instead use a simple list of structures, and to have kthreadd start from init_task immediately after our kernel thread that execs /sbin/init. By being a true child of init_task we only have to change those process settings that we want to have different from init_task, such as our process name, the cpus that are allowed, blocking all signals and setting SIGCHLD to SIG_IGN so that all of our children are reaped automatically. By being a true child of init_task we also naturally get our ppid set to 0 and do not wind up as a child of PID == 1. Ensuring that tasks generated by kthread_create will not slow down the functioning of the wait family of functions. [akpm@linux-foundation.org: use interruptible sleeps] Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-11[PATCH] Numerous fixes to kernel-doc info in source files.Robert P. J. Day1-3/+3
A variety of (mostly) innocuous fixes to the embedded kernel-doc content in source files, including: * make multi-line initial descriptions single line * denote some function names, constants and structs as such * change erroneous opening '/*' to '/**' in a few places * reword some text for clarity Signed-off-by: Robert P. J. Day <rpjday@mindspring.com> Cc: "Randy.Dunlap" <rdunlap@xenotime.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2006-11-22WorkStruct: Pass the work_struct pointer instead of context dataDavid Howells1-5/+8
Pass the work_struct pointer to the work function rather than context data. The work function can use container_of() to work out the data. For the cases where the container of the work_struct may go away the moment the pending bit is cleared, it is made possible to defer the release of the structure by deferring the clearing of the pending bit. To make this work, an extra flag is introduced into the management side of the work_struct. This governs auto-release of the structure upon execution. Ordinarily, the work queue executor would release the work_struct for further scheduling or deallocation by clearing the pending bit prior to jumping to the work function. This means that, unless the driver makes some guarantee itself that the work_struct won't go away, the work function may not access anything else in the work_struct or its container lest they be deallocated.. This is a problem if the auxiliary data is taken away (as done by the last patch). However, if the pending bit is *not* cleared before jumping to the work function, then the work function *may* access the work_struct and its container with no problems. But then the work function must itself release the work_struct by calling work_release(). In most cases, automatic release is fine, so this is the default. Special initiators exist for the non-auto-release case (ending in _NAR). Signed-Off-By: David Howells <dhowells@redhat.com>
2006-07-15[PATCH] remove kernel/kthread.c:kthread_stop_sem()Adrian Bunk1-22/+2
Remove the now-unneeded kthread_stop_sem(). Signed-off-by: Adrian Bunk <bunk@stusta.de> Acked-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-25[PATCH] kthread: move kernel-doc and put it into DocBookRandy Dunlap1-1/+60
Move kthread API kernel-doc from kthread.h to kthread.c & fix it. Add kthread API to kernel-api DocBook. Signed-off-by: Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-25[PATCH] find_task_by_pid() needs tasklist_lockAndrew Morton1-0/+2
A couple of places are forgetting to take it. The kswapd case is probably unimportant. keventd_create_kthread() was racy. The whole thing is a bit flakey: you start a kernel thread, get its pid from kernel_thread() then look up its task_struct. a) It assumes that pid recycling takes a "long" time. b) We get a task_struct but no reference was taken on it. The owner of the kswapd and kthread task_struct*'s must assume that the new thread won't exit unexpectedly. Because if it does, they're left holding dead memory and any attempt to control or stop that task will crash. Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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