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  1. 23 7月, 2012 1 次提交
  3. 24 11月, 2011 1 次提交
    • T
      freezer: kill unused set_freezable_with_signal() · 34b087e4
      由 Tejun Heo 提交于 
      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: NTejun Heo <tj@kernel.org>
Acked-by: NOleg Nesterov <oleg@redhat.com>
      34b087e4
  5. 22 11月, 2011 1 次提交
    • T
      freezer: implement and use kthread_freezable_should_stop() · 8a32c441
      由 Tejun Heo 提交于 
      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: NTejun Heo <tj@kernel.org>
Acked-by: NHenrique de Moraes Holschuh <ibm-acpi@hmh.eng.br>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Oleg Nesterov <oleg@redhat.com>
      8a32c441
  7. 31 10月, 2011 1 次提交
  9. 28 5月, 2011 1 次提交
  11. 31 3月, 2011 1 次提交
  13. 23 3月, 2011 1 次提交
  15. 07 1月, 2011 1 次提交
  17. 22 12月, 2010 1 次提交
  19. 23 10月, 2010 1 次提交
  21. 29 6月, 2010 2 次提交
    • T
      kthread: implement kthread_data() · 82805ab7
      由 Tejun Heo 提交于 
      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: NTejun Heo <tj@kernel.org>
      82805ab7
    • T
      kthread: implement kthread_worker · b56c0d89
      由 Tejun Heo 提交于 
      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: NTejun Heo <tj@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
      b56c0d89
  23. 25 3月, 2010 1 次提交
  25. 09 2月, 2010 2 次提交
  27. 17 12月, 2009 1 次提交
  29. 03 11月, 2009 1 次提交
  31. 09 9月, 2009 1 次提交
  33. 28 7月, 2009 1 次提交
  35. 19 6月, 2009 2 次提交
    • O
      kthreads: rework kthread_stop() · 63706172
      由 Oleg Nesterov 提交于 
      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: NOleg 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: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      63706172
    • O
      kthreads: simplify the startup synchronization · cdd140bd
      由 Oleg Nesterov 提交于 
      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: NOleg 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: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      cdd140bd
  37. 17 6月, 2009 1 次提交
    • M
      cpuset,mm: update tasks' mems_allowed in time · 58568d2a
      由 Miao Xie 提交于 
      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: NMiao 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: NLee Schermerhorn <lee.schermerhorn@hp.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      58568d2a
  39. 15 4月, 2009 2 次提交
    • S
      tracing/events: move trace point headers into include/trace/events · ad8d75ff
      由 Steven Rostedt 提交于 
      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: NSteven Rostedt <rostedt@goodmis.org>
      ad8d75ff
    • S
      tracing: create automated trace defines · a8d154b0
      由 Steven Rostedt 提交于 
      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: NSteven Rostedt <rostedt@goodmis.org>
      a8d154b0
  41. 09 4月, 2009 2 次提交
  43. 30 3月, 2009 1 次提交
    • R
      cpumask: remove dangerous CPU_MASK_ALL_PTR, &CPU_MASK_ALL · 1a2142af
      由 Rusty Russell 提交于 
      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: NRusty Russell <rusty@rustcorp.com.au>
Acked-by: NIngo Molnar <mingo@elte.hu>
Reported-by: NAl Viro <viro@zeniv.linux.org.uk>
Cc: Mike Travis <travis@sgi.com>
      1a2142af
  45. 16 11月, 2008 1 次提交
    • M
      tracepoints: add DECLARE_TRACE() and DEFINE_TRACE() · 7e066fb8
      由 Mathieu Desnoyers 提交于 
      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: NMathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      7e066fb8
  47. 20 10月, 2008 1 次提交
  49. 14 10月, 2008 1 次提交
    • M
      tracing, sched: LTTng instrumentation - scheduler · 0a16b607
      由 Mathieu Desnoyers 提交于 
      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: NMathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Acked-by: N'Peter Zijlstra' <peterz@infradead.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      0a16b607
  51. 27 7月, 2008 1 次提交
  53. 19 7月, 2008 1 次提交
  55. 17 7月, 2008 1 次提交
    • R
      Freezer: Introduce PF_FREEZER_NOSIG · ebb12db5
      由 Rafael J. Wysocki 提交于 
      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: NRafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Acked-by: NPavel Machek <pavel@suse.cz>
Signed-off-by: NLen Brown <len.brown@intel.com>
      ebb12db5
  57. 10 6月, 2008 1 次提交
  59. 30 4月, 2008 1 次提交
  61. 29 4月, 2008 1 次提交
  63. 20 4月, 2008 1 次提交
  65. 19 4月, 2008 1 次提交
  67. 26 1月, 2008 1 次提交
  69. 01 8月, 2007 1 次提交