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  1. 04 3月, 2018 1 次提交
    • I
      sched/headers: Simplify and clean up header usage in the scheduler · 325ea10c
      由 Ingo Molnar 提交于 
      Do the following cleanups and simplifications:

 - sched/sched.h already includes <asm/paravirt.h>, so no need to
   include it in sched/core.c again.

 - order the <linux/sched/*.h> headers alphabetically

 - add all <linux/sched/*.h> headers to kernel/sched/sched.h

 - remove all unnecessary includes from the .c files that
   are already included in kernel/sched/sched.h.

Finally, make all scheduler .c files use a single common header:

  #include "sched.h"

... which now contains a union of the relied upon headers.

This makes the various .c files easier to read and easier to handle.

Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>
      325ea10c
  3. 03 3月, 2018 1 次提交
    • I
      sched: Clean up and harmonize the coding style of the scheduler code base · 97fb7a0a
      由 Ingo Molnar 提交于 
      A good number of small style inconsistencies have accumulated
in the scheduler core, so do a pass over them to harmonize
all these details:

 - fix speling in comments,

 - use curly braces for multi-line statements,

 - remove unnecessary parentheses from integer literals,

 - capitalize consistently,

 - remove stray newlines,

 - add comments where necessary,

 - remove invalid/unnecessary comments,

 - align structure definitions and other data types vertically,

 - add missing newlines for increased readability,

 - fix vertical tabulation where it's misaligned,

 - harmonize preprocessor conditional block labeling
   and vertical alignment,

 - remove line-breaks where they uglify the code,

 - add newline after local variable definitions,

No change in functionality:

  md5:
     1191fa0a890cfa8132156d2959d7e9e2  built-in.o.before.asm
     1191fa0a890cfa8132156d2959d7e9e2  built-in.o.after.asm

Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>
      97fb7a0a
  5. 21 2月, 2018 2 次提交
  7. 02 11月, 2017 1 次提交
    • G
      License cleanup: add SPDX GPL-2.0 license identifier to files with no license · b2441318
      由 Greg Kroah-Hartman 提交于 
      Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier.  The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
 - file had no licensing information it it.
 - file was a */uapi/* one with no licensing information in it,
 - file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne.  Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed.  Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
 - Files considered eligible had to be source code files.
 - Make and config files were included as candidates if they contained >5
   lines of source
 - File already had some variant of a license header in it (even if <5
   lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

 - when both scanners couldn't find any license traces, file was
   considered to have no license information in it, and the top level
   COPYING file license applied.

   For non */uapi/* files that summary was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0                                              11139

   and resulted in the first patch in this series.

   If that file was a */uapi/* path one, it was "GPL-2.0 WITH
   Linux-syscall-note" otherwise it was "GPL-2.0".  Results of that was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0 WITH Linux-syscall-note                        930

   and resulted in the second patch in this series.

 - if a file had some form of licensing information in it, and was one
   of the */uapi/* ones, it was denoted with the Linux-syscall-note if
   any GPL family license was found in the file or had no licensing in
   it (per prior point).  Results summary:

   SPDX license identifier                            # files
   ---------------------------------------------------|------
   GPL-2.0 WITH Linux-syscall-note                       270
   GPL-2.0+ WITH Linux-syscall-note                      169
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause)    21
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)    17
   LGPL-2.1+ WITH Linux-syscall-note                      15
   GPL-1.0+ WITH Linux-syscall-note                       14
   ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause)    5
   LGPL-2.0+ WITH Linux-syscall-note                       4
   LGPL-2.1 WITH Linux-syscall-note                        3
   ((GPL-2.0 WITH Linux-syscall-note) OR MIT)              3
   ((GPL-2.0 WITH Linux-syscall-note) AND MIT)             1

   and that resulted in the third patch in this series.

 - when the two scanners agreed on the detected license(s), that became
   the concluded license(s).

 - when there was disagreement between the two scanners (one detected a
   license but the other didn't, or they both detected different
   licenses) a manual inspection of the file occurred.

 - In most cases a manual inspection of the information in the file
   resulted in a clear resolution of the license that should apply (and
   which scanner probably needed to revisit its heuristics).

 - When it was not immediately clear, the license identifier was
   confirmed with lawyers working with the Linux Foundation.

 - If there was any question as to the appropriate license identifier,
   the file was flagged for further research and to be revisited later
   in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights.  The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
 - a full scancode scan run, collecting the matched texts, detected
   license ids and scores
 - reviewing anything where there was a license detected (about 500+
   files) to ensure that the applied SPDX license was correct
 - reviewing anything where there was no detection but the patch license
   was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
   SPDX license was correct

This produced a worksheet with 20 files needing minor correction.  This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg.  Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected.  This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.)  Finally Greg ran the script using the .csv files to
generate the patches.
Reviewed-by: NKate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: NPhilippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      b2441318
  9. 14 1月, 2017 1 次提交
    • M
      sched/core: Add wrappers for lockdep_(un)pin_lock() · d8ac8971
      由 Matt Fleming 提交于 
      In preparation for adding diagnostic checks to catch missing calls to
update_rq_clock(), provide wrappers for (re)pinning and unpinning
rq->lock.

Because the pending diagnostic checks allow state to be maintained in
rq_flags across pin contexts, swap the 'struct pin_cookie' arguments
for 'struct rq_flags *'.
Signed-off-by: NMatt Fleming <matt@codeblueprint.co.uk>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Byungchul Park <byungchul.park@lge.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luca Abeni <luca.abeni@unitn.it>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Mike Galbraith <umgwanakikbuti@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Wanpeng Li <wanpeng.li@hotmail.com>
Cc: Yuyang Du <yuyang.du@intel.com>
Link: http://lkml.kernel.org/r/20160921133813.31976-5-matt@codeblueprint.co.ukSigned-off-by: NIngo Molnar <mingo@kernel.org>
      d8ac8971
  11. 30 9月, 2016 1 次提交
    • P
      sched/core: Rewrite and improve select_idle_siblings() · 10e2f1ac
      由 Peter Zijlstra 提交于 
      select_idle_siblings() is a known pain point for a number of
workloads; it either does too much or not enough and sometimes just
does plain wrong.

This rewrite attempts to address a number of issues (but sadly not
all).

The current code does an unconditional sched_domain iteration; with
the intent of finding an idle core (on SMT hardware). The problems
which this patch tries to address are:

 - its pointless to look for idle cores if the machine is real busy;
   at which point you're just wasting cycles.

 - it's behaviour is inconsistent between SMT and !SMT hardware in
   that !SMT hardware ends up doing a scan for any idle CPU in the LLC
   domain, while SMT hardware does a scan for idle cores and if that
   fails, falls back to a scan for idle threads on the 'target' core.

The new code replaces the sched_domain scan with 3 explicit scans:

 1) search for an idle core in the LLC
 2) search for an idle CPU in the LLC
 3) search for an idle thread in the 'target' core

where 1 and 3 are conditional on SMT support and 1 and 2 have runtime
heuristics to skip the step.

Step 1) is conditional on sd_llc_shared->has_idle_cores; when a cpu
goes idle and sd_llc_shared->has_idle_cores is false, we scan all SMT
siblings of the CPU going idle. Similarly, we clear
sd_llc_shared->has_idle_cores when we fail to find an idle core.

Step 2) tracks the average cost of the scan and compares this to the
average idle time guestimate for the CPU doing the wakeup. There is a
significant fudge factor involved to deal with the variability of the
averages. Esp. hackbench was sensitive to this.

Step 3) is unconditional; we assume (also per step 1) that scanning
all SMT siblings in a core is 'cheap'.

With this; SMT systems gain step 2, which cures a few benchmarks --
notably one from Facebook.

One 'feature' of the sched_domain iteration, which we preserve in the
new code, is that it would start scanning from the 'target' CPU,
instead of scanning the cpumask in cpu id order. This avoids multiple
CPUs in the LLC scanning for idle to gang up and find the same CPU
quite as much. The down side is that tasks can end up hopping across
the LLC for no apparent reason.
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>
      10e2f1ac
  13. 05 9月, 2016 1 次提交
  15. 05 5月, 2016 1 次提交
    • P
      locking/lockdep, sched/core: Implement a better lock pinning scheme · e7904a28
      由 Peter Zijlstra 提交于 
      The problem with the existing lock pinning is that each pin is of
value 1; this mean you can simply unpin if you know its pinned,
without having any extra information.

This scheme generates a random (16 bit) cookie for each pin and
requires this same cookie to unpin. This means you have to keep the
cookie in context.

No objsize difference for !LOCKDEP kernels.
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>
      e7904a28
  17. 23 11月, 2015 1 次提交
  19. 12 8月, 2015 1 次提交
  21. 24 11月, 2014 1 次提交
    • T
      sched: Provide update_curr callbacks for stop/idle scheduling classes · 90e362f4
      由 Thomas Gleixner 提交于 
      Chris bisected a NULL pointer deference in task_sched_runtime() to
commit 6e998916 'sched/cputime: Fix clock_nanosleep()/clock_gettime()
inconsistency'.

Chris observed crashes in atop or other /proc walking programs when he
started fork bombs on his machine.  He assumed that this is a new exit
race, but that does not make any sense when looking at that commit.

What's interesting is that, the commit provides update_curr callbacks
for all scheduling classes except stop_task and idle_task.

While nothing can ever hit that via the clock_nanosleep() and
clock_gettime() interfaces, which have been the target of the commit in
question, the author obviously forgot that there are other code paths
which invoke task_sched_runtime()

do_task_stat(()
 thread_group_cputime_adjusted()
   thread_group_cputime()
     task_cputime()
       task_sched_runtime()
        if (task_current(rq, p) && task_on_rq_queued(p)) {
          update_rq_clock(rq);
          up->sched_class->update_curr(rq);
        }

If the stats are read for a stomp machine task, aka 'migration/N' and
that task is current on its cpu, this will happily call the NULL pointer
of stop_task->update_curr.  Ooops.

Chris observation that this happens faster when he runs the fork bomb
makes sense as the fork bomb will kick migration threads more often so
the probability to hit the issue will increase.

Add the missing update_curr callbacks to the scheduler classes stop_task
and idle_task.  While idle tasks cannot be monitored via /proc we have
other means to hit the idle case.

Fixes: 6e998916 'sched/cputime: Fix clock_nanosleep()/clock_gettime() inconsistency'
Reported-by: NChris Mason <clm@fb.com>
Reported-and-tested-by: NBorislav Petkov <bp@alien8.de>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Stanislaw Gruszka <sgruszka@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      90e362f4
  23. 16 7月, 2014 1 次提交
    • K
      sched: Transform resched_task() into resched_curr() · 8875125e
      由 Kirill Tkhai 提交于 
      We always use resched_task() with rq->curr argument.
It's not possible to reschedule any task but rq's current.

The patch introduces resched_curr(struct rq *) to
replace all of the repeating patterns. The main aim
is cleanup, but there is a little size profit too:

  (before)
	$ size kernel/sched/built-in.o
	   text	   data	    bss	    dec	    hex	filename
	155274	  16445	   7042	 178761	  2ba49	kernel/sched/built-in.o

	$ size vmlinux
	   text	   data	    bss	    dec	    hex	filename
	7411490	1178376	 991232	9581098	 92322a	vmlinux

  (after)
	$ size kernel/sched/built-in.o
	   text	   data	    bss	    dec	    hex	filename
	155130	  16445	   7042	 178617	  2b9b9	kernel/sched/built-in.o

	$ size vmlinux
	   text	   data	    bss	    dec	    hex	filename
	7411362	1178376	 991232	9580970	 9231aa	vmlinux

	I was choosing between resched_curr() and resched_rq(),
	and the first name looks better for me.

A little lie in Documentation/trace/ftrace.txt. I have not
actually collected the tracing again. With a hope the patch
won't make execution times much worse :)
Signed-off-by: NKirill Tkhai <tkhai@yandex.ru>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/20140628200219.1778.18735.stgit@localhostSigned-off-by: NIngo Molnar <mingo@kernel.org>
      8875125e
  25. 11 3月, 2014 1 次提交
  27. 22 2月, 2014 2 次提交
  29. 11 2月, 2014 1 次提交
    • P
      sched: Push down pre_schedule() and idle_balance() · 38033c37
      由 Peter Zijlstra 提交于 
      This patch both merged idle_balance() and pre_schedule() and pushes
both of them into pick_next_task().

Conceptually pre_schedule() and idle_balance() are rather similar,
both are used to pull more work onto the current CPU.

We cannot however first move idle_balance() into pre_schedule_fair()
since there is no guarantee the last runnable task is a fair task, and
thus we would miss newidle balances.

Similarly, the dl and rt pre_schedule calls must be ran before
idle_balance() since their respective tasks have higher priority and
it would not do to delay their execution searching for less important
tasks first.

However, by noticing that pick_next_tasks() already traverses the
sched_class hierarchy in the right order, we can get the right
behaviour and do away with both calls.

We must however change the special case optimization to also require
that prev is of sched_class_fair, otherwise we can miss doing a dl or
rt pull where we needed one.
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/n/tip-a8k6vvaebtn64nie345kx1je@git.kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
      38033c37
  31. 10 2月, 2014 2 次提交
  33. 09 10月, 2013 1 次提交
  35. 04 5月, 2013 1 次提交
    • F
      sched: Keep at least 1 tick per second for active dynticks tasks · 265f22a9
      由 Frederic Weisbecker 提交于 
      The scheduler doesn't yet fully support environments
with a single task running without a periodic tick.

In order to ensure we still maintain the duties of scheduler_tick(),
keep at least 1 tick per second.

This makes sure that we keep the progression of various scheduler
accounting and background maintainance even with a very low granularity.
Examples include cpu load, sched average, CFS entity vruntime,
avenrun and events such as load balancing, amongst other details
handled in sched_class::task_tick().

This limitation will be removed in the future once we get
these individual items to work in full dynticks CPUs.
Suggested-by: NIngo Molnar <mingo@kernel.org>
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Hakan Akkan <hakanakkan@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
      265f22a9
  37. 21 4月, 2013 1 次提交
    • V
      sched: Fix wrong rq's runnable_avg update with rt tasks · 642dbc39
      由 Vincent Guittot 提交于 
      The current update of the rq's load can be erroneous when RT
tasks are involved.

The update of the load of a rq that becomes idle, is done only
if the avg_idle is less than sysctl_sched_migration_cost. If RT
tasks and short idle duration alternate, the runnable_avg will
not be updated correctly and the time will be accounted as idle
time when a CFS task wakes up.

A new idle_enter function is called when the next task is the
idle function so the elapsed time will be accounted as run time
in the load of the rq, whatever the average idle time is. The
function update_rq_runnable_avg is removed from idle_balance.

When a RT task is scheduled on an idle CPU, the update of the
rq's load is not done when the rq exit idle state because CFS's
functions are not called. Then, the idle_balance, which is
called just before entering the idle function, updates the rq's
load and makes the assumption that the elapsed time since the
last update, was only running time.

As a consequence, the rq's load of a CPU that only runs a
periodic RT task, is close to LOAD_AVG_MAX whatever the running
duration of the RT task is.

A new idle_exit function is called when the prev task is the
idle function so the elapsed time will be accounted as idle time
in the rq's load.
Signed-off-by: NVincent Guittot <vincent.guittot@linaro.org>
Acked-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: NSteven Rostedt <rostedt@goodmis.org>
Cc: linaro-kernel@lists.linaro.org
Cc: peterz@infradead.org
Cc: pjt@google.com
Cc: fweisbec@gmail.com
Cc: efault@gmx.de
Link: http://lkml.kernel.org/r/1366302867-5055-1-git-send-email-vincent.guittot@linaro.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
      642dbc39
  39. 06 7月, 2012 1 次提交
  41. 07 5月, 2012 1 次提交
  43. 17 11月, 2011 2 次提交
  45. 14 4月, 2011 1 次提交
  47. 23 3月, 2011 1 次提交
  49. 26 1月, 2011 2 次提交
  51. 23 4月, 2010 1 次提交
  53. 03 4月, 2010 2 次提交
    • P
      sched: Add enqueue/dequeue flags · 371fd7e7
      由 Peter Zijlstra 提交于 
      In order to reduce the dependency on TASK_WAKING rework the enqueue
interface to support a proper flags field.

Replace the int wakeup, bool head arguments with an int flags argument
and create the following flags:

  ENQUEUE_WAKEUP - the enqueue is a wakeup of a sleeping task,
  ENQUEUE_WAKING - the enqueue has relative vruntime due to
                   having sched_class::task_waking() called,
  ENQUEUE_HEAD - the waking task should be places on the head
                 of the priority queue (where appropriate).

For symmetry also convert sched_class::dequeue() to a flags scheme.
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      371fd7e7
    • P
      sched: Fix TASK_WAKING vs fork deadlock · 0017d735
      由 Peter Zijlstra 提交于 
      Oleg noticed a few races with the TASK_WAKING usage on fork.

 - since TASK_WAKING is basically a spinlock, it should be IRQ safe
 - since we set TASK_WAKING (*) without holding rq->lock it could
   be there still is a rq->lock holder, thereby not actually
   providing full serialization.

(*) in fact we clear PF_STARTING, which in effect enables TASK_WAKING.

Cure the second issue by not setting TASK_WAKING in sched_fork(), but
only temporarily in wake_up_new_task() while calling select_task_rq().

Cure the first by holding rq->lock around the select_task_rq() call,
this will disable IRQs, this however requires that we push down the
rq->lock release into select_task_rq_fair()'s cgroup stuff.

Because select_task_rq_fair() still needs to drop the rq->lock we
cannot fully get rid of TASK_WAKING.
Reported-by: NOleg Nesterov <oleg@redhat.com>
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      0017d735
  55. 21 1月, 2010 1 次提交
  57. 17 1月, 2010 1 次提交
  59. 21 12月, 2009 1 次提交
    • P
      sched: Restore printk sanity · 3df0fc5b
      由 Peter Zijlstra 提交于 
      Revert the braindead pr_* crap. (Commit 663997d4 "sched: Use
pr_fmt() and pr_<level>()")

It's dumb and causes stupid "sched: " strings all over the place.
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Acked-by: NMike Galbraith <efault@gmx.de>
Cc: Joe Perches <joe@perches.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
LKML-Reference: <1261315437.4314.6.camel@laptop>
[ i dont mind the pr_*() patterns that much - but Peter dislikes them with a vengence. ]
[ - v2: remove spurious diffstat from changelog :-/ ]
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      3df0fc5b
  61. 15 12月, 2009 1 次提交
  63. 13 12月, 2009 1 次提交
    • J
      sched: Use pr_fmt() and pr_<level>() · 663997d4
      由 Joe Perches 提交于 
      - Convert printk(KERN_<level> to pr_<level> (not KERN_DEBUG)
 - Add #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 - Coalesce long format strings
 - Add missing \n to "ERROR: !SD_LOAD_BALANCE domain has parent"
Signed-off-by: NJoe Perches <joe@perches.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1260655047.2637.7.camel@Joe-Laptop.home>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      663997d4
  65. 09 12月, 2009 1 次提交
  67. 21 9月, 2009 1 次提交