<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-toradex.git/include/linux/init_task.h, branch v2.6.34-rc3</title>
<subtitle>Linux kernel for Apalis and Colibri modules</subtitle>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/'/>
<entry>
<title>nsproxy: remove INIT_NSPROXY()</title>
<updated>2010-03-12T23:52:40+00:00</updated>
<author>
<name>Alexey Dobriyan</name>
<email>adobriyan@gmail.com</email>
</author>
<published>2010-03-10T23:23:10+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=8467005da3ef6104b89a4cc5e9c9d9445b75565f'/>
<id>8467005da3ef6104b89a4cc5e9c9d9445b75565f</id>
<content type='text'>
Remove INIT_NSPROXY(), use C99 initializer.
Remove INIT_IPC_NS(), INIT_NET_NS() while I'm at it.

Note: headers trim will be done later, now it's quite pointless because
results will be invalidated by merge window.

Signed-off-by: Alexey Dobriyan &lt;adobriyan@gmail.com&gt;
Acked-by: Serge Hallyn &lt;serue@us.ibm.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Remove INIT_NSPROXY(), use C99 initializer.
Remove INIT_IPC_NS(), INIT_NET_NS() while I'm at it.

Note: headers trim will be done later, now it's quite pointless because
results will be invalidated by merge window.

Signed-off-by: Alexey Dobriyan &lt;adobriyan@gmail.com&gt;
Acked-by: Serge Hallyn &lt;serue@us.ibm.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Revert "task_struct: make journal_info conditional"</title>
<updated>2009-12-17T21:23:24+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2009-12-17T21:23:24+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=b6e3224fb20954f155e41ec5709b2ab70b50ae2d'/>
<id>b6e3224fb20954f155e41ec5709b2ab70b50ae2d</id>
<content type='text'>
This reverts commit e4c570c4cb7a95dbfafa3d016d2739bf3fdfe319, as
requested by Alexey:

 "I think I gave a good enough arguments to not merge it.
  To iterate:
   * patch makes impossible to start using ext3 on EXT3_FS=n kernels
     without reboot.
   * this is done only for one pointer on task_struct"

  None of config options which define task_struct are tristate directly
  or effectively."

Requested-by: Alexey Dobriyan &lt;adobriyan@gmail.com&gt;
Acked-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This reverts commit e4c570c4cb7a95dbfafa3d016d2739bf3fdfe319, as
requested by Alexey:

 "I think I gave a good enough arguments to not merge it.
  To iterate:
   * patch makes impossible to start using ext3 on EXT3_FS=n kernels
     without reboot.
   * this is done only for one pointer on task_struct"

  None of config options which define task_struct are tristate directly
  or effectively."

Requested-by: Alexey Dobriyan &lt;adobriyan@gmail.com&gt;
Acked-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge branch 'core-locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip</title>
<updated>2009-12-15T17:02:01+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2009-12-15T17:02:01+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=8f0ddf91f2aeb09602373e400cf8b403e9017210'/>
<id>8f0ddf91f2aeb09602373e400cf8b403e9017210</id>
<content type='text'>
* 'core-locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (26 commits)
  clockevents: Convert to raw_spinlock
  clockevents: Make tick_device_lock static
  debugobjects: Convert to raw_spinlocks
  perf_event: Convert to raw_spinlock
  hrtimers: Convert to raw_spinlocks
  genirq: Convert irq_desc.lock to raw_spinlock
  smp: Convert smplocks to raw_spinlocks
  rtmutes: Convert rtmutex.lock to raw_spinlock
  sched: Convert pi_lock to raw_spinlock
  sched: Convert cpupri lock to raw_spinlock
  sched: Convert rt_runtime_lock to raw_spinlock
  sched: Convert rq-&gt;lock to raw_spinlock
  plist: Make plist debugging raw_spinlock aware
  bkl: Fixup core_lock fallout
  locking: Cleanup the name space completely
  locking: Further name space cleanups
  alpha: Fix fallout from locking changes
  locking: Implement new raw_spinlock
  locking: Convert raw_rwlock functions to arch_rwlock
  locking: Convert raw_rwlock to arch_rwlock
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
* 'core-locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (26 commits)
  clockevents: Convert to raw_spinlock
  clockevents: Make tick_device_lock static
  debugobjects: Convert to raw_spinlocks
  perf_event: Convert to raw_spinlock
  hrtimers: Convert to raw_spinlocks
  genirq: Convert irq_desc.lock to raw_spinlock
  smp: Convert smplocks to raw_spinlocks
  rtmutes: Convert rtmutex.lock to raw_spinlock
  sched: Convert pi_lock to raw_spinlock
  sched: Convert cpupri lock to raw_spinlock
  sched: Convert rt_runtime_lock to raw_spinlock
  sched: Convert rq-&gt;lock to raw_spinlock
  plist: Make plist debugging raw_spinlock aware
  bkl: Fixup core_lock fallout
  locking: Cleanup the name space completely
  locking: Further name space cleanups
  alpha: Fix fallout from locking changes
  locking: Implement new raw_spinlock
  locking: Convert raw_rwlock functions to arch_rwlock
  locking: Convert raw_rwlock to arch_rwlock
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>task_struct: make journal_info conditional</title>
<updated>2009-12-15T16:53:27+00:00</updated>
<author>
<name>Hiroshi Shimamoto</name>
<email>h-shimamoto@ct.jp.nec.com</email>
</author>
<published>2009-12-15T02:00:26+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=e4c570c4cb7a95dbfafa3d016d2739bf3fdfe319'/>
<id>e4c570c4cb7a95dbfafa3d016d2739bf3fdfe319</id>
<content type='text'>
journal_info in task_struct is used in journaling file system only.  So
introduce CONFIG_FS_JOURNAL_INFO and make it conditional.

Signed-off-by: Hiroshi Shimamoto &lt;h-shimamoto@ct.jp.nec.com&gt;
Cc: Chris Mason &lt;chris.mason@oracle.com&gt;
Cc: "Theodore Ts'o" &lt;tytso@mit.edu&gt;
Cc: Steven Whitehouse &lt;swhiteho@redhat.com&gt;
Cc: KONISHI Ryusuke &lt;konishi.ryusuke@lab.ntt.co.jp&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
journal_info in task_struct is used in journaling file system only.  So
introduce CONFIG_FS_JOURNAL_INFO and make it conditional.

Signed-off-by: Hiroshi Shimamoto &lt;h-shimamoto@ct.jp.nec.com&gt;
Cc: Chris Mason &lt;chris.mason@oracle.com&gt;
Cc: "Theodore Ts'o" &lt;tytso@mit.edu&gt;
Cc: Steven Whitehouse &lt;swhiteho@redhat.com&gt;
Cc: KONISHI Ryusuke &lt;konishi.ryusuke@lab.ntt.co.jp&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>sched: Convert pi_lock to raw_spinlock</title>
<updated>2009-12-14T22:55:33+00:00</updated>
<author>
<name>Thomas Gleixner</name>
<email>tglx@linutronix.de</email>
</author>
<published>2009-11-17T13:54:03+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=1d615482547584b9a8bb6316a58fed6ce90dd9ff'/>
<id>1d615482547584b9a8bb6316a58fed6ce90dd9ff</id>
<content type='text'>
Convert locks which cannot be sleeping locks in preempt-rt to
raw_spinlocks.

Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Acked-by: Peter Zijlstra &lt;peterz@infradead.org&gt;
Acked-by: Ingo Molnar &lt;mingo@elte.hu&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Convert locks which cannot be sleeping locks in preempt-rt to
raw_spinlocks.

Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Acked-by: Peter Zijlstra &lt;peterz@infradead.org&gt;
Acked-by: Ingo Molnar &lt;mingo@elte.hu&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>remove CONFIG_SECURITY_FILE_CAPABILITIES compile option</title>
<updated>2009-11-24T04:06:47+00:00</updated>
<author>
<name>Serge E. Hallyn</name>
<email>serue@us.ibm.com</email>
</author>
<published>2009-11-23T22:21:30+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=b3a222e52e4d4be77cc4520a57af1a4a0d8222d1'/>
<id>b3a222e52e4d4be77cc4520a57af1a4a0d8222d1</id>
<content type='text'>
As far as I know, all distros currently ship kernels with default
CONFIG_SECURITY_FILE_CAPABILITIES=y.  Since having the option on
leaves a 'no_file_caps' option to boot without file capabilities,
the main reason to keep the option is that turning it off saves
you (on my s390x partition) 5k.  In particular, vmlinux sizes
came to:

without patch fscaps=n:		 	53598392
without patch fscaps=y:		 	53603406
with this patch applied:		53603342

with the security-next tree.

Against this we must weigh the fact that there is no simple way for
userspace to figure out whether file capabilities are supported,
while things like per-process securebits, capability bounding
sets, and adding bits to pI if CAP_SETPCAP is in pE are not supported
with SECURITY_FILE_CAPABILITIES=n, leaving a bit of a problem for
applications wanting to know whether they can use them and/or why
something failed.

It also adds another subtly different set of semantics which we must
maintain at the risk of severe security regressions.

So this patch removes the SECURITY_FILE_CAPABILITIES compile
option.  It drops the kernel size by about 50k over the stock
SECURITY_FILE_CAPABILITIES=y kernel, by removing the
cap_limit_ptraced_target() function.

Changelog:
	Nov 20: remove cap_limit_ptraced_target() as it's logic
		was ifndef'ed.

Signed-off-by: Serge E. Hallyn &lt;serue@us.ibm.com&gt;
Acked-by: Andrew G. Morgan" &lt;morgan@kernel.org&gt;
Signed-off-by: James Morris &lt;jmorris@namei.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
As far as I know, all distros currently ship kernels with default
CONFIG_SECURITY_FILE_CAPABILITIES=y.  Since having the option on
leaves a 'no_file_caps' option to boot without file capabilities,
the main reason to keep the option is that turning it off saves
you (on my s390x partition) 5k.  In particular, vmlinux sizes
came to:

without patch fscaps=n:		 	53598392
without patch fscaps=y:		 	53603406
with this patch applied:		53603342

with the security-next tree.

Against this we must weigh the fact that there is no simple way for
userspace to figure out whether file capabilities are supported,
while things like per-process securebits, capability bounding
sets, and adding bits to pI if CAP_SETPCAP is in pE are not supported
with SECURITY_FILE_CAPABILITIES=n, leaving a bit of a problem for
applications wanting to know whether they can use them and/or why
something failed.

It also adds another subtly different set of semantics which we must
maintain at the risk of severe security regressions.

So this patch removes the SECURITY_FILE_CAPABILITIES compile
option.  It drops the kernel size by about 50k over the stock
SECURITY_FILE_CAPABILITIES=y kernel, by removing the
cap_limit_ptraced_target() function.

Changelog:
	Nov 20: remove cap_limit_ptraced_target() as it's logic
		was ifndef'ed.

Signed-off-by: Serge E. Hallyn &lt;serue@us.ibm.com&gt;
Acked-by: Andrew G. Morgan" &lt;morgan@kernel.org&gt;
Signed-off-by: James Morris &lt;jmorris@namei.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf: Do the big rename: Performance Counters -&gt; Performance Events</title>
<updated>2009-09-21T12:28:04+00:00</updated>
<author>
<name>Ingo Molnar</name>
<email>mingo@elte.hu</email>
</author>
<published>2009-09-21T10:02:48+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=cdd6c482c9ff9c55475ee7392ec8f672eddb7be6'/>
<id>cdd6c482c9ff9c55475ee7392ec8f672eddb7be6</id>
<content type='text'>
Bye-bye Performance Counters, welcome Performance Events!

In the past few months the perfcounters subsystem has grown out its
initial role of counting hardware events, and has become (and is
becoming) a much broader generic event enumeration, reporting, logging,
monitoring, analysis facility.

Naming its core object 'perf_counter' and naming the subsystem
'perfcounters' has become more and more of a misnomer. With pending
code like hw-breakpoints support the 'counter' name is less and
less appropriate.

All in one, we've decided to rename the subsystem to 'performance
events' and to propagate this rename through all fields, variables
and API names. (in an ABI compatible fashion)

The word 'event' is also a bit shorter than 'counter' - which makes
it slightly more convenient to write/handle as well.

Thanks goes to Stephane Eranian who first observed this misnomer and
suggested a rename.

User-space tooling and ABI compatibility is not affected - this patch
should be function-invariant. (Also, defconfigs were not touched to
keep the size down.)

This patch has been generated via the following script:

  FILES=$(find * -type f | grep -vE 'oprofile|[^K]config')

  sed -i \
    -e 's/PERF_EVENT_/PERF_RECORD_/g' \
    -e 's/PERF_COUNTER/PERF_EVENT/g' \
    -e 's/perf_counter/perf_event/g' \
    -e 's/nb_counters/nb_events/g' \
    -e 's/swcounter/swevent/g' \
    -e 's/tpcounter_event/tp_event/g' \
    $FILES

  for N in $(find . -name perf_counter.[ch]); do
    M=$(echo $N | sed 's/perf_counter/perf_event/g')
    mv $N $M
  done

  FILES=$(find . -name perf_event.*)

  sed -i \
    -e 's/COUNTER_MASK/REG_MASK/g' \
    -e 's/COUNTER/EVENT/g' \
    -e 's/\&lt;event\&gt;/event_id/g' \
    -e 's/counter/event/g' \
    -e 's/Counter/Event/g' \
    $FILES

... to keep it as correct as possible. This script can also be
used by anyone who has pending perfcounters patches - it converts
a Linux kernel tree over to the new naming. We tried to time this
change to the point in time where the amount of pending patches
is the smallest: the end of the merge window.

Namespace clashes were fixed up in a preparatory patch - and some
stylistic fallout will be fixed up in a subsequent patch.

( NOTE: 'counters' are still the proper terminology when we deal
  with hardware registers - and these sed scripts are a bit
  over-eager in renaming them. I've undone some of that, but
  in case there's something left where 'counter' would be
  better than 'event' we can undo that on an individual basis
  instead of touching an otherwise nicely automated patch. )

Suggested-by: Stephane Eranian &lt;eranian@google.com&gt;
Acked-by: Peter Zijlstra &lt;a.p.zijlstra@chello.nl&gt;
Acked-by: Paul Mackerras &lt;paulus@samba.org&gt;
Reviewed-by: Arjan van de Ven &lt;arjan@linux.intel.com&gt;
Cc: Mike Galbraith &lt;efault@gmx.de&gt;
Cc: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Cc: Frederic Weisbecker &lt;fweisbec@gmail.com&gt;
Cc: Steven Rostedt &lt;rostedt@goodmis.org&gt;
Cc: Benjamin Herrenschmidt &lt;benh@kernel.crashing.org&gt;
Cc: David Howells &lt;dhowells@redhat.com&gt;
Cc: Kyle McMartin &lt;kyle@mcmartin.ca&gt;
Cc: Martin Schwidefsky &lt;schwidefsky@de.ibm.com&gt;
Cc: "David S. Miller" &lt;davem@davemloft.net&gt;
Cc: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Cc: "H. Peter Anvin" &lt;hpa@zytor.com&gt;
Cc: &lt;linux-arch@vger.kernel.org&gt;
LKML-Reference: &lt;new-submission&gt;
Signed-off-by: Ingo Molnar &lt;mingo@elte.hu&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Bye-bye Performance Counters, welcome Performance Events!

In the past few months the perfcounters subsystem has grown out its
initial role of counting hardware events, and has become (and is
becoming) a much broader generic event enumeration, reporting, logging,
monitoring, analysis facility.

Naming its core object 'perf_counter' and naming the subsystem
'perfcounters' has become more and more of a misnomer. With pending
code like hw-breakpoints support the 'counter' name is less and
less appropriate.

All in one, we've decided to rename the subsystem to 'performance
events' and to propagate this rename through all fields, variables
and API names. (in an ABI compatible fashion)

The word 'event' is also a bit shorter than 'counter' - which makes
it slightly more convenient to write/handle as well.

Thanks goes to Stephane Eranian who first observed this misnomer and
suggested a rename.

User-space tooling and ABI compatibility is not affected - this patch
should be function-invariant. (Also, defconfigs were not touched to
keep the size down.)

This patch has been generated via the following script:

  FILES=$(find * -type f | grep -vE 'oprofile|[^K]config')

  sed -i \
    -e 's/PERF_EVENT_/PERF_RECORD_/g' \
    -e 's/PERF_COUNTER/PERF_EVENT/g' \
    -e 's/perf_counter/perf_event/g' \
    -e 's/nb_counters/nb_events/g' \
    -e 's/swcounter/swevent/g' \
    -e 's/tpcounter_event/tp_event/g' \
    $FILES

  for N in $(find . -name perf_counter.[ch]); do
    M=$(echo $N | sed 's/perf_counter/perf_event/g')
    mv $N $M
  done

  FILES=$(find . -name perf_event.*)

  sed -i \
    -e 's/COUNTER_MASK/REG_MASK/g' \
    -e 's/COUNTER/EVENT/g' \
    -e 's/\&lt;event\&gt;/event_id/g' \
    -e 's/counter/event/g' \
    -e 's/Counter/Event/g' \
    $FILES

... to keep it as correct as possible. This script can also be
used by anyone who has pending perfcounters patches - it converts
a Linux kernel tree over to the new naming. We tried to time this
change to the point in time where the amount of pending patches
is the smallest: the end of the merge window.

Namespace clashes were fixed up in a preparatory patch - and some
stylistic fallout will be fixed up in a subsequent patch.

( NOTE: 'counters' are still the proper terminology when we deal
  with hardware registers - and these sed scripts are a bit
  over-eager in renaming them. I've undone some of that, but
  in case there's something left where 'counter' would be
  better than 'event' we can undo that on an individual basis
  instead of touching an otherwise nicely automated patch. )

Suggested-by: Stephane Eranian &lt;eranian@google.com&gt;
Acked-by: Peter Zijlstra &lt;a.p.zijlstra@chello.nl&gt;
Acked-by: Paul Mackerras &lt;paulus@samba.org&gt;
Reviewed-by: Arjan van de Ven &lt;arjan@linux.intel.com&gt;
Cc: Mike Galbraith &lt;efault@gmx.de&gt;
Cc: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
Cc: Frederic Weisbecker &lt;fweisbec@gmail.com&gt;
Cc: Steven Rostedt &lt;rostedt@goodmis.org&gt;
Cc: Benjamin Herrenschmidt &lt;benh@kernel.crashing.org&gt;
Cc: David Howells &lt;dhowells@redhat.com&gt;
Cc: Kyle McMartin &lt;kyle@mcmartin.ca&gt;
Cc: Martin Schwidefsky &lt;schwidefsky@de.ibm.com&gt;
Cc: "David S. Miller" &lt;davem@davemloft.net&gt;
Cc: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Cc: "H. Peter Anvin" &lt;hpa@zytor.com&gt;
Cc: &lt;linux-arch@vger.kernel.org&gt;
LKML-Reference: &lt;new-submission&gt;
Signed-off-by: Ingo Molnar &lt;mingo@elte.hu&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>rcu: Create rcutree plugins to handle hotplug CPU for multi-level trees</title>
<updated>2009-08-29T13:34:39+00:00</updated>
<author>
<name>Paul E. McKenney</name>
<email>paulmck@linux.vnet.ibm.com</email>
</author>
<published>2009-08-27T21:58:16+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=dd5d19bafd90d33043a4a14b2e2d98612caa293c'/>
<id>dd5d19bafd90d33043a4a14b2e2d98612caa293c</id>
<content type='text'>
When offlining CPUs from a multi-level tree, there is the
possibility of offlining the last CPU from a given node when
there are preempted RCU read-side critical sections that
started life on one of the CPUs on that node.

In this case, the corresponding tasks will be enqueued via the
task_struct's rcu_node_entry list_head onto one of the
rcu_node's blocked_tasks[] lists.  These tasks need to be moved
somewhere else so that they will prevent the current grace
period from ending. That somewhere is the root rcu_node.

Signed-off-by: Paul E. McKenney &lt;paulmck@linux.vnet.ibm.com&gt;
Cc: laijs@cn.fujitsu.com
Cc: dipankar@in.ibm.com
Cc: akpm@linux-foundation.org
Cc: mathieu.desnoyers@polymtl.ca
Cc: josht@linux.vnet.ibm.com
Cc: dvhltc@us.ibm.com
Cc: niv@us.ibm.com
Cc: peterz@infradead.org
Cc: rostedt@goodmis.org
LKML-Reference: &lt;20090827215816.GA30472@linux.vnet.ibm.com&gt;
Signed-off-by: Ingo Molnar &lt;mingo@elte.hu&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
When offlining CPUs from a multi-level tree, there is the
possibility of offlining the last CPU from a given node when
there are preempted RCU read-side critical sections that
started life on one of the CPUs on that node.

In this case, the corresponding tasks will be enqueued via the
task_struct's rcu_node_entry list_head onto one of the
rcu_node's blocked_tasks[] lists.  These tasks need to be moved
somewhere else so that they will prevent the current grace
period from ending. That somewhere is the root rcu_node.

Signed-off-by: Paul E. McKenney &lt;paulmck@linux.vnet.ibm.com&gt;
Cc: laijs@cn.fujitsu.com
Cc: dipankar@in.ibm.com
Cc: akpm@linux-foundation.org
Cc: mathieu.desnoyers@polymtl.ca
Cc: josht@linux.vnet.ibm.com
Cc: dvhltc@us.ibm.com
Cc: niv@us.ibm.com
Cc: peterz@infradead.org
Cc: rostedt@goodmis.org
LKML-Reference: &lt;20090827215816.GA30472@linux.vnet.ibm.com&gt;
Signed-off-by: Ingo Molnar &lt;mingo@elte.hu&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>rcu: Remove CONFIG_PREEMPT_RCU</title>
<updated>2009-08-23T08:32:40+00:00</updated>
<author>
<name>Paul E. McKenney</name>
<email>paulmck@linux.vnet.ibm.com</email>
</author>
<published>2009-08-22T20:56:53+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=6b3ef48adf847f7adf11c870e3ffacac150f1564'/>
<id>6b3ef48adf847f7adf11c870e3ffacac150f1564</id>
<content type='text'>
Now that CONFIG_TREE_PREEMPT_RCU is in place, there is no
further need for CONFIG_PREEMPT_RCU.  Remove it, along with
whatever subtle bugs it may (or may not) contain.

Signed-off-by: Paul E. McKenney &lt;paulmck@linux.vnet.ibm.com&gt;
Cc: laijs@cn.fujitsu.com
Cc: dipankar@in.ibm.com
Cc: akpm@linux-foundation.org
Cc: mathieu.desnoyers@polymtl.ca
Cc: josht@linux.vnet.ibm.com
Cc: dvhltc@us.ibm.com
Cc: niv@us.ibm.com
Cc: peterz@infradead.org
Cc: rostedt@goodmis.org
LKML-Reference: &lt;125097461396-git-send-email-&gt;
Signed-off-by: Ingo Molnar &lt;mingo@elte.hu&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Now that CONFIG_TREE_PREEMPT_RCU is in place, there is no
further need for CONFIG_PREEMPT_RCU.  Remove it, along with
whatever subtle bugs it may (or may not) contain.

Signed-off-by: Paul E. McKenney &lt;paulmck@linux.vnet.ibm.com&gt;
Cc: laijs@cn.fujitsu.com
Cc: dipankar@in.ibm.com
Cc: akpm@linux-foundation.org
Cc: mathieu.desnoyers@polymtl.ca
Cc: josht@linux.vnet.ibm.com
Cc: dvhltc@us.ibm.com
Cc: niv@us.ibm.com
Cc: peterz@infradead.org
Cc: rostedt@goodmis.org
LKML-Reference: &lt;125097461396-git-send-email-&gt;
Signed-off-by: Ingo Molnar &lt;mingo@elte.hu&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>rcu: Merge preemptable-RCU functionality into hierarchical RCU</title>
<updated>2009-08-23T08:32:40+00:00</updated>
<author>
<name>Paul E. McKenney</name>
<email>paulmck@linux.vnet.ibm.com</email>
</author>
<published>2009-08-22T20:56:52+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=f41d911f8c49a5d65c86504c19e8204bb605c4fd'/>
<id>f41d911f8c49a5d65c86504c19e8204bb605c4fd</id>
<content type='text'>
Create a kernel/rcutree_plugin.h file that contains definitions
for preemptable RCU (or, under the #else branch of the #ifdef,
empty definitions for the classic non-preemptable semantics).
These definitions fit into plugins defined in kernel/rcutree.c
for this purpose.

This variant of preemptable RCU uses a new algorithm whose
read-side expense is roughly that of classic hierarchical RCU
under CONFIG_PREEMPT. This new algorithm's update-side expense
is similar to that of classic hierarchical RCU, and, in absence
of read-side preemption or blocking, is exactly that of classic
hierarchical RCU.  Perhaps more important, this new algorithm
has a much simpler implementation, saving well over 1,000 lines
of code compared to mainline's implementation of preemptable
RCU, which will hopefully be retired in favor of this new
algorithm.

The simplifications are obtained by maintaining per-task
nesting state for running tasks, and using a simple
lock-protected algorithm to handle accounting when tasks block
within RCU read-side critical sections, making use of lessons
learned while creating numerous user-level RCU implementations
over the past 18 months.

Signed-off-by: Paul E. McKenney &lt;paulmck@linux.vnet.ibm.com&gt;
Cc: laijs@cn.fujitsu.com
Cc: dipankar@in.ibm.com
Cc: akpm@linux-foundation.org
Cc: mathieu.desnoyers@polymtl.ca
Cc: josht@linux.vnet.ibm.com
Cc: dvhltc@us.ibm.com
Cc: niv@us.ibm.com
Cc: peterz@infradead.org
Cc: rostedt@goodmis.org
LKML-Reference: &lt;12509746134003-git-send-email-&gt;
Signed-off-by: Ingo Molnar &lt;mingo@elte.hu&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Create a kernel/rcutree_plugin.h file that contains definitions
for preemptable RCU (or, under the #else branch of the #ifdef,
empty definitions for the classic non-preemptable semantics).
These definitions fit into plugins defined in kernel/rcutree.c
for this purpose.

This variant of preemptable RCU uses a new algorithm whose
read-side expense is roughly that of classic hierarchical RCU
under CONFIG_PREEMPT. This new algorithm's update-side expense
is similar to that of classic hierarchical RCU, and, in absence
of read-side preemption or blocking, is exactly that of classic
hierarchical RCU.  Perhaps more important, this new algorithm
has a much simpler implementation, saving well over 1,000 lines
of code compared to mainline's implementation of preemptable
RCU, which will hopefully be retired in favor of this new
algorithm.

The simplifications are obtained by maintaining per-task
nesting state for running tasks, and using a simple
lock-protected algorithm to handle accounting when tasks block
within RCU read-side critical sections, making use of lessons
learned while creating numerous user-level RCU implementations
over the past 18 months.

Signed-off-by: Paul E. McKenney &lt;paulmck@linux.vnet.ibm.com&gt;
Cc: laijs@cn.fujitsu.com
Cc: dipankar@in.ibm.com
Cc: akpm@linux-foundation.org
Cc: mathieu.desnoyers@polymtl.ca
Cc: josht@linux.vnet.ibm.com
Cc: dvhltc@us.ibm.com
Cc: niv@us.ibm.com
Cc: peterz@infradead.org
Cc: rostedt@goodmis.org
LKML-Reference: &lt;12509746134003-git-send-email-&gt;
Signed-off-by: Ingo Molnar &lt;mingo@elte.hu&gt;
</pre>
</div>
</content>
</entry>
</feed>
