20 Aug, 2010
3 commits
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Currently, if RCU CPU stall warnings are enabled, they are enabled
immediately upon boot. They can be manually disabled via /sys (and
also re-enabled via /sys), and are automatically disabled upon panic.
However, some users need RCU CPU stalls to be disabled at boot time,
but to be enabled without rebuilding/rebooting. For example, someone
running a real-time application in production might not want the
additional latency of RCU CPU stall detection in normal operation, but
might need to enable it at any point for fault isolation purposes.This commit therefore provides a new CONFIG_RCU_CPU_STALL_DETECTOR_RUNNABLE
kernel configuration parameter that maintains the current behavior
(enable at boot) by default, but allows a kernel to be configured
with RCU CPU stall detection built into the kernel, but disabled at
boot time.Requested-by: Clark Williams
Requested-by: John Kacur
Signed-off-by: Paul E. McKenney -
Also set the default to 60 seconds, up from the previous hard-coded timeout
of 10 seconds. This allows people who care to set short timeouts, while
avoiding people with unusual configurations (make randconfig!!!) from being
bothered with spurious CPU stall warnings.Signed-off-by: Paul E. McKenney
Reviewed-by: Josh Triplett -
This commit provides definitions for the __rcu annotation defined earlier.
This annotation permits sparse to check for correct use of RCU-protected
pointers. If a pointer that is annotated with __rcu is accessed
directly (as opposed to via rcu_dereference(), rcu_assign_pointer(),
or one of their variants), sparse can be made to complain. To enable
such complaints, use the new default-disabled CONFIG_SPARSE_RCU_POINTER
kernel configuration option. Please note that these sparse complaints are
intended to be a debugging aid, -not- a code-style-enforcement mechanism.There are special rcu_dereference_protected() and rcu_access_pointer()
accessors for use when RCU read-side protection is not required, for
example, when no other CPU has access to the data structure in question
or while the current CPU hold the update-side lock.This patch also updates a number of docbook comments that were showing
their age.Signed-off-by: Arnd Bergmann
Signed-off-by: Paul E. McKenney
Cc: Christopher Li
Reviewed-by: Josh Triplett
17 Aug, 2010
1 commit
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warning: (LATENCYTOP && HAVE_LATENCYTOP_SUPPORT) selects
SCHED_DEBUG which has unmet direct dependencies (DEBUG_KERNEL &&
PROC_FS) warning: (LATENCYTOP && HAVE_LATENCYTOP_SUPPORT) selects
SCHEDSTATS which has unmet direct dependencies (DEBUG_KERNEL && PROC_FS)Add depends on STACKTRACE_SUPPORT for 'select STACKTRACE'.
Add depends on PROC_FS since that is where the output goes.Signed-off-by: Randy Dunlap
Cc: Arjan van de Ven
LKML-Reference:
Signed-off-by: Ingo Molnar
11 Aug, 2010
1 commit
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* 'kmemleak' of git://git.kernel.org/pub/scm/linux/kernel/git/cmarinas/linux-2.6-cm:
kmemleak: Fix typo in the comment
lib/scatterlist: Hook sg_kmalloc into kmemleak (v2)
kmemleak: Add DocBook style comments to kmemleak.c
kmemleak: Introduce a default off mode for kmemleak
kmemleak: Show more information for objects found by alias
07 Aug, 2010
3 commits
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* git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core-2.6: (28 commits)
driver core: device_rename's new_name can be const
sysfs: Remove owner field from sysfs struct attribute
powerpc/pci: Remove owner field from attribute initialization in PCI bridge init
regulator: Remove owner field from attribute initialization in regulator core driver
leds: Remove owner field from attribute initialization in bd2802 driver
scsi: Remove owner field from attribute initialization in ARCMSR driver
scsi: Remove owner field from attribute initialization in LPFC driver
cgroupfs: create /sys/fs/cgroup to mount cgroupfs on
Driver core: Add BUS_NOTIFY_BIND_DRIVER
driver core: fix memory leak on one error path in bus_register()
debugfs: no longer needs to depend on SYSFS
sysfs: Fix one more signature discrepancy between sysfs implementation and docs.
sysfs: fix discrepancies between implementation and documentation
dcdbas: remove a redundant smi_data_buf_free in dcdbas_exit
dmi-id: fix a memory leak in dmi_id_init error path
sysfs: sysfs_chmod_file's attr can be const
firmware: Update hotplug script
Driver core: move platform device creation helpers to .init.text (if MODULE=n)
Driver core: reduce duplicated code for platform_device creation
Driver core: use kmemdup in platform_device_add_resources
... -
…git/tip/linux-2.6-tip
* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (162 commits)
tracing/kprobes: unregister_trace_probe needs to be called under mutex
perf: expose event__process function
perf events: Fix mmap offset determination
perf, powerpc: fsl_emb: Restore setting perf_sample_data.period
perf, powerpc: Convert the FSL driver to use local64_t
perf tools: Don't keep unreferenced maps when unmaps are detected
perf session: Invalidate last_match when removing threads from rb_tree
perf session: Free the ref_reloc_sym memory at the right place
x86,mmiotrace: Add support for tracing STOS instruction
perf, sched migration: Librarize task states and event headers helpers
perf, sched migration: Librarize the GUI class
perf, sched migration: Make the GUI class client agnostic
perf, sched migration: Make it vertically scrollable
perf, sched migration: Parameterize cpu height and spacing
perf, sched migration: Fix key bindings
perf, sched migration: Ignore unhandled task states
perf, sched migration: Handle ignored migrate out events
perf: New migration tool overview
tracing: Drop cpparg() macro
perf: Use tracepoint_synchronize_unregister() to flush any pending tracepoint call
...Fix up trivial conflicts in Makefile and drivers/cpufreq/cpufreq.c
-
* 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
Revert "net: Make accesses to ->br_port safe for sparse RCU"
mce: convert to rcu_dereference_index_check()
net: Make accesses to ->br_port safe for sparse RCU
vfs: add fs.h to define struct file
lockdep: Add an in_workqueue_context() lockdep-based test function
rcu: add __rcu API for later sparse checking
rcu: add an rcu_dereference_index_check()
tree/tiny rcu: Add debug RCU head objects
mm: remove all rcu head initializations
fs: remove all rcu head initializations, except on_stack initializations
powerpc: remove all rcu head initializations
06 Aug, 2010
2 commits
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* 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild-2.6:
modpost: support objects with more than 64k sections
trivial: fix a typo in a filename
frv: clean up arch/frv/Makefile
kbuild: allow assignment to {A,C}FLAGS_KERNEL on the command line
kbuild: allow assignment to {A,C,LD}FLAGS_MODULE on the command line
Kbuild: Add option to set -femit-struct-debug-baseonly
Makefile: "make kernelrelease" should show the correct full kernel version
Makefile.build: make KBUILD_SYMTYPES work again -
debugfs no longer uses 'kernel_subsys' (which is gone), and other
kernel/ksysfs.c code is always built, so DEBUG_FS does not need
to depend on SYSFS.Fixes this kconfig warning:
warning: (TREE_RCU_TRACE || AMD_IOMMU_STATS && AMD_IOMMU || MTD_UBI_DEBUG && MTD && SYSFS && MTD_UBI || UBIFS_FS_DEBUG && MISC_FILESYSTEMS && UBIFS_FS || DEBUG_KMEMLEAK && DEBUG_KERNEL && EXPERIMENTAL && !MEMORY_HOTPLUG && (X86 || ARM || PPC || S390 || SPARC64 || SUPERH || MICROBLAZE) && SYSFS || TRACING || X86_PTDUMP && DEBUG_KERNEL || BLK_DEV_IO_TRACE && TRACING_SUPPORT && FTRACE && SYSFS && BLOCK) selects DEBUG_FS which has unmet direct dependencies (SYSFS)
Signed-off-by: Randy Dunlap
Signed-off-by: Greg Kroah-Hartman
05 Aug, 2010
2 commits
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* 'for-linus' of git://git.monstr.eu/linux-2.6-microblaze: (49 commits)
microblaze: Add KGDB support
microblaze: Support brki rX, 0x18 for user application debugging
microblaze: Remove nop after MSRCLR/SET, MTS, MFS instructions
microblaze: Simplify syscall rutine
microblaze: Move PT_MODE saving to delay slot
microblaze: Fix _interrupt function
microblaze: Fix _user_exception function
microblaze: Put together addik instructions
microblaze: Use delay slot in syscall macros
microblaze: Save kernel mode in delay slot
microblaze: Do not mix register saving and mode setting
microblaze: Move SAVE_STATE upward
microblaze: entry.S: Macro optimization
microblaze: Optimize hw exception rutine
microblaze: Implement clear_ums macro and fix SAVE_STATE macro
microblaze: Remove additional setup for kernel_mode
microblaze: Optimize SAVE_STATE macro
microblaze: Remove additional loading
microblaze: Completely remove working with R11 register
microblaze: Do not setup BIP in _debug_exception
... -
Conflicts:
kernel/MakefileMerge reason: Add the now complete topic, fix the conflict.
Signed-off-by: Ingo Molnar
04 Aug, 2010
2 commits
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Conflicts:
arch/powerpc/Makefile -
Microblaze doesn't support frame pointers. Ftrace code
uses CALLER_ADDR1 which is defined in linux/ftrace.h. For Microblaze
is 0.Signed-off-by: Michal Simek
21 Jul, 2010
1 commit
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The last 't' of 'fault' is missing in the description of FAIL_IO_TIMEOUT.
Signed-off-by: Takuya Yoshikawa
Signed-off-by: Jiri Kosina
19 Jul, 2010
1 commit
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Introduce a new DEBUG_KMEMLEAK_DEFAULT_OFF config parameter that allows
kmemleak to be disabled by default, but enabled on the command line
via: kmemleak=on. Although a reboot is required to turn it on, its still
useful to not require a re-compile.Signed-off-by: Jason Baron
Signed-off-by: Catalin Marinas
Acked-by: Pekka Enberg
14 Jul, 2010
1 commit
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Newer gcc has a -femit-struct-debug-baseonly option that dramatically
reduces the size of object files with debug info. What it does
is to only emit type information for structures when the structures
are defined in the same file or in a header file.This means the type information for most headers are not included.
This is not good when the type information is actually
needed (e.g. with kgdb or systemtap)But often kernel hackers only care about line numbers and don't
need all the type information anyways. In this case setting
the option can be a big win:A build dir for a specific x86-64 configuration with gcc 4.5
shrunk from 2.3G to 1.2G. The compilation was also nearly a minute
faster.Signed-off-by: Andi Kleen
[mmarek: reformatted help text]
Signed-off-by: Michal Marek
15 Jun, 2010
1 commit
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Helps finding racy users of call_rcu(), which results in hangs because list
entries are overwritten and/or skipped.Changelog since v4:
- Bissectability is now OK
- Now generate a WARN_ON_ONCE() for non-initialized rcu_head passed to
call_rcu(). Statically initialized objects are detected with
object_is_static().
- Rename rcu_head_init_on_stack to init_rcu_head_on_stack.
- Remove init_rcu_head() completely.Changelog since v3:
- Include comments from Lai JiangshanThis new patch version is based on the debugobjects with the newly introduced
"active state" tracker.Non-initialized entries are all considered as "statically initialized". An
activation fixup (triggered by call_rcu()) takes care of performing the debug
object initialization without issuing any warning. Since we cannot increase the
size of struct rcu_head, I don't see much room to put an identifier for
statically initialized rcu_head structures. So for now, we have to live without
"activation without explicit init" detection. But the main purpose of this debug
option is to detect double-activations (double call_rcu() use of a rcu_head
before the callback is executed), which is correctly addressed here.This also detects potential internal RCU callback corruption, which would cause
the callbacks to be executed twice.Signed-off-by: Mathieu Desnoyers
CC: David S. Miller
CC: "Paul E. McKenney"
CC: akpm@linux-foundation.org
CC: mingo@elte.hu
CC: laijs@cn.fujitsu.com
CC: dipankar@in.ibm.com
CC: josh@joshtriplett.org
CC: dvhltc@us.ibm.com
CC: niv@us.ibm.com
CC: tglx@linutronix.de
CC: peterz@infradead.org
CC: rostedt@goodmis.org
CC: Valdis.Kletnieks@vt.edu
CC: dhowells@redhat.com
CC: eric.dumazet@gmail.com
CC: Alexey Dobriyan
Signed-off-by: Paul E. McKenney
Reviewed-by: Lai Jiangshan
28 May, 2010
1 commit
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I used this module to test the series of modification to the cpu notifiers
code.Example1: inject CPU offline error (-1 == -EPERM)
# modprobe cpu-notifier-error-inject cpu_down_prepare_error=-1
# echo 0 > /sys/devices/system/cpu/cpu1/online
bash: echo: write error: Operation not permittedExample2: inject CPU online error (-2 == -ENOENT)
# modprobe cpu-notifier-error-inject cpu_up_prepare_error=-2
# echo 1 > /sys/devices/system/cpu/cpu1/online
bash: echo: write error: No such file or directory[akpm@linux-foundation.org: fix Kconfig help text]
Signed-off-by: Akinobu Mita
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
25 May, 2010
1 commit
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[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Florian Ragwitz
Cc: Jason Baron
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
19 May, 2010
1 commit
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The lockup detector is a new feature that now involves the
nmi watchdog. Drop the default y and let the user choose.Signed-off-by: Frederic Weisbecker
Cc: Don Zickus
Cc: Ingo Molnar
Cc: Peter Zijlstra
Cc: Cyrill Gorcunov
18 May, 2010
1 commit
-
…/git/tip/linux-2.6-tip
* 'x86-atomic-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86: Fix LOCK_PREFIX_HERE for uniprocessor build
x86, atomic64: In selftest, distinguish x86-64 from 586+
x86-32: Fix atomic64_inc_not_zero return value convention
lib: Fix atomic64_inc_not_zero test
lib: Fix atomic64_add_unless return value convention
x86-32: Fix atomic64_add_unless return value convention
lib: Fix atomic64_add_unless test
x86: Implement atomic[64]_dec_if_positive()
lib: Only test atomic64_dec_if_positive on archs having it
x86-32: Rewrite 32-bit atomic64 functions in assembly
lib: Add self-test for atomic64_t
x86-32: Allow UP/SMP lock replacement in cmpxchg64
x86: Add support for lock prefix in alternatives
16 May, 2010
2 commits
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This new config is deemed to simplify even more the lockup detector
dependencies and can make it easier to bring a smooth sorting
between archs that support the new generic lockup detector and those
that still have their own, especially for those that are in the
middle of this migration.Instead of checking whether we have CONFIG_LOCKUP_DETECTOR +
CONFIG_PERF_EVENTS_NMI each time an arch wants to know if it needs
to build its own lockup detector, take a shortcut with this new
config. It is enabled only if the hardlockup detection part of
the whole lockup detector is on.Signed-off-by: Frederic Weisbecker
Cc: Ingo Molnar
Cc: Peter Zijlstra
Cc: Don Zickus
Cc: Cyrill Gorcunov -
We kept CONFIG_DETECT_SOFTLOCKUP around for compatibility with
older configs. But it was enabled by default if CONFIG_DEBUG_KERNEL.So if we want to enable CONFIG_LOCKUP_DETECTOR on configs that had
CONFIG_DETECT_SOFTLOCKUP, all we need is to have the same enabling
by default if CONFIG_DEBUG_KERNEL. We can then remove
CONFIG_DETECT_SOFTLOCKUP directly.So tag CONFIG_LOCKUP_DETECTOR as default y. This is what we want for
most serious kernel debugging anyway.And also forbid the lockup detector in S390 as it was for the
previous softlockup detector, event though the true reason for that
is not outlined.Signed-off-by: Frederic Weisbecker
Cc: Ingo Molnar
Cc: Don Zickus
Cc: Peter Zijlstra
Cc: Cyrill Gorcunov
13 May, 2010
3 commits
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Panic on softlockups was still depending on the softlockup detector.
But the latter has been merged into the lockup detector now.Let's update this config dependency.
Signed-off-by: Frederic Weisbecker
Cc: Don Zickus
Cc: Ingo Molnar
Cc: Peter Zijlstra
Cc: Cyrill Gorcunov
Cc: Eric Paris
Cc: Randy Dunlap -
The new nmi_watchdog (which uses the perf event subsystem) is very
similar in structure to the softlockup detector. Using Ingo's
suggestion, I combined the two functionalities into one file:
kernel/watchdog.c.Now both the nmi_watchdog (or hardlockup detector) and softlockup
detector sit on top of the perf event subsystem, which is run every
60 seconds or so to see if there are any lockups.To detect hardlockups, cpus not responding to interrupts, I
implemented an hrtimer that runs 5 times for every perf event
overflow event. If that stops counting on a cpu, then the cpu is
most likely in trouble.To detect softlockups, tasks not yielding to the scheduler, I used the
previous kthread idea that now gets kicked every time the hrtimer fires.
If the kthread isn't being scheduled neither is anyone else and the
warning is printed to the console.I tested this on x86_64 and both the softlockup and hardlockup paths
work.V2:
- cleaned up the Kconfig and softlockup combination
- surrounded hardlockup cases with #ifdef CONFIG_PERF_EVENTS_NMI
- seperated out the softlockup case from perf event subsystem
- re-arranged the enabling/disabling nmi watchdog from proc space
- added cpumasks for hardlockup failure cases
- removed fallback to soft events if no PMU exists for hard eventsV3:
- comment cleanups
- drop support for older softlockup code
- per_cpu cleanups
- completely remove software clock base hardlockup detector
- use per_cpu masking on hard/soft lockup detection
- #ifdef cleanups
- rename config option NMI_WATCHDOG to LOCKUP_DETECTOR
- documentation additionsV4:
- documentation fixes
- convert per_cpu to __get_cpu_var
- powerpc compile fixesV5:
- split apart warn flags for hard and soft lockupsTODO:
- figure out how to make an arch-agnostic clock2cycles call
(if possible) to feed into perf events as a sample period[fweisbec: merged conflict patch]
Signed-off-by: Don Zickus
Cc: Ingo Molnar
Cc: Peter Zijlstra
Cc: Cyrill Gorcunov
Cc: Eric Paris
Cc: Randy Dunlap
LKML-Reference:
Signed-off-by: Frederic Weisbecker -
Merge reason: catch up with latest softlockup detector changes.
11 May, 2010
2 commits
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The CPU_STALL_VERBOSE kernel configuration parameter was added to
2.6.34 to identify any preempted/blocked tasks that were preventing
the current grace period from completing when running preemptible
RCU. As is conventional for new configurations parameters, this
defaulted disabled. It is now time to enable it by default.Signed-off-by: Paul E. McKenney
-
There is no need to disable lockdep after an RCU lockdep splat,
so remove the debug_lockdeps_off() from lockdep_rcu_dereference().
To avoid repeated lockdep splats, use a static variable in the inlined
rcu_dereference_check() and rcu_dereference_protected() macros so that
a given instance splats only once, but so that multiple instances can
be detected per boot.This is controlled by a new config variable CONFIG_PROVE_RCU_REPEATEDLY,
which is disabled by default. This provides the normal lockdep behavior
by default, but permits people who want to find multiple RCU-lockdep
splats per boot to easily do so.Requested-by: Eric Paris
Signed-off-by: Lai Jiangshan
Tested-by: Eric Paris
Signed-off-by: Paul E. McKenney
30 Apr, 2010
1 commit
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Merge reason:
Conflict between LOCK_PREFIX_HERE and relative alternatives
pointersResolved Conflicts:
arch/x86/include/asm/alternative.h
arch/x86/kernel/alternative.cSigned-off-by: H. Peter Anvin
13 Apr, 2010
2 commits
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Conflicts:
lib/Kconfig.debug -
Only missing thing was an _sdata marker in vmlinux.lds.S
Signed-off-by: David S. Miller
07 Apr, 2010
1 commit
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Enable DEBUG_KMEMLEAK for microblaze
Signed-off-by: Michal Simek
25 Mar, 2010
1 commit
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We see only one section mismatch now after thousands of randconfigs, and a
bug has been filed about that one.Signed-off-by: Mike Frysinger
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
10 Mar, 2010
1 commit
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Conflicts:
tools/perf/util/probe-event.cMerge reason: Pick up -rc1 and resolve the conflict as well.
Signed-off-by: Ingo Molnar
07 Mar, 2010
1 commit
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Add adds a debugfs interface and additional failure modes to LKDTM to
provide similar functionality to the provoke-crash driver submitted here:http://lwn.net/Articles/371208/
Crashes can now be induced either through module parameters (as before)
or through the debugfs interface as in provoke-crash.The patch also provides a new "direct" interface, where KPROBES are not
used, i.e., the crash is invoked directly upon write to the debugfs
file. When built without KPROBES configured, only this mode is available.Signed-off-by: Simon Kagstrom
Cc: M. Mohan Kumar
Cc: Americo Wang
Cc: David Woodhouse
Cc: Ingo Molnar
Cc: "Eric W. Biederman" ,
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
01 Mar, 2010
2 commits
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It was nice to enable it by default for testing - but before we
push it upstream we want it to be off - so that people can
opt-in gradually.Cc: Don Zickus
Cc: peterz@infradead.org
Cc: gorcunov@gmail.com
Cc: aris@redhat.com
LKML-Reference:
Signed-off-by: Ingo Molnar -
* 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (44 commits)
rcu: Fix accelerated GPs for last non-dynticked CPU
rcu: Make non-RCU_PROVE_LOCKING rcu_read_lock_sched_held() understand boot
rcu: Fix accelerated grace periods for last non-dynticked CPU
rcu: Export rcu_scheduler_active
rcu: Make rcu_read_lock_sched_held() take boot time into account
rcu: Make lockdep_rcu_dereference() message less alarmist
sched, cgroups: Fix module export
rcu: Add RCU_CPU_STALL_VERBOSE to dump detailed per-task information
rcu: Fix rcutorture mod_timer argument to delay one jiffy
rcu: Fix deadlock in TREE_PREEMPT_RCU CPU stall detection
rcu: Convert to raw_spinlocks
rcu: Stop overflowing signed integers
rcu: Use canonical URL for Mathieu's dissertation
rcu: Accelerate grace period if last non-dynticked CPU
rcu: Fix citation of Mathieu's dissertation
rcu: Documentation update for CONFIG_PROVE_RCU
security: Apply lockdep-based checking to rcu_dereference() uses
idr: Apply lockdep-based diagnostics to rcu_dereference() uses
radix-tree: Disable RCU lockdep checking in radix tree
vfs: Abstract rcu_dereference_check for files-fdtable use
...
28 Feb, 2010
2 commits
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Remove pointless union in the breakpoint field of hw_perf_event.
Signed-off-by: Frederic Weisbecker
Cc: Peter Zijlstra
Cc: Paul Mackerras -
I've forgot to add 'perf lock' line to command-list.txt,
so users of perf could not find perf lock when they type 'perf'.Fixing command-list.txt requires document
(tools/perf/Documentation/perf-lock.txt).
But perf lock is too much "under construction" to write a
stable document, so this is something like pseudo document for now.And I wrote description of perf lock at help section of
CONFIG_LOCK_STAT, this will navigate users of lock trace events.Signed-off-by: Hitoshi Mitake
Cc: Peter Zijlstra
Cc: Paul Mackerras
Cc: Arnaldo Carvalho de Melo
LKML-Reference:
Signed-off-by: Frederic Weisbecker
