Patch 1 implements support for interval trees, on top of the augmented
rbtree API. It also adds synthetic tests to compare the performance of
interval trees vs prio trees. Short answers is that interval trees are
slightly faster (~25%) on insert/erase, and much faster (~2.4 - 3x)
on search. It is debatable how realistic the synthetic test is, and I have
not made such measurements yet, but my impression is that interval trees
would still come out faster.
Patch 2 uses a preprocessor template to make the interval tree generic,
and uses it as a replacement for the vma prio_tree.
Patch 3 takes the other prio_tree user, kmemleak, and converts it to use
a basic rbtree. We don't actually need the augmented rbtree support here
because the intervals are always non-overlapping.
Patch 4 removes the now-unused prio tree library.
Patch 5 proposes an additional optimization to rb_erase_augmented, now
providing it as an inline function so that the augmented callbacks can be
inlined in. This provides an additional 5-10% performance improvement
for the interval tree insert/erase benchmark. There is a maintainance cost
as it exposes augmented rbtree users to some of the rbtree library internals;
however I think this cost shouldn't be too high as I expect the augmented
rbtree will always have much less users than the base rbtree.
I should probably add a quick summary of why I think it makes sense to
replace prio trees with augmented rbtree based interval trees now. One of
the drivers is that we need augmented rbtrees for Rik's vma gap finding
code, and once you have them, it just makes sense to use them for interval
trees as well, as this is the simpler and more well known algorithm. prio
trees, in comparison, seem *too* clever: they impose an additional 'heap'
constraint on the tree, which they use to guarantee a faster worst-case
complexity of O(k+log N) for stabbing queries in a well-balanced prio
tree, vs O(k*log N) for interval trees (where k=number of matches,
N=number of intervals). Now this sounds great, but in practice prio trees
don't realize this theorical benefit. First, the additional constraint
makes them harder to update, so that the kernel implementation has to
simplify things by balancing them like a radix tree, which is not always
ideal. Second, the fact that there are both index and heap properties
makes both tree manipulation and search more complex, which results in a
higher multiplicative time constant. As it turns out, the simple interval
tree algorithm ends up running faster than the more clever prio tree.
This patch:
Add two test modules:
- prio_tree_test measures the performance of lib/prio_tree.c, both for
insertion/removal and for stabbing searches
- interval_tree_test measures the performance of a library of equivalent
functionality, built using the augmented rbtree support.
In order to support the second test module, lib/interval_tree.c is
introduced. It is kept separate from the interval_tree_test main file
for two reasons: first we don't want to provide an unfair advantage
over prio_tree_test by having everything in a single compilation unit,
and second there is the possibility that the interval tree functionality
could get some non-test users in kernel over time.
Signed-off-by: Michel Lespinasse <walken@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Hillf Danton <dhillf@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This small module helps measure the performance of rbtree insert and
erase.
Additionally, we run a few correctness tests to check that the rbtrees
have all desired properties:
- contains the right number of nodes in the order desired,
- never two consecutive red nodes on any path,
- all paths to leaf nodes have the same number of black nodes,
- root node is black
[akpm@linux-foundation.org: fix printk warning: sparc64 cycles_t is unsigned long]
Signed-off-by: Michel Lespinasse <walken@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: David Woodhouse <David.Woodhouse@intel.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Daniel Santos <daniel.santos@pobox.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Introduce HAVE_DEBUG_KMEMLEAK config option and select it in corresponding
architecture Kconfig files. DEBUG_KMEMLEAK now only depends on
HAVE_DEBUG_KMEMLEAK.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The main option should not appear in the resulting .config when the
dependencies aren't met (i.e. use "depends on" rather than directly
setting the default from the combined dependency values).
The sub-options should depend on the main option rather than a more
generic higher level one.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Don Zickus <dzickus@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Features currently supported:
- 39-bit address space for user and kernel (each)
- 4KB and 64KB page configurations
- Compat (32-bit) user applications (ARMv7, EABI only)
- Flattened Device Tree (mandated for all AArch64 platforms)
- ARM generic timers
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Merge tag 'arm64-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/cmarinas/linux-aarch64
Pull arm64 support from Catalin Marinas:
"Linux support for the 64-bit ARM architecture (AArch64)
Features currently supported:
- 39-bit address space for user and kernel (each)
- 4KB and 64KB page configurations
- Compat (32-bit) user applications (ARMv7, EABI only)
- Flattened Device Tree (mandated for all AArch64 platforms)
- ARM generic timers"
* tag 'arm64-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/cmarinas/linux-aarch64: (35 commits)
arm64: ptrace: remove obsolete ptrace request numbers from user headers
arm64: Do not set the SMP/nAMP processor bit
arm64: MAINTAINERS update
arm64: Build infrastructure
arm64: Miscellaneous header files
arm64: Generic timers support
arm64: Loadable modules
arm64: Miscellaneous library functions
arm64: Performance counters support
arm64: Add support for /proc/sys/debug/exception-trace
arm64: Debugging support
arm64: Floating point and SIMD
arm64: 32-bit (compat) applications support
arm64: User access library functions
arm64: Signal handling support
arm64: VDSO support
arm64: System calls handling
arm64: ELF definitions
arm64: SMP support
arm64: DMA mapping API
...
There have been some recent bugs that were triggered only when
preemptible RCU's __rcu_read_unlock() was preempted just after setting
->rcu_read_lock_nesting to INT_MIN, which is a low-probability event.
Therefore, reproducing those bugs (to say nothing of gaining confidence
in alleged fixes) was quite difficult. This commit therefore creates
a new debug-only RCU kernel config option that forces a short delay
in __rcu_read_unlock() to increase the probability of those sorts of
bugs occurring.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
This patch adds Makefile and Kconfig files required for building an
AArch64 kernel.
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Acked-by: Nicolas Pitre <nico@linaro.org>
Acked-by: Olof Johansson <olof@lixom.net>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
This provides the ability to inject artifical errors to pSeries reconfig
notifier chain callbacks. It is controlled through debugfs interface
under /sys/kernel/debug/notifier-error-inject/pSeries-reconfig
If the notifier call chain should be failed with some events
notified, write the error code to "actions/<notifier event>/error".
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Greg KH <greg@kroah.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <michael@ellerman.id.au>
Cc: Dave Jones <davej@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This provides the ability to inject artifical errors to memory hotplug
notifier chain callbacks. It is controlled through debugfs interface
under /sys/kernel/debug/notifier-error-inject/memory
If the notifier call chain should be failed with some events notified,
write the error code to "actions/<notifier event>/error".
Example: Inject memory hotplug offline error (-12 == -ENOMEM)
# cd /sys/kernel/debug/notifier-error-inject/memory
# echo -12 > actions/MEM_GOING_OFFLINE/error
# echo offline > /sys/devices/system/memory/memoryXXX/state
bash: echo: write error: Cannot allocate memory
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Greg KH <greg@kroah.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <michael@ellerman.id.au>
Cc: Dave Jones <davej@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This provides the ability to inject artifical errors to PM notifier chain
callbacks. It is controlled through debugfs interface under
/sys/kernel/debug/notifier-error-inject/pm
Each of the files in "error" directory represents an event which can be
failed and contains the error code. If the notifier call chain should be
failed with some events notified, write the error code to the files.
If the notifier call chain should be failed with some events notified,
write the error code to "actions/<notifier event>/error".
Example: Inject PM suspend error (-12 = -ENOMEM)
# cd /sys/kernel/debug/notifier-error-inject/pm
# echo -12 > actions/PM_SUSPEND_PREPARE/error
# echo mem > /sys/power/state
bash: echo: write error: Cannot allocate memory
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Acked-by: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Greg KH <greg@kroah.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <michael@ellerman.id.au>
Cc: Dave Jones <davej@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Rewrite existing cpu-notifier-error-inject module to use debugfs based new
framework.
This change removes cpu_up_prepare_error and cpu_down_prepare_error module
parameters which were used to specify error code to be injected. We could
keep these module parameters for backward compatibility by module_param_cb
but it seems overkill for this module.
This provides the ability to inject artifical errors to CPU notifier chain
callbacks. It is controlled through debugfs interface under
/sys/kernel/debug/notifier-error-inject/cpu
If the notifier call chain should be failed with some events notified,
write the error code to "actions/<notifier event>/error".
Example1: inject CPU offline error (-1 == -EPERM)
# cd /sys/kernel/debug/notifier-error-inject/cpu
# echo -1 > actions/CPU_DOWN_PREPARE/error
# echo 0 > /sys/devices/system/cpu/cpu1/online
bash: echo: write error: Operation not permitted
Example2: inject CPU online error (-2 == -ENOENT)
# cd /sys/kernel/debug/notifier-error-inject/cpu
# echo -2 > actions/CPU_UP_PREPARE/error
# echo 1 > /sys/devices/system/cpu/cpu1/online
bash: echo: write error: No such file or directory
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Greg KH <greg@kroah.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <michael@ellerman.id.au>
Cc: Dave Jones <davej@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patchset provides kernel modules that can be used to test the error
handling of notifier call chain failures by injecting artifical errors to
the following notifier chain callbacks.
* CPU notifier
* PM notifier
* memory hotplug notifier
* powerpc pSeries reconfig notifier
Example: Inject CPU offline error (-1 == -EPERM)
# cd /sys/kernel/debug/notifier-error-inject/cpu
# echo -1 > actions/CPU_DOWN_PREPARE/error
# echo 0 > /sys/devices/system/cpu/cpu1/online
bash: echo: write error: Operation not permitted
The patchset also adds cpu and memory hotplug tests to
tools/testing/selftests These tests first do simple online and offline
test and then do fault injection tests if notifier error injection
module is available.
This patch:
The notifier error injection provides the ability to inject artifical
errors to specified notifier chain callbacks. It is useful to test the
error handling of notifier call chain failures.
This adds common basic functions to define which type of events can be
fail and to initialize the debugfs interface to control what error code
should be returned and which event should be failed.
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Greg KH <greg@kroah.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <michael@ellerman.id.au>
Cc: Dave Jones <davej@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Merge tag 'please-pull-misc-3.6' of git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux
Pull misc Itanium fixes from Tony Luck.
* tag 'please-pull-misc-3.6' of git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux:
debug: Do not permit CONFIG_DEBUG_STACK_USAGE=y on IA64 or PARISC
[IA64] Port OOM changes to ia64_do_page_fault
The stack_not_used() function in <linux/sched.h> assumes that stacks
grow downwards. This is not true on IA64 or PARISC, so this function
would walk off in the wrong direction and into the weeds.
Found on IA64 because of a compilation failure with recursive dependencies
on IA64_TASKSIZE and IA64_THREAD_INFO_SIZE.
Fixing the code is possible, but should be combined with other
infrastructure additions to set up the "canary" at the end of the stack.
Reported-by: Fengguang Wu <fengguang.wu@intel.com> (failed allmodconfig build)
Signed-off-by: Tony Luck <tony.luck@intel.com>
The output of the timestamps got lost with the conversion of the
kmsg buffer to records; restore the old behavior.
Document, that CONFIG_PRINTK_TIME now only controls the output of
the timestamps in the syslog() system call and on the console, and
not the recording of the timestamps.
Cc: Joe Perches <joe@perches.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Sasha Levin <levinsasha928@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Reported-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Kay Sievers <kay@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Several distros set this by default by patching panic_on_oops.
It seems to fit with the BOOTPARAM_{HARD,SOFT}_PANIC options
though, so let's add a Kconfig entry and reduce some more
upstream delta.
Signed-off-by: Kyle McMartin <kyle@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20120411121529.GH26688@redacted.bos.redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
In dynamic-debug-howto.txt:
- add section: Debug Messages at Module Initialization Time
- update flags indicators in example outputs to include '='
- make flags descriptions tabular
- add item on '_' flag-char
- add dyndbg, boot-args examples
- rewrap some paragraphs with long lines
In Kconfig.debug, note that compiling with -DDEBUG enables all
pr_debug()s in that code.
In kernel-parameters.txt, add dyndbg and module.dyndbg items,
and deprecate ddebug_query.
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Acked-by: Jason Baron <jbaron@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add a config option to disable various gcc compiler optimizations that
make assembler listings much harder to read. This is everything that reorders
code significantly or creates partial functions.
This is mainly to keep kernel hackers sane.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/1332960678-11879-2-git-send-email-andi@firstfloor.org
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Pull x86 updates from Ingo Molnar.
This touches some non-x86 files due to the sanitized INLINE_SPIN_UNLOCK
config usage.
Fixed up trivial conflicts due to just header include changes (removing
headers due to cpu_idle() merge clashing with the <asm/system.h> split).
* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/apic/amd: Be more verbose about LVT offset assignments
x86, tls: Off by one limit check
x86/ioapic: Add io_apic_ops driver layer to allow interception
x86/olpc: Add debugfs interface for EC commands
x86: Merge the x86_32 and x86_64 cpu_idle() functions
x86/kconfig: Remove CONFIG_TR=y from the defconfigs
x86: Stop recursive fault in print_context_stack after stack overflow
x86/io_apic: Move and reenable irq only when CONFIG_GENERIC_PENDING_IRQ=y
x86/apic: Add separate apic_id_valid() functions for selected apic drivers
locking/kconfig: Simplify INLINE_SPIN_UNLOCK usage
x86/kconfig: Update defconfigs
x86: Fix excessive MSR print out when show_msr is not specified
Pull sysctl updates from Eric Biederman:
- Rewrite of sysctl for speed and clarity.
Insert/remove/Lookup in sysctl are all now O(NlogN) operations, and
are no longer bottlenecks in the process of adding and removing
network devices.
sysctl is now focused on being a filesystem instead of system call
and the code can all be found in fs/proc/proc_sysctl.c. Hopefully
this means the code is now approachable.
Much thanks is owed to Lucian Grinjincu for keeping at this until
something was found that was usable.
- The recent proc_sys_poll oops found by the fuzzer during hibernation
is fixed.
* git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/sysctl: (36 commits)
sysctl: protect poll() in entries that may go away
sysctl: Don't call sysctl_follow_link unless we are a link.
sysctl: Comments to make the code clearer.
sysctl: Correct error return from get_subdir
sysctl: An easier to read version of find_subdir
sysctl: fix memset parameters in setup_sysctl_set()
sysctl: remove an unused variable
sysctl: Add register_sysctl for normal sysctl users
sysctl: Index sysctl directories with rbtrees.
sysctl: Make the header lists per directory.
sysctl: Move sysctl_check_dups into insert_header
sysctl: Modify __register_sysctl_paths to take a set instead of a root and an nsproxy
sysctl: Replace root_list with links between sysctl_table_sets.
sysctl: Add sysctl_print_dir and use it in get_subdir
sysctl: Stop requiring explicit management of sysctl directories
sysctl: Add a root pointer to ctl_table_set
sysctl: Rewrite proc_sys_readdir in terms of first_entry and next_entry
sysctl: Rewrite proc_sys_lookup introducing find_entry and lookup_entry.
sysctl: Normalize the root_table data structure.
sysctl: Factor out insert_header and erase_header
...
ARCH_HAS_NMI_WATCHDOG is a macro defined by arch, but config
HARDLOCKUP_DETECTOR depends on it. This is wrong, ARCH_HAS_NMI_WATCHDOG
has to be a Kconfig config, and arch's need it should select it
explicitly.
Signed-off-by: WANG Cong <xiyou.wangcong@gmail.com>
Acked-by: Don Zickus <dzickus@redhat.com>
Acked-by: Mike Frysinger <vapier@gentoo.org>
Cc: David Howells <dhowells@redhat.com>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Get rid of INLINE_SPIN_UNLOCK entirely replacing it with
UNINLINE_SPIN_UNLOCK instead of the reverse meaning.
Whoever wants to change the default spinlock inlining
behavior and uninline the spinlocks for some weird reason,
such as spinlock debugging, paravirt etc. can now all just
select UNINLINE_SPIN_UNLOCK
Original discussion at: https://lkml.org/lkml/2012/3/21/357
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: linux-mips@linux-mips.org
Link: http://lkml.kernel.org/r/20120322095502.30866.75756.sendpatchset@codeblue
[ tidied up the changelog a bit ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull perf events changes for v3.4 from Ingo Molnar:
- New "hardware based branch profiling" feature both on the kernel and
the tooling side, on CPUs that support it. (modern x86 Intel CPUs
with the 'LBR' hardware feature currently.)
This new feature is basically a sophisticated 'magnifying glass' for
branch execution - something that is pretty difficult to extract from
regular, function histogram centric profiles.
The simplest mode is activated via 'perf record -b', and the result
looks like this in perf report:
$ perf record -b any_call,u -e cycles:u branchy
$ perf report -b --sort=symbol
52.34% [.] main [.] f1
24.04% [.] f1 [.] f3
23.60% [.] f1 [.] f2
0.01% [k] _IO_new_file_xsputn [k] _IO_file_overflow
0.01% [k] _IO_vfprintf_internal [k] _IO_new_file_xsputn
0.01% [k] _IO_vfprintf_internal [k] strchrnul
0.01% [k] __printf [k] _IO_vfprintf_internal
0.01% [k] main [k] __printf
This output shows from/to branch columns and shows the highest
percentage (from,to) jump combinations - i.e. the most likely taken
branches in the system. "branches" can also include function calls
and any other synchronous and asynchronous transitions of the
instruction pointer that are not 'next instruction' - such as system
calls, traps, interrupts, etc.
This feature comes with (hopefully intuitive) flat ascii and TUI
support in perf report.
- Various 'perf annotate' visual improvements for us assembly junkies.
It will now recognize function calls in the TUI and by hitting enter
you can follow the call (recursively) and back, amongst other
improvements.
- Multiple threads/processes recording support in perf record, perf
stat, perf top - which is activated via a comma-list of PIDs:
perf top -p 21483,21485
perf stat -p 21483,21485 -ddd
perf record -p 21483,21485
- Support for per UID views, via the --uid paramter to perf top, perf
report, etc. For example 'perf top --uid mingo' will only show the
tasks that I am running, excluding other users, root, etc.
- Jump label restructurings and improvements - this includes the
factoring out of the (hopefully much clearer) include/linux/static_key.h
generic facility:
struct static_key key = STATIC_KEY_INIT_FALSE;
...
if (static_key_false(&key))
do unlikely code
else
do likely code
...
static_key_slow_inc();
...
static_key_slow_inc();
...
The static_key_false() branch will be generated into the code with as
little impact to the likely code path as possible. the
static_key_slow_*() APIs flip the branch via live kernel code patching.
This facility can now be used more widely within the kernel to
micro-optimize hot branches whose likelihood matches the static-key
usage and fast/slow cost patterns.
- SW function tracer improvements: perf support and filtering support.
- Various hardenings of the perf.data ABI, to make older perf.data's
smoother on newer tool versions, to make new features integrate more
smoothly, to support cross-endian recording/analyzing workflows
better, etc.
- Restructuring of the kprobes code, the splitting out of 'optprobes',
and a corner case bugfix.
- Allow the tracing of kernel console output (printk).
- Improvements/fixes to user-space RDPMC support, allowing user-space
self-profiling code to extract PMU counts without performing any
system calls, while playing nice with the kernel side.
- 'perf bench' improvements
- ... and lots of internal restructurings, cleanups and fixes that made
these features possible. And, as usual this list is incomplete as
there were also lots of other improvements
* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (120 commits)
perf report: Fix annotate double quit issue in branch view mode
perf report: Remove duplicate annotate choice in branch view mode
perf/x86: Prettify pmu config literals
perf report: Enable TUI in branch view mode
perf report: Auto-detect branch stack sampling mode
perf record: Add HEADER_BRANCH_STACK tag
perf record: Provide default branch stack sampling mode option
perf tools: Make perf able to read files from older ABIs
perf tools: Fix ABI compatibility bug in print_event_desc()
perf tools: Enable reading of perf.data files from different ABI rev
perf: Add ABI reference sizes
perf report: Add support for taken branch sampling
perf record: Add support for sampling taken branch
perf tools: Add code to support PERF_SAMPLE_BRANCH_STACK
x86/kprobes: Split out optprobe related code to kprobes-opt.c
x86/kprobes: Fix a bug which can modify kernel code permanently
x86/kprobes: Fix instruction recovery on optimized path
perf: Add callback to flush branch_stack on context switch
perf: Disable PERF_SAMPLE_BRANCH_* when not supported
perf/x86: Add LBR software filter support for Intel CPUs
...
There have been situations where RCU CPU stall warnings were caused by
issues in scheduling-clock timer initialization. To make it easier to
track these down, this commit causes the RCU CPU stall-warning messages
to print out the number of scheduling-clock interrupts taken in the
current grace period for each stalled CPU.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The RCU_TRACE kernel parameter has always been intended for debugging,
not for production use. Formalize this by moving RCU_TRACE from
init/Kconfig to lib/Kconfig.debug.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The soft and hard lockup thresholds have changed so the
corresponding Kconfig entries need to be updated accordingly.
Add a reference to watchdog_thresh while at it.
Signed-off-by: Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
Signed-off-by: Don Zickus <dzickus@redhat.com>
Link: http://lkml.kernel.org/r/1328827342-6253-2-git-send-email-dzickus@redhat.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
- Stop validating subdirectories now that we only register leaf tables
- Cleanup and improve the duplicate filename check.
* Run the duplicate filename check under the sysctl_lock to guarantee
we never add duplicate names.
* Reduce the duplicate filename check to nearly O(M*N) where M is the
number of entries in tthe table we are registering and N is the
number of entries in the directory before we got there.
- Move the duplicate filename check into it's own function and call
it directtly from __register_sysctl_table
- Kill the config option as the sanity checks are now cheap enough
the config option is unnecessary. The original reason for the config
option was because we had a huge table used to verify the proc filename
to binary sysctl mapping. That table has now evolved into the binary_sysctl
translation layer and is no longer part of the sysctl_check code.
- Tighten up the permission checks. Guarnateeing that files only have read
or write permissions.
- Removed redudant check for parents having a procname as now everything has
a procname.
- Generalize the backtrace logic so that we print a backtrace from
any failure of __register_sysctl_table that was not caused by
a memmory allocation failure. The backtrace allows us to track
down who erroneously registered a sysctl table.
Bechmark before (CONFIG_SYSCTL_CHECK=y):
make-dummies 0 999 -> 12s
rmmod dummy -> 0.08s
Bechmark before (CONFIG_SYSCTL_CHECK=n):
make-dummies 0 999 -> 0.7s
rmmod dummy -> 0.06s
make-dummies 0 99999 -> 1m13s
rmmod dummy -> 0.38s
Benchmark after:
make-dummies 0 999 -> 0.65s
rmmod dummy -> 0.055s
make-dummies 0 9999 -> 1m10s
rmmod dummy -> 0.39s
The sysctl sanity checks now impose no measurable cost.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Ensure that memory hotplug can co-exist with kmemleak
by taking the hotplug lock before scanning the memory
banks.
Signed-off-by: Laura Abbott <lauraa@codeaurora.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Added missing _secs in the help message of config DEFAULT_HUNG_TASK_TIMEOUT.
Signed-off-by: Jiaju Zhang <jjzhang@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/cjb/mmc: (83 commits)
mmc: fix compile error when CONFIG_BLOCK is not enabled
mmc: core: Cleanup eMMC4.5 conditionals
mmc: omap_hsmmc: if multiblock reads are broken, disable them
mmc: core: add workaround for controllers with broken multiblock reads
mmc: core: Prevent too long response times for suspend
mmc: recognise SDIO cards with SDIO_CCCR_REV 3.00
mmc: sd: Handle SD3.0 cards not supporting UHS-I bus speed mode
mmc: core: support HPI send command
mmc: core: Add cache control for eMMC4.5 device
mmc: core: Modify the timeout value for writing power class
mmc: core: new discard feature support at eMMC v4.5
mmc: core: mmc sanitize feature support for v4.5
mmc: dw_mmc: modify DATA register offset
mmc: sdhci-pci: add flag for devices that can support runtime PM
mmc: omap_hsmmc: ensure pbias configuration is always done
mmc: core: Add Power Off Notify Feature eMMC 4.5
mmc: sdhci-s3c: fix potential NULL dereference
mmc: replace printk with appropriate display macro
mmc: core: Add default timeout value for CMD6
mmc: sdhci-pci: add runtime pm support
...
This adds support to inject data errors after a completed host transfer.
The mmc core will return error even though the host transfer is successful.
This simple fault injection proved to be very useful to test the
non-blocking error handling in the mmc_blk_issue_rw_rq().
Random faults can also test how the host driver handles pre_req()
and post_req() in case of errors.
Signed-off-by: Per Forlin <per.forlin@linaro.org>
Acked-by: Akinobu Mita <akinobu.mita@gmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Chris Ball <cjb@laptop.org>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (59 commits)
MAINTAINERS: linux-m32r is moderated for non-subscribers
linux@lists.openrisc.net is moderated for non-subscribers
Drop default from "DM365 codec select" choice
parisc: Kconfig: cleanup Kernel page size default
Kconfig: remove redundant CONFIG_ prefix on two symbols
cris: remove arch/cris/arch-v32/lib/nand_init.S
microblaze: add missing CONFIG_ prefixes
h8300: drop puzzling Kconfig dependencies
MAINTAINERS: microblaze-uclinux@itee.uq.edu.au is moderated for non-subscribers
tty: drop superfluous dependency in Kconfig
ARM: mxc: fix Kconfig typo 'i.MX51'
Fix file references in Kconfig files
aic7xxx: fix Kconfig references to READMEs
Fix file references in drivers/ide/
thinkpad_acpi: Fix printk typo 'bluestooth'
bcmring: drop commented out line in Kconfig
btmrvl_sdio: fix typo 'btmrvl_sdio_sd6888'
doc: raw1394: Trivial typo fix
CIFS: Don't free volume_info->UNC until we are entirely done with it.
treewide: Correct spelling of successfully in comments
...
Thumb2 kernels cannot be built with frame pointers, but can use the
ARM_UNWIND feature for unwinding instead. This makes sure that all
features that rely on unwinding includeing CONFIG_LATENCYTOP and
FAULT_INJECTION_STACKTRACE_FILTER do not enable frame pointers
when the unwinder is already selected, and we always build with
the unwinder when we want a thumb2 kernel, to make sure we do not
get the frame pointers instead.
A different option would be to redefine the CONFIG_FRAME_POINTERS
option on ARM to mean builing with either frame pointers or
the unwinder, and then select which one to use based on the
CPU architecture or another user option. That would still allow
building thumb2 kernels without the unwinder but would also be
more confusing.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
The patch below removes an extra "it" in the comment.
Signed-off-by: Justin P. Mattock <justinmattock@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (24 commits)
sched: Cleanup duplicate local variable in [enqueue|dequeue]_task_fair
sched: Replace use of entity_key()
sched: Separate group-scheduling code more clearly
sched: Reorder root_domain to remove 64 bit alignment padding
sched: Do not attempt to destroy uninitialized rt_bandwidth
sched: Remove unused function cpu_cfs_rq()
sched: Fix (harmless) typo 'CONFG_FAIR_GROUP_SCHED'
sched, cgroup: Optimize load_balance_fair()
sched: Don't update shares twice on on_rq parent
sched: update correct entity's runtime in check_preempt_wakeup()
xtensa: Use generic config PREEMPT definition
h8300: Use generic config PREEMPT definition
m32r: Use generic PREEMPT config
sched: Skip autogroup when looking for all rt sched groups
sched: Simplify mutex_spin_on_owner()
sched: Remove rcu_read_lock() from wake_affine()
sched: Generalize sleep inside spinlock detection
sched: Make sleeping inside spinlock detection working in !CONFIG_PREEMPT
sched: Isolate preempt counting in its own config option
sched: Remove pointless in_atomic() definition check
...
The sleeping inside spinlock detection is actually used
for more general sleeping inside atomic sections
debugging: preemption disabled, rcu read side critical
sections, interrupts, interrupt disabled, etc...
Change the name of the config and its help section to
reflect its more general role.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Ingo Molnar <mingo@elte.hu>
Select CONFIG_PREEMPT_COUNT when we enable the sleeping inside
spinlock detection, so that the preempt offset gets correctly
incremented/decremented from preempt_disable()/preempt_enable().
This makes the preempt count eventually working in !CONFIG_PREEMPT
when that debug option is set and thus fixes the detection of explicit
preemption disabled sections under such config. Code that sleeps
in explicitly preempt disabled section can be finally spotted
in non-preemptible kernels.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Most arches define CONFIG_DEBUG_STACK_USAGE exactly the same way. Move it
to lib/Kconfig.debug so each arch doesn't have to define it. This
obviously makes the option generic, but that's fine because the config is
already used in generic code.
It's not obvious to me that sysrq-P actually does anything caution by
keeping the most inclusive wording.
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Acked-by: David S. Miller <davem@davemloft.net>
Acked-by: Richard Weinberger <richard@nod.at>
Acked-by: Mike Frysinger <vapier@gentoo.org>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Hirokazu Takata <takata@linux-m32r.org>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Mackerras <paulus@samba.org>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Chen Liqin <liqin.chen@sunplusct.com>
Cc: Lennox Wu <lennox.wu@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
DEBUG_PER_CPU_MAPS is used in lib/cpumask.c as well as in
inlcude/linux/cpumask.h and thus it has outgrown its use within x86 and
powerpc alone. Any arch with SMP support may want to get some more
debugging, so make this option generic.
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Cc: <linux-arch@vger.kernel.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (39 commits)
b43: fix comment typo reqest -> request
Haavard Skinnemoen has left Atmel
cris: typo in mach-fs Makefile
Kconfig: fix copy/paste-ism for dell-wmi-aio driver
doc: timers-howto: fix a typo ("unsgined")
perf: Only include annotate.h once in tools/perf/util/ui/browsers/annotate.c
md, raid5: Fix spelling error in comment ('Ofcourse' --> 'Of course').
treewide: fix a few typos in comments
regulator: change debug statement be consistent with the style of the rest
Revert "arm: mach-u300/gpio: Fix mem_region resource size miscalculations"
audit: acquire creds selectively to reduce atomic op overhead
rtlwifi: don't touch with treewide double semicolon removal
treewide: cleanup continuations and remove logging message whitespace
ath9k_hw: don't touch with treewide double semicolon removal
include/linux/leds-regulator.h: fix syntax in example code
tty: fix typo in descripton of tty_termios_encode_baud_rate
xtensa: remove obsolete BKL kernel option from defconfig
m68k: fix comment typo 'occcured'
arch:Kconfig.locks Remove unused config option.
treewide: remove extra semicolons
...
* 'core-locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
seqlock: Don't smp_rmb in seqlock reader spin loop
watchdog, hung_task_timeout: Add Kconfig configurable default
lockdep: Remove cmpxchg to update nr_chain_hlocks
lockdep: Print a nicer description for simple irq lock inversions
lockdep: Replace "Bad BFS generated tree" message with something less cryptic
lockdep: Print a nicer description for irq inversion bugs
lockdep: Print a nicer description for simple deadlocks
lockdep: Print a nicer description for normal deadlocks
lockdep: Print a nicer description for irq lock inversions
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/cmarinas/linux-2.6-cm:
kmemleak: Initialise kmemleak after debug_objects_mem_init()
kmemleak: Select DEBUG_FS unconditionally in DEBUG_KMEMLEAK
kmemleak: Do not return a pointer to an object that kmemleak did not get
In the past DEBUG_FS used to depend on SYSFS and DEBUG_KMEMLEAK selected
it conditionally. This is no longer the case, so always select DEBUG_FS
via DEBUG_KMEMLEAK.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
The prohibition of DEBUG_OBJECTS_RCU_HEAD from !PREEMPT was due to the
fixup actions. So just produce a warning from !PREEMPT.
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
The RCU CPU stall warnings can now be controlled using the
rcu_cpu_stall_suppress boot-time parameter or via the same parameter
from sysfs. There is therefore no longer any reason to have
kernel config parameters for this feature. This commit therefore
removes the RCU_CPU_STALL_DETECTOR and RCU_CPU_STALL_DETECTOR_RUNNABLE
kernel config parameters. The RCU_CPU_STALL_TIMEOUT parameter remains
to allow the timeout to be tuned and the RCU_CPU_STALL_VERBOSE parameter
remains to allow task-stall information to be suppressed if desired.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
This patch allows the default value for sysctl_hung_task_timeout_secs
to be set at build time. The feature carries virtually no overhead,
so it makes sense to keep it enabled. On heavily loaded systems, though,
it can end up triggering stack traces when there is no bug other than
the system being underprovisioned. We use this patch to keep the hung task
facility available but disabled at boot-time.
The default of 120 seconds is preserved. As a note, commit e162b39a may
have accidentally reverted commit fb822db4, which raised the default from
120 seconds to 480 seconds.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Acked-by: Mandeep Singh Baines <msb@google.com>
Link: http://lkml.kernel.org/r/4DB8600C.8080000@suse.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cite Documentation/kernel-parameters.txt for an alternative to
building with PRINTK_TIME compiled in.
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
mm/kmemleak-test.c is used to provide an example of how kmemleak
tool works.
Memory is leaked at module unload-time, so building the test
in kernel (Y) makes the leaks impossible and the test useless.
Qualify DEBUG_KMEMLEAK_TEST config symbol with "depends on m",
to restrict module-only building.
Signed-off-by: Daniel Baluta <dbaluta@ixiacom.com>
Acked-by: Pekka Enberg <penberg@kernel.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1. simple_strto*() do not contain overflow checks and crufty,
libc way to indicate failure.
2. strict_strto*() also do not have overflow checks but the name and
comments pretend they do.
3. Both families have only "long long" and "long" variants,
but users want strtou8()
4. Both "simple" and "strict" prefixes are wrong:
Simple doesn't exactly say what's so simple, strict should not exist
because conversion should be strict by default.
The solution is to use "k" prefix and add convertors for more types.
Enter
kstrtoull()
kstrtoll()
kstrtoul()
kstrtol()
kstrtouint()
kstrtoint()
kstrtou64()
kstrtos64()
kstrtou32()
kstrtos32()
kstrtou16()
kstrtos16()
kstrtou8()
kstrtos8()
Include runtime testsuite (somewhat incomplete) as well.
strict_strto*() become deprecated, stubbed to kstrto*() and
eventually will be removed altogether.
Use kstrto*() in code today!
Note: on some archs _kstrtoul() and _kstrtol() are left in tree, even if
they'll be unused at runtime. This is temporarily solution,
because I don't want to hardcode list of archs where these
functions aren't needed. Current solution with sizeof() and
__alignof__ at least always works.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We've been burned by regressions/bugs which we later realized could have
been triaged quicker if only we'd paid closer attention to dmesg. To make
it easier to audit dmesg, we'd like to make DEFAULT_MESSAGE_LEVEL
Kconfig-settable. That way we can set it to KERN_NOTICE and audit any
messages <= KERN_WARNING.
Signed-off-by: Mandeep Singh Baines <msb@chromium.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Joe Perches <joe@perches.com>
Cc: Olof Johansson <olofj@chromium.org>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When a cpu is considered stuck, instead of limping along and just printing
a warning, it is sometimes preferred to just panic, let kdump capture the
vmcore and reboot. This gets the machine back into a stable state quickly
while saving the info that got it into a stuck state to begin with.
Add a Kconfig option to allow users to set the hardlockup to panic
by default. Also add in a 'nmi_watchdog=nopanic' to override this.
[akpm@linux-foundation.org: fix strncmp length]
Signed-off-by: Don Zickus <dzickus@redhat.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: WANG Cong <xiyou.wangcong@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild-2.6:
kbuild: Make DEBUG_SECTION_MISMATCH selectable, but not on by default
genksyms: Regenerate lexer and parser
genksyms: Track changes to enum constants
genksyms: simplify usage of find_symbol()
genksyms: Add helpers for building string lists
genksyms: Simplify printing of symbol types
genksyms: Simplify lexer
genksyms: Do not paste the bison header file to lex.c
modpost: fix trailing comma
KBuild: silence "'scripts/unifdef' is up to date."
kbuild: Add extra gcc checks
kbuild: reenable section mismatch analysis
unifdef: update to upstream version 2.5
CONFIG_DEBUG_SECTION_MISMATCH has also runtime effects due to the
-fno-inline-functions-called-once compiler flag, so forcing it on
everyone is not a good idea.
Signed-off-by: Michal Marek <mmarek@suse.cz>
This removes the implementation of the big kernel lock,
at last. A lot of people have worked on this in the
past, I so the credit for this patch should be with
everyone who participated in the hunt.
The names on the Cc list are the people that were the
most active in this, according to the recorded git
history, in alphabetical order.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Alan Cox <alan@linux.intel.com>
Cc: Alessio Igor Bogani <abogani@texware.it>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Hendry <andrew.hendry@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Hans Verkuil <hverkuil@xs4all.nl>
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: Jan Blunck <jblunck@infradead.org>
Cc: John Kacur <jkacur@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matthew Wilcox <matthew@wil.cx>
Cc: Oliver Neukum <oliver@neukum.org>
Cc: Paul Menage <menage@google.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
This was disabled in commit
e5f95c8 (kbuild: print only total number of section mismatces found)
because there were too many warnings. Now we're down to a reasonable
number again, so we start scaring people with the details.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Randy Dunlap <rdunlap@xenotime.net>
Acked-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Michal Marek <mmarek@suse.cz>
The meaning of CONFIG_EMBEDDED has long since been obsoleted; the option
is used to configure any non-standard kernel with a much larger scope than
only small devices.
This patch renames the option to CONFIG_EXPERT in init/Kconfig and fixes
references to the option throughout the kernel. A new CONFIG_EMBEDDED
option is added that automatically selects CONFIG_EXPERT when enabled and
can be used in the future to isolate options that should only be
considered for embedded systems (RISC architectures, SLOB, etc).
Calling the option "EXPERT" more accurately represents its intention: only
expert users who understand the impact of the configuration changes they
are making should enable it.
Reviewed-by: Ingo Molnar <mingo@elte.hu>
Acked-by: David Woodhouse <david.woodhouse@intel.com>
Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Greg KH <gregkh@suse.de>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Robin Holt <holt@sgi.com>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The x86 arch has shifted its use of the nmi_watchdog from a
local implementation to the global one provide by
kernel/watchdog.c. This shift has caused a whole bunch of
compile problems under different config options. I attempt to
simplify things with the patch below.
In order to simplify things, I had to come to terms with the
meaning of two terms ARCH_HAS_NMI_WATCHDOG and
CONFIG_HARDLOCKUP_DETECTOR. Basically they mean the same thing,
the former on a local level and the latter on a global level.
With the old x86 nmi watchdog gone, there is no need to rely on
defining the ARCH_HAS_NMI_WATCHDOG variable because it doesn't
make sense any more. x86 will now use the global
implementation.
The changes below do a few things. First it changes the few
places that relied on ARCH_HAS_NMI_WATCHDOG to use
CONFIG_X86_LOCAL_APIC (the former was an alias for the latter
anyway, so nothing unusual here). Those pieces of code were
relying more on local apic functionality the nmi watchdog
functionality, so the change should make sense.
Second, I removed the x86 implementation of
touch_nmi_watchdog(). It isn't need now, instead x86 will rely
on kernel/watchdog.c's implementation.
Third, I removed the #define ARCH_HAS_NMI_WATCHDOG itself from
x86. And tweaked the include/linux/nmi.h file to tell users to
look for an externally defined touch_nmi_watchdog in the case of
ARCH_HAS_NMI_WATCHDOG _or_ CONFIG_HARDLOCKUP_DETECTOR. This
changes removes some of the ugliness in that file.
Finally, I added a Kconfig dependency for
CONFIG_HARDLOCKUP_DETECTOR that said you can't have
ARCH_HAS_NMI_WATCHDOG _and_ CONFIG_HARDLOCKUP_DETECTOR. You can
only have one nmi_watchdog.
Tested with
ARCH=i386: allnoconfig, defconfig, allyesconfig, (various broken
configs) ARCH=x86_64: allnoconfig, defconfig, allyesconfig,
(various broken configs)
Hopefully, after this patch I won't get any more compile broken
emails. :-)
v3:
changed a couple of 'linux/nmi.h' -> 'asm/nmi.h' to pick-up correct function
prototypes when CONFIG_HARDLOCKUP_DETECTOR is not set.
Signed-off-by: Don Zickus <dzickus@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: fweisbec@gmail.com
LKML-Reference: <1293044403-14117-1-git-send-email-dzickus@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/djbw/async_tx: (48 commits)
DMAENGINE: move COH901318 to arch_initcall
dma: imx-dma: fix signedness bug
dma/timberdale: simplify conditional
ste_dma40: remove channel_type
ste_dma40: remove enum for endianess
ste_dma40: remove TIM_FOR_LINK option
ste_dma40: move mode_opt to separate config
ste_dma40: move channel mode to a separate field
ste_dma40: move priority to separate field
ste_dma40: add variable to indicate valid dma_cfg
async_tx: make async_tx channel switching opt-in
move async raid6 test to lib/Kconfig.debug
dmaengine: Add Freescale i.MX1/21/27 DMA driver
intel_mid_dma: change the slave interface
intel_mid_dma: fix the WARN_ONs
intel_mid_dma: Add sg list support to DMA driver
intel_mid_dma: Allow DMAC2 to share interrupt
intel_mid_dma: Allow IRQ sharing
intel_mid_dma: Add runtime PM support
DMAENGINE: define a dummy filter function for ste_dma40
...
* git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile:
arch/tile: convert a BUG_ON to BUILD_BUG_ON
arch/tile: make ptrace() work properly for TILE-Gx COMPAT mode
arch/tile: support new info op generated by compiler
arch/tile: minor whitespace/naming changes for string support files
arch/tile: enable single-step support for TILE-Gx
arch/tile: parameterize system PLs to support KVM port
arch/tile: add Tilera's <arch/sim.h> header as an open-source header
arch/tile: Bomb C99 comments to C89 comments in tile's <arch/sim_def.h>
arch/tile: prevent corrupt top frame from causing backtracer runaway
arch/tile: various top-level Makefile cleanups
arch/tile: change lower bound on syscall error return to -4095
arch/tile: properly export __mb_incoherent for modules
arch/tile: provide a definition of MAP_STACK
kmemleak: add TILE to the list of supported architectures.
char: hvc: check for error case
arch/tile: Add a warning if we try to allocate too much vmalloc memory.
arch/tile: update some comments to clarify register usage.
arch/tile: use better "punctuation" for VMSPLIT_3_5G and friends
arch/tile: Use <asm-generic/syscalls.h>
tile: replace some BUG_ON checks with BUILD_BUG_ON checks
While hunting a non-existing bug in 'list_sort()', I've improved the
'list_sort_test()' function which tests the 'list_sort()' library call.
Although at the end I found a bug in my code, but not in 'list_sort()', I
think my clean-ups and improvements are worth merging because they make
the test function better.
This patch:
Make the self-tests selectable via Kconfig rather than by manual enabling
of DEBUG_LIST_SORT.
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Cc: Don Mullis <don.mullis@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
All percpu counters are linked to a global list on initialization and
removed from it on destruction. The list is walked during CPU up/down.
If a percpu counter is freed without being properly destroyed, the system
will oops only on the next CPU up/down making it pretty nasty to track
down. This patch adds debugobj support for percpu counters so that such
problems can be found easily.
As percpu counters don't make sense on stack and can't be statically
initialized, debugobj support is pretty simple. It's initialized and
activated on counter initialization, and deactivatd and destroyed on
counter destruction. With this patch applied, the bug fixed by commit
602586a83b (shmem: put_super must
percpu_counter_destroy) triggers the following warning on tmpfs unmount
and the system won't oops on the next cpu up/down operation.
------------[ cut here ]------------
WARNING: at lib/debugobjects.c:259 debug_print_object+0x5c/0x70()
Hardware name: Bochs
ODEBUG: free active (active state 0) object type: percpu_counter
Modules linked in:
Pid: 3999, comm: umount Not tainted 2.6.36-rc2-work+ #5
Call Trace:
[<ffffffff81083f7f>] warn_slowpath_common+0x7f/0xc0
[<ffffffff81084076>] warn_slowpath_fmt+0x46/0x50
[<ffffffff813b45cc>] debug_print_object+0x5c/0x70
[<ffffffff813b50e5>] debug_check_no_obj_freed+0x125/0x210
[<ffffffff811577d3>] kfree+0xb3/0x2f0
[<ffffffff81132edd>] shmem_put_super+0x1d/0x30
[<ffffffff81162e96>] generic_shutdown_super+0x56/0xe0
[<ffffffff81162f86>] kill_anon_super+0x16/0x60
[<ffffffff81162ff7>] kill_litter_super+0x27/0x30
[<ffffffff81163295>] deactivate_locked_super+0x45/0x60
[<ffffffff81163cfa>] deactivate_super+0x4a/0x70
[<ffffffff8117d446>] mntput_no_expire+0x86/0xe0
[<ffffffff8117df7f>] sys_umount+0x6f/0x360
[<ffffffff8103f01b>] system_call_fastpath+0x16/0x1b
---[ end trace cce2a341ba3611a7 ]---
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Thomas Gleixner <tglxlinutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'config' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/bkl:
BKL: introduce CONFIG_BKL.
dabusb: remove the BKL
sunrpc: remove the big kernel lock
init/main.c: remove BKL notations
blktrace: remove the big kernel lock
rtmutex-tester: make it build without BKL
dvb-core: kill the big kernel lock
dvb/bt8xx: kill the big kernel lock
tlclk: remove big kernel lock
fix rawctl compat ioctls breakage on amd64 and itanic
uml: kill big kernel lock
parisc: remove big kernel lock
cris: autoconvert trivial BKL users
alpha: kill big kernel lock
isapnp: BKL removal
s390/block: kill the big kernel lock
hpet: kill BKL, add compat_ioctl
With all the patches we have queued in the BKL removal tree, only a
few dozen modules are left that actually rely on the BKL, and even
there are lots of low-hanging fruit. We need to decide what to do
about them, this patch illustrates one of the options:
Every user of the BKL is marked as 'depends on BKL' in Kconfig,
and the CONFIG_BKL becomes a user-visible option. If it gets
disabled, no BKL using module can be built any more and the BKL
code itself is compiled out.
The one exception is file locking, which is practically always
enabled and does a 'select BKL' instead. This effectively forces
CONFIG_BKL to be enabled until we have solved the fs/lockd
mess and can apply the patch that removes the BKL from fs/locks.c.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
All the necessary functionality was already there; we just need
to make it possible to select the config option.
Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
The prompt for "Self test for hardware accelerated raid6 recovery" does not
belong in the top level configuration menu. All the options in
crypto/async_tx/Kconfig are selected and do not depend on CRYPTO.
Kconfig.debug seems like a reasonable fit.
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Currently disabling CONFIG_SLUB_DEBUG also disabled SYSFS support meaning
that the slabs cannot be tuned without DEBUG.
Make SYSFS support independent of CONFIG_SLUB_DEBUG
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
The PROVE_RCU_REPEATEDLY has no "Say Y"/"Say N" advice, so this commit
adds it.
Reported-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
When CONFIG_IRQSOFF_TRACER is set and CONFIG_PROVE_LOCKING is not, we
get the following error:
$ make oldconfig
scripts/kconfig/conf --oldconfig arch/x86/Kconfig
warning: (IRQSOFF_TRACER && TRACING_SUPPORT && FTRACE && TRACE_IRQFLAGS_SUPPORT && !ARCH_USES_GETTIMEOFFSET) selects TRACE_IRQFLAGS which has unmet direct dependencies (DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && PROVE_LOCKING)
warning: (IRQSOFF_TRACER && TRACING_SUPPORT && FTRACE && TRACE_IRQFLAGS_SUPPORT && !ARCH_USES_GETTIMEOFFSET) selects TRACE_IRQFLAGS which has unmet direct dependencies (DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && PROVE_LOCKING)
This is because IRQSOFF_TRACER selects TRACE_IRQFLAGS but TRACE_IRQFLAGS
has PROVE_LOCKING as a dependency. This code is incorrect, and
this patch changes the TRACE_IRQFLAGS to be just a simple bool that
does not depend or select anything. Instead both IRQSOFF_TRACER and
PROVE_LOCKING select it.
Reported-by: Richard Kennedy <richard@rsk.demon.co.uk>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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 <williams@redhat.com>
Requested-by: John Kacur <jkacur@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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 <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
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 <arnd@arndb.de>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Christopher Li <sparse@chrisli.org>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
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 <randy.dunlap@oracle.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
LKML-Reference: <20100812123121.a7c99cde.randy.dunlap@oracle.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* '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
* 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
...
* '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
* '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
* '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
...
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 <monstr@monstr.eu>
The last 't' of 'fault' is missing in the description of FAIL_IO_TIMEOUT.
Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
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 <jbaron@redhat.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
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 <ak@linux.intel.com>
[mmarek: reformatted help text]
Signed-off-by: Michal Marek <mmarek@suse.cz>
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 Jiangshan
This 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 <mathieu.desnoyers@efficios.com>
CC: David S. Miller <davem@davemloft.net>
CC: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
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 <adobriyan@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com>
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 permitted
Example2: 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 <akinobu.mita@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
