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2008-10-22Merge branch 'tracing/ftrace' into tracing/urgentIngo Molnar
2008-10-20Merge branch 'tracing-v28-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'tracing-v28-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (131 commits) tracing/fastboot: improve help text tracing/stacktrace: improve help text tracing/fastboot: fix initcalls disposition in bootgraph.pl tracing/fastboot: fix bootgraph.pl initcall name regexp tracing/fastboot: fix issues and improve output of bootgraph.pl tracepoints: synchronize unregister static inline tracepoints: tracepoint_synchronize_unregister() ftrace: make ftrace_test_p6nop disassembler-friendly markers: fix synchronize marker unregister static inline tracing/fastboot: add better resolution to initcall debug/tracing trace: add build-time check to avoid overrunning hex buffer ftrace: fix hex output mode of ftrace tracing/fastboot: fix initcalls disposition in bootgraph.pl tracing/fastboot: fix printk format typo in boot tracer ftrace: return an error when setting a nonexistent tracer ftrace: make some tracers reentrant ring-buffer: make reentrant ring-buffer: move page indexes into page headers tracing/fastboot: only trace non-module initcalls ftrace: move pc counter in irqtrace ... Manually fix conflicts: - init/main.c: initcall tracing - kernel/module.c: verbose level vs tracepoints - scripts/bootgraph.pl: fallout from cherry-picking commits.
2008-10-20ftrace: rename FTRACE to FUNCTION_TRACERSteven Rostedt
Due to confusion between the ftrace infrastructure and the gcc profiling tracer "ftrace", this patch renames the config options from FTRACE to FUNCTION_TRACER. The other two names that are offspring from FTRACE DYNAMIC_FTRACE and FTRACE_MCOUNT_RECORD will stay the same. This patch was generated mostly by script, and partially by hand. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-20container freezer: implement freezer cgroup subsystemMatt Helsley
This patch implements a new freezer subsystem in the control groups framework. It provides a way to stop and resume execution of all tasks in a cgroup by writing in the cgroup filesystem. The freezer subsystem in the container filesystem defines a file named freezer.state. Writing "FROZEN" to the state file will freeze all tasks in the cgroup. Subsequently writing "RUNNING" will unfreeze the tasks in the cgroup. Reading will return the current state. * Examples of usage : # mkdir /containers/freezer # mount -t cgroup -ofreezer freezer /containers # mkdir /containers/0 # echo $some_pid > /containers/0/tasks to get status of the freezer subsystem : # cat /containers/0/freezer.state RUNNING to freeze all tasks in the container : # echo FROZEN > /containers/0/freezer.state # cat /containers/0/freezer.state FREEZING # cat /containers/0/freezer.state FROZEN to unfreeze all tasks in the container : # echo RUNNING > /containers/0/freezer.state # cat /containers/0/freezer.state RUNNING This is the basic mechanism which should do the right thing for user space task in a simple scenario. It's important to note that freezing can be incomplete. In that case we return EBUSY. This means that some tasks in the cgroup are busy doing something that prevents us from completely freezing the cgroup at this time. After EBUSY, the cgroup will remain partially frozen -- reflected by freezer.state reporting "FREEZING" when read. The state will remain "FREEZING" until one of these things happens: 1) Userspace cancels the freezing operation by writing "RUNNING" to the freezer.state file 2) Userspace retries the freezing operation by writing "FROZEN" to the freezer.state file (writing "FREEZING" is not legal and returns EIO) 3) The tasks that blocked the cgroup from entering the "FROZEN" state disappear from the cgroup's set of tasks. [akpm@linux-foundation.org: coding-style fixes] [akpm@linux-foundation.org: export thaw_process] Signed-off-by: Cedric Le Goater <clg@fr.ibm.com> Signed-off-by: Matt Helsley <matthltc@us.ibm.com> Acked-by: Serge E. Hallyn <serue@us.ibm.com> Tested-by: Matt Helsley <matthltc@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-20container freezer: make refrigerator always availableMatt Helsley
Now that the TIF_FREEZE flag is available in all architectures, extract the refrigerator() and freeze_task() from kernel/power/process.c and make it available to all. The refrigerator() can now be used in a control group subsystem implementing a control group freezer. Signed-off-by: Cedric Le Goater <clg@fr.ibm.com> Signed-off-by: Matt Helsley <matthltc@us.ibm.com> Acked-by: Serge E. Hallyn <serue@us.ibm.com> Tested-by: Matt Helsley <matthltc@us.ibm.com> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-14tracing: Kernel TracepointsMathieu Desnoyers
Implementation of kernel tracepoints. Inspired from the Linux Kernel Markers. Allows complete typing verification by declaring both tracing statement inline functions and probe registration/unregistration static inline functions within the same macro "DEFINE_TRACE". No format string is required. See the tracepoint Documentation and Samples patches for usage examples. Taken from the documentation patch : "A tracepoint placed in code provides a hook to call a function (probe) that you can provide at runtime. A tracepoint can be "on" (a probe is connected to it) or "off" (no probe is attached). When a tracepoint is "off" it has no effect, except for adding a tiny time penalty (checking a condition for a branch) and space penalty (adding a few bytes for the function call at the end of the instrumented function and adds a data structure in a separate section). When a tracepoint is "on", the function you provide is called each time the tracepoint is executed, in the execution context of the caller. When the function provided ends its execution, it returns to the caller (continuing from the tracepoint site). You can put tracepoints at important locations in the code. They are lightweight hooks that can pass an arbitrary number of parameters, which prototypes are described in a tracepoint declaration placed in a header file." Addition and removal of tracepoints is synchronized by RCU using the scheduler (and preempt_disable) as guarantees to find a quiescent state (this is really RCU "classic"). The update side uses rcu_barrier_sched() with call_rcu_sched() and the read/execute side uses "preempt_disable()/preempt_enable()". We make sure the previous array containing probes, which has been scheduled for deletion by the rcu callback, is indeed freed before we proceed to the next update. It therefore limits the rate of modification of a single tracepoint to one update per RCU period. The objective here is to permit fast batch add/removal of probes on _different_ tracepoints. Changelog : - Use #name ":" #proto as string to identify the tracepoint in the tracepoint table. This will make sure not type mismatch happens due to connexion of a probe with the wrong type to a tracepoint declared with the same name in a different header. - Add tracepoint_entry_free_old. - Change __TO_TRACE to get rid of the 'i' iterator. Masami Hiramatsu <mhiramat@redhat.com> : Tested on x86-64. Performance impact of a tracepoint : same as markers, except that it adds about 70 bytes of instructions in an unlikely branch of each instrumented function (the for loop, the stack setup and the function call). It currently adds a memory read, a test and a conditional branch at the instrumentation site (in the hot path). Immediate values will eventually change this into a load immediate, test and branch, which removes the memory read which will make the i-cache impact smaller (changing the memory read for a load immediate removes 3-4 bytes per site on x86_32 (depending on mov prefixes), or 7-8 bytes on x86_64, it also saves the d-cache hit). About the performance impact of tracepoints (which is comparable to markers), even without immediate values optimizations, tests done by Hideo Aoki on ia64 show no regression. His test case was using hackbench on a kernel where scheduler instrumentation (about 5 events in code scheduler code) was added. Quoting Hideo Aoki about Markers : I evaluated overhead of kernel marker using linux-2.6-sched-fixes git tree, which includes several markers for LTTng, using an ia64 server. While the immediate trace mark feature isn't implemented on ia64, there is no major performance regression. So, I think that we don't have any issues to propose merging marker point patches into Linus's tree from the viewpoint of performance impact. I prepared two kernels to evaluate. The first one was compiled without CONFIG_MARKERS. The second one was enabled CONFIG_MARKERS. I downloaded the original hackbench from the following URL: http://devresources.linux-foundation.org/craiger/hackbench/src/hackbench.c I ran hackbench 5 times in each condition and calculated the average and difference between the kernels. The parameter of hackbench: every 50 from 50 to 800 The number of CPUs of the server: 2, 4, and 8 Below is the results. As you can see, major performance regression wasn't found in any case. Even if number of processes increases, differences between marker-enabled kernel and marker- disabled kernel doesn't increase. Moreover, if number of CPUs increases, the differences doesn't increase either. Curiously, marker-enabled kernel is better than marker-disabled kernel in more than half cases, although I guess it comes from the difference of memory access pattern. * 2 CPUs Number of | without | with | diff | diff | processes | Marker [Sec] | Marker [Sec] | [Sec] | [%] | -------------------------------------------------------------- 50 | 4.811 | 4.872 | +0.061 | +1.27 | 100 | 9.854 | 10.309 | +0.454 | +4.61 | 150 | 15.602 | 15.040 | -0.562 | -3.6 | 200 | 20.489 | 20.380 | -0.109 | -0.53 | 250 | 25.798 | 25.652 | -0.146 | -0.56 | 300 | 31.260 | 30.797 | -0.463 | -1.48 | 350 | 36.121 | 35.770 | -0.351 | -0.97 | 400 | 42.288 | 42.102 | -0.186 | -0.44 | 450 | 47.778 | 47.253 | -0.526 | -1.1 | 500 | 51.953 | 52.278 | +0.325 | +0.63 | 550 | 58.401 | 57.700 | -0.701 | -1.2 | 600 | 63.334 | 63.222 | -0.112 | -0.18 | 650 | 68.816 | 68.511 | -0.306 | -0.44 | 700 | 74.667 | 74.088 | -0.579 | -0.78 | 750 | 78.612 | 79.582 | +0.970 | +1.23 | 800 | 85.431 | 85.263 | -0.168 | -0.2 | -------------------------------------------------------------- * 4 CPUs Number of | without | with | diff | diff | processes | Marker [Sec] | Marker [Sec] | [Sec] | [%] | -------------------------------------------------------------- 50 | 2.586 | 2.584 | -0.003 | -0.1 | 100 | 5.254 | 5.283 | +0.030 | +0.56 | 150 | 8.012 | 8.074 | +0.061 | +0.76 | 200 | 11.172 | 11.000 | -0.172 | -1.54 | 250 | 13.917 | 14.036 | +0.119 | +0.86 | 300 | 16.905 | 16.543 | -0.362 | -2.14 | 350 | 19.901 | 20.036 | +0.135 | +0.68 | 400 | 22.908 | 23.094 | +0.186 | +0.81 | 450 | 26.273 | 26.101 | -0.172 | -0.66 | 500 | 29.554 | 29.092 | -0.461 | -1.56 | 550 | 32.377 | 32.274 | -0.103 | -0.32 | 600 | 35.855 | 35.322 | -0.533 | -1.49 | 650 | 39.192 | 38.388 | -0.804 | -2.05 | 700 | 41.744 | 41.719 | -0.025 | -0.06 | 750 | 45.016 | 44.496 | -0.520 | -1.16 | 800 | 48.212 | 47.603 | -0.609 | -1.26 | -------------------------------------------------------------- * 8 CPUs Number of | without | with | diff | diff | processes | Marker [Sec] | Marker [Sec] | [Sec] | [%] | -------------------------------------------------------------- 50 | 2.094 | 2.072 | -0.022 | -1.07 | 100 | 4.162 | 4.273 | +0.111 | +2.66 | 150 | 6.485 | 6.540 | +0.055 | +0.84 | 200 | 8.556 | 8.478 | -0.078 | -0.91 | 250 | 10.458 | 10.258 | -0.200 | -1.91 | 300 | 12.425 | 12.750 | +0.325 | +2.62 | 350 | 14.807 | 14.839 | +0.032 | +0.22 | 400 | 16.801 | 16.959 | +0.158 | +0.94 | 450 | 19.478 | 19.009 | -0.470 | -2.41 | 500 | 21.296 | 21.504 | +0.208 | +0.98 | 550 | 23.842 | 23.979 | +0.137 | +0.57 | 600 | 26.309 | 26.111 | -0.198 | -0.75 | 650 | 28.705 | 28.446 | -0.259 | -0.9 | 700 | 31.233 | 31.394 | +0.161 | +0.52 | 750 | 34.064 | 33.720 | -0.344 | -1.01 | 800 | 36.320 | 36.114 | -0.206 | -0.57 | -------------------------------------------------------------- Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Acked-by: Masami Hiramatsu <mhiramat@redhat.com> Acked-by: 'Peter Zijlstra' <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-07-29Merge branch 'linus' into core/generic-dma-coherentIngo Molnar
Conflicts: arch/x86/Kconfig Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-07-25build kernel/profile.o only when requestedAdrian Bunk
Build kernel/profile.o only if CONFIG_PROFILING is enabled. This makes CONFIG_PROFILING=n kernels smaller. As a bonus, some profile_tick() calls and one branch from schedule() are now eliminated with CONFIG_PROFILING=n (but I doubt these are measurable effects). This patch changes the effects of CONFIG_PROFILING=n, but I don't think having more than two choices would be the better choice. This patch also adds the name of the first parameter to the prototypes of profile_{hits,tick}() since I anyway had to add them for the dummy functions. Signed-off-by: Adrian Bunk <bunk@kernel.org> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-18Merge branch 'linus' into core/generic-dma-coherentIngo Molnar
Conflicts: kernel/Makefile Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-07-18Revert parts of "ftrace: do not trace scheduler functions"Ingo Molnar
the removal of -mno-spe in the !ftrace case was not intended. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-07-17ftrace: do not trace scheduler functionsIngo Molnar
do not trace scheduler functions - it's still a bit fragile and can lock up with: http://redhat.com/~mingo/misc/config-Thu_Jul_17_13_34_52_CEST_2008 Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-07-15Merge branch 'generic-ipi' into generic-ipi-for-linusIngo Molnar
Conflicts: arch/powerpc/Kconfig arch/s390/kernel/time.c arch/x86/kernel/apic_32.c arch/x86/kernel/cpu/perfctr-watchdog.c arch/x86/kernel/i8259_64.c arch/x86/kernel/ldt.c arch/x86/kernel/nmi_64.c arch/x86/kernel/smpboot.c arch/x86/xen/smp.c include/asm-x86/hw_irq_32.h include/asm-x86/hw_irq_64.h include/asm-x86/mach-default/irq_vectors.h include/asm-x86/mach-voyager/irq_vectors.h include/asm-x86/smp.h kernel/Makefile Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-07-14Merge branch 'auto-ftrace-next' into tracing/for-linusIngo Molnar
Conflicts: arch/x86/kernel/entry_32.S arch/x86/kernel/process_32.c arch/x86/kernel/process_64.c arch/x86/lib/Makefile include/asm-x86/irqflags.h kernel/Makefile kernel/sched.c Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-07-11ftrace: trace scheduleSteven Rostedt
After the sched_clock code has been removed from sched.c we can now trace the scheduler. The scheduler has a lot of functions that would be worth tracing. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Cc: Steven Rostedt <srostedt@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-06-30generic: per-device coherent dma allocatorDmitry Baryshkov
Currently x86_32, sh and cris-v32 provide per-device coherent dma memory allocator. However their implementation is nearly identical. Refactor out common code to be reused by them. Signed-off-by: Dmitry Baryshkov <dbaryshkov@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-06-26Add generic helpers for arch IPI function callsJens Axboe
This adds kernel/smp.c which contains helpers for IPI function calls. In addition to supporting the existing smp_call_function() in a more efficient manner, it also adds a more scalable variant called smp_call_function_single() for calling a given function on a single CPU only. The core of this is based on the x86-64 patch from Nick Piggin, lots of changes since then. "Alan D. Brunelle" <Alan.Brunelle@hp.com> has contributed lots of fixes and suggestions as well. Also thanks to Paul E. McKenney <paulmck@linux.vnet.ibm.com> for reviewing RCU usage and getting rid of the data allocation fallback deadlock. Acked-by: Ingo Molnar <mingo@elte.hu> Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-06-06sched: Move cpu masks from kernel/sched.c into kernel/cpu.cMax Krasnyansky
kernel/cpu.c seems a more logical place for those maps since they do not really have much to do with the scheduler these days. kernel/cpu.c is now built for the UP kernel too, but it does not affect the size the kernel sections. $ size vmlinux before text data bss dec hex filename 3313797 307060 310352 3931209 3bfc49 vmlinux after text data bss dec hex filename 3313797 307060 310352 3931209 3bfc49 vmlinux Signed-off-by: Max Krasnyansky <maxk@qualcomm.com> Cc: pj@sgi.com Cc: menage@google.com Cc: rostedt@goodmis.org Cc: mingo@elte.hu Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-06-06sched: use a 2-d bitmap for searching lowest-pri CPUGregory Haskins
The current code use a linear algorithm which causes scaling issues on larger SMP machines. This patch replaces that algorithm with a 2-dimensional bitmap to reduce latencies in the wake-up path. Signed-off-by: Gregory Haskins <ghaskins@novell.com> Acked-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-23ftrace: use the new kbuild CFLAGS_REMOVE for kernel directorySteven Rostedt
This patch removes the Makefile turd and uses the nice CFLAGS_REMOVE macro in the kernel directory. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-23ftrace: use Makefile to remove tracing from lockdepSteven Rostedt
This patch removes the "notrace" annotation from lockdep and adds the debugging files in the kernel director to those that should not be compiled with "-pg" mcount tracing. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-23ftrace: latency tracer infrastructureSteven Rostedt
This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-23ftrace: add basic support for gcc profiler instrumentationArnaldo Carvalho de Melo
If CONFIG_FTRACE is selected and /proc/sys/kernel/ftrace_enabled is set to a non-zero value the ftrace routine will be called everytime we enter a kernel function that is not marked with the "notrace" attribute. The ftrace routine will then call a registered function if a function happens to be registered. [ This code has been highly hacked by Steven Rostedt and Ingo Molnar, so don't blame Arnaldo for all of this ;-) ] Update: It is now possible to register more than one ftrace function. If only one ftrace function is registered, that will be the function that ftrace calls directly. If more than one function is registered, then ftrace will call a function that will loop through the functions to call. Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-05sched: add optional support for CONFIG_HAVE_UNSTABLE_SCHED_CLOCKPeter Zijlstra
this replaces the rq->clock stuff (and possibly cpu_clock()). - architectures that have an 'imperfect' hardware clock can set CONFIG_HAVE_UNSTABLE_SCHED_CLOCK - the 'jiffie' window might be superfulous when we update tick_gtod before the __update_sched_clock() call in sched_clock_tick() - cpu_clock() might be implemented as: sched_clock_cpu(smp_processor_id()) if the accuracy proves good enough - how far can TSC drift in a single jiffie when considering the filtering and idle hooks? [ mingo@elte.hu: various fixes and cleanups ] Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-04-29sysctl: allow embedded targets to disable sysctl_check.cHolger Schurig
Disable sysctl_check.c for embedded targets. This saves about about 11 kB in .text and another 11 kB in .data on a PXA255 embedded platform. Signed-off-by: Holger Schurig <hs4233@mail.mn-solutions.de> 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>
2008-04-18Merge git://git.kernel.org/pub/scm/linux/kernel/git/mingo/linux-2.6-kgdbLinus Torvalds
* git://git.kernel.org/pub/scm/linux/kernel/git/mingo/linux-2.6-kgdb: kgdb: always use icache flush for sw breakpoints kgdb: fix SMP NMI kgdb_handle_exception exit race kgdb: documentation fixes kgdb: allow static kgdbts boot configuration kgdb: add documentation kgdb: Kconfig fix kgdb: add kgdb internal test suite kgdb: fix several kgdb regressions kgdb: kgdboc pl011 I/O module kgdb: fix optional arch functions and probe_kernel_* kgdb: add x86 HW breakpoints kgdb: print breakpoint removed on exception kgdb: clocksource watchdog kgdb: fix NMI hangs kgdb: fix kgdboc dynamic module configuration kgdb: document parameters x86: kgdb support consoles: polling support, kgdboc kgdb: core uaccess: add probe_kernel_write()
2008-04-17kgdb: coreJason Wessel
kgdb core code. Handles the protocol and the arch details. [ mingo@elte.hu: heavily modified, simplified and cleaned up. ] [ xemul@openvz.org: use find_task_by_pid_ns ] Signed-off-by: Jason Wessel <jason.wessel@windriver.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Jan Kiszka <jan.kiszka@web.de> Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
2008-04-17Generic semaphore implementationMatthew Wilcox
Semaphores are no longer performance-critical, so a generic C implementation is better for maintainability, debuggability and extensibility. Thanks to Peter Zijlstra for fixing the lockdep warning. Thanks to Harvey Harrison for pointing out that the unlikely() was unnecessary. Signed-off-by: Matthew Wilcox <willy@linux.intel.com> Acked-by: Ingo Molnar <mingo@elte.hu>
2008-02-08avoid overflows in kernel/time.cH. Peter Anvin
When the conversion factor between jiffies and milli- or microseconds is not a single multiply or divide, as for the case of HZ == 300, we currently do a multiply followed by a divide. The intervening result, however, is subject to overflows, especially since the fraction is not simplified (for HZ == 300, we multiply by 300 and divide by 1000). This is exposed to the user when passing a large timeout to poll(), for example. This patch replaces the multiply-divide with a reciprocal multiplication on 32-bit platforms. When the input is an unsigned long, there is no portable way to do this on 64-bit platforms there is no portable way to do this since it requires a 128-bit intermediate result (which gcc does support on 64-bit platforms but may generate libgcc calls, e.g. on 64-bit s390), but since the output is a 32-bit integer in the cases affected, just simplify the multiply-divide (*3/10 instead of *300/1000). The reciprocal multiply used can have off-by-one errors in the upper half of the valid output range. This could be avoided at the expense of having to deal with a potential 65-bit intermediate result. Since the intent is to avoid overflow problems and most of the other time conversions are only semiexact, the off-by-one errors were considered an acceptable tradeoff. At Ralf Baechle's suggestion, this version uses a Perl script to compute the necessary constants. We already have dependencies on Perl for kernel compiles. This does, however, require the Perl module Math::BigInt, which is included in the standard Perl distribution starting with version 5.8.0. In order to support older versions of Perl, include a table of canned constants in the script itself, and structure the script so that Math::BigInt isn't required if pulling values from said table. Running the script requires that the HZ value is available from the Makefile. Thus, this patch also adds the Kconfig variable CONFIG_HZ to the architectures which didn't already have it (alpha, cris, frv, h8300, m32r, m68k, m68knommu, sparc, v850, and xtensa.) It does *not* touch the sh or sh64 architectures, since Paul Mundt has dealt with those separately in the sh tree. Signed-off-by: H. Peter Anvin <hpa@zytor.com> Cc: Ralf Baechle <ralf@linux-mips.org>, Cc: Sam Ravnborg <sam@ravnborg.org>, Cc: Paul Mundt <lethal@linux-sh.org>, Cc: Richard Henderson <rth@twiddle.net>, Cc: Michael Starvik <starvik@axis.com>, Cc: David Howells <dhowells@redhat.com>, Cc: Yoshinori Sato <ysato@users.sourceforge.jp>, Cc: Hirokazu Takata <takata@linux-m32r.org>, Cc: Geert Uytterhoeven <geert@linux-m68k.org>, Cc: Roman Zippel <zippel@linux-m68k.org>, Cc: William L. Irwin <sparclinux@vger.kernel.org>, Cc: Chris Zankel <chris@zankel.net>, Cc: H. Peter Anvin <hpa@zytor.com>, Cc: Jan Engelhardt <jengelh@computergmbh.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08namespaces: cleanup the code managed with PID_NS optionPavel Emelyanov
Just like with the user namespaces, move the namespace management code into the separate .c file and mark the (already existing) PID_NS option as "depend on NAMESPACES" [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Acked-by: Serge Hallyn <serue@us.ibm.com> Cc: Cedric Le Goater <clg@fr.ibm.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Herbert Poetzl <herbert@13thfloor.at> Cc: Kirill Korotaev <dev@sw.ru> Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08namespaces: cleanup the code managed with the USER_NS optionPavel Emelyanov
Make the user_namespace.o compilation depend on this option and move the init_user_ns into user.c file to make the kernel compile and work without the namespaces support. This make the user namespace code be organized similar to other namespaces'. Also mask the USER_NS option as "depend on NAMESPACES". [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Acked-by: Serge Hallyn <serue@us.ibm.com> Cc: Cedric Le Goater <clg@fr.ibm.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Herbert Poetzl <herbert@13thfloor.at> Cc: Kirill Korotaev <dev@sw.ru> Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08namespaces: move the UTS namespace under UTS_NS optionPavel Emelyanov
Currently all the namespace management code is in the kernel/utsname.c file, so just compile it out and make stubs in the appropriate header. The init namespace itself is in init/version.c and is in the kernel all the time. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Acked-by: Serge Hallyn <serue@us.ibm.com> Cc: Cedric Le Goater <clg@fr.ibm.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Herbert Poetzl <herbert@13thfloor.at> Cc: Kirill Korotaev <dev@sw.ru> Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-07Memory controller: resource countersPavel Emelianov
With fixes from David Rientjes <rientjes@google.com> Introduce generic structures and routines for resource accounting. Each resource accounting cgroup is supposed to aggregate it, cgroup_subsystem_state and its resource-specific members within. Signed-off-by: Pavel Emelianov <xemul@openvz.org> Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Paul Menage <menage@google.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: Kirill Korotaev <dev@sw.ru> Cc: Herbert Poetzl <herbert@13thfloor.at> Cc: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com> Signed-off-by: David Rientjes <rientjes@google.com> Cc: Pavel Emelianov <xemul@openvz.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-05latency.c: use QoS infrastructureMark Gross
Replace latency.c use with pm_qos_params use. Signed-off-by: mark gross <mgross@linux.intel.com> Cc: "John W. Linville" <linville@tuxdriver.com> Cc: Len Brown <lenb@kernel.org> Cc: Jaroslav Kysela <perex@suse.cz> Cc: Takashi Iwai <tiwai@suse.de> Cc: Arjan van de Ven <arjan@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-05pm qos infrastructure and interfaceMark Gross
The following patch is a generalization of the latency.c implementation done by Arjan last year. It provides infrastructure for more than one parameter, and exposes a user mode interface for processes to register pm_qos expectations of processes. This interface provides a kernel and user mode interface for registering performance expectations by drivers, subsystems and user space applications on one of the parameters. Currently we have {cpu_dma_latency, network_latency, network_throughput} as the initial set of pm_qos parameters. The infrastructure exposes multiple misc device nodes one per implemented parameter. The set of parameters implement is defined by pm_qos_power_init() and pm_qos_params.h. This is done because having the available parameters being runtime configurable or changeable from a driver was seen as too easy to abuse. For each parameter a list of performance requirements is maintained along with an aggregated target value. The aggregated target value is updated with changes to the requirement list or elements of the list. Typically the aggregated target value is simply the max or min of the requirement values held in the parameter list elements. >From kernel mode the use of this interface is simple: pm_qos_add_requirement(param_id, name, target_value): Will insert a named element in the list for that identified PM_QOS parameter with the target value. Upon change to this list the new target is recomputed and any registered notifiers are called only if the target value is now different. pm_qos_update_requirement(param_id, name, new_target_value): Will search the list identified by the param_id for the named list element and then update its target value, calling the notification tree if the aggregated target is changed. with that name is already registered. pm_qos_remove_requirement(param_id, name): Will search the identified list for the named element and remove it, after removal it will update the aggregate target and call the notification tree if the target was changed as a result of removing the named requirement. >From user mode: Only processes can register a pm_qos requirement. To provide for automatic cleanup for process the interface requires the process to register its parameter requirements in the following way: To register the default pm_qos target for the specific parameter, the process must open one of /dev/[cpu_dma_latency, network_latency, network_throughput] As long as the device node is held open that process has a registered requirement on the parameter. The name of the requirement is "process_<PID>" derived from the current->pid from within the open system call. To change the requested target value the process needs to write a s32 value to the open device node. This translates to a pm_qos_update_requirement call. To remove the user mode request for a target value simply close the device node. [akpm@linux-foundation.org: fix warnings] [akpm@linux-foundation.org: fix build] [akpm@linux-foundation.org: fix build again] [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: mark gross <mgross@linux.intel.com> Cc: "John W. Linville" <linville@tuxdriver.com> Cc: Len Brown <lenb@kernel.org> Cc: Jaroslav Kysela <perex@suse.cz> Cc: Takashi Iwai <tiwai@suse.de> Cc: Arjan van de Ven <arjan@infradead.org> Cc: Venki Pallipadi <venkatesh.pallipadi@intel.com> Cc: Adam Belay <abelay@novell.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-02kobject: Always build in kernel/ksysfs.o.Paul Mundt
kernel/ksysfs.c seems to be a random dumping group for misc globals that the rest of the tree depend on. This has caused problems with exports in the past when sysfs is disabled, which can already be observed in commit-id 51107301b629640f9ab76fe23bf385e187b9ac29. The latest one is the kernel_kobj usage, which presently results in: fs/built-in.o: In function `debugfs_init': inode.c:(.init.text+0xc34): undefined reference to `kernel_kobj' make: *** [.tmp_vmlinux1] Error 1 kernel/ksysfs.c itself at this point only contains globals and some basic sysfs initialization, the sysfs initialization code is optimized out when we build with sysfs disabled. Given that, it's easier to just build in unconditionally, rather than trying to find some other random place to dump and initialize the globals. Additionally, the current trend seems to be decoupling of kobjects from sysfs, in which case it still makes sense to perform the kernel_kobj initialization that happens here even if sysfs is disabled, as lib/kobject.o is built-in unconditionally. Signed-off-by: Paul Mundt <lethal@linux-sh.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2008-01-30x86: add a simple backtrace test moduleArjan van de Ven
During the work on the x86 32 and 64 bit backtrace code I found it useful to have a simple test module to test a process and irq context backtrace. Since the existing backtrace code was buggy, I figure it might be useful to have such a test module in the kernel so that maybe we can even detect such bugs earlier.. [ mingo@elte.hu: build fix ] Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30x86: kprobes: add kprobes smoke tests that run on bootAnanth N Mavinakayanahalli
Here is a quick and naive smoke test for kprobes. This is intended to just verify if some unrelated change broke the *probes subsystem. It is self contained, architecture agnostic and isn't of any great use by itself. This needs to be built in the kernel and runs a basic set of tests to verify if kprobes, jprobes and kretprobes run fine on the kernel. In case of an error, it'll print out a message with a "BUG" prefix. This is a start; we intend to add more tests to this bucket over time. Thanks to Jim Keniston and Masami Hiramatsu for comments and suggestions. Tested on x86 (32/64) and powerpc. Signed-off-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Acked-by: Masami Hiramatsu <mhiramat@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-01-25sched: latencytop supportArjan van de Ven
LatencyTOP kernel infrastructure; it measures latencies in the scheduler and tracks it system wide and per process. Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-01-25Preempt-RCU: implementationPaul E. McKenney
This patch implements a new version of RCU which allows its read-side critical sections to be preempted. It uses a set of counter pairs to keep track of the read-side critical sections and flips them when all tasks exit read-side critical section. The details of this implementation can be found in this paper - http://www.rdrop.com/users/paulmck/RCU/OLSrtRCU.2006.08.11a.pdf and the article- http://lwn.net/Articles/253651/ This patch was developed as a part of the -rt kernel development and meant to provide better latencies when read-side critical sections of RCU don't disable preemption. As a consequence of keeping track of RCU readers, the readers have a slight overhead (optimizations in the paper). This implementation co-exists with the "classic" RCU implementations and can be switched to at compiler. Also includes RCU tracing summarized in debugfs. [ akpm@linux-foundation.org: build fixes on non-preempt architectures ] Signed-off-by: Gautham R Shenoy <ego@in.ibm.com> Signed-off-by: Dipankar Sarma <dipankar@in.ibm.com> Signed-off-by: Paul E. McKenney <paulmck@us.ibm.com> Reviewed-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-01-25Preempt-RCU: reorganize RCU code into rcuclassic.c and rcupdate.cPaul E. McKenney
This patch re-organizes the RCU code to enable multiple implementations of RCU. Users of RCU continues to include rcupdate.h and the RCU interfaces remain the same. This is in preparation for subsequently merging the preemptible RCU implementation. Signed-off-by: Gautham R Shenoy <ego@in.ibm.com> Signed-off-by: Dipankar Sarma <dipankar@in.ibm.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2007-11-14revert "Task Control Groups: example CPU accounting subsystem"Andrew Morton
Revert 62d0df64065e7c135d0002f069444fbdfc64768f. This was originally intended as a simple initial example of how to create a control groups subsystem; it wasn't intended for mainline, but I didn't make this clear enough to Andrew. The CFS cgroup subsystem now has better functionality for the per-cgroup usage accounting (based directly on CFS stats) than the "usage" status file in this patch, and the "load" status file is rather simplistic - although having a per-cgroup load average report would be a useful feature, I don't believe this patch actually provides it. If it gets into the final 2.6.24 we'd probably have to support this interface for ever. Cc: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-21[PATCH] audit: watching subtreesAl Viro
New kind of audit rule predicates: "object is visible in given subtree". The part that can be sanely implemented, that is. Limitations: * if you have hardlink from outside of tree, you'd better watch it too (or just watch the object itself, obviously) * if you mount something under a watched tree, tell audit that new chunk should be added to watched subtrees * if you umount something in a watched tree and it's still mounted elsewhere, you will get matches on events happening there. New command tells audit to recalculate the trees, trimming such sources of false positives. Note that it's _not_ about path - if something mounted in several places (multiple mount, bindings, different namespaces, etc.), the match does _not_ depend on which one we are using for access. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2007-10-19sysctl: Don't compile sysctl_check when !CONFIG_SYSCTLEric W. Biederman
Weird I thought I had written the makefile so this would be handled. Oh well this should fix it. Sorry about that. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Acked-and-tested-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-19Linux Kernel MarkersMathieu Desnoyers
The marker activation functions sits in kernel/marker.c. A hash table is used to keep track of the registered probes and armed markers, so the markers within a newly loaded module that should be active can be activated at module load time. marker_query has been removed. marker_get_first, marker_get_next and marker_release should be used as iterators on the markers. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Acked-by: "Frank Ch. Eigler" <fche@redhat.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Mike Mason <mmlnx@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-19cgroups: implement namespace tracking subsystemSerge E. Hallyn
When a task enters a new namespace via a clone() or unshare(), a new cgroup is created and the task moves into it. This version names cgroups which are automatically created using cgroup_clone() as "node_<pid>" where pid is the pid of the unsharing or cloned process. (Thanks Pavel for the idea) This is safe because if the process unshares again, it will create /cgroups/(...)/node_<pid>/node_<pid> The only possibilities (AFAICT) for a -EEXIST on unshare are 1. pid wraparound 2. a process fails an unshare, then tries again. Case 1 is unlikely enough that I ignore it (at least for now). In case 2, the node_<pid> will be empty and can be rmdir'ed to make the subsequent unshare() succeed. Changelog: Name cloned cgroups as "node_<pid>". [clg@fr.ibm.com: fix order of cgroup subsystems in init/Kconfig] Signed-off-by: Serge E. Hallyn <serue@us.ibm.com> Cc: Paul Menage <menage@google.com> Signed-off-by: Cedric Le Goater <clg@fr.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-19Task Control Groups: simple task cgroup debug info subsystemPaul Menage
This example subsystem exports debugging information as an aid to diagnosing refcount leaks, etc, in the cgroup framework. Signed-off-by: Paul Menage <menage@google.com> Cc: Serge E. Hallyn <serue@us.ibm.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Dave Hansen <haveblue@us.ibm.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Paul Jackson <pj@sgi.com> Cc: Kirill Korotaev <dev@openvz.org> Cc: Herbert Poetzl <herbert@13thfloor.at> Cc: Srivatsa Vaddagiri <vatsa@in.ibm.com> Cc: Cedric Le Goater <clg@fr.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-19Task Control Groups: example CPU accounting subsystemPaul Menage
This example demonstrates how to use the generic cgroup subsystem for a simple resource tracker that counts, for the processes in a cgroup, the total CPU time used and the %CPU used in the last complete 10 second interval. Portions contributed by Balbir Singh <balbir@in.ibm.com> Signed-off-by: Paul Menage <menage@google.com> Cc: Serge E. Hallyn <serue@us.ibm.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Dave Hansen <haveblue@us.ibm.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Paul Jackson <pj@sgi.com> Cc: Kirill Korotaev <dev@openvz.org> Cc: Herbert Poetzl <herbert@13thfloor.at> Cc: Srivatsa Vaddagiri <vatsa@in.ibm.com> Cc: Cedric Le Goater <clg@fr.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-19Task Control Groups: basic task cgroup frameworkPaul Menage
Generic Process Control Groups -------------------------- There have recently been various proposals floating around for resource management/accounting and other task grouping subsystems in the kernel, including ResGroups, User BeanCounters, NSProxy cgroups, and others. These all need the basic abstraction of being able to group together multiple processes in an aggregate, in order to track/limit the resources permitted to those processes, or control other behaviour of the processes, and all implement this grouping in different ways. This patchset provides a framework for tracking and grouping processes into arbitrary "cgroups" and assigning arbitrary state to those groupings, in order to control the behaviour of the cgroup as an aggregate. The intention is that the various resource management and virtualization/cgroup efforts can also become task cgroup clients, with the result that: - the userspace APIs are (somewhat) normalised - it's easier to test e.g. the ResGroups CPU controller in conjunction with the BeanCounters memory controller, or use either of them as the resource-control portion of a virtual server system. - the additional kernel footprint of any of the competing resource management systems is substantially reduced, since it doesn't need to provide process grouping/containment, hence improving their chances of getting into the kernel This patch: Add the main task cgroups framework - the cgroup filesystem, and the basic structures for tracking membership and associating subsystem state objects to tasks. Signed-off-by: Paul Menage <menage@google.com> Cc: Serge E. Hallyn <serue@us.ibm.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Dave Hansen <haveblue@us.ibm.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Paul Jackson <pj@sgi.com> Cc: Kirill Korotaev <dev@openvz.org> Cc: Herbert Poetzl <herbert@13thfloor.at> Cc: Srivatsa Vaddagiri <vatsa@in.ibm.com> Cc: Cedric Le Goater <clg@fr.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-19Add kernel/notifier.cAlexey Dobriyan
There is separate notifier header, but no separate notifier .c file. Extract notifier code out of kernel/sys.c which will remain for misc syscalls I hope. Merge kernel/die_notifier.c into kernel/notifier.c. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Alexey Dobriyan <adobriyan@sw.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-18sysctl: Error on bad sysctl tablesEric W. Biederman
After going through the kernels sysctl tables several times it has become clear that code review and testing is just not effective in prevent problematic sysctl tables from being used in the stable kernel. I certainly can't seem to fix the problems as fast as they are introduced. Therefore this patch adds sysctl_check_table which is called when a sysctl table is registered and checks to see if we have a problematic sysctl table. The biggest part of the code is the table of valid binary sysctl entries, but since we have frozen our set of binary sysctls this table should not need to change, and it makes it much easier to detect when someone unintentionally adds a new binary sysctl value. As best as I can determine all of the several hundred errors spewed on boot up now are legitimate. [bunk@kernel.org: kernel/sysctl_check.c must #include <linux/string.h>] Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Cc: Alexey Dobriyan <adobriyan@sw.ru> Signed-off-by: Adrian Bunk <bunk@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>