The swapaccount kernel parameter without any values has been removed by
commit a2c8990aed ("memsw: remove noswapaccount kernel parameter") but
it seems that we didn't get rid of all the left overs.
Make sure that menuconfig help text and kernel-parameters.txt are clear
about value for the paramter and remove the stalled comment which is not
very much useful on its own.
Signed-off-by: Michal Hocko <mhocko@suse.cz>
Reported-by: Gergely Risko <gergely@risko.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The __cpuinit type of throwaway sections might have made sense
some time ago when RAM was more constrained, but now the savings
do not offset the cost and complications. For example, the fix in
commit 5e427ec2d0 ("x86: Fix bit corruption at CPU resume time")
is a good example of the nasty type of bugs that can be created
with improper use of the various __init prefixes.
After a discussion on LKML[1] it was decided that cpuinit should go
the way of devinit and be phased out. Once all the users are gone,
we can then finally remove the macros themselves from linux/init.h.
This removes all the uses of the __cpuinit macros from C files in
the core kernel directories (kernel, init, lib, mm, and include)
that don't really have a specific maintainer.
[1] https://lkml.org/lkml/2013/5/20/589
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Pull slab update from Pekka Enberg:
"Highlights:
- Fix for boot-time problems on some architectures due to
init_lock_keys() not respecting kmalloc_caches boundaries
(Christoph Lameter)
- CONFIG_SLUB_CPU_PARTIAL requested by RT folks (Joonsoo Kim)
- Fix for excessive slab freelist draining (Wanpeng Li)
- SLUB and SLOB cleanups and fixes (various people)"
I ended up editing the branch, and this avoids two commits at the end
that were immediately reverted, and I instead just applied the oneliner
fix in between myself.
* 'slab/for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/linux
slub: Check for page NULL before doing the node_match check
mm/slab: Give s_next and s_stop slab-specific names
slob: Check for NULL pointer before calling ctor()
slub: Make cpu partial slab support configurable
slab: add kmalloc() to kernel API documentation
slab: fix init_lock_keys
slob: use DIV_ROUND_UP where possible
slub: do not put a slab to cpu partial list when cpu_partial is 0
mm/slub: Use node_nr_slabs and node_nr_objs in get_slabinfo
mm/slub: Drop unnecessary nr_partials
mm/slab: Fix /proc/slabinfo unwriteable for slab
mm/slab: Sharing s_next and s_stop between slab and slub
mm/slab: Fix drain freelist excessively
slob: Rework #ifdeffery in slab.h
mm, slab: moved kmem_cache_alloc_node comment to correct place
CPU partial support can introduce level of indeterminism that is not
wanted in certain context (like a realtime kernel). Make it
configurable.
This patch is based on Christoph Lameter's "slub: Make cpu partial slab
support configurable V2".
Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
Pull timer core updates from Thomas Gleixner:
"The timer changes contain:
- posix timer code consolidation and fixes for odd corner cases
- sched_clock implementation moved from ARM to core code to avoid
duplication by other architectures
- alarm timer updates
- clocksource and clockevents unregistration facilities
- clocksource/events support for new hardware
- precise nanoseconds RTC readout (Xen feature)
- generic support for Xen suspend/resume oddities
- the usual lot of fixes and cleanups all over the place
The parts which touch other areas (ARM/XEN) have been coordinated with
the relevant maintainers. Though this results in an handful of
trivial to solve merge conflicts, which we preferred over nasty cross
tree merge dependencies.
The patches which have been committed in the last few days are bug
fixes plus the posix timer lot. The latter was in akpms queue and
next for quite some time; they just got forgotten and Frederic
collected them last minute."
* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (59 commits)
hrtimer: Remove unused variable
hrtimers: Move SMP function call to thread context
clocksource: Reselect clocksource when watchdog validated high-res capability
posix-cpu-timers: don't account cpu timer after stopped thread runtime accounting
posix_timers: fix racy timer delta caching on task exit
posix-timers: correctly get dying task time sample in posix_cpu_timer_schedule()
selftests: add basic posix timers selftests
posix_cpu_timers: consolidate expired timers check
posix_cpu_timers: consolidate timer list cleanups
posix_cpu_timer: consolidate expiry time type
tick: Sanitize broadcast control logic
tick: Prevent uncontrolled switch to oneshot mode
tick: Make oneshot broadcast robust vs. CPU offlining
x86: xen: Sync the CMOS RTC as well as the Xen wallclock
x86: xen: Sync the wallclock when the system time is set
timekeeping: Indicate that clock was set in the pvclock gtod notifier
timekeeping: Pass flags instead of multiple bools to timekeeping_update()
xen: Remove clock_was_set() call in the resume path
hrtimers: Support resuming with two or more CPUs online (but stopped)
timer: Fix jiffies wrap behavior of round_jiffies_common()
...
git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks into timers/core
Frederic sayed: "Most of these patches have been hanging around for
several month now, in -mmotm for a significant chunk. They already
missed a few releases."
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
do_one_initcall() uses a 64 byte string buffer to save a message. This
buffer is declared static and is only used at boot up and when a module
is loaded. As 64 bytes is very small, and this function has very limited
scope, there's no reason to waste permanent memory with this string and
not just simply put it on the stack.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull perf updates from Ingo Molnar:
"Kernel improvements:
- watchdog driver improvements by Li Zefan
- Power7 CPI stack events related improvements by Sukadev Bhattiprolu
- event multiplexing via hrtimers and other improvements by Stephane
Eranian
- kernel stack use optimization by Andrew Hunter
- AMD IOMMU uncore PMU support by Suravee Suthikulpanit
- NMI handling rate-limits by Dave Hansen
- various hw_breakpoint fixes by Oleg Nesterov
- hw_breakpoint overflow period sampling and related signal handling
fixes by Jiri Olsa
- Intel Haswell PMU support by Andi Kleen
Tooling improvements:
- Reset SIGTERM handler in workload child process, fix from David
Ahern.
- Makefile reorganization, prep work for Kconfig patches, from Jiri
Olsa.
- Add automated make test suite, from Jiri Olsa.
- Add --percent-limit option to 'top' and 'report', from Namhyung
Kim.
- Sorting improvements, from Namhyung Kim.
- Expand definition of sysfs format attribute, from Michael Ellerman.
Tooling fixes:
- 'perf tests' fixes from Jiri Olsa.
- Make Power7 CPI stack events available in sysfs, from Sukadev
Bhattiprolu.
- Handle death by SIGTERM in 'perf record', fix from David Ahern.
- Fix printing of perf_event_paranoid message, from David Ahern.
- Handle realloc failures in 'perf kvm', from David Ahern.
- Fix divide by 0 in variance, from David Ahern.
- Save parent pid in thread struct, from David Ahern.
- Handle JITed code in shared memory, from Andi Kleen.
- Fixes for 'perf diff', from Jiri Olsa.
- Remove some unused struct members, from Jiri Olsa.
- Add missing liblk.a dependency for python/perf.so, fix from Jiri
Olsa.
- Respect CROSS_COMPILE in liblk.a, from Rabin Vincent.
- No need to do locking when adding hists in perf report, only 'top'
needs that, from Namhyung Kim.
- Fix alignment of symbol column in in the hists browser (top,
report) when -v is given, from NAmhyung Kim.
- Fix 'perf top' -E option behavior, from Namhyung Kim.
- Fix bug in isupper() and islower(), from Sukadev Bhattiprolu.
- Fix compile errors in bp_signal 'perf test', from Sukadev
Bhattiprolu.
... and more things"
* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (102 commits)
perf/x86: Disable PEBS-LL in intel_pmu_pebs_disable()
perf/x86: Fix shared register mutual exclusion enforcement
perf/x86/intel: Support full width counting
x86: Add NMI duration tracepoints
perf: Drop sample rate when sampling is too slow
x86: Warn when NMI handlers take large amounts of time
hw_breakpoint: Introduce "struct bp_cpuinfo"
hw_breakpoint: Simplify *register_wide_hw_breakpoint()
hw_breakpoint: Introduce cpumask_of_bp()
hw_breakpoint: Simplify the "weight" usage in toggle_bp_slot() paths
hw_breakpoint: Simplify list/idx mess in toggle_bp_slot() paths
perf/x86/intel: Add mem-loads/stores support for Haswell
perf/x86/intel: Support Haswell/v4 LBR format
perf/x86/intel: Move NMI clearing to end of PMI handler
perf/x86/intel: Add Haswell PEBS support
perf/x86/intel: Add simple Haswell PMU support
perf/x86/intel: Add Haswell PEBS record support
perf/x86/intel: Fix sparse warning
perf/x86/amd: AMD IOMMU Performance Counter PERF uncore PMU implementation
perf/x86/amd: Add IOMMU Performance Counter resource management
...
Some drivers can be built on more platforms than they run on. This is
a burden for users and distributors who package a kernel. They have to
manually deselect some (for them useless) drivers when updating their
configs via oldconfig. And yet, sometimes it is even impossible to
disable the drivers without patching the kernel.
Introduce a new config option COMPILE_TEST and make all those drivers
to depend on the platform they run on, or on the COMPILE_TEST option.
Now, when users/distributors choose COMPILE_TEST=n they will not have
the drivers in their allmodconfig setups, but developers still can
compile-test them with COMPILE_TEST=y.
Now the drivers where we use this new option:
* PTP_1588_CLOCK_PCH: The PCH EG20T is only compatible with Intel Atom
processors so it should depend on x86.
* FB_GEODE: Geode is 32-bit only so only enable it for X86_32.
* USB_CHIPIDEA_IMX: The OF_DEVICE dependency will be met on powerpc
systems -- which do not actually support the hardware via that
method.
* INTEL_MID_PTI: It is specific to the Penwell type of Intel Atom
device.
[v2]
* remove EXPERT dependency
[gregkh - remove chipidea portion, as it's incorrect, and also doesn't
apply to my driver-core tree]
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Jeff Mahoney <jeffm@suse.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: linux-usb@vger.kernel.org
Cc: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
Cc: linux-geode@lists.infradead.org
Cc: linux-fbdev@vger.kernel.org
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: netdev@vger.kernel.org
Cc: Ben Hutchings <ben@decadent.org.uk>
Cc: "Keller, Jacob E" <jacob.e.keller@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Nothing about the sched_clock implementation in the ARM port is
specific to the architecture. Generalize the code so that other
architectures can use it by selecting GENERIC_SCHED_CLOCK.
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
[jstultz: Merge minor collisions with other patches in my tree]
Signed-off-by: John Stultz <john.stultz@linaro.org>
TINY_PREEMPT_RCU adds significant code and complexity, but does not
offer commensurate benefits. People currently using TINY_PREEMPT_RCU
can get much better memory footprint with TINY_RCU, or, if they really
need preemptible RCU, they can use TREE_PREEMPT_RCU with a relatively
minor degradation in memory footprint. Please note that this move
has been widely publicized on LKML (https://lkml.org/lkml/2012/11/12/545)
and on LWN (http://lwn.net/Articles/541037/).
This commit therefore removes TINY_PREEMPT_RCU.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
[ paulmck: Updated to eliminate #else in rcutiny.h as suggested by Josh ]
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
The Kconfig help text for the RCU_NOCB_CPU_NONE, RCU_NOCB_CPU_ZERO,
and RCU_NOCB_CPU_ALL Kconfig options was unclear, so this commit
adds a bit more detail.
Reported-by: Dave Jones <davej@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The current scheme of using the timer tick was fine for per-thread
events. However, it was causing bias issues in system-wide mode
(including for uncore PMUs). Event groups would not get their fair
share of runtime on the PMU. With tickless kernels, if a core is idle
there is no timer tick, and thus no event rotation (multiplexing).
However, there are events (especially uncore events) which do count
even though cores are asleep.
This patch changes the timer source for multiplexing. It introduces a
per-PMU per-cpu hrtimer. The advantage is that even when a core goes
idle, it will come back to service the hrtimer, thus multiplexing on
system-wide events works much better.
The per-PMU implementation (suggested by PeterZ) enables adjusting the
multiplexing interval per PMU. The preferred interval is stashed into
the struct pmu. If not set, it will be forced to the default interval
value.
In order to minimize the impact of the hrtimer, it is turned on and
off on demand. When the PMU on a CPU is overcommited, the hrtimer is
activated. It is stopped when the PMU is not overcommitted.
In order for this to work properly, we had to change the order of
initialization in start_kernel() such that hrtimer_init() is run
before perf_event_init().
The default interval in milliseconds is set to a timer tick just like
with the old code. We will provide a sysctl to tune this in another
patch.
Signed-off-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Link: http://lkml.kernel.org/r/1364991694-5876-2-git-send-email-eranian@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull 'full dynticks' support from Ingo Molnar:
"This tree from Frederic Weisbecker adds a new, (exciting! :-) core
kernel feature to the timer and scheduler subsystems: 'full dynticks',
or CONFIG_NO_HZ_FULL=y.
This feature extends the nohz variable-size timer tick feature from
idle to busy CPUs (running at most one task) as well, potentially
reducing the number of timer interrupts significantly.
This feature got motivated by real-time folks and the -rt tree, but
the general utility and motivation of full-dynticks runs wider than
that:
- HPC workloads get faster: CPUs running a single task should be able
to utilize a maximum amount of CPU power. A periodic timer tick at
HZ=1000 can cause a constant overhead of up to 1.0%. This feature
removes that overhead - and speeds up the system by 0.5%-1.0% on
typical distro configs even on modern systems.
- Real-time workload latency reduction: CPUs running critical tasks
should experience as little jitter as possible. The last remaining
source of kernel-related jitter was the periodic timer tick.
- A single task executing on a CPU is a pretty common situation,
especially with an increasing number of cores/CPUs, so this feature
helps desktop and mobile workloads as well.
The cost of the feature is mainly related to increased timer
reprogramming overhead when a CPU switches its tick period, and thus
slightly longer to-idle and from-idle latency.
Configuration-wise a third mode of operation is added to the existing
two NOHZ kconfig modes:
- CONFIG_HZ_PERIODIC: [formerly !CONFIG_NO_HZ], now explicitly named
as a config option. This is the traditional Linux periodic tick
design: there's a HZ tick going on all the time, regardless of
whether a CPU is idle or not.
- CONFIG_NO_HZ_IDLE: [formerly CONFIG_NO_HZ=y], this turns off the
periodic tick when a CPU enters idle mode.
- CONFIG_NO_HZ_FULL: this new mode, in addition to turning off the
tick when a CPU is idle, also slows the tick down to 1 Hz (one
timer interrupt per second) when only a single task is running on a
CPU.
The .config behavior is compatible: existing !CONFIG_NO_HZ and
CONFIG_NO_HZ=y settings get translated to the new values, without the
user having to configure anything. CONFIG_NO_HZ_FULL is turned off by
default.
This feature is based on a lot of infrastructure work that has been
steadily going upstream in the last 2-3 cycles: related RCU support
and non-periodic cputime support in particular is upstream already.
This tree adds the final pieces and activates the feature. The pull
request is marked RFC because:
- it's marked 64-bit only at the moment - the 32-bit support patch is
small but did not get ready in time.
- it has a number of fresh commits that came in after the merge
window. The overwhelming majority of commits are from before the
merge window, but still some aspects of the tree are fresh and so I
marked it RFC.
- it's a pretty wide-reaching feature with lots of effects - and
while the components have been in testing for some time, the full
combination is still not very widely used. That it's default-off
should reduce its regression abilities and obviously there are no
known regressions with CONFIG_NO_HZ_FULL=y enabled either.
- the feature is not completely idempotent: there is no 100%
equivalent replacement for a periodic scheduler/timer tick. In
particular there's ongoing work to map out and reduce its effects
on scheduler load-balancing and statistics. This should not impact
correctness though, there are no known regressions related to this
feature at this point.
- it's a pretty ambitious feature that with time will likely be
enabled by most Linux distros, and we'd like you to make input on
its design/implementation, if you dislike some aspect we missed.
Without flaming us to crisp! :-)
Future plans:
- there's ongoing work to reduce 1Hz to 0Hz, to essentially shut off
the periodic tick altogether when there's a single busy task on a
CPU. We'd first like 1 Hz to be exposed more widely before we go
for the 0 Hz target though.
- once we reach 0 Hz we can remove the periodic tick assumption from
nr_running>=2 as well, by essentially interrupting busy tasks only
as frequently as the sched_latency constraints require us to do -
once every 4-40 msecs, depending on nr_running.
I am personally leaning towards biting the bullet and doing this in
v3.10, like the -rt tree this effort has been going on for too long -
but the final word is up to you as usual.
More technical details can be found in Documentation/timers/NO_HZ.txt"
* 'timers-nohz-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (39 commits)
sched: Keep at least 1 tick per second for active dynticks tasks
rcu: Fix full dynticks' dependency on wide RCU nocb mode
nohz: Protect smp_processor_id() in tick_nohz_task_switch()
nohz_full: Add documentation.
cputime_nsecs: use math64.h for nsec resolution conversion helpers
nohz: Select VIRT_CPU_ACCOUNTING_GEN from full dynticks config
nohz: Reduce overhead under high-freq idling patterns
nohz: Remove full dynticks' superfluous dependency on RCU tree
nohz: Fix unavailable tick_stop tracepoint in dynticks idle
nohz: Add basic tracing
nohz: Select wide RCU nocb for full dynticks
nohz: Disable the tick when irq resume in full dynticks CPU
nohz: Re-evaluate the tick for the new task after a context switch
nohz: Prepare to stop the tick on irq exit
nohz: Implement full dynticks kick
nohz: Re-evaluate the tick from the scheduler IPI
sched: New helper to prevent from stopping the tick in full dynticks
sched: Kick full dynticks CPU that have more than one task enqueued.
perf: New helper to prevent full dynticks CPUs from stopping tick
perf: Kick full dynticks CPU if events rotation is needed
...
The full dynticks tree needs the latest RCU and sched
upstream updates in order to fix some dependencies.
Merge a common upstream merge point that has these
updates.
Conflicts:
include/linux/perf_event.h
kernel/rcutree.h
kernel/rcutree_plugin.h
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
