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2013-08-23memcg: get rid of swapaccount leftoversMichal Hocko
The swapaccount kernel parameter without any values has been removed by commit a2c8990aed5a ("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>
2013-07-14kernel: delete __cpuinit usage from all core kernel filesPaul Gortmaker
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>
2013-07-14Merge branch 'slab/for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/penberg/linux 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
2013-07-09lib: add support for LZ4-compressed kernelKyungsik Lee
Add support for extracting LZ4-compressed kernel images, as well as LZ4-compressed ramdisk images in the kernel boot process. Signed-off-by: Kyungsik Lee <kyungsik.lee@lge.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Borislav Petkov <bp@alien8.de> Cc: Florian Fainelli <florian@openwrt.org> Cc: Yann Collet <yann.collet.73@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-07-07slub: Make cpu partial slab support configurableJoonsoo Kim
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>
2013-07-06Merge branch 'timers-core-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 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() ...
2013-07-04Merge branch 'timers/posix-cpu-timers-for-tglx' ofThomas Gleixner
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>
2013-07-03insert missing space in printk line of root_delayToralf Förster
Trivial, but it really looks better. Signed-off-by: Toralf Förster <toralf.foerster@gmx.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-07-03init: remove permanent string buffer from do_one_initcall()Steven Rostedt
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>
2013-07-03memcg: Kconfig info updateSergey Dyasly
Now there are only 2 members in struct page_cgroup. Update config MEMCG description accordingly. Signed-off-by: Sergey Dyasly <dserrg@gmail.com> Acked-by: Michal Hocko <mhocko@suse.cz> Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-07-02Merge branch 'perf-core-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 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 ...
2013-07-02Merge branch 'core-rcu-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull RCU updates from Ingo Molnar: "The major changes: - Simplify RCU's grace-period and callback processing based on the new numbering for callbacks. - Removal of TINY_PREEMPT_RCU in favor of TREE_PREEMPT_RCU for single-CPU low-latency systems. - SRCU-related changes and fixes. - Miscellaneous fixes, including converting a few remaining printk() calls to pr_*(). - Documentation updates" * 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (32 commits) rcu: Shrink TINY_RCU by reworking CPU-stall ifdefs rcu: Shrink TINY_RCU by moving exit_rcu() rcu: Remove TINY_PREEMPT_RCU tracing documentation rcu: Consolidate rcutiny_plugin.h ifdefs rcu: Remove rcu_preempt_note_context_switch() rcu: Remove the CONFIG_TINY_RCU ifdefs in rcutiny.h rcu: Remove check_cpu_stall_preempt() rcu: Simplify RCU_TINY RCU callback invocation rcu: Remove rcu_preempt_process_callbacks() rcu: Remove rcu_preempt_remove_callbacks() rcu: Remove rcu_preempt_check_callbacks() rcu: Remove show_tiny_preempt_stats() rcu: Remove TINY_PREEMPT_RCU powerpc,kvm: fix imbalance srcu_read_[un]lock() rcu: Remove srcu_read_lock_raw() and srcu_read_unlock_raw(). rcu: Apply Dave Jones's NOCB Kconfig help feedback rcu: Merge adjacent identical ifdefs rcu: Drive quiescent-state-forcing delay from HZ rcu: Remove "Experimental" flags kthread: Add kworker kthreads to OS-jitter documentation ...
2013-06-24build some drivers only when compile-testingJiri Slaby
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>
2013-06-17Merge 3.10-rc6 into driver-core-nextGreg Kroah-Hartman
We want these fixes here too. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-06-12sched_clock: Make ARM's sched_clock generic for all architecturesStephen Boyd
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>
2013-06-10Merge branches 'cbnum.2013.06.10a', 'doc.2013.06.10a', 'fixes.2013.06.10a', ↵Paul E. McKenney
'srcu.2013.06.10a' and 'tiny.2013.06.10a' into HEAD cbnum.2013.06.10a: Apply simplifications stemming from the new callback numbering. doc.2013.06.10a: Documentation updates. fixes.2013.06.10a: Miscellaneous fixes. srcu.2013.06.10a: Updates to SRCU. tiny.2013.06.10a: Eliminate TINY_PREEMPT_RCU.
2013-06-10rcu: Remove TINY_PREEMPT_RCUPaul E. McKenney
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>
2013-06-10rcu: Apply Dave Jones's NOCB Kconfig help feedbackPaul E. McKenney
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>
2013-06-10rcu: Remove "Experimental" flagsPaul E. McKenney
After a release or two, features are no longer experimental. Therefore, this commit removes the "Experimental" tag from them. Reported-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2013-06-10rcu: Don't call wakeup() with rcu_node structure ->lock heldSteven Rostedt
This commit fixes a lockdep-detected deadlock by moving a wake_up() call out from a rnp->lock critical section. Please see below for the long version of this story. On Tue, 2013-05-28 at 16:13 -0400, Dave Jones wrote: > [12572.705832] ====================================================== > [12572.750317] [ INFO: possible circular locking dependency detected ] > [12572.796978] 3.10.0-rc3+ #39 Not tainted > [12572.833381] ------------------------------------------------------- > [12572.862233] trinity-child17/31341 is trying to acquire lock: > [12572.870390] (rcu_node_0){..-.-.}, at: [<ffffffff811054ff>] rcu_read_unlock_special+0x9f/0x4c0 > [12572.878859] > but task is already holding lock: > [12572.894894] (&ctx->lock){-.-...}, at: [<ffffffff811390ed>] perf_lock_task_context+0x7d/0x2d0 > [12572.903381] > which lock already depends on the new lock. > > [12572.927541] > the existing dependency chain (in reverse order) is: > [12572.943736] > -> #4 (&ctx->lock){-.-...}: > [12572.960032] [<ffffffff810b9851>] lock_acquire+0x91/0x1f0 > [12572.968337] [<ffffffff816ebc90>] _raw_spin_lock+0x40/0x80 > [12572.976633] [<ffffffff8113c987>] __perf_event_task_sched_out+0x2e7/0x5e0 > [12572.984969] [<ffffffff81088953>] perf_event_task_sched_out+0x93/0xa0 > [12572.993326] [<ffffffff816ea0bf>] __schedule+0x2cf/0x9c0 > [12573.001652] [<ffffffff816eacfe>] schedule_user+0x2e/0x70 > [12573.009998] [<ffffffff816ecd64>] retint_careful+0x12/0x2e > [12573.018321] > -> #3 (&rq->lock){-.-.-.}: > [12573.034628] [<ffffffff810b9851>] lock_acquire+0x91/0x1f0 > [12573.042930] [<ffffffff816ebc90>] _raw_spin_lock+0x40/0x80 > [12573.051248] [<ffffffff8108e6a7>] wake_up_new_task+0xb7/0x260 > [12573.059579] [<ffffffff810492f5>] do_fork+0x105/0x470 > [12573.067880] [<ffffffff81049686>] kernel_thread+0x26/0x30 > [12573.076202] [<ffffffff816cee63>] rest_init+0x23/0x140 > [12573.084508] [<ffffffff81ed8e1f>] start_kernel+0x3f1/0x3fe > [12573.092852] [<ffffffff81ed856f>] x86_64_start_reservations+0x2a/0x2c > [12573.101233] [<ffffffff81ed863d>] x86_64_start_kernel+0xcc/0xcf > [12573.109528] > -> #2 (&p->pi_lock){-.-.-.}: > [12573.125675] [<ffffffff810b9851>] lock_acquire+0x91/0x1f0 > [12573.133829] [<ffffffff816ebe9b>] _raw_spin_lock_irqsave+0x4b/0x90 > [12573.141964] [<ffffffff8108e881>] try_to_wake_up+0x31/0x320 > [12573.150065] [<ffffffff8108ebe2>] default_wake_function+0x12/0x20 > [12573.158151] [<ffffffff8107bbf8>] autoremove_wake_function+0x18/0x40 > [12573.166195] [<ffffffff81085398>] __wake_up_common+0x58/0x90 > [12573.174215] [<ffffffff81086909>] __wake_up+0x39/0x50 > [12573.182146] [<ffffffff810fc3da>] rcu_start_gp_advanced.isra.11+0x4a/0x50 > [12573.190119] [<ffffffff810fdb09>] rcu_start_future_gp+0x1c9/0x1f0 > [12573.198023] [<ffffffff810fe2c4>] rcu_nocb_kthread+0x114/0x930 > [12573.205860] [<ffffffff8107a91d>] kthread+0xed/0x100 > [12573.213656] [<ffffffff816f4b1c>] ret_from_fork+0x7c/0xb0 > [12573.221379] > -> #1 (&rsp->gp_wq){..-.-.}: > [12573.236329] [<ffffffff810b9851>] lock_acquire+0x91/0x1f0 > [12573.243783] [<ffffffff816ebe9b>] _raw_spin_lock_irqsave+0x4b/0x90 > [12573.251178] [<ffffffff810868f3>] __wake_up+0x23/0x50 > [12573.258505] [<ffffffff810fc3da>] rcu_start_gp_advanced.isra.11+0x4a/0x50 > [12573.265891] [<ffffffff810fdb09>] rcu_start_future_gp+0x1c9/0x1f0 > [12573.273248] [<ffffffff810fe2c4>] rcu_nocb_kthread+0x114/0x930 > [12573.280564] [<ffffffff8107a91d>] kthread+0xed/0x100 > [12573.287807] [<ffffffff816f4b1c>] ret_from_fork+0x7c/0xb0 Notice the above call chain. rcu_start_future_gp() is called with the rnp->lock held. Then it calls rcu_start_gp_advance, which does a wakeup. You can't do wakeups while holding the rnp->lock, as that would mean that you could not do a rcu_read_unlock() while holding the rq lock, or any lock that was taken while holding the rq lock. This is because... (See below). > [12573.295067] > -> #0 (rcu_node_0){..-.-.}: > [12573.309293] [<ffffffff810b8d36>] __lock_acquire+0x1786/0x1af0 > [12573.316568] [<ffffffff810b9851>] lock_acquire+0x91/0x1f0 > [12573.323825] [<ffffffff816ebc90>] _raw_spin_lock+0x40/0x80 > [12573.331081] [<ffffffff811054ff>] rcu_read_unlock_special+0x9f/0x4c0 > [12573.338377] [<ffffffff810760a6>] __rcu_read_unlock+0x96/0xa0 > [12573.345648] [<ffffffff811391b3>] perf_lock_task_context+0x143/0x2d0 > [12573.352942] [<ffffffff8113938e>] find_get_context+0x4e/0x1f0 > [12573.360211] [<ffffffff811403f4>] SYSC_perf_event_open+0x514/0xbd0 > [12573.367514] [<ffffffff81140e49>] SyS_perf_event_open+0x9/0x10 > [12573.374816] [<ffffffff816f4dd4>] tracesys+0xdd/0xe2 Notice the above trace. perf took its own ctx->lock, which can be taken while holding the rq lock. While holding this lock, it did a rcu_read_unlock(). The perf_lock_task_context() basically looks like: rcu_read_lock(); raw_spin_lock(ctx->lock); rcu_read_unlock(); Now, what looks to have happened, is that we scheduled after taking that first rcu_read_lock() but before taking the spin lock. When we scheduled back in and took the ctx->lock, the following rcu_read_unlock() triggered the "special" code. The rcu_read_unlock_special() takes the rnp->lock, which gives us a possible deadlock scenario. CPU0 CPU1 CPU2 ---- ---- ---- rcu_nocb_kthread() lock(rq->lock); lock(ctx->lock); lock(rnp->lock); wake_up(); lock(rq->lock); rcu_read_unlock(); rcu_read_unlock_special(); lock(rnp->lock); lock(ctx->lock); **** DEADLOCK **** > [12573.382068] > other info that might help us debug this: > > [12573.403229] Chain exists of: > rcu_node_0 --> &rq->lock --> &ctx->lock > > [12573.424471] Possible unsafe locking scenario: > > [12573.438499] CPU0 CPU1 > [12573.445599] ---- ---- > [12573.452691] lock(&ctx->lock); > [12573.459799] lock(&rq->lock); > [12573.467010] lock(&ctx->lock); > [12573.474192] lock(rcu_node_0); > [12573.481262] > *** DEADLOCK *** > > [12573.501931] 1 lock held by trinity-child17/31341: > [12573.508990] #0: (&ctx->lock){-.-...}, at: [<ffffffff811390ed>] perf_lock_task_context+0x7d/0x2d0 > [12573.516475] > stack backtrace: > [12573.530395] CPU: 1 PID: 31341 Comm: trinity-child17 Not tainted 3.10.0-rc3+ #39 > [12573.545357] ffffffff825b4f90 ffff880219f1dbc0 ffffffff816e375b ffff880219f1dc00 > [12573.552868] ffffffff816dfa5d ffff880219f1dc50 ffff88023ce4d1f8 ffff88023ce4ca40 > [12573.560353] 0000000000000001 0000000000000001 ffff88023ce4d1f8 ffff880219f1dcc0 > [12573.567856] Call Trace: > [12573.575011] [<ffffffff816e375b>] dump_stack+0x19/0x1b > [12573.582284] [<ffffffff816dfa5d>] print_circular_bug+0x200/0x20f > [12573.589637] [<ffffffff810b8d36>] __lock_acquire+0x1786/0x1af0 > [12573.596982] [<ffffffff810918f5>] ? sched_clock_cpu+0xb5/0x100 > [12573.604344] [<ffffffff810b9851>] lock_acquire+0x91/0x1f0 > [12573.611652] [<ffffffff811054ff>] ? rcu_read_unlock_special+0x9f/0x4c0 > [12573.619030] [<ffffffff816ebc90>] _raw_spin_lock+0x40/0x80 > [12573.626331] [<ffffffff811054ff>] ? rcu_read_unlock_special+0x9f/0x4c0 > [12573.633671] [<ffffffff811054ff>] rcu_read_unlock_special+0x9f/0x4c0 > [12573.640992] [<ffffffff811390ed>] ? perf_lock_task_context+0x7d/0x2d0 > [12573.648330] [<ffffffff810b429e>] ? put_lock_stats.isra.29+0xe/0x40 > [12573.655662] [<ffffffff813095a0>] ? delay_tsc+0x90/0xe0 > [12573.662964] [<ffffffff810760a6>] __rcu_read_unlock+0x96/0xa0 > [12573.670276] [<ffffffff811391b3>] perf_lock_task_context+0x143/0x2d0 > [12573.677622] [<ffffffff81139070>] ? __perf_event_enable+0x370/0x370 > [12573.684981] [<ffffffff8113938e>] find_get_context+0x4e/0x1f0 > [12573.692358] [<ffffffff811403f4>] SYSC_perf_event_open+0x514/0xbd0 > [12573.699753] [<ffffffff8108cd9d>] ? get_parent_ip+0xd/0x50 > [12573.707135] [<ffffffff810b71fd>] ? trace_hardirqs_on_caller+0xfd/0x1c0 > [12573.714599] [<ffffffff81140e49>] SyS_perf_event_open+0x9/0x10 > [12573.721996] [<ffffffff816f4dd4>] tracesys+0xdd/0xe2 This commit delays the wakeup via irq_work(), which is what perf and ftrace use to perform wakeups in critical sections. Reported-by: Dave Jones <davej@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2013-06-03Finally eradicate CONFIG_HOTPLUGStephen Rothwell
Ever since commit 45f035ab9b8f ("CONFIG_HOTPLUG should be always on"), it has been basically impossible to build a kernel with CONFIG_HOTPLUG turned off. Remove all the remaining references to it. Cc: Russell King <linux@arm.linux.org.uk> Cc: Doug Thompson <dougthompson@xmission.com> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Pavel Machek <pavel@ucw.cz> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Acked-by: Mauro Carvalho Chehab <mchehab@redhat.com> Acked-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-05-28perf: Use hrtimers for event multiplexingStephane Eranian
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>
2013-05-05Merge branch 'timers-nohz-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 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 ...
2013-05-04rcu: Fix full dynticks' dependency on wide RCU nocb modeFrederic Weisbecker
Commit 0637e029392386e6996f5d6574aadccee8315efa ("nohz: Select wide RCU nocb for full dynticks") intended to force CONFIG_RCU_NOCB_CPU_ALL=y when full dynticks is enabled. However this option is part of a choice menu and Kconfig's "select" instruction has no effect on such targets. Fix this by using reverse dependencies on the targets we don't want instead. Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Christoph Lameter <cl@linux.com> Cc: Hakan Akkan <hakanakkan@gmail.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Kevin Hilman <khilman@linaro.org> Cc: Li Zhong <zhong@linux.vnet.ibm.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de>
2013-05-02Merge commit '8700c95adb03' into timers/nohzFrederic Weisbecker
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>
2013-05-01Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull VFS updates from Al Viro, Misc cleanups all over the place, mainly wrt /proc interfaces (switch create_proc_entry to proc_create(), get rid of the deprecated create_proc_read_entry() in favor of using proc_create_data() and seq_file etc). 7kloc removed. * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (204 commits) don't bother with deferred freeing of fdtables proc: Move non-public stuff from linux/proc_fs.h to fs/proc/internal.h proc: Make the PROC_I() and PDE() macros internal to procfs proc: Supply a function to remove a proc entry by PDE take cgroup_open() and cpuset_open() to fs/proc/base.c ppc: Clean up scanlog ppc: Clean up rtas_flash driver somewhat hostap: proc: Use remove_proc_subtree() drm: proc: Use remove_proc_subtree() drm: proc: Use minor->index to label things, not PDE->name drm: Constify drm_proc_list[] zoran: Don't print proc_dir_entry data in debug reiserfs: Don't access the proc_dir_entry in r_open(), r_start() r_show() proc: Supply an accessor for getting the data from a PDE's parent airo: Use remove_proc_subtree() rtl8192u: Don't need to save device proc dir PDE rtl8187se: Use a dir under /proc/net/r8180/ proc: Add proc_mkdir_data() proc: Move some bits from linux/proc_fs.h to linux/{of.h,signal.h,tty.h} proc: Move PDE_NET() to fs/proc/proc_net.c ...
2013-05-01proc: Split the namespace stuff out into linux/proc_ns.hDavid Howells
Split the proc namespace stuff out into linux/proc_ns.h. Signed-off-by: David Howells <dhowells@redhat.com> cc: netdev@vger.kernel.org cc: Serge E. Hallyn <serge.hallyn@ubuntu.com> cc: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-05-01init: Do not warn on non-zero initcall returnSteven Rostedt
Commit f91eb62f71b3 ("init: scream bloody murder if interrupts are enabled too early") added three new warnings. The first two seemed reasonable, but the third included a warning when an initcall returned non-zero. Although, the third WARN() does include an imbalanced preempt disabled, or irqs disable, it shouldn't warn if it only had an initcall that just returns non-zero. In fact, according to Linus, it shouldn't print at all. As it only prints with initcall_debug set, and that already shows enough information to fix things. Link: http://lkml.kernel.org/r/CA+55aFzaBC5SFi7=F2mfm+KWY5qTsBmOqgbbs8E+LUS8JK-sBg@mail.gmail.com Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Reported-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-30init/Kconfig: re-order CONFIG_EXPERT options to fix menuconfig displayMike Frysinger
The kconfig language requires that dependent options all follow the menuconfig symbol in order to be collapsed below it. Recently some hidden options were added below the EXPERT menuconfig, but did not depend on EXPERT (because hidden options can't). This broke the display. So re-order all these options, and while we're here stick the PCI quirks under the EXPERT menu (since it isn't sitting with any related options). Before this commit, we get: [*] Configure standard kernel features (expert users) ---> [ ] Sysctl syscall support [*] Load all symbols for debugging/ksymoops ... [ ] Embedded system Now we get the older (and correct) behavior: [*] Configure standard kernel features (expert users) ---> [ ] Embedded system And if you go into the expert menu you get the expert options: [ ] Sysctl syscall support [*] Load all symbols for debugging/ksymoops ... Signed-off-by: Mike Frysinger <vapier@gentoo.org> Acked-by: Randy Dunlap <rdunlap@infradead.org> Cc: zhangwei(Jovi) <jovi.zhangwei@huawei.com> Cc: Michal Marek <mmarek@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-30usermodehelper: split remaining calls to call_usermodehelper_fns()Lucas De Marchi
These are the only users of call_usermodehelper_fns(). This function suffers from not being able to determine if the cleanup is called. Even if in this places the cleanup pointer is NULL, convert them to use the separate call_usermodehelper_setup() + call_usermodehelper_exec() functions so we can remove the _fns variant. Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi> Cc: Oleg Nesterov <oleg@redhat.com> Cc: David Howells <dhowells@redhat.com> Cc: James Morris <james.l.morris@oracle.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Tejun Heo <tj@kernel.org> 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>
2013-04-30Merge branch 'timers-core-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull core timer updates from Ingo Molnar: "The main changes in this cycle's merge are: - Implement shadow timekeeper to shorten in kernel reader side blocking, by Thomas Gleixner. - Posix timers enhancements by Pavel Emelyanov: - allocate timer ID per process, so that exact timer ID allocations can be re-created be checkpoint/restore code. - debuggability and tooling (/proc/PID/timers, etc.) improvements. - suspend/resume enhancements by Feng Tang: on certain new Intel Atom processors (Penwell and Cloverview), there is a feature that the TSC won't stop in S3 state, so the TSC value won't be reset to 0 after resume. This can be taken advantage of by the generic via the CLOCK_SOURCE_SUSPEND_NONSTOP flag: instead of using the RTC to recover/approximate sleep time, the main (and precise) clocksource can be used. - Fix /proc/timer_list for 4096 CPUs by Nathan Zimmer: on so many CPUs the file goes beyond 4MB of size and thus the current simplistic seqfile approach fails. Convert /proc/timer_list to a proper seq_file with its own iterator. - Cleanups and refactorings of the core timekeeping code by John Stultz. - International Atomic Clock time is managed by the NTP code internally currently but not exposed externally. Separate the TAI code out and add CLOCK_TAI support and TAI support to the hrtimer and posix-timer code, by John Stultz. - Add deep idle support enhacement to the broadcast clockevents core timer code, by Daniel Lezcano: add an opt-in CLOCK_EVT_FEAT_DYNIRQ clockevents feature (which will be utilized by future clockevents driver updates), which allows the use of IRQ affinities to avoid spurious wakeups of idle CPUs - the right CPU with an expiring timer will be woken. - Add new ARM bcm281xx clocksource driver, by Christian Daudt - ... various other fixes and cleanups" * 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (52 commits) clockevents: Set dummy handler on CPU_DEAD shutdown timekeeping: Update tk->cycle_last in resume posix-timers: Remove unused variable clockevents: Switch into oneshot mode even if broadcast registered late timer_list: Convert timer list to be a proper seq_file timer_list: Split timer_list_show_tickdevices posix-timers: Show sigevent info in proc file posix-timers: Introduce /proc/PID/timers file posix timers: Allocate timer id per process (v2) timekeeping: Make sure to notify hrtimers when TAI offset changes hrtimer: Fix ktime_add_ns() overflow on 32bit architectures hrtimer: Add expiry time overflow check in hrtimer_interrupt timekeeping: Shorten seq_count region timekeeping: Implement a shadow timekeeper timekeeping: Delay update of clock->cycle_last timekeeping: Store cycle_last value in timekeeper struct as well ntp: Remove ntp_lock, using the timekeeping locks to protect ntp state timekeeping: Simplify tai updating from do_adjtimex timekeeping: Hold timekeepering locks in do_adjtimex and hardpps timekeeping: Move ADJ_SETOFFSET to top level do_adjtimex() ...
2013-04-30Merge branch 'smp-hotplug-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull SMP/hotplug changes from Ingo Molnar: "This is a pretty large, multi-arch series unifying and generalizing the various disjunct pieces of idle routines that architectures have historically copied from each other and have grown in random, wildly inconsistent and sometimes buggy directions: 101 files changed, 455 insertions(+), 1328 deletions(-) this went through a number of review and test iterations before it was committed, it was tested on various architectures, was exposed to linux-next for quite some time - nevertheless it might cause problems on architectures that don't read the mailing lists and don't regularly test linux-next. This cat herding excercise was motivated by the -rt kernel, and was brought to you by Thomas "the Whip" Gleixner." * 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (40 commits) idle: Remove GENERIC_IDLE_LOOP config switch um: Use generic idle loop ia64: Make sure interrupts enabled when we "safe_halt()" sparc: Use generic idle loop idle: Remove unused ARCH_HAS_DEFAULT_IDLE bfin: Fix typo in arch_cpu_idle() xtensa: Use generic idle loop x86: Use generic idle loop unicore: Use generic idle loop tile: Use generic idle loop tile: Enter idle with preemption disabled sh: Use generic idle loop score: Use generic idle loop s390: Use generic idle loop powerpc: Use generic idle loop parisc: Use generic idle loop openrisc: Use generic idle loop mn10300: Use generic idle loop mips: Use generic idle loop microblaze: Use generic idle loop ...
2013-04-30Merge branch 'sched-core-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler changes from Ingo Molnar: "The main changes in this development cycle were: - full dynticks preparatory work by Frederic Weisbecker - factor out the cpu time accounting code better, by Li Zefan - multi-CPU load balancer cleanups and improvements by Joonsoo Kim - various smaller fixes and cleanups" * 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (45 commits) sched: Fix init NOHZ_IDLE flag sched: Prevent to re-select dst-cpu in load_balance() sched: Rename load_balance_tmpmask to load_balance_mask sched: Move up affinity check to mitigate useless redoing overhead sched: Don't consider other cpus in our group in case of NEWLY_IDLE sched: Explicitly cpu_idle_type checking in rebalance_domains() sched: Change position of resched_cpu() in load_balance() sched: Fix wrong rq's runnable_avg update with rt tasks sched: Document task_struct::personality field sched/cpuacct/UML: Fix header file dependency bug on the UML build cgroup: Kill subsys.active flag sched/cpuacct: No need to check subsys active state sched/cpuacct: Initialize cpuacct subsystem earlier sched/cpuacct: Initialize root cpuacct earlier sched/cpuacct: Allocate per_cpu cpuusage for root cpuacct statically sched/cpuacct: Clean up cpuacct.h sched/cpuacct: Remove redundant NULL checks in cpuacct_acount_field() sched/cpuacct: Remove redundant NULL checks in cpuacct_charge() sched/cpuacct: Add cpuacct_acount_field() sched/cpuacct: Add cpuacct_init() ...
2013-04-30Merge branch 'core-rcu-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull RCU updates from Ingo Molnar: "The main changes in this cycle are mostly related to preparatory work for the full-dynticks work: - Remove restrictions on no-CBs CPUs, make RCU_FAST_NO_HZ take advantage of numbered callbacks, do callback accelerations based on numbered callbacks. Posted to LKML at https://lkml.org/lkml/2013/3/18/960 - RCU documentation updates. Posted to LKML at https://lkml.org/lkml/2013/3/18/570 - Miscellaneous fixes. Posted to LKML at https://lkml.org/lkml/2013/3/18/594" * 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (24 commits) rcu: Make rcu_accelerate_cbs() note need for future grace periods rcu: Abstract rcu_start_future_gp() from rcu_nocb_wait_gp() rcu: Rename n_nocb_gp_requests to need_future_gp rcu: Push lock release to rcu_start_gp()'s callers rcu: Repurpose no-CBs event tracing to future-GP events rcu: Rearrange locking in rcu_start_gp() rcu: Make RCU_FAST_NO_HZ take advantage of numbered callbacks rcu: Accelerate RCU callbacks at grace-period end rcu: Export RCU_FAST_NO_HZ parameters to sysfs rcu: Distinguish "rcuo" kthreads by RCU flavor rcu: Add event tracing for no-CBs CPUs' grace periods rcu: Add event tracing for no-CBs CPUs' callback registration rcu: Introduce proper blocking to no-CBs kthreads GP waits rcu: Provide compile-time control for no-CBs CPUs rcu: Tone down debugging during boot-up and shutdown. rcu: Add softirq-stall indications to stall-warning messages rcu: Documentation update rcu: Make bugginess of code sample more evident rcu: Fix hlist_bl_set_first_rcu() annotation rcu: Delete unused rcu_node "wakemask" field ...
2013-04-29init/main.c: convert to pr_foo()Andrew Morton
Also enables cleanup of some 80-col trickery. Cc: Richard Weinberger <richard@nod.at> Cc: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-29init: raise log levelRichard Weinberger
If the kernel was booted with the "quiet" boot option we have currently no chance to see why an initrd fails. Change KERN_WARNING to KERN_ERR to see what is going on. Signed-off-by: Richard Weinberger <richard@nod.at> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Jim Cromie <jim.cromie@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-29init: scream bloody murder if interrupts are enabled too earlySteven Rostedt
As I was testing a lot of my code recently, and having several "successes", I accidentally noticed in the dmesg this little line: start_kernel(): bug: interrupts were enabled *very* early, fixing it Sure enough, one of my patches two commits ago enabled interrupts early. The sad part here is that I never noticed it, and I ran several tests with ktest too, and ktest did not notice this line. What ktest looks for (and so does many other automated testing scripts) is a back trace produced by a WARN_ON() or BUG(). As a back trace was never produced, my buggy patch could have slipped into linux-next, or even worse, mainline. Adding a WARN(!irqs_disabled()) makes this bug a little more obvious: PID hash table entries: 4096 (order: 3, 32768 bytes) __ex_table already sorted, skipping sort Checking aperture... No AGP bridge found Calgary: detecting Calgary via BIOS EBDA area Calgary: Unable to locate Rio Grande table in EBDA - bailing! Memory: 2003252k/2054848k available (4857k kernel code, 460k absent, 51136k reserved, 6210k data, 1096k init) ------------[ cut here ]------------ WARNING: at /home/rostedt/work/git/linux-trace.git/init/main.c:543 start_kernel+0x21e/0x415() Hardware name: To Be Filled By O.E.M. Interrupts were enabled *very* early, fixing it Modules linked in: Pid: 0, comm: swapper/0 Not tainted 3.8.0-test+ #286 Call Trace: warn_slowpath_common+0x83/0x9b warn_slowpath_fmt+0x46/0x48 start_kernel+0x21e/0x415 x86_64_start_reservations+0x10e/0x112 x86_64_start_kernel+0x102/0x111 ---[ end trace 007d8b0491b4f5d8 ]--- Preemptible hierarchical RCU implementation. RCU restricting CPUs from NR_CPUS=8 to nr_cpu_ids=4. NR_IRQS:4352 nr_irqs:712 16 Console: colour VGA+ 80x25 console [ttyS0] enabled, bootconsole disabled Do you see it? The original version of this patch just slapped a WARN_ON() in there and kept the printk(). Ard van Breemen suggested using the WARN() interface, which makes the code a bit cleaner. Also, while examining other warnings in init/main.c, I found two other locations that deserve a bloody murder scream if their conditions are hit, and updated them accordingly. Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Cc: Ard van Breemen <ard@telegraafnet.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-26nohz: Select VIRT_CPU_ACCOUNTING_GEN from full dynticks configFrederic Weisbecker
Turn the full dynticks passive dependency on VIRT_CPU_ACCOUNTING_GEN to an active one. The full dynticks Kconfig is currently hidden behind the full dynticks cputime accounting, which is an awkward and counter-intuitive layout: the user first has to select the dynticks cputime accounting in order to make the full dynticks feature to be visible. We definetly want it the other way around. The usual way to perform this kind of active dependency is use "select" on the depended target. Now we can't use the Kconfig "select" instruction when the target is a "choice". So this patch inspires on how the RCU subsystem Kconfig interact with its dependencies on SMP and PREEMPT: we make sure that cputime accounting can't propose another option than VIRT_CPU_ACCOUNTING_GEN when NO_HZ_FULL is selected by using the right "depends on" instruction for each cputime accounting choices. v2: Keep full dynticks cputime accounting available even without full dynticks, as per Paul McKenney's suggestion. Reported-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Christoph Lameter <cl@linux.com> Cc: Hakan Akkan <hakanakkan@gmail.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Kevin Hilman <khilman@linaro.org> Cc: Li Zhong <zhong@linux.vnet.ibm.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de>
2013-04-24Merge branch 'linus' into timers/coreThomas Gleixner
Reason: Get upstream fixes before adding conflicting code. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2013-04-19nohz: Ensure full dynticks CPUs are RCU nocbsFrederic Weisbecker
We need full dynticks CPU to also be RCU nocb so that we don't have to keep the tick to handle RCU callbacks. Make sure the range passed to nohz_full= boot parameter is a subset of rcu_nocbs= The CPUs that fail to meet this requirement will be excluded from the nohz_full range. This is checked early in boot time, before any CPU has the opportunity to stop its tick. Suggested-by: Steven Rostedt <rostedt@goodmis.org> Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Christoph Lameter <cl@linux.com> Cc: Geoff Levand <geoff@infradead.org> Cc: Gilad Ben Yossef <gilad@benyossef.com> Cc: Hakan Akkan <hakanakkan@gmail.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Kevin Hilman <khilman@linaro.org> Cc: Li Zhong <zhong@linux.vnet.ibm.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de>
2013-04-10Merge branch 'rcu/next' of ↵Ingo Molnar
git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu Pull RCU updates from Paul E. McKenney: * Remove restrictions on no-CBs CPUs, make RCU_FAST_NO_HZ take advantage of numbered callbacks, do additional callback accelerations based on numbered callbacks. Posted to LKML at https://lkml.org/lkml/2013/3/18/960. * RCU documentation updates. Posted to LKML at https://lkml.org/lkml/2013/3/18/570. * Miscellaneous fixes. Posted to LKML at https://lkml.org/lkml/2013/3/18/594. Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-04-08idle: Provide a generic entry point for the idle codeThomas Gleixner
For now this calls cpu_idle(), but in the long run we want to move the cpu bringup code to the core and therefor we add a state argument. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Paul McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Reviewed-by: Cc: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Cc: Magnus Damm <magnus.damm@gmail.com> Link: http://lkml.kernel.org/r/20130321215233.583190032@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2013-04-03nohz: Rename CONFIG_NO_HZ to CONFIG_NO_HZ_COMMONFrederic Weisbecker
We are planning to convert the dynticks Kconfig options layout into a choice menu. The user must be able to easily pick any of the following implementations: constant periodic tick, idle dynticks, full dynticks. As this implies a mutual exclusion, the two dynticks implementions need to converge on the selection of a common Kconfig option in order to ease the sharing of a common infrastructure. It would thus seem pretty natural to reuse CONFIG_NO_HZ to that end. It already implements all the idle dynticks code and the full dynticks depends on all that code for now. So ideally the choice menu would propose CONFIG_NO_HZ_IDLE and CONFIG_NO_HZ_EXTENDED then both would select CONFIG_NO_HZ. On the other hand we want to stay backward compatible: if CONFIG_NO_HZ is set in an older config file, we want to enable CONFIG_NO_HZ_IDLE by default. But we can't afford both at the same time or we run into a circular dependency: 1) CONFIG_NO_HZ_IDLE and CONFIG_NO_HZ_EXTENDED both select CONFIG_NO_HZ 2) If CONFIG_NO_HZ is set, we default to CONFIG_NO_HZ_IDLE We might be able to support that from Kconfig/Kbuild but it may not be wise to introduce such a confusing behaviour. So to solve this, create a new CONFIG_NO_HZ_COMMON option which gathers the common code between idle and full dynticks (that common code for now is simply the idle dynticks code) and select it from their referring Kconfig. Then we'll later create CONFIG_NO_HZ_IDLE and map CONFIG_NO_HZ to it for backward compatibility. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Christoph Lameter <cl@linux.com> Cc: Geoff Levand <geoff@infradead.org> Cc: Gilad Ben Yossef <gilad@benyossef.com> Cc: Hakan Akkan <hakanakkan@gmail.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Kevin Hilman <khilman@linaro.org> Cc: Li Zhong <zhong@linux.vnet.ibm.com> Cc: Namhyung Kim <namhyung.kim@lge.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de>
2013-03-26rcu: Make RCU_FAST_NO_HZ take advantage of numbered callbacksPaul E. McKenney
Because RCU callbacks are now associated with the number of the grace period that they must wait for, CPUs can now take advance callbacks corresponding to grace periods that ended while a given CPU was in dyntick-idle mode. This eliminates the need to try forcing the RCU state machine while entering idle, thus reducing the CPU intensiveness of RCU_FAST_NO_HZ, which should increase its energy efficiency. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2013-03-26rcu: Distinguish "rcuo" kthreads by RCU flavorPaul E. McKenney
Currently, the per-no-CBs-CPU kthreads are named "rcuo" followed by the CPU number, for example, "rcuo". This is problematic given that there are either two or three RCU flavors, each of which gets a per-CPU kthread with exactly the same name. This commit therefore introduces a one-letter abbreviation for each RCU flavor, namely 'b' for RCU-bh, 'p' for RCU-preempt, and 's' for RCU-sched. This abbreviation is used to distinguish the "rcuo" kthreads, for example, for CPU 0 we would have "rcuob/0", "rcuop/0", and "rcuos/0". Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Tested-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
2013-03-26rcu: Provide compile-time control for no-CBs CPUsPaul E. McKenney
Currently, the only way to specify no-CBs CPUs is via the rcu_nocbs kernel command-line parameter. This is inconvenient in some cases, particularly for randconfig testing, so this commit adds a new set of kernel configuration parameters. CONFIG_RCU_NOCB_CPU_NONE (the default) retains the old behavior, CONFIG_RCU_NOCB_CPU_ZERO offloads callback processing from CPU 0 (along with any other CPUs specified by the rcu_nocbs boot-time parameter), and CONFIG_RCU_NOCB_CPU_ALL offloads callback processing from all CPUs. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2013-03-12final removal of CONFIG_EXPERIMENTALKees Cook
Remove "config EXPERIMENTAL" itself, now that every "depends on" it has been removed from the tree. Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-12rcu: Remove restrictions on no-CBs CPUsPaul E. McKenney
Currently, CPU 0 is constrained to not be a no-CBs CPU, and furthermore at least one no-CBs CPU must remain online at any given time. These restrictions are problematic in some situations, such as cases where all CPUs must run a real-time workload that needs to be insulated from OS jitter and latencies due to RCU callback invocation. This commit therefore provides no-CBs CPUs a (very crude and energy-inefficient) way to start and to wait for grace periods independently of the normal RCU callback mechanisms. This approach allows any or all of the CPUs to be designated as no-CBs CPUs, and allows any proper subset of the CPUs (whether no-CBs CPUs or not) to be offlined. This commit also provides a fix for a locking bug spotted by Xie ChanglongX <changlongx.xie@intel.com>. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2013-03-07context_tracking: Enable probes by default for selftestingFrederic Weisbecker
Until we provide the nohz_mask boot parameter, keeping the context tracking probes disabled by default is pointless since what we want is to runtime test this code anyway. It's furthermore confusing for the users which don't expect the probes to be off when they select RCU user mode or full dynticks cputime accounting. Let's enable these probes selftests by default for now. Suggested: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Li Zhong <zhong@linux.vnet.ibm.com> Cc: Kevin Hilman <khilman@linaro.org> Cc: Mats Liljegren <mats.liljegren@enea.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Namhyung Kim <namhyung.kim@lge.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2013-03-07tick: Call tick_init lateThomas Gleixner
To convert the clockevents code to cpumask_var_t we need to move the init call after the allocator setup. Clockevents are earliest registered from time_init() as they need interrupts being set up, so this is safe. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20130306111537.304379448@linutronix.de Cc: Rusty Russell <rusty@rustcorp.com.au>