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2012-01-06Merge branch 'sched-core-for-linus' of ↵Linus Torvalds3-19/+43
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip * 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (40 commits) sched/tracing: Add a new tracepoint for sleeptime sched: Disable scheduler warnings during oopses sched: Fix cgroup movement of waking process sched: Fix cgroup movement of newly created process sched: Fix cgroup movement of forking process sched: Remove cfs bandwidth period check in tg_set_cfs_period() sched: Fix load-balance lock-breaking sched: Replace all_pinned with a generic flags field sched: Only queue remote wakeups when crossing cache boundaries sched: Add missing rcu_dereference() around ->real_parent usage [S390] fix cputime overflow in uptime_proc_show [S390] cputime: add sparse checking and cleanup sched: Mark parent and real_parent as __rcu sched, nohz: Fix missing RCU read lock sched, nohz: Set the NOHZ_BALANCE_KICK flag for idle load balancer sched, nohz: Fix the idle cpu check in nohz_idle_balance sched: Use jump_labels for sched_feat sched/accounting: Fix parameter passing in task_group_account_field sched/accounting: Fix user/system tick double accounting sched/accounting: Re-use scheduler statistics for the root cgroup ... Fix up conflicts in - arch/ia64/include/asm/cputime.h, include/asm-generic/cputime.h usecs_to_cputime64() vs the sparse cleanups - kernel/sched/fair.c, kernel/time/tick-sched.c scheduler changes in multiple branches
2012-01-06Merge branch 'perf-core-for-linus' of ↵Linus Torvalds3-5/+40
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip * 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (106 commits) perf kvm: Fix copy & paste error in description perf script: Kill script_spec__delete perf top: Fix a memory leak perf stat: Introduce get_ratio_color() helper perf session: Remove impossible condition check perf tools: Fix feature-bits rework fallout, remove unused variable perf script: Add generic perl handler to process events perf tools: Use for_each_set_bit() to iterate over feature flags perf tools: Unify handling of features when writing feature section perf report: Accept fifos as input file perf tools: Moving code in some files perf tools: Fix out-of-bound access to struct perf_session perf tools: Continue processing header on unknown features perf tools: Improve macros for struct feature_ops perf: builtin-record: Document and check that mmap_pages must be a power of two. perf: builtin-record: Provide advice if mmap'ing fails with EPERM. perf tools: Fix truncated annotation perf script: look up thread using tid instead of pid perf tools: Look up thread names for system wide profiling perf tools: Fix comm for processes with named threads ...
2012-01-06Merge branch 'core-rcu-for-linus' of ↵Linus Torvalds6-80/+163
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip * 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (64 commits) cpu: Export cpu_up() rcu: Apply ACCESS_ONCE() to rcu_boost() return value Revert "rcu: Permit rt_mutex_unlock() with irqs disabled" docs: Additional LWN links to RCU API rcu: Augment rcu_batch_end tracing for idle and callback state rcu: Add rcutorture tests for srcu_read_lock_raw() rcu: Make rcutorture test for hotpluggability before offlining CPUs driver-core/cpu: Expose hotpluggability to the rest of the kernel rcu: Remove redundant rcu_cpu_stall_suppress declaration rcu: Adaptive dyntick-idle preparation rcu: Keep invoking callbacks if CPU otherwise idle rcu: Irq nesting is always 0 on rcu_enter_idle_common rcu: Don't check irq nesting from rcu idle entry/exit rcu: Permit dyntick-idle with callbacks pending rcu: Document same-context read-side constraints rcu: Identify dyntick-idle CPUs on first force_quiescent_state() pass rcu: Remove dynticks false positives and RCU failures rcu: Reduce latency of rcu_prepare_for_idle() rcu: Eliminate RCU_FAST_NO_HZ grace-period hang rcu: Avoid needlessly IPIing CPUs at GP end ...
2012-01-06Merge branch 'core-printk-for-linus' of ↵Linus Torvalds1-0/+4
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip * 'core-printk-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: printk, lockdep: Switch to tracked irq ops printk, lockdep: Remove superfluous preempt_disable() printk, lockdep: Disable lock debugging on zap_locks()
2012-01-06Merge branch 'core-memblock-for-linus' of ↵Linus Torvalds5-79/+141
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip * 'core-memblock-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (52 commits) memblock: Reimplement memblock allocation using reverse free area iterator memblock: Kill early_node_map[] score: Use HAVE_MEMBLOCK_NODE_MAP s390: Use HAVE_MEMBLOCK_NODE_MAP mips: Use HAVE_MEMBLOCK_NODE_MAP ia64: Use HAVE_MEMBLOCK_NODE_MAP SuperH: Use HAVE_MEMBLOCK_NODE_MAP sparc: Use HAVE_MEMBLOCK_NODE_MAP powerpc: Use HAVE_MEMBLOCK_NODE_MAP memblock: Implement memblock_add_node() memblock: s/memblock_analyze()/memblock_allow_resize()/ and update users memblock: Track total size of regions automatically powerpc: Cleanup memblock usage memblock: Reimplement memblock_enforce_memory_limit() using __memblock_remove() memblock: Make memblock functions handle overflowing range @size memblock: Reimplement __memblock_remove() using memblock_isolate_range() memblock: Separate out memblock_isolate_range() from memblock_set_node() memblock: Kill memblock_init() memblock: Kill sentinel entries at the end of static region arrays memblock: Add __memblock_dump_all() ...
2012-01-06Merge branch 'core-locking-for-linus' of ↵Linus Torvalds1-2/+2
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip * 'core-locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: lockdep/waitqueues: Add better annotation lockdep, bug: Exclude TAINT_OOT_MODULE from disabling lock debugging lockdep: Print lock name in lockdep_init_error() init/main.c: Execute lockdep_init() as early as possible lockdep, kmemcheck: Annotate ->lock in lockdep_init_map() lockdep, rtmutex, bug: Show taint flags on error lockdep, bug: Exclude TAINT_FIRMWARE_WORKAROUND from disabling lockdep lockdep: Always try to set ->class_cache in register_lock_class() lockdep_init_map()
2012-01-06Merge branch 'core-debugobjects-for-linus' of ↵Linus Torvalds1-0/+6
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip * 'core-debugobjects-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: timer: Use debugobjects to catch deletion of uninitialized timers timer: Setup uninitialized timer with a stub callback debugobjects: Extend to assert that an object is initialized debugobjects: Be smarter about static objects
2012-01-03security: Fix security_old_inode_init_security() when CONFIG_SECURITY is not setJan Kara1-1/+1
Commit 1e39f384bb01 ("evm: fix build problems") makes the stub version of security_old_inode_init_security() return 0 when CONFIG_SECURITY is not set. But that makes callers such as reiserfs_security_init() assume that security_old_inode_init_security() has set name, value, and len arguments properly - but security_old_inode_init_security() left them uninitialized which then results in interesting failures. Revert security_old_inode_init_security() to the old behavior of returning EOPNOTSUPP since both callers (reiserfs and ocfs2) handle this just fine. [ Also fixed the S_PRIVATE(inode) case of the actual non-stub security_old_inode_init_security() function to return EOPNOTSUPP for the same reason, as pointed out by Mimi Zohar. It got incorrectly changed to match the new function in commit fb88c2b6cbb1: "evm: fix security/security_old_init_security return code". - Linus ] Reported-by: Jorge Bastos <mysql.jorge@decimal.pt> Acked-by: James Morris <jmorris@namei.org> Acked-by: Mimi Zohar <zohar@us.ibm.com> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-12-26KVM: Don't automatically expose the TSC deadline timer in cpuidJan Kiszka1-0/+1
Unlike all of the other cpuid bits, the TSC deadline timer bit is set unconditionally, regardless of what userspace wants. This is broken in several ways: - if userspace doesn't use KVM_CREATE_IRQCHIP, and doesn't emulate the TSC deadline timer feature, a guest that uses the feature will break - live migration to older host kernels that don't support the TSC deadline timer will cause the feature to be pulled from under the guest's feet; breaking it - guests that are broken wrt the feature will fail. Fix by not enabling the feature automatically; instead report it to userspace. Because the feature depends on KVM_CREATE_IRQCHIP, which we cannot guarantee will be called, we expose it via a KVM_CAP_TSC_DEADLINE_TIMER and not KVM_GET_SUPPORTED_CPUID. Fixes the Illumos guest kernel, which uses the TSC deadline timer feature. [avi: add the KVM_CAP + documentation] Reported-by: Alexey Zaytsev <alexey.zaytsev@gmail.com> Tested-by: Alexey Zaytsev <alexey.zaytsev@gmail.com> Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2011-12-22VFS: Fix race between CPU hotplug and lglocksSrivatsa S. Bhat1-4/+32
Currently, the *_global_[un]lock_online() routines are not at all synchronized with CPU hotplug. Soft-lockups detected as a consequence of this race was reported earlier at https://lkml.org/lkml/2011/8/24/185. (Thanks to Cong Meng for finding out that the root-cause of this issue is the race condition between br_write_[un]lock() and CPU hotplug, which results in the lock states getting messed up). Fixing this race by just adding {get,put}_online_cpus() at appropriate places in *_global_[un]lock_online() is not a good option, because, then suddenly br_write_[un]lock() would become blocking, whereas they have been kept as non-blocking all this time, and we would want to keep them that way. So, overall, we want to ensure 3 things: 1. br_write_lock() and br_write_unlock() must remain as non-blocking. 2. The corresponding lock and unlock of the per-cpu spinlocks must not happen for different sets of CPUs. 3. Either prevent any new CPU online operation in between this lock-unlock, or ensure that the newly onlined CPU does not proceed with its corresponding per-cpu spinlock unlocked. To achieve all this: (a) We introduce a new spinlock that is taken by the *_global_lock_online() routine and released by the *_global_unlock_online() routine. (b) We register a callback for CPU hotplug notifications, and this callback takes the same spinlock as above. (c) We maintain a bitmap which is close to the cpu_online_mask, and once it is initialized in the lock_init() code, all future updates to it are done in the callback, under the above spinlock. (d) The above bitmap is used (instead of cpu_online_mask) while locking and unlocking the per-cpu locks. The callback takes the spinlock upon the CPU_UP_PREPARE event. So, if the br_write_lock-unlock sequence is in progress, the callback keeps spinning, thus preventing the CPU online operation till the lock-unlock sequence is complete. This takes care of requirement (3). The bitmap that we maintain remains unmodified throughout the lock-unlock sequence, since all updates to it are managed by the callback, which takes the same spinlock as the one taken by the lock code and released only by the unlock routine. Combining this with (d) above, satisfies requirement (2). Overall, since we use a spinlock (mentioned in (a)) to prevent CPU hotplug operations from racing with br_write_lock-unlock, requirement (1) is also taken care of. By the way, it is to be noted that a CPU offline operation can actually run in parallel with our lock-unlock sequence, because our callback doesn't react to notifications earlier than CPU_DEAD (in order to maintain our bitmap properly). And this means, since we use our own bitmap (which is stale, on purpose) during the lock-unlock sequence, we could end up unlocking the per-cpu lock of an offline CPU (because we had locked it earlier, when the CPU was online), in order to satisfy requirement (2). But this is harmless, though it looks a bit awkward. Debugged-by: Cong Meng <mc@linux.vnet.ibm.com> Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Cc: stable@vger.kernel.org
2011-12-21perf events: Add PERF_COUNT_HW_REF_CPU_CYCLES generic PMU eventStephane Eranian1-0/+1
This event counts the number of reference core cpu cycles. Reference means that the event increments at a constant rate which is not subject to core CPU frequency adjustments. The event may not count when the processor is in halted (low power) state. As such, it may not be equivalent to wall clock time. However, when the processor is not halted state, the event keeps a constant correlation with wall clock time. Signed-off-by: Stephane Eranian <eranian@google.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1323559734-3488-3-git-send-email-eranian@google.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-12-21lockdep/waitqueues: Add better annotationPeter Zijlstra1-2/+2
-> #2 (&tty->write_wait){-.-...}: is a lot more informative than: -> #2 (key#19){-.....}: Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/n/tip-8zpopbny51023rdb0qq67eye@git.kernel.org Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-12-20Merge branch 'timers-urgent-for-linus' of ↵Linus Torvalds1-3/+8
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip * 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: time/clocksource: Fix kernel-doc warnings rtc: m41t80: Workaround broken alarm functionality rtc: Expire alarms after the time is set.
2011-12-20Merge commit 'v3.2-rc6' into perf/coreIngo Molnar37-158/+225
Merge reason: Update with the latest fixes. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-12-20Merge branch 'memblock-kill-early_node_map' of ↵Ingo Molnar5-79/+141
git://git.kernel.org/pub/scm/linux/kernel/git/tj/misc into core/memblock
2011-12-19Merge branch 'sched/core' of ↵Martin Schwidefsky3-17/+41
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip into cputime-tip Conflicts: drivers/cpufreq/cpufreq_conservative.c drivers/cpufreq/cpufreq_ondemand.c drivers/macintosh/rack-meter.c fs/proc/stat.c fs/proc/uptime.c kernel/sched/core.c
2011-12-19time/clocksource: Fix kernel-doc warningsKusanagi Kouichi1-3/+8
Fix various KernelDoc build warnings. Signed-off-by: Kusanagi Kouichi <slash@ac.auone-net.jp> Cc: John Stultz <johnstul@us.ibm.com> Link: http://lkml.kernel.org/r/20111219091320.0D5AF6FC03D@msa105.auone-net.jp Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-12-16Merge branch 'drm-intel-fixes' of git://people.freedesktop.org/~keithp/linuxLinus Torvalds1-0/+2
* 'drm-intel-fixes' of git://people.freedesktop.org/~keithp/linux: drm/i915/dp: Dither down to 6bpc if it makes the mode fit drm/i915: enable semaphores on per-device defaults drm/i915: don't set unpin_work if vblank_get fails drm/i915: By default, enable RC6 on IVB and SNB when reasonable iommu: Export intel_iommu_enabled to signal when iommu is in use drm/i915/sdvo: Include LVDS panels for the IS_DIGITAL check drm/i915: prevent division by zero when asking for chipset power drm/i915: add PCH info to i915_capabilities drm/i915: set the right SDVO transcoder for CPT drm/i915: no-lvds quirk for ASUS AT5NM10T-I drm/i915: Treat pre-gen4 backlight duty cycle value consistently drm/i915: Hook up Ivybridge eDP drm/i915: add multi-threaded forcewake support
2011-12-16Merge branch 'for-linus' of git://git.kernel.dk/linux-blockLinus Torvalds1-3/+0
* 'for-linus' of git://git.kernel.dk/linux-block: block: don't kick empty queue in blk_drain_queue() block/swim3: Locking fixes loop: Fix discard_alignment default setting cfq-iosched: fix cfq_cic_link() race confition cfq-iosched: free cic_index if blkio_alloc_blkg_stats fails cciss: fix flush cache transfer length cciss: Add IRQF_SHARED back in for the non-MSI(X) interrupt handler loop: fix loop block driver discard and encryption comment block: initialize request_queue's numa node during
2011-12-16iommu: Export intel_iommu_enabled to signal when iommu is in useEugeni Dodonov1-0/+2
In i915 driver, we do not enable either rc6 or semaphores on SNB when dmar is enabled. The new 'intel_iommu_enabled' variable signals when the iommu code is in operation. Cc: Ted Phelps <phelps@gnusto.com> Cc: Peter <pab1612@gmail.com> Cc: Lukas Hejtmanek <xhejtman@fi.muni.cz> Cc: Andrew Lutomirski <luto@mit.edu> CC: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: Eugeni Dodonov <eugeni.dodonov@intel.com> Signed-off-by: Keith Packard <keithp@keithp.com>
2011-12-15[S390] cputime: add sparse checking and cleanupMartin Schwidefsky1-2/+2
Make cputime_t and cputime64_t nocast to enable sparse checking to detect incorrect use of cputime. Drop the cputime macros for simple scalar operations. The conversion macros are still needed. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2011-12-15sched: Mark parent and real_parent as __rcuKees Cook1-2/+2
The parent and real_parent pointers should be considered __rcu, since they should be held under either tasklist_lock or rcu_read_lock. Signed-off-by: Kees Cook <keescook@chromium.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Link: http://lkml.kernel.org/r/20111214223925.GA27578@www.outflux.net Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-12-15Merge commit 'v3.2-rc5' into sched/coreIngo Molnar35-153/+217
Merge reason: Pick up the latest fixes. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-12-14Merge branch 'rcu/next' of ↵Ingo Molnar6-80/+163
git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu
2011-12-12linux/log2.h: Fix rounddown_pow_of_two(1)Linus Torvalds1-1/+0
Exactly like roundup_pow_of_two(1), the rounddown version was buggy for the case of a compile-time constant '1' argument. Probably because it originated from the same code, sharing history with the roundup version from before the bugfix (for that one, see commit 1a06a52ee1b0: "Fix roundup_pow_of_two(1)"). However, unlike the roundup version, the fix for rounddown is to just remove the broken special case entirely. It's simply not needed - the generic code 1UL << ilog2(n) does the right thing for the constant '1' argment too. The only reason roundup needed that special case was because rounding up does so by subtracting one from the argument (and then adding one to the result) causing the obvious problems with "ilog2(0)". But rounddown doesn't do any of that, since ilog2() naturally truncates (ie "rounds down") to the right rounded down value. And without the ilog2(0) case, there's no reason for the special case that had the wrong value. tl;dr: rounddown_pow_of_two(1) should be 1, not 0. Acked-by: Dmitry Torokhov <dtor@vmware.com> Cc: stable@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-12-12Merge branch 'for-linus' of ↵Linus Torvalds1-0/+6
git://git.kernel.org/pub/scm/linux/kernel/git/cjb/mmc * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/cjb/mmc: mmc: core: Fix deadlock when the CONFIG_MMC_UNSAFE_RESUME is not defined mmc: sdhci-s3c: Remove old and misprototyped suspend operations mmc: tmio: fix clock gating on platforms with a .set_pwr() method mmc: sh_mmcif: fix clock gating on platforms with a .down_pwr() method mmc: core: Fix typo at mmc_card_sleep mmc: core: Fix power_off_notify during suspend mmc: core: Fix setting power notify state variable for non-eMMC mmc: core: Add quirk for long data read time mmc: Add module.h include to sdhci-cns3xxx.c mmc: mxcmmc: fix falling back to PIO mmc: omap_hsmmc: DMA unmap only once in case of MMC error
2011-12-11driver-core/cpu: Expose hotpluggability to the rest of the kernelJosh Triplett1-0/+1
When architectures register CPUs, they indicate whether the CPU allows hotplugging; notably, x86 and ARM don't allow hotplugging CPU 0. Userspace can easily query the hotpluggability of a CPU via sysfs; however, the kernel has no convenient way of accessing that property in an architecture-independent way. While the kernel can simply try it and see, some code needs to distinguish between "hotplug failed" and "hotplug has no hope of working on this CPU"; for example, rcutorture's CPU hotplug tests want to avoid drowning out real hotplug failures with expected failures. Expose this property via a new cpu_is_hotpluggable function, so that the rest of the kernel can access it in an architecture-independent way. Signed-off-by: Josh Triplett <josh@joshtriplett.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2011-12-11rcu: Document same-context read-side constraintsPaul E. McKenney2-0/+20
The intent is that a given RCU read-side critical section be confined to a single context. For example, it is illegal to invoke rcu_read_lock() in an exception handler and then invoke rcu_read_unlock() from the context of the task that received the exception. Suggested-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2011-12-11nohz: Remove tick_nohz_idle_enter_norcu() / tick_nohz_idle_exit_norcu()Frederic Weisbecker1-46/+1
Those two APIs were provided to optimize the calls of tick_nohz_idle_enter() and rcu_idle_enter() into a single irq disabled section. This way no interrupt happening in-between would needlessly process any RCU job. Now we are talking about an optimization for which benefits have yet to be measured. Let's start simple and completely decouple idle rcu and dyntick idle logics to simplify. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Reviewed-by: Josh Triplett <josh@joshtriplett.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2011-12-11sched: Add is_idle_task() to handle invalidated uses of idle_cpu()Paul E. McKenney1-0/+8
Commit 908a3283 (Fix idle_cpu()) invalidated some uses of idle_cpu(), which used to say whether or not the CPU was running the idle task, but now instead says whether or not the CPU is running the idle task in the absence of pending wakeups. Although this new implementation gives a better answer to the question "is this CPU idle?", it also invalidates other uses that were made of idle_cpu(). This commit therefore introduces a new is_idle_task() API member that determines whether or not the specified task is one of the idle tasks, allowing open-coded "->pid == 0" sequences to be replaced by something more meaningful. Suggested-by: Josh Triplett <josh@joshtriplett.org> Suggested-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2011-12-11rcu: Introduce raw SRCU read-side primitivesPaul E. McKenney1-0/+43
The RCU implementations, including SRCU, are designed to be used in a lock-like fashion, so that the read-side lock and unlock primitives must execute in the same context for any given read-side critical section. This constraint is enforced by lockdep-RCU. However, there is a need to enter an SRCU read-side critical section within the context of an exception and then exit in the context of the task that encountered the exception. The cost of this capability is that the read-side operations incur the overhead of disabling interrupts. Note that although the current implementation allows a given read-side critical section to be entered by one task and then exited by another, all known possible implementations that allow this have scalability problems. Therefore, a given read-side critical section must be exited by the same task that entered it, though perhaps from an interrupt or exception handler running within that task's context. But if you are thinking in terms of interrupt handlers, make sure that you have considered the possibility of threaded interrupt handlers. Credit goes to Peter Zijlstra for suggesting use of the existing _raw suffix to indicate disabling lockdep over the earlier "bulkref" names. Requested-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Tested-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
2011-12-11nohz: Allow rcu extended quiescent state handling seperately from tick stopFrederic Weisbecker1-3/+43
It is assumed that rcu won't be used once we switch to tickless mode and until we restart the tick. However this is not always true, as in x86-64 where we dereference the idle notifiers after the tick is stopped. To prepare for fixing this, add two new APIs: tick_nohz_idle_enter_norcu() and tick_nohz_idle_exit_norcu(). If no use of RCU is made in the idle loop between tick_nohz_enter_idle() and tick_nohz_exit_idle() calls, the arch must instead call the new *_norcu() version such that the arch doesn't need to call rcu_idle_enter() and rcu_idle_exit(). Otherwise the arch must call tick_nohz_enter_idle() and tick_nohz_exit_idle() and also call explicitly: - rcu_idle_enter() after its last use of RCU before the CPU is put to sleep. - rcu_idle_exit() before the first use of RCU after the CPU is woken up. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Mike Frysinger <vapier@gentoo.org> Cc: Guan Xuetao <gxt@mprc.pku.edu.cn> Cc: David Miller <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Hans-Christian Egtvedt <hans-christian.egtvedt@atmel.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Paul Mackerras <paulus@samba.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Paul Mundt <lethal@linux-sh.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2011-12-11nohz: Separate out irq exit and idle loop dyntick logicFrederic Weisbecker1-6/+7
The tick_nohz_stop_sched_tick() function, which tries to delay the next timer tick as long as possible, can be called from two places: - From the idle loop to start the dytick idle mode - From interrupt exit if we have interrupted the dyntick idle mode, so that we reprogram the next tick event in case the irq changed some internal state that requires this action. There are only few minor differences between both that are handled by that function, driven by the ts->inidle cpu variable and the inidle parameter. The whole guarantees that we only update the dyntick mode on irq exit if we actually interrupted the dyntick idle mode, and that we enter in RCU extended quiescent state from idle loop entry only. Split this function into: - tick_nohz_idle_enter(), which sets ts->inidle to 1, enters dynticks idle mode unconditionally if it can, and enters into RCU extended quiescent state. - tick_nohz_irq_exit() which only updates the dynticks idle mode when ts->inidle is set (ie: if tick_nohz_idle_enter() has been called). To maintain symmetry, tick_nohz_restart_sched_tick() has been renamed into tick_nohz_idle_exit(). This simplifies the code and micro-optimize the irq exit path (no need for local_irq_save there). This also prepares for the split between dynticks and rcu extended quiescent state logics. We'll need this split to further fix illegal uses of RCU in extended quiescent states in the idle loop. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Mike Frysinger <vapier@gentoo.org> Cc: Guan Xuetao <gxt@mprc.pku.edu.cn> Cc: David Miller <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Hans-Christian Egtvedt <hans-christian.egtvedt@atmel.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Paul Mackerras <paulus@samba.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Paul Mundt <lethal@linux-sh.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2011-12-11rcu: Make srcu_read_lock_held() call common lockdep-enabled functionPaul E. McKenney1-1/+4
A common debug_lockdep_rcu_enabled() function is used to check whether RCU lockdep splats should be reported, but srcu_read_lock() does not use it. This commit therefore brings srcu_read_lock_held() up to date. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2011-12-11rcu: Warn when srcu_read_lock() is used in an extended quiescent statePaul E. McKenney1-13/+23
Catch SRCU up to the other variants of RCU by making PROVE_RCU complain if either srcu_read_lock() or srcu_read_lock_held() are used from within RCU-idle mode. Frederic reworked this to allow for the new versions of his patches that check for extended quiescent states. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2011-12-11rcu: Remove one layer of abstraction from PROVE_RCU checkingPaul E. McKenney1-45/+8
Simplify things a bit by substituting the definitions of the single-line rcu_read_acquire(), rcu_read_release(), rcu_read_acquire_bh(), rcu_read_release_bh(), rcu_read_acquire_sched(), and rcu_read_release_sched() functions at their call points. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2011-12-11rcu: Warn when rcu_read_lock() is used in extended quiescent stateFrederic Weisbecker1-10/+42
We are currently able to detect uses of rcu_dereference_check() inside extended quiescent states (such as the RCU-free window in idle). But rcu_read_lock() and friends can be used without rcu_dereference(), so that the earlier commit checking for use of rcu_dereference() and friends while in RCU idle mode miss some error conditions. This commit therefore adds extended quiescent state checking to rcu_read_lock() and friends. Uses of RCU from within RCU-idle mode are totally ignored by RCU, hence the importance of these checks. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Lai Jiangshan <laijs@cn.fujitsu.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2011-12-11rcu: Detect illegal rcu dereference in extended quiescent stateFrederic Weisbecker1-0/+26
Report that none of the rcu read lock maps are held while in an RCU extended quiescent state (the section between rcu_idle_enter() and rcu_idle_exit()). This helps detect any use of rcu_dereference() and friends from within the section in idle where RCU is not allowed. This way we can guarantee an extended quiescent window where the CPU can be put in dyntick idle mode or can simply aoid to be part of any global grace period completion while in the idle loop. Uses of RCU from such mode are totally ignored by RCU, hence the importance of these checks. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Lai Jiangshan <laijs@cn.fujitsu.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2011-12-11rcu: Add failure tracing to rcutorturePaul E. McKenney1-0/+8
Trace the rcutorture RCU accesses and dump the trace buffer when the first failure is detected. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2011-12-11rcu: Track idleness independent of idle tasksPaul E. McKenney3-40/+13
Earlier versions of RCU used the scheduling-clock tick to detect idleness by checking for the idle task, but handled idleness differently for CONFIG_NO_HZ=y. But there are now a number of uses of RCU read-side critical sections in the idle task, for example, for tracing. A more fine-grained detection of idleness is therefore required. This commit presses the old dyntick-idle code into full-time service, so that rcu_idle_enter(), previously known as rcu_enter_nohz(), is always invoked at the beginning of an idle loop iteration. Similarly, rcu_idle_exit(), previously known as rcu_exit_nohz(), is always invoked at the end of an idle-loop iteration. This allows the idle task to use RCU everywhere except between consecutive rcu_idle_enter() and rcu_idle_exit() calls, in turn allowing architecture maintainers to specify exactly where in the idle loop that RCU may be used. Because some of the userspace upcall uses can result in what looks to RCU like half of an interrupt, it is not possible to expect that the irq_enter() and irq_exit() hooks will give exact counts. This patch therefore expands the ->dynticks_nesting counter to 64 bits and uses two separate bitfields to count process/idle transitions and interrupt entry/exit transitions. It is presumed that userspace upcalls do not happen in the idle loop or from usermode execution (though usermode might do a system call that results in an upcall). The counter is hard-reset on each process/idle transition, which avoids the interrupt entry/exit error from accumulating. Overflow is avoided by the 64-bitness of the ->dyntick_nesting counter. This commit also adds warnings if a non-idle task asks RCU to enter idle state (and these checks will need some adjustment before applying Frederic's OS-jitter patches (http://lkml.org/lkml/2011/10/7/246). In addition, validation of ->dynticks and ->dynticks_nesting is added. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2011-12-10mmc: core: Add quirk for long data read timeStefan Nilsson XK1-0/+6
Adds a quirk that sets the data read timeout to a fixed value instead of relying on the information in the CSD. The timeout value chosen is 300ms since that has proven enough for the problematic cards found, but could be increased if other cards require this. This patch also enables this quirk for certain Micron cards known to have this problem. Signed-off-by: Stefan Nilsson XK <stefan.xk.nilsson@stericsson.com> Signed-off-by: Ulf Hansson <ulf.hansson@stericsson.com> Acked-by: Linus Walleij <linus.walleij@linaro.org> Cc: <stable@kernel.org> Signed-off-by: Chris Ball <cjb@laptop.org>
2011-12-09Merge git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tileLinus Torvalds1-0/+9
* git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile: arch/tile: use new generic {enable,disable}_percpu_irq() routines drivers/net/ethernet/tile: use skb_frag_page() API asm-generic/unistd.h: support new process_vm_{readv,write} syscalls arch/tile: fix double-free bug in homecache_free_pages() arch/tile: add a few #includes and an EXPORT to catch up with kernel changes.
2011-12-09vmscan: use atomic-long for shrinker batchingKonstantin Khlebnikov3-2/+3
Use atomic-long operations instead of looping around cmpxchg(). [akpm@linux-foundation.org: massage atomic.h inclusions] Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org> Cc: Dave Chinner <david@fromorbit.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-12-08memblock: Reimplement memblock allocation using reverse free area iteratorTejun Heo1-2/+22
Now that all early memory information is in memblock when enabled, we can implement reverse free area iterator and use it to implement NUMA aware allocator which is then wrapped for simpler variants instead of the confusing and inefficient mending of information in separate NUMA aware allocator. Implement for_each_free_mem_range_reverse(), use it to reimplement memblock_find_in_range_node() which in turn is used by all allocators. The visible allocator interface is inconsistent and can probably use some cleanup too. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Yinghai Lu <yinghai@kernel.org>
2011-12-08memblock: Kill early_node_map[]Tejun Heo3-46/+35
Now all ARCH_POPULATES_NODE_MAP archs select HAVE_MEBLOCK_NODE_MAP - there's no user of early_node_map[] left. Kill early_node_map[] and replace ARCH_POPULATES_NODE_MAP with HAVE_MEMBLOCK_NODE_MAP. Also, relocate for_each_mem_pfn_range() and helper from mm.h to memblock.h as page_alloc.c would no longer host an alternative implementation. This change is ultimately one to one mapping and shouldn't cause any observable difference; however, after the recent changes, there are some functions which now would fit memblock.c better than page_alloc.c and dependency on HAVE_MEMBLOCK_NODE_MAP instead of HAVE_MEMBLOCK doesn't make much sense on some of them. Further cleanups for functions inside HAVE_MEMBLOCK_NODE_MAP in mm.h would be nice. -v2: Fix compile bug introduced by mis-spelling CONFIG_HAVE_MEMBLOCK_NODE_MAP to CONFIG_MEMBLOCK_HAVE_NODE_MAP in mmzone.h. Reported by Stephen Rothwell. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Yinghai Lu <yinghai@kernel.org> Cc: Tony Luck <tony.luck@intel.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Chen Liqin <liqin.chen@sunplusct.com> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: "H. Peter Anvin" <hpa@zytor.com>
2011-12-08memblock: Implement memblock_add_node()Tejun Heo1-0/+1
Implement memblock_add_node() which can add a new memblock memory region with specific node ID. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Yinghai Lu <yinghai@kernel.org>
2011-12-08memblock: s/memblock_analyze()/memblock_allow_resize()/ and update usersTejun Heo1-2/+1
The only function of memblock_analyze() is now allowing resize of memblock region arrays. Rename it to memblock_allow_resize() and update its users. * The following users remain the same other than renaming. arm/mm/init.c::arm_memblock_init() microblaze/kernel/prom.c::early_init_devtree() powerpc/kernel/prom.c::early_init_devtree() openrisc/kernel/prom.c::early_init_devtree() sh/mm/init.c::paging_init() sparc/mm/init_64.c::paging_init() unicore32/mm/init.c::uc32_memblock_init() * In the following users, analyze was used to update total size which is no longer necessary. powerpc/kernel/machine_kexec.c::reserve_crashkernel() powerpc/kernel/prom.c::early_init_devtree() powerpc/mm/init_32.c::MMU_init() powerpc/mm/tlb_nohash.c::__early_init_mmu() powerpc/platforms/ps3/mm.c::ps3_mm_add_memory() powerpc/platforms/embedded6xx/wii.c::wii_memory_fixups() sh/kernel/machine_kexec.c::reserve_crashkernel() * x86/kernel/e820.c::memblock_x86_fill() was directly setting memblock_can_resize before populating memblock and calling analyze afterwards. Call memblock_allow_resize() before start populating. memblock_can_resize is now static inside memblock.c. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Yinghai Lu <yinghai@kernel.org> Cc: Russell King <linux@arm.linux.org.uk> Cc: Michal Simek <monstr@monstr.eu> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Guan Xuetao <gxt@mprc.pku.edu.cn> Cc: "H. Peter Anvin" <hpa@zytor.com>
2011-12-08memblock: Track total size of regions automaticallyTejun Heo1-1/+1
Total size of memory regions was calculated by memblock_analyze() requiring explicitly calling the function between operations which can change memory regions and possible users of total size, which is cumbersome and fragile. This patch makes each memblock_type track total size automatically with minor modifications to memblock manipulation functions and remove requirements on calling memblock_analyze(). [__]memblock_dump_all() now also dumps the total size of reserved regions. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Yinghai Lu <yinghai@kernel.org>
2011-12-08memblock: Kill memblock_init()Tejun Heo1-1/+0
memblock_init() initializes arrays for regions and memblock itself; however, all these can be done with struct initializers and memblock_init() can be removed. This patch kills memblock_init() and initializes memblock with struct initializer. The only difference is that the first dummy entries don't have .nid set to MAX_NUMNODES initially. This doesn't cause any behavior difference. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Yinghai Lu <yinghai@kernel.org> Cc: Russell King <linux@arm.linux.org.uk> Cc: Michal Simek <monstr@monstr.eu> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Guan Xuetao <gxt@mprc.pku.edu.cn> Cc: "H. Peter Anvin" <hpa@zytor.com>
2011-12-08memblock: Kill sentinel entries at the end of static region arraysTejun Heo1-6/+0
memblock no longer depends on having one more entry at the end during addition making the sentinel entries at the end of region arrays not too useful. Remove the sentinels. This eases further updates. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Yinghai Lu <yinghai@kernel.org>