linux/kernel/sched/core.c, branch v3.7-rc7

Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2012-10-12T13:13:05Z

Pull scheduler fixes from Ingo Molnar: "A CPU hotplug related crash fix and a nohz accounting fixlet." * 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched: Update sched_domains_numa_masks[][] when new cpus are onlined sched: Ensure 'sched_domains_numa_levels' is safe to use in other functions nohz: Fix one jiffy count too far in idle cputime

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal

2012-10-12T01:49:08Z

Pull pile 2 of execve and kernel_thread unification work from Al Viro: "Stuff in there: kernel_thread/kernel_execve/sys_execve conversions for several more architectures plus assorted signal fixes and cleanups. There'll be more (in particular, real fixes for the alpha do_notify_resume() irq mess)..." * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal: (43 commits) alpha: don't open-code trace_report_syscall_{enter,exit} Uninclude linux/freezer.h m32r: trim masks avr32: trim masks tile: don't bother with SIGTRAP in setup_frame microblaze: don't bother with SIGTRAP in setup_rt_frame() mn10300: don't bother with SIGTRAP in setup_frame() frv: no need to raise SIGTRAP in setup_frame() x86: get rid of duplicate code in case of CONFIG_VM86 unicore32: remove pointless test h8300: trim _TIF_WORK_MASK parisc: decide whether to go to slow path (tracesys) based on thread flags parisc: don't bother looping in do_signal() parisc: fix double restarts bury the rest of TIF_IRET sanitize tsk_is_polling() bury _TIF_RESTORE_SIGMASK unicore32: unobfuscate _TIF_WORK_MASK mips: NOTIFY_RESUME is not needed in TIF masks mips: merge the identical "return from syscall" per-ABI code ... Conflicts: arch/arm/include/asm/thread_info.h

sched: Update sched_domains_numa_masks[][] when new cpus are onlined

2012-10-05T11:54:48Z

Once array sched_domains_numa_masks[] []is defined, it is never updated. When a new cpu on a new node is onlined, the coincident member in sched_domains_numa_masks[][] is not initialized, and all the masks are 0. As a result, the build_overlap_sched_groups() will initialize a NULL sched_group for the new cpu on the new node, which will lead to kernel panic: [ 3189.403280] Call Trace: [ 3189.403286] [] warn_slowpath_common+0x7f/0xc0 [ 3189.403289] [] warn_slowpath_null+0x1a/0x20 [ 3189.403292] [] build_sched_domains+0x467/0x470 [ 3189.403296] [] partition_sched_domains+0x307/0x510 [ 3189.403299] [] ? partition_sched_domains+0x142/0x510 [ 3189.403305] [] cpuset_update_active_cpus+0x83/0x90 [ 3189.403308] [] cpuset_cpu_active+0x38/0x70 [ 3189.403316] [] notifier_call_chain+0x67/0x150 [ 3189.403320] [] ? native_cpu_up+0x18a/0x1b5 [ 3189.403328] [] __raw_notifier_call_chain+0xe/0x10 [ 3189.403333] [] __cpu_notify+0x20/0x40 [ 3189.403337] [] _cpu_up+0xe9/0x131 [ 3189.403340] [] cpu_up+0xdb/0xee [ 3189.403348] [] store_online+0x9c/0xd0 [ 3189.403355] [] dev_attr_store+0x20/0x30 [ 3189.403361] [] sysfs_write_file+0xa3/0x100 [ 3189.403368] [] vfs_write+0xd0/0x1a0 [ 3189.403371] [] sys_write+0x54/0xa0 [ 3189.403375] [] system_call_fastpath+0x16/0x1b [ 3189.403377] ---[ end trace 1e6cf85d0859c941 ]--- [ 3189.403398] BUG: unable to handle kernel NULL pointer dereference at 0000000000000018 This patch registers a new notifier for cpu hotplug notify chain, and updates sched_domains_numa_masks every time a new cpu is onlined or offlined. Signed-off-by: Tang Chen Signed-off-by: Wen Congyang [ fixed compile warning ] Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/1348578751-16904-3-git-send-email-tangchen@cn.fujitsu.com Signed-off-by: Ingo Molnar

sched: Ensure 'sched_domains_numa_levels' is safe to use in other functions

2012-10-05T11:54:46Z

We should temporarily reset 'sched_domains_numa_levels' to 0 after it is reset to 'level' in sched_init_numa(). If it fails to allocate memory for array sched_domains_numa_masks[][], the array will contain less then 'level' members. This could be dangerous when we use it to iterate array sched_domains_numa_masks[][] in other functions. This patch set sched_domains_numa_levels to 0 before initializing array sched_domains_numa_masks[][], and reset it to 'level' when sched_domains_numa_masks[][] is fully initialized. Signed-off-by: Tang Chen Signed-off-by: Wen Congyang Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/1348578751-16904-2-git-send-email-tangchen@cn.fujitsu.com Signed-off-by: Ingo Molnar

Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2012-10-01T17:43:39Z

Pull scheduler changes from Ingo Molnar: "Continued quest to clean up and enhance the cputime code by Frederic Weisbecker, in preparation for future tickless kernel features. Other than that, smallish changes." Fix up trivial conflicts due to additions next to each other in arch/{x86/}Kconfig * 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (24 commits) cputime: Make finegrained irqtime accounting generally available cputime: Gather time/stats accounting config options into a single menu ia64: Reuse system and user vtime accounting functions on task switch ia64: Consolidate user vtime accounting vtime: Consolidate system/idle context detection cputime: Use a proper subsystem naming for vtime related APIs sched: cpu_power: enable ARCH_POWER sched/nohz: Clean up select_nohz_load_balancer() sched: Fix load avg vs. cpu-hotplug sched: Remove __ARCH_WANT_INTERRUPTS_ON_CTXSW sched: Fix nohz_idle_balance() sched: Remove useless code in yield_to() sched: Add time unit suffix to sched sysctl knobs sched/debug: Limit sd->*_idx range on sysctl sched: Remove AFFINE_WAKEUPS feature flag s390: Remove leftover account_tick_vtime() header cputime: Consolidate vtime handling on context switch sched: Move cputime code to its own file cputime: Generalize CONFIG_VIRT_CPU_ACCOUNTING tile: Remove SD_PREFER_LOCAL leftover ...

sanitize tsk_is_polling()

2012-10-01T13:58:13Z

Make default just return 0. The current default (checking TIF_POLLING_NRFLAG) is taken to architectures that need it; ones that don't do polling in their idle threads don't need to defined TIF_POLLING_NRFLAG at all. ia64 defined both TS_POLLING (used by its tsk_is_polling()) and TIF_POLLING_NRFLAG (not used at all). Killed the latter... Signed-off-by: Al Viro

rcu: Exit RCU extended QS on user preemption

2012-09-26T13:47:11Z

When exceptions or irq are about to resume userspace, if the task needs to be rescheduled, the arch low level code calls schedule() directly. If we call it, it is because we have the TIF_RESCHED flag: - It can be set after random local calls to set_need_resched() (RCU, drm, ...) - A wake up happened and the CPU needs preemption. This can happen in several ways: * Remotely: the remote waking CPU has set TIF_RESCHED and send the wakee an IPI to schedule the new task. * Remotely enqueued: the remote waking CPU sends an IPI to the target and the wake up is made by the target. * Locally: waking CPU == wakee CPU and the wakeup is done locally. set_need_resched() is called without IPI. In the case of local and remotely enqueued wake ups, the tick can be restarted when we enqueue the new task and RCU can exit the extended quiescent state at the same time. Then by the time we reach irq exit path and we call schedule, we are not in RCU user mode. But if we call schedule() only because something called set_need_resched(), RCU may still be in user mode when we reach schedule. Also if a wake up is done remotely, the CPU might see the TIF_RESCHED flag and call schedule while the IPI has not yet happen to restart the tick and exit RCU user mode. We need to manually protect against these corner cases. Create a new API schedule_user() that calls schedule() inside rcu_user_exit()-rcu_user_enter() in order to protect it. Archs will need to rely on it now to implement user preemption safely. Signed-off-by: Frederic Weisbecker Cc: Alessio Igor Bogani Cc: Andrew Morton Cc: Avi Kivity Cc: Chris Metcalf Cc: Christoph Lameter Cc: Geoff Levand Cc: Gilad Ben Yossef Cc: Hakan Akkan Cc: H. Peter Anvin Cc: Ingo Molnar Cc: Josh Triplett Cc: Kevin Hilman Cc: Max Krasnyansky Cc: Peter Zijlstra Cc: Stephen Hemminger Cc: Steven Rostedt Cc: Sven-Thorsten Dietrich Cc: Thomas Gleixner Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett

rcu: Exit RCU extended QS on kernel preemption after irq/exception

2012-09-26T13:47:09Z

When an exception or an irq exits, and we are going to resume into interrupted kernel code, the low level architecture code calls preempt_schedule_irq() if there is a need to reschedule. If the interrupt/exception occured between a call to rcu_user_enter() (from syscall exit, exception exit, do_notify_resume exit, ...) and a real resume to userspace (iret,...), preempt_schedule_irq() can be called whereas RCU thinks we are in userspace. But preempt_schedule_irq() is going to run kernel code and may be some RCU read side critical section. We must exit the userspace extended quiescent state before we call it. To solve this, just call rcu_user_exit() in the beginning of preempt_schedule_irq(). Signed-off-by: Frederic Weisbecker Cc: Alessio Igor Bogani Cc: Andrew Morton Cc: Avi Kivity Cc: Chris Metcalf Cc: Christoph Lameter Cc: Geoff Levand Cc: Gilad Ben Yossef Cc: Hakan Akkan Cc: H. Peter Anvin Cc: Ingo Molnar Cc: Josh Triplett Cc: Kevin Hilman Cc: Max Krasnyansky Cc: Peter Zijlstra Cc: Stephen Hemminger Cc: Steven Rostedt Cc: Sven-Thorsten Dietrich Cc: Thomas Gleixner Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett

rcu: Switch task's syscall hooks on context switch

2012-09-26T13:47:02Z

Clear the syscalls hook of a task when it's scheduled out so that if the task migrates, it doesn't run the syscall slow path on a CPU that might not need it. Also set the syscalls hook on the next task if needed. Signed-off-by: Frederic Weisbecker Cc: Alessio Igor Bogani Cc: Andrew Morton Cc: Avi Kivity Cc: Chris Metcalf Cc: Christoph Lameter Cc: Geoff Levand Cc: Gilad Ben Yossef Cc: Hakan Akkan Cc: H. Peter Anvin Cc: Ingo Molnar Cc: Josh Triplett Cc: Kevin Hilman Cc: Max Krasnyansky Cc: Peter Zijlstra Cc: Stephen Hemminger Cc: Steven Rostedt Cc: Sven-Thorsten Dietrich Cc: Thomas Gleixner Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett

Merge remote-tracking branch 'tip/core/rcu' into next.2012.09.25b

2012-09-25T17:03:56Z

Resolved conflict in kernel/sched/core.c using Peter Zijlstra's approach from https://lkml.org/lkml/2012/9/5/585.