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2008-10-03rcu: RCU-based detection of stalled CPUs for Classic RCU, fixIngo Molnar
fix the !CONFIG_RCU_CPU_STALL_DETECTOR path: kernel/rcuclassic.c: In function '__rcu_pending': kernel/rcuclassic.c:609: error: too few arguments to function 'check_cpu_stall' Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-03rcu: RCU-based detection of stalled CPUs for Classic RCUPaul E. McKenney
This patch adds stalled-CPU detection to Classic RCU. This capability is enabled by a new config variable CONFIG_RCU_CPU_STALL_DETECTOR, which defaults disabled. This is a debugging feature to detect infinite loops in kernel code, not something that non-kernel-hackers would be expected to care about. This feature can detect looping CPUs in !PREEMPT builds and looping CPUs with preemption disabled in PREEMPT builds. This is essentially a port of this functionality from the treercu patch, replacing the stall debug patch that is already in tip/core/rcu (commit 67182ae1c4). The changes from the patch in tip/core/rcu include making the config variable name match that in treercu, changing from seconds to jiffies to avoid spurious warnings, and printing a boot message when this feature is enabled. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-03Merge commit 'v2.6.27-rc8' into core/rcuIngo Molnar
2008-10-02fix error-path NULL deref in alloc_posix_timer()Dan Carpenter
Found by static checker (http://repo.or.cz/w/smatch.git). Signed-off-by: Dan Carpenter <error27@gmail.com> Acked-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-02softirqs, debug: preemption checkThomas Gleixner
if a preempt count leaks out of a softirq handler it can be very hard to figure it out. Add a debug check for this. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-02genirq: record trigger typeDavid Brownell
Genirq hasn't previously recorded the trigger type used by any given IRQ, although some irq_chip support has done so. That data can be useful when troubleshooting. This patch records it in the relevant irq_desc.status bits, and improves consistency between the two driver-visible calls affected: - Make set_irq_type() usage match request_irq() usage: * IRQ_TYPE_NONE should be a NOP; succeed, so irq_chip methods won't have to handle that case any more (many do it wrong). * IRQ_TYPE_PROBE is ignored; any buggy out-of-tree callers might need to switch over to the real IRQ probing code. * emit the same diagnostics (from shared utility code) - Their kerneldoc now reflects usage: * request_irq() flags include IRQF_TRIGGER_* to specify active edge(s)/level ... docs previously omitted that * set_irq_type() is declared in <linux/irq.h> so callers should use the (bit-equivalent) IRQ_TYPE_* symbols there Also: adds a warning about shared IRQs that don't end up using the requested trigger mode; and fix an unrelated "sparse" warning. Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-02Merge commit 'v2.6.27-rc8' into genirqIngo Molnar
2008-09-30Merge branch 'timers-fixes-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: hrtimer: prevent migration of per CPU hrtimers hrtimer: mark migration state hrtimer: fix migration of CB_IRQSAFE_NO_SOFTIRQ hrtimers hrtimer: migrate pending list on cpu offline Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Tested-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2008-09-30sched: minor optimizations in wake_affine and select_task_rq_fairAmit K. Arora
This patch does following: o Removes unused variable and argument "rq". o Optimizes one of the "if" conditions in wake_affine() - i.e. if "balanced" is true, we need not do rest of the calculations in the condition. o If this cpu is same as the previous cpu (on which woken up task was running when it went to sleep), no need to call wake_affine at all. Signed-off-by: Amit K Arora <aarora@linux.vnet.ibm.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-30timers: fix itimer/many thread hang, fixIngo Molnar
fix bogus rq dereference: v3 removed the locking but also removed the rq initialization. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-29Configure out file locking featuresThomas Petazzoni
This patch adds the CONFIG_FILE_LOCKING option which allows to remove support for advisory locks. With this patch enabled, the flock() system call, the F_GETLK, F_SETLK and F_SETLKW operations of fcntl() and NFS support are disabled. These features are not necessarly needed on embedded systems. It allows to save ~11 Kb of kernel code and data: text data bss dec hex filename 1125436 118764 212992 1457192 163c28 vmlinux.old 1114299 118564 212992 1445855 160fdf vmlinux -11137 -200 0 -11337 -2C49 +/- This patch has originally been written by Matt Mackall <mpm@selenic.com>, and is part of the Linux Tiny project. Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com> Signed-off-by: Matt Mackall <mpm@selenic.com> Cc: matthew@wil.cx Cc: linux-fsdevel@vger.kernel.org Cc: mpm@selenic.com Cc: akpm@linux-foundation.org Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2008-09-29mm owner: fix race between swapoff and exitBalbir Singh
There's a race between mm->owner assignment and swapoff, more easily seen when task slab poisoning is turned on. The condition occurs when try_to_unuse() runs in parallel with an exiting task. A similar race can occur with callers of get_task_mm(), such as /proc/<pid>/<mmstats> or ptrace or page migration. CPU0 CPU1 try_to_unuse looks at mm = task0->mm increments mm->mm_users task 0 exits mm->owner needs to be updated, but no new owner is found (mm_users > 1, but no other task has task->mm = task0->mm) mm_update_next_owner() leaves mmput(mm) decrements mm->mm_users task0 freed dereferencing mm->owner fails The fix is to notify the subsystem via mm_owner_changed callback(), if no new owner is found, by specifying the new task as NULL. Jiri Slaby: mm->owner was set to NULL prior to calling cgroup_mm_owner_callbacks(), but must be set after that, so as not to pass NULL as old owner causing oops. Daisuke Nishimura: mm_update_next_owner() may set mm->owner to NULL, but mem_cgroup_from_task() and its callers need to take account of this situation to avoid oops. Hugh Dickins: Lockdep warning and hang below exec_mmap() when testing these patches. exit_mm() up_reads mmap_sem before calling mm_update_next_owner(), so exec_mmap() now needs to do the same. And with that repositioning, there's now no point in mm_need_new_owner() allowing for NULL mm. Reported-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com> Signed-off-by: Jiri Slaby <jirislaby@gmail.com> Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Signed-off-by: Hugh Dickins <hugh@veritas.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-09-29hrtimer: prevent migration of per CPU hrtimersThomas Gleixner
Impact: per CPU hrtimers can be migrated from a dead CPU The hrtimer code has no knowledge about per CPU timers, but we need to prevent the migration of such timers and warn when such a timer is active at migration time. Explicitely mark the timers as per CPU and use a more understandable mode descriptor for the interrupts safe unlocked callback mode, which is used by hrtimer_sleeper and the scheduler code. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-09-29hrtimer: mark migration stateThomas Gleixner
Impact: during migration active hrtimers can be seen as inactive The migration code removes the hrtimers from the queues of the dead CPU and sets the state temporary to INACTIVE. The enqueue code sets it to ACTIVE/PENDING again. Prevent that the wrong state can be seen by using a separate migration state bit. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-09-29hrtimer: fix migration of CB_IRQSAFE_NO_SOFTIRQ hrtimersThomas Gleixner
Impact: Stale timers after a CPU went offline. commit 37bb6cb4097e29ffee970065b74499cbf10603a3 hrtimer: unlock hrtimer_wakeup changed the hrtimer sleeper callback mode to CB_IRQSAFE_NO_SOFTIRQ due to locking problems. A result of this change is that when enqueue is called for an already expired hrtimer the callback function is not longer called directly from the enqueue code. The normal callers have been fixed in the code, but the migration code which moves hrtimers from a dead CPU to a live CPU was not made aware of this. This can be fixed by checking the timer state after the call to enqueue in the migration code. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-09-29hrtimer: migrate pending list on cpu offlineThomas Gleixner
Impact: hrtimers which are on the pending list are not migrated at cpu offline and can be stale forever Add the pending list migration when CONFIG_HIGH_RES_TIMERS is enabled Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-09-27timers: fix itimer/many thread hang, v3Frank Mayhar
- fix UP lockup - another set of UP/SMP cleanups and simplifications Signed-off-by: Frank Mayhar <fmayhar@google.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-26kgdb, x86, arm, mips, powerpc: ignore user space single steppingJason Wessel
On the x86 arch, user space single step exceptions should be ignored if they occur in the kernel space, such as ptrace stepping through a system call. First check if it is kgdb that is executing a single step, then ensure it is not an accidental traversal into the user space, while in kgdb, any other time the TIF_SINGLESTEP is set, kgdb should ignore the exception. On x86, arm, mips and powerpc, the kgdb_contthread usage was inconsistent with the way single stepping is implemented in the kgdb core. The arch specific stub should always set the kgdb_cpu_doing_single_step correctly if it is single stepping. This allows kgdb to correctly process an instruction steps if ptrace happens to be requesting an instruction step over a system call. Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
2008-09-26kgdb: could not write to the last of valid memory with kgdbAtsuo Igarashi
On the ARM architecture, kgdb will crash the kernel if the last byte of valid memory is written due to a flush_icache_range flushing beyond the memory boundary. Signed-off-by: Atsuo Igarashi <atsuo_igarashi@tripeaks.co.jp> Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
2008-09-26IO resources, x86: ioremap sanity check to catch mapping requests exceeding, fixIngo Molnar
fix this build error: kernel/resource.c: In function 'iomem_map_sanity_check': kernel/resource.c:842: error: implicit declaration of function 'r_next' kernel/resource.c:842: warning: assignment makes pointer from integer without a cast r_next() was only available if CONFIG_PROCFS was enabled. and fix this build warning: kernel/resource.c:855: warning: format '%llx' expects type 'long long unsigned int', but argument 2 has type 'resource_size_t' kernel/resource.c:855: warning: format '%llx' expects type 'long long unsigned int', but argument 3 has type 'long unsigned int' kernel/resource.c:855: warning: format '%llx' expects type 'long long unsigned int', but argument 4 has type 'resource_size_t' kernel/resource.c:855: warning: format '%llx' expects type 'long long unsigned int', but argument 5 has type 'resource_size_t' resource_t can be 32 bits. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-26IO resources, x86: ioremap sanity check to catch mapping requests exceeding ↵Suresh Siddha
the BAR sizes Go through the iomem resource tree to check if any of the ioremap() requests span more than any slot in the iomem resource tree and do a WARN_ON() if we hit this check. This will raise a red-flag, if some driver is mapping more than what is needed. And hopefully identify possible corruptions much earlier. Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-25sched: maintain only task entities in cfs_rq->tasks listBharata B Rao
cfs_rq->tasks list is used by the load balancer to iterate over all the tasks. Currently it holds all the entities (both task and group entities) because of which there is a need to check for group entities explicitly during load balancing. This patch changes the cfs_rq->tasks list to hold only task entities. Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-24ntp: improve adjtimex frequency roundingRoman Zippel
Change PPM_SCALE_INV_SHIFT so that it doesn't throw away any input bits (19 is the amount of the factor 2 in PPM_SCALE), the output frequency can then be calculated back to its input value, as the inverse divide produce a slightly larger value, which is then correctly rounded by the final shift. Reported-by: Martin Ziegler <ziegler@uni-freiburg.de> Signed-off-by: Roman Zippel <zippel@linux-m68k.org> Cc: John Stultz <johnstul@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-09-24timekeeping: fix rounding problem during clock updateRoman Zippel
Due to a rounding problem during a clock update it's possible for readers to observe the clock jumping back by 1nsec. The following simplified example demonstrates the problem: cycle xtime 0 0 1000 999999.6 2000 1999999.2 3000 2999998.8 ... 1500 = 1499999.4 = 0.0 + 1499999.4 = 999999.6 + 499999.8 When reading the clock only the full nanosecond part is used, while timekeeping internally keeps nanosecond fractions. If the clock is now updated at cycle 1500 here, a nanosecond is missing due to the truncation. The simple fix is to round up the xtime value during the update, this also changes the distance to the reference time, but the adjustment will automatically take care that it stays under control. Signed-off-by: Roman Zippel <zippel@linux-m68k.org> Signed-off-by: John Stultz <johnstul@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-09-24ntp: let update_persistent_clock() sleepMaciej W. Rozycki
This is a change that makes the 11-minute RTC update be run in the process context. This is so that update_persistent_clock() can sleep, which may be required for certain types of RTC hardware -- most notably I2C devices. Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org> Cc: Roman Zippel <zippel@linux-m68k.org> Cc: Rik van Riel <riel@redhat.com> Cc: David Brownell <david-b@pacbell.net> Acked-by: Alessandro Zummo <a.zummo@towertech.it> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-09-24posix-timers: lock_timer: make it readableOleg Nesterov
Cleanup. Imho makes the code much more understandable. At least this patch lessens both the source and compiled code. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: mingo@elte.hu Cc: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-09-24posix-timers: lock_timer: kill the bogus ->it_id checkOleg Nesterov
lock_timer() checks that the timer found by idr_find(timer_id) has ->it_id == timer_id. This buys nothing. This check can fail only if sys_timer_create() unlocked idr_lock after idr_get_new(), but didn't set ->it_id = new_timer_id yet. But in that case ->it_process == NULL so lock_timer() can't succeed anyway. Also remove a couple of unneeded typecasts. Note that with or without this patch we have a small problem. sys_timer_create() doesn't ensure that the result of setting (say) ->it_sigev_notify must be visible if lock_timer() succeeds. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: mingo@elte.hu Cc: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-09-24posix-timers: kill ->it_sigev_signo and ->it_sigev_valueOleg Nesterov
With the recent changes ->it_sigev_signo and ->it_sigev_value are only used in sys_timer_create(), kill them. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: mingo@elte.hu Cc: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-09-24posix-timers: sys_timer_create: cleanup the error handlingOleg Nesterov
Cleanup. - sys_timer_create() is big and complicated. The code above the "out:" label relies on the fact that "error" must be == 0. This is not very robust, make the code more explicit. Remove the unneeded initialization of error. - If idr_get_new() succeeds (as it normally should), we check the returned value twice. Move the "-EAGAIN" check under "if (error)". Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: mingo@elte.hu Cc: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-09-24posix-timers: move the initialization of timer->sigq from send to create pathOleg Nesterov
posix_timer_event() always populates timer->sigq with the same numbers, move this code into sys_timer_create(). Note that with this patch we can kill it_sigev_signo and it_sigev_value. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: mingo@elte.hu Cc: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-09-24posix-timers: sys_timer_create: simplify and s/tasklist/rcu/Oleg Nesterov
- Change the code to do rcu_read_lock() instead of taking tasklist_lock, it is safe to get_task_struct(p) if p was found under RCU. However, now we must not use process's sighand/signal, they may be NULL. We can use current->sighand/signal instead, this "process" must belong to the current's thread-group. - Factor out the common code for 2 "if (timer_event_spec)" branches, the !timer_event_spec case can use current too. - use spin_lock_irq() instead of _irqsave(), kill "flags". Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: mingo@elte.hu Cc: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-09-24posix-timers: sys_timer_create: remove the buggy PF_EXITING checkOleg Nesterov
sys_timer_create() return -EINVAL if the target thread has PF_EXITING. This doesn't really make sense, the sub-thread can die right after unlock. And in fact, this is just wrong. Without SIGEV_THREAD_ID good_sigevent() returns ->group_leader, and it is very possible that the leader is already dead. This is OK, we shouldn't return the error in this case. Remove this check and the comment. Note that the "process" was found under tasklist_lock, it must have ->sighand != NULL. Also, remove a couple of unneeded initializations. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: mingo@elte.hu Cc: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-09-24posix-timers: always do get_task_struct(timer->it_process)Oleg Nesterov
Change the code to get/put timer->it_process regardless of SIGEV_THREAD_ID. This streamlines the create/destroy paths and allows us to simplify the usage of exit_itimers() in de_thread(). Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: mingo@elte.hu Cc: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-09-24posix-timers: don't switch to ->group_leader if ->it_process diesOleg Nesterov
posix_timer_event() drops SIGEV_THREAD_ID and switches to ->group_leader if send_sigqueue() fails. This is not very useful and doesn't work reliably. send_sigqueue() can only fail if ->it_process is dead. But it can die before it dequeues the SI_TIMER signal, in that case the timer stops anyway. Remove this code. I guess it was needed a long ago to ensure that the timer is not destroyed when when its creator thread dies. Q: perhaps it makes sense to change sys_timer_settime() to return an error if ->it_process is dead? Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: mingo@elte.hu Cc: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-09-23Merge branch 'timers-fixes-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: timers: fix build error in !oneshot case x86: c1e_idle: don't mark TSC unstable if CPU has invariant TSC x86: prevent C-states hang on AMD C1E enabled machines clockevents: prevent mode mismatch on cpu online clockevents: check broadcast device not tick device clockevents: prevent stale tick_next_period for onlining CPUs x86: prevent stale state of c1e_mask across CPU offline/online clockevents: prevent cpu online to interfere with nohz
2008-09-23Merge branch 'sched-fixes-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: sched: fix init_hrtick() section mismatch warning
2008-09-23kexec: fix segmentation fault in kimage_add_entryJonathan Steel
A segmentation fault can occur in kimage_add_entry in kexec.c when loading a kernel image into memory. The fault occurs because a page is requested by calling kimage_alloc_page with gfp_mask GFP_KERNEL and the function may actually return a page with gfp_mask GFP_HIGHUSER. The high mem page is returned because it was swapped with the kernel page due to the kernel page being a page that will shortly be copied to. This patch ensures that kimage_alloc_page returns a page that was created with the correct gfp flags. I have verified the change and fixed the whitespace damage of the original patch. Jonathan did a great job of tracking this down after he hit the problem. -- Eric Signed-off-by: Jonathan Steel <jon.steel@esentire.com> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Acked-by: Simon Horman <horms@verge.net.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-09-23sched: fixup buddy selectionPeter Zijlstra
We should set the buddy even though we might already have the TIF_RESCHED flag set. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-23sched: more sanity checks on the bandwidth settingsPeter Zijlstra
While playing around with it, I noticed we missed some sanity checks. Also add some comments while we're there. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-23sched: add some comments to the bandwidth codePeter Zijlstra
Hopefully clarify some of this code a little. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-23sched: fixlet for group load balancePeter Zijlstra
We should not only correct the increment for the initial group, but should be consistent and do so for all the groups we encounter. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-23Merge branches 'sched/urgent' and 'sched/rt' into sched/develIngo Molnar
2008-09-23sched: rework wakeup preemptionPeter Zijlstra
Rework the wakeup preemption to work on real runtime instead of the virtual runtime. This greatly simplifies the code. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-23timers: fix itimer/many thread hang, v2Frank Mayhar
This is the second resubmission of the posix timer rework patch, posted a few days ago. This includes the changes from the previous resubmittion, which addressed Oleg Nesterov's comments, removing the RCU stuff from the patch and un-inlining the thread_group_cputime() function for SMP. In addition, per Ingo Molnar it simplifies the UP code, consolidating much of it with the SMP version and depending on lower-level SMP/UP handling to take care of the differences. It also cleans up some UP compile errors, moves the scheduler stats-related macros into kernel/sched_stats.h, cleans up a merge error in kernel/fork.c and has a few other minor fixes and cleanups as suggested by Oleg and Ingo. Thanks for the review, guys. Signed-off-by: Frank Mayhar <fmayhar@google.com> Cc: Roland McGrath <roland@redhat.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-23timers: fix build error in !oneshot caseIngo Molnar
kernel/time/tick-common.c: In function ‘tick_setup_periodic’: kernel/time/tick-common.c:113: error: implicit declaration of function ‘tick_broadcast_oneshot_active’ Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-23clockevents: prevent mode mismatch on cpu onlineThomas Gleixner
Impact: timer hang on CPU online observed on AMD C1E systems When a CPU is brought online then the broadcast machinery can be in the one shot state already. Check this and setup the timer device of the new CPU in one shot mode so the broadcast code can pick up the next_event value correctly. Another AMD C1E oddity, as we switch to broadcast immediately and not after the full bring up via the ACPI cpu idle code. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-09-23clockevents: check broadcast device not tick deviceThomas Gleixner
Impact: Possible hang on CPU online observed on AMD C1E machines. The broadcast setup code looks at the mode of the tick device to determine whether it needs to be shut down or setup. This is wrong when the broadcast mode is set to one shot already. This can happen when a CPU is brought online as it goes through the periodic setup first. The problem went unnoticed as sane systems do not call into that code before the switch to one shot for the clock event device happens. The AMD C1E idle routine switches over immediately and thereby shuts down the just setup device before the first interrupt happens. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-09-23clockevents: prevent stale tick_next_period for onlining CPUsThomas Gleixner
Impact: possible hang on CPU onlining in timer one shot mode. The tick_next_period variable is only used during boot on nohz/highres enabled systems, but for CPU onlining it needs to be maintained when the per cpu clock events device operates in one shot mode. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-09-23clockevents: prevent cpu online to interfere with nohzThomas Gleixner
Impact: rare hang which can be triggered on CPU online. tick_do_timer_cpu keeps track of the CPU which updates jiffies via do_timer. The value -1 is used to signal, that currently no CPU is doing this. There are two cases, where the variable can have this state: boot: necessary for systems where the boot cpu id can be != 0 nohz long idle sleep: When the CPU which did the jiffies update last goes into a long idle sleep it drops the update jiffies duty so another CPU which is not idle can pick it up and keep jiffies going. Using the same value for both situations is wrong, as the CPU online code can see the -1 state when the timer of the newly onlined CPU is setup. The setup for a newly onlined CPU goes through periodic mode and can pick up the do_timer duty without being aware of the nohz / highres mode of the already running system. Use two separate states and make them constants to avoid magic numbers confusion. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-09-23rcu: fix sparse shadowed variable warningHarvey Harrison
kernel/rcuclassic.c:564:18: warning: symbol 'flags' shadows an earlier one kernel/rcuclassic.c:527:16: originally declared here Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>