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2012-02-15timer-fd: Prevent live lockThomas Gleixner
If hrtimer_try_to_cancel() requires a retry, then depending on the priority setting te retry loop might prevent timer callback completion on RT. Prevent that by waiting for completion on RT, no change for a non RT kernel. Reported-by: Sankara Muthukrishnan <sankara.m@gmail.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: stable-rt@vger.kernel.org
2012-02-15hrtimer-fix-reprogram-madness.patchThomas Gleixner
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-02-15hrtimer: Add missing debug_activate() aid [Was: Re: [ANNOUNCE] 3.0.6-rt17]Yong Zhang
On Fri, Oct 07, 2011 at 10:25:25AM -0700, Fernando Lopez-Lezcano wrote: > On 10/06/2011 06:15 PM, Thomas Gleixner wrote: > >Dear RT Folks, > > > >I'm pleased to announce the 3.0.6-rt17 release. > > Hi and thanks again. So far this one is not hanging which is very > good news. But I still see the hrtimer_fixup_activate warnings I > reported for rt16... Hi Fernando, I think below patch will smooth your concern? Thanks, Yong
2012-02-15hrtimer: Don't call the timer handler from hrtimer_startPeter Zijlstra
[<ffffffff812de4a9>] __delay+0xf/0x11 [<ffffffff812e36e9>] do_raw_spin_lock+0xd2/0x13c [<ffffffff815028ee>] _raw_spin_lock+0x60/0x73 rt_b->rt_runtime_lock [<ffffffff81068f68>] ? sched_rt_period_timer+0xad/0x281 [<ffffffff81068f68>] sched_rt_period_timer+0xad/0x281 [<ffffffff8109e5e1>] __run_hrtimer+0x1e4/0x347 [<ffffffff81068ebb>] ? enqueue_rt_entity+0x36/0x36 [<ffffffff8109f2b1>] __hrtimer_start_range_ns+0x2b5/0x40a base->cpu_base->lock (lock_hrtimer_base) [<ffffffff81068b6f>] __enqueue_rt_entity+0x26f/0x2aa rt_b->rt_runtime_lock (start_rt_bandwidth) [<ffffffff81068ead>] enqueue_rt_entity+0x28/0x36 [<ffffffff81069355>] enqueue_task_rt+0x3d/0xb0 [<ffffffff810679d6>] enqueue_task+0x5d/0x64 [<ffffffff810714fc>] task_setprio+0x210/0x29c rq->lock [<ffffffff810b56cb>] __rt_mutex_adjust_prio+0x25/0x2a p->pi_lock [<ffffffff810b5d2c>] task_blocks_on_rt_mutex+0x196/0x20f Instead make __hrtimer_start_range_ns() return -ETIME when the timer is in the past. Since body actually uses the hrtimer_start*() return value its pretty safe to wreck it. Also, it will only ever return -ETIME for timer->irqsafe || !wakeup timers. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
2012-02-15hrtimer: fixup hrtimer callback changes for preempt-rtThomas Gleixner
In preempt-rt we can not call the callbacks which take sleeping locks from the timer interrupt context. Bring back the softirq split for now, until we fixed the signal delivery problem for real. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-02-15hrtimers: prepare full preemptionIngo Molnar
Make cancellation of a running callback in softirq context safe against preemption. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-02-15printk: Don't call printk_tick in printk_needs_cpu() on RTYong Zhang
printk_tick() can't be called in atomic context when RT is enabled, otherwise below warning will show: [ 117.597095] BUG: sleeping function called from invalid context at kernel/rtmutex.c:645 [ 117.597102] in_atomic(): 1, irqs_disabled(): 1, pid: 0, name: kworker/0:0 [ 117.597111] Pid: 0, comm: kworker/0:0 Not tainted 3.0.6-rt17-00284-gb76d419-dirty #7 [ 117.597116] Call Trace: [ 117.597131] [<c06e3b61>] ? printk+0x1d/0x24 [ 117.597142] [<c01390b6>] __might_sleep+0xe6/0x110 [ 117.597151] [<c06e634c>] rt_spin_lock+0x1c/0x30 [ 117.597158] [<c0142f26>] __wake_up+0x26/0x60 [ 117.597166] [<c014c78e>] printk_tick+0x3e/0x40 [ 117.597173] [<c014c7b4>] printk_needs_cpu+0x24/0x30 [ 117.597181] [<c017ecc8>] tick_nohz_stop_sched_tick+0x2e8/0x410 [ 117.597191] [<c017305a>] ? sched_clock_idle_wakeup_event+0x1a/0x20 [ 117.597201] [<c010182a>] cpu_idle+0x4a/0xb0 [ 117.597209] [<c06e0b97>] start_secondary+0xd3/0xd7 Now this is a really rare case and it's very unlikely that we starve an logbuf waiter that way. Signed-off-by: Yong Zhang <yong.zhang0@gmail.com> Link: http://lkml.kernel.org/r/1318762607-2261-4-git-send-email-yong.zhang0@gmail.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-02-15timers: Avoid the switch timers base set to NULL trick on RTThomas Gleixner
On RT that code is preemptible, so we cannot assign NULL to timers base as a preempter would spin forever in lock_timer_base(). Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-02-15timer: delay waking softirqs from the jiffy tickPeter Zijlstra
People were complaining about broken balancing with the recent -rt series. A look at /proc/sched_debug yielded: cpu#0, 2393.874 MHz .nr_running : 0 .load : 0 .cpu_load[0] : 177522 .cpu_load[1] : 177522 .cpu_load[2] : 177522 .cpu_load[3] : 177522 .cpu_load[4] : 177522 cpu#1, 2393.874 MHz .nr_running : 4 .load : 4096 .cpu_load[0] : 181618 .cpu_load[1] : 180850 .cpu_load[2] : 180274 .cpu_load[3] : 179938 .cpu_load[4] : 179758 Which indicated the cpu_load computation was hosed, the 177522 value indicates that there is one RT task runnable. Initially I thought the old problem of calculating the cpu_load from a softirq had re-surfaced, however looking at the code shows its being done from scheduler_tick(). [ we really should fix this RT/cfs interaction some day... ] A few trace_printk()s later: sirq-timer/1-19 [001] 174.289744: 19: 50:S ==> [001] 0:140:R <idle> <idle>-0 [001] 174.290724: enqueue_task_rt: adding task: 19/sirq-timer/1 with load: 177522 <idle>-0 [001] 174.290725: 0:140:R + [001] 19: 50:S sirq-timer/1 <idle>-0 [001] 174.290730: scheduler_tick: current load: 177522 <idle>-0 [001] 174.290732: scheduler_tick: current: 0/swapper <idle>-0 [001] 174.290736: 0:140:R ==> [001] 19: 50:R sirq-timer/1 sirq-timer/1-19 [001] 174.290741: dequeue_task_rt: removing task: 19/sirq-timer/1 with load: 177522 sirq-timer/1-19 [001] 174.290743: 19: 50:S ==> [001] 0:140:R <idle> We see that we always raise the timer softirq before doing the load calculation. Avoid this by re-ordering the scheduler_tick() call in update_process_times() to occur before we deal with timers. This lowers the load back to sanity and restores regular load-balancing behaviour. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-02-15timers: mov printk_tick to soft interruptThomas Gleixner
Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-02-15timers: fix timer hotplug on -rtIngo Molnar
Here we are in the CPU_DEAD notifier, and we must not sleep nor enable interrupts. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-02-15timers: preempt-rt supportIngo Molnar
Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-02-15timers: prepare for full preemptionIngo Molnar
When softirqs can be preempted we need to make sure that cancelling the timer from the active thread can not deadlock vs. a running timer callback. Add a waitqueue to resolve that. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-02-15workqueue-avoid-the-lock-in-cpu-dying.patchThomas Gleixner
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-02-15net-ipv4-route-use-locks-on-up-rt.patchThomas Gleixner
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-02-15relay: fix timer madnessIngo Molnar
remove timer calls (!!!) from deep within the tracing infrastructure. This was totally bogus code that can cause lockups and worse. Poll the buffer every 2 jiffies for now. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-02-15ipc/mqueue: Add a critical section to avoid a deadlockKOBAYASHI Yoshitake
(Repost for v3.0-rt1 and changed the distination addreses) I have tested the following patch on v3.0-rt1 with PREEMPT_RT_FULL. In POSIX message queue, if a sender process uses SCHED_FIFO and has a higher priority than a receiver process, the sender will be stuck at ipc/mqueue.c:452 452 while (ewp->state == STATE_PENDING) 453 cpu_relax(); Description of the problem (receiver process) 1. receiver changes sender's state to STATE_PENDING (mqueue.c:846) 2. wake up sender process and "switch to sender" (mqueue.c:847) Note: This context switch only happens in PREEMPT_RT_FULL kernel. (sender process) 3. sender check the own state in above loop (mqueue.c:452-453) *. receiver will never wake up and cannot change sender's state to STATE_READY because sender has higher priority Signed-off-by: Yoshitake Kobayashi <yoshitake.kobayashi@toshiba.co.jp> Cc: viro@zeniv.linux.org.uk Cc: dchinner@redhat.com Cc: npiggin@kernel.dk Cc: hch@lst.de Cc: arnd@arndb.de Link: http://lkml.kernel.org/r/4E2A38A0.1090601@toshiba.co.jp Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-02-15ipc: Make the ipc code -rt awareIngo Molnar
RT serializes the code with the (rt)spinlock but keeps preemption enabled. Some parts of the code need to be atomic nevertheless. Protect it with preempt_disable/enable_rt pairts. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-02-15panic-disable-random-on-rtThomas Gleixner
2012-02-15radix-tree-rt-aware.patchThomas Gleixner
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-02-15mm: Allow only slab on RTIngo Molnar
Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-02-15ARM: Initialize ptl->lock for vector pageFrank Rowand
Without this patch, ARM can not use SPLIT_PTLOCK_CPUS if PREEMPT_RT_FULL=y because vectors_user_mapping() creates a VM_ALWAYSDUMP mapping of the vector page (address 0xffff0000), but no ptl->lock has been allocated for the page. An attempt to coredump that page will result in a kernel NULL pointer dereference when follow_page() attempts to lock the page. The call tree to the NULL pointer dereference is: do_notify_resume() get_signal_to_deliver() do_coredump() elf_core_dump() get_dump_page() __get_user_pages() follow_page() pte_offset_map_lock() <----- a #define ... rt_spin_lock() The underlying problem is exposed by mm-shrink-the-page-frame-to-rt-size.patch. Signed-off-by: Frank Rowand <frank.rowand@am.sony.com> Cc: Frank <Frank_Rowand@sonyusa.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/4E87C535.2030907@am.sony.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-02-15mm: shrink the page frame to !-rt sizePeter Zijlstra
He below is a boot-tested hack to shrink the page frame size back to normal. Should be a net win since there should be many less PTE-pages than page-frames. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-02-15mm: make vmstat -rt awareIngo Molnar
Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-02-15mm-vmstat-fix-the-irq-lock-asymetry.patchThomas Gleixner
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-02-15mm: convert swap to percpu lockedIngo Molnar
Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-02-15mm-page-alloc-fix.patchThomas Gleixner
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-02-15mm: page_alloc reduce lock sections furtherPeter Zijlstra
Split out the pages which are to be freed into a separate list and call free_pages_bulk() outside of the percpu page allocator locks. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-02-15mm: page_alloc: rt-friendly per-cpu pagesIngo Molnar
rt-friendly per-cpu pages: convert the irqs-off per-cpu locking method into a preemptible, explicit-per-cpu-locks method. Contains fixes from: Peter Zijlstra <a.p.zijlstra@chello.nl> Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-02-15mm: More lock breaks in slab.cPeter Zijlstra
Handle __free_pages outside of the locked regions. This reduces the lock contention on the percpu slab locks in -rt significantly. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-02-15slab: Fix __do_drain to use the right array cacheSteven Rostedt
The array cache in __do_drain() was using the cpu_cache_get() function which uses smp_processor_id() to get the proper array. On mainline, this is fine as __do_drain() is called by for_each_cpu() which runs __do_drain() on the CPU it is processing. In RT locks are used instead and __do_drain() is only called from a single CPU. This can cause the accounting to be off and trigger the following bug: slab error in kmem_cache_destroy(): cache `nfs_write_data': Can't free all objects Pid: 2905, comm: rmmod Not tainted 3.0.6-test-rt17+ #78 Call Trace: [<ffffffff810fb623>] kmem_cache_destroy+0xa0/0xdf [<ffffffffa03aaffb>] nfs_destroy_writepagecache+0x49/0x4e [nfs] [<ffffffffa03c0fe0>] exit_nfs_fs+0xe/0x46 [nfs] [<ffffffff8107af09>] sys_delete_module+0x1ba/0x22c [<ffffffff8109429d>] ? audit_syscall_entry+0x11c/0x148 [<ffffffff814b6442>] system_call_fastpath+0x16/0x1b This can be easily triggered by a simple while loop: # while :; do modprobe nfs; rmmod nfs; done The proper function to use is cpu_cache_get_on_cpu(). It works for both RT and non-RT as the non-RT passes in smp_processor_id() into __do_drain(). Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Cc: Luis Claudio R. Goncalves <lgoncalv@redhat.com> Cc: Clark Williams <clark@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1318391783.13262.11.camel@gandalf.stny.rr.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-02-15mm-slab-wrap-functions.patchThomas Gleixner
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-02-15cpu-rt-variants.patchThomas Gleixner
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-02-15rt-local-irq-lock.patchThomas Gleixner
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-02-15local-var.patchThomas Gleixner
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-02-15USB: Fix the mouse problem when copying large amounts of dataWu Zhangjin
When copying large amounts of data between the USB storage devices and the hard disk, the USB mouse will not work, this patch fixes it. [NOTE: This problem have been found in the Loongson family machines, not sure whether it is producible on other platforms] Signed-off-by: Hu Hongbing <huhb@lemote.com> Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com>
2012-02-15drivers: net: gianfar: Make RT awareThomas Gleixner
The adjust_link() disables interrupts before taking the queue locks. On RT those locks are converted to "sleeping" locks and therefor the local_irq_save/restore must be converted to local_irq_save/restore_nort. Reported-by: Xianghua Xiao <xiaoxianghua@gmail.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Xianghua Xiao <xiaoxianghua@gmail.com>
2012-02-15drivers/net: vortex fix locking issuesSteven Rostedt
Argh, cut and paste wasn't enough... Use this patch instead. It needs an irq disable. But, believe it or not, on SMP this is actually better. If the irq is shared (as it is in Mark's case), we don't stop the irq of other devices from being handled on another CPU (unfortunately for Mark, he pinned all interrupts to one CPU). Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> drivers/net/ethernet/3com/3c59x.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-02-15drivers/net: fix livelock issuesThomas Gleixner
Preempt-RT runs into a live lock issue with the NETDEV_TX_LOCKED micro optimization. The reason is that the softirq thread is rescheduling itself on that return value. Depending on priorities it starts to monoplize the CPU and livelock on UP systems. Remove it. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-02-15genirq-force-threading.patchThomas Gleixner
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-02-15genirq: disable irqpoll on -rtIngo Molnar
Creates long latencies for no value Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-02-15genirq: Disable random call on preempt-rtThomas Gleixner
The random call introduces high latencies and is almost unused. Disable it for -rt. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-02-15genirq: Disable DEBUG_SHIRQ for rtThomas Gleixner
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-02-15fs: jbd/jbd2: Make state lock and journal head lock rt safeThomas Gleixner
bit_spin_locks break under RT. Based on a previous patch from Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> -- include/linux/buffer_head.h | 10 ++++++++++ include/linux/jbd_common.h | 24 ++++++++++++++++++++++++ 2 files changed, 34 insertions(+)
2012-02-15buffer_head: Replace bh_uptodate_lock for -rtThomas Gleixner
Wrap the bit_spin_lock calls into a separate inline and add the RT replacements with a real spinlock. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-02-15mm: Replace cgroup_page bit spinlockThomas Gleixner
Bit spinlocks are not working on RT. Replace them. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-02-15net-wireless-warn-nort.patchThomas Gleixner
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-02-15signal-fix-up-rcu-wreckage.patchThomas Gleixner
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-02-15mm: scatterlist dont disable irqs on RTThomas Gleixner
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-02-15tty: Do not disable interrupts in put_ldisc on -rtThomas Gleixner
Fixes the following on PREEMPT_RT: BUG: sleeping function called from invalid context at kernel/rtmutex.c:684 in_atomic(): 0, irqs_disabled(): 1, pid: 9116, name: sshd Pid: 9116, comm: sshd Not tainted 2.6.31-rc6-rt2 #6 Call Trace: [<ffffffff81034a4f>] __might_sleep+0xec/0xee [<ffffffff812fbc6d>] rt_spin_lock+0x34/0x75 [ffffffff81064a83>] atomic_dec_and_spin_lock+0x36/0x54 [<ffffffff811df7c7>] put_ldisc+0x57/0xa6 [<ffffffff811dfb87>] tty_ldisc_hangup+0xe7/0x19f [<ffffffff811d9224>] do_tty_hangup+0xff/0x319 [<ffffffff811d9453>] tty_vhangup+0x15/0x17 [<ffffffff811e1263>] pty_close+0x127/0x12b [<ffffffff811dac41>] tty_release_dev+0x1ad/0x4c0 .... Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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