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2009-11-05sched: Fix affinity logic in select_task_rq_fair()Mike Galbraith
Ingo Molnar reported: [ 26.804000] BUG: using smp_processor_id() in preemptible [00000000] code: events/1/10 [ 26.808000] caller is vmstat_update+0x26/0x70 [ 26.812000] Pid: 10, comm: events/1 Not tainted 2.6.32-rc5 #6887 [ 26.816000] Call Trace: [ 26.820000] [<c1924a24>] ? printk+0x28/0x3c [ 26.824000] [<c13258a0>] debug_smp_processor_id+0xf0/0x110 [ 26.824000] mount used greatest stack depth: 1464 bytes left [ 26.828000] [<c111d086>] vmstat_update+0x26/0x70 [ 26.832000] [<c1086418>] worker_thread+0x188/0x310 [ 26.836000] [<c10863b7>] ? worker_thread+0x127/0x310 [ 26.840000] [<c108d310>] ? autoremove_wake_function+0x0/0x60 [ 26.844000] [<c1086290>] ? worker_thread+0x0/0x310 [ 26.848000] [<c108cf0c>] kthread+0x7c/0x90 [ 26.852000] [<c108ce90>] ? kthread+0x0/0x90 [ 26.856000] [<c100c0a7>] kernel_thread_helper+0x7/0x10 [ 26.860000] BUG: using smp_processor_id() in preemptible [00000000] code: events/1/10 [ 26.864000] caller is vmstat_update+0x3c/0x70 Because this commit: a1f84a3: sched: Check for an idle shared cache in select_task_rq_fair() broke ->cpus_allowed. Signed-off-by: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: arjan@infradead.org Cc: <stable@kernel.org> LKML-Reference: <1257415066.12867.1.camel@marge.simson.net> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-11-05nohz: Introduce arch_needs_cpuMartin Schwidefsky
Allow the architecture to request a normal jiffy tick when the system goes idle and tick_nohz_stop_sched_tick is called . On s390 the hook is used to prevent the system going fully idle if there has been an interrupt other than a clock comparator interrupt since the last wakeup. On s390 the HiperSockets response time for 1 connection ping-pong goes down from 42 to 34 microseconds. The CPU cost decreases by 27%. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> LKML-Reference: <20090929122533.402715150@de.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2009-11-05nohz: Reuse ktime in sub-functions of tick_check_idle.Martin Schwidefsky
On a system with NOHZ=y tick_check_idle calls tick_nohz_stop_idle and tick_nohz_update_jiffies. Given the right conditions (ts->idle_active and/or ts->tick_stopped) both function get a time stamp with ktime_get. The same time stamp can be reused if both function require one. On s390 this change has the additional benefit that gcc inlines the tick_nohz_stop_idle function into tick_check_idle. The number of instructions to execute tick_check_idle drops from 225 to 144 (without the ktime_get optimization it is 367 vs 215 instructions). before: 0) | tick_check_idle() { 0) | tick_nohz_stop_idle() { 0) | ktime_get() { 0) | read_tod_clock() { 0) 0.601 us | } 0) 1.765 us | } 0) 3.047 us | } 0) | ktime_get() { 0) | read_tod_clock() { 0) 0.570 us | } 0) 1.727 us | } 0) | tick_do_update_jiffies64() { 0) 0.609 us | } 0) 8.055 us | } after: 0) | tick_check_idle() { 0) | ktime_get() { 0) | read_tod_clock() { 0) 0.617 us | } 0) 1.773 us | } 0) | tick_do_update_jiffies64() { 0) 0.593 us | } 0) 4.477 us | } Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: john stultz <johnstul@us.ibm.com> LKML-Reference: <20090929122533.206589318@de.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2009-11-04resources: when allocate_resource() fails, leave resource untouchedBjorn Helgaas
When "allocate_resource(root, new, size, ...)" fails, we currently clobber "new". This is inconvenient for the caller, who might care about the original contents of the resource. For example, when pci_bus_alloc_resource() fails, the "can't allocate mem resource %pR" message from pci_assign_resources() currently contains junk for the resource start/end. This patch delays the "new" update until we're about to return success. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Yinghai Lu <yhlu.kernel@gmail.com> Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2009-11-04sched: Rate-limit newidleMike Galbraith
Rate limit newidle to migration_cost. It's a win for all stages of sysbench oltp tests. Signed-off-by: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-11-04sched: Check for an idle shared cache in select_task_rq_fair()Mike Galbraith
When waking affine, check for an idle shared cache, and if found, wake to that CPU/sibling instead of the waker's CPU. This improves pgsql+oltp ramp up by roughly 8%. Possibly more for other loads, depending on overlap. The trade-off is a roughly 1% peak downturn if tasks are truly synchronous. Signed-off-by: Mike Galbraith <efault@gmx.de> Cc: Arjan van de Ven <arjan@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: <stable@kernel.org> LKML-Reference: <1256654138.17752.7.camel@marge.simson.net> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-11-04irq: Remove unused debug_poll_all_shared_irqs()Thomas Gleixner
commit 74296a8ed added this function for debug purposes, but it was never used for anything. Remove it. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2009-11-04irq: Fix docbook commentsLiuweni
Fix docbook comments to match the actual function names (set_irq_msi, handle_percpu_irq). Signed-off-by: Liuwenyi <qingshenlwy@gmail.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2009-11-04cpumask: Partition_sched_domains takes array of cpumask_var_tRusty Russell
Currently partition_sched_domains() takes a 'struct cpumask *doms_new' which is a kmalloc'ed array of cpumask_t. You can't have such an array if 'struct cpumask' is undefined, as we plan for CONFIG_CPUMASK_OFFSTACK=y. So, we make this an array of cpumask_var_t instead: this is the same for the CONFIG_CPUMASK_OFFSTACK=n case, but requires multiple allocations for the CONFIG_CPUMASK_OFFSTACK=y case. Hence we add alloc_sched_domains() and free_sched_domains() functions. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Cc: Peter Zijlstra <peterz@infradead.org> LKML-Reference: <200911031453.40668.rusty@rustcorp.com.au> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-11-04cpumask: Simplify sched_rt.cRusty Russell
find_lowest_rq() wants to call pick_optimal_cpu() on the intersection of sched_domain_span(sd) and lowest_mask. Rather than doing a cpus_and into a temporary, we can open-code it. This actually makes the code slightly clearer, IMHO. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Acked-by: Gregory Haskins <ghaskins@novell.com> Cc: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <200911031453.15350.rusty@rustcorp.com.au> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-11-04tracing/kprobes: Rename Kprobe-tracer to kprobe-eventMasami Hiramatsu
Rename Kprobes-based event tracer to kprobes-based tracing event (kprobe-event), since it is not a tracer but an extensible tracing event interface. This also changes CONFIG_KPROBE_TRACER to CONFIG_KPROBE_EVENT and sets it y by default. Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com> Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Jim Keniston <jkenisto@us.ibm.com> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Frank Ch. Eigler <fche@redhat.com> Cc: Jason Baron <jbaron@redhat.com> Cc: K.Prasad <prasad@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> LKML-Reference: <20091104001247.3454.14131.stgit@harusame> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-11-04Merge commit 'v2.6.32-rc6' into perf/coreIngo Molnar
Conflicts: tools/perf/Makefile Merge reason: Resolve the conflict, merge to upstream and merge in perf fixes so we can add a dependent patch. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-11-04sched: Remove unused cpu_nr_migrations()Hiroshi Shimamoto
cpu_nr_migrations() is not used, remove it. Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <4AF12A66.6020609@ct.jp.nec.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-11-04sched: Remove unused __schedule() declarationHiroshi Shimamoto
__schedule() had been removed. Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <4AF129C8.3030008@ct.jp.nec.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-11-04ftrace: Fix unmatched locking in ftrace_regex_write()Li Zefan
When a command is passed to the set_ftrace_filter, then the ftrace_regex_lock is still held going back to user space. # echo 'do_open : foo' > set_ftrace_filter (still holding ftrace_regex_lock when returning to user space!) Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> LKML-Reference: <4AEF7F8A.3080300@cn.fujitsu.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-11-04ring-buffer: Synchronize resizing buffer with reader lockLai Jiangshan
We got a sudden panic when we reduced the size of the ringbuffer. We can reproduce the panic by the following steps: echo 1 > events/sched/enable cat trace_pipe > /dev/null & while ((1)) do echo 12000 > buffer_size_kb echo 512 > buffer_size_kb done (not more than 5 seconds, panic ...) Reported-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> LKML-Reference: <4AF01735.9060409@cn.fujitsu.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-11-03perf/core: Add a callback to perf eventsFrederic Weisbecker
A simple callback in a perf event can be used for multiple purposes. For example it is useful for triggered based events like hardware breakpoints that need a callback to dispatch a triggered breakpoint event. v2: Simplify a bit the callback attribution as suggested by Paul Mackerras Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: "K.Prasad" <prasad@linux.vnet.ibm.com> Cc: Alan Stern <stern@rowland.harvard.edu> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Paul Mackerras <paulus@samba.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul Mundt <lethal@linux-sh.org>
2009-11-03perf/core: Provide a kernel-internal interface to get to performance countersArjan van de Ven
There are reasons for kernel code to ask for, and use, performance counters. For example, in CPU freq governors this tends to be a good idea, but there are other examples possible as well of course. This patch adds the needed bits to do enable this functionality; they have been tested in an experimental cpufreq driver that I'm working on, and the changes are all that I needed to access counters properly. [fweisbec@gmail.com: added pid to perf_event_create_kernel_counter so that we can profile a particular task too TODO: Have a better error reporting, don't just return NULL in fail case.] v2: Remove the wrong comment about the fact perf_event_create_kernel_counter must be called from a kernel thread. Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: "K.Prasad" <prasad@linux.vnet.ibm.com> Cc: Alan Stern <stern@rowland.harvard.edu> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Jan Kiszka <jan.kiszka@siemens.com> Cc: Jiri Slaby <jirislaby@gmail.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Avi Kivity <avi@redhat.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Masami Hiramatsu <mhiramat@redhat.com> Cc: Paul Mundt <lethal@linux-sh.org> Cc: Jan Kiszka <jan.kiszka@web.de> Cc: Avi Kivity <avi@redhat.com> LKML-Reference: <20090925122556.2f8bd939@infradead.org> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-11-03Merge branch 'pm-fixes' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/rafael/suspend-2.6 * 'pm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/suspend-2.6: PM: Remove some debug messages producing too much noise PM: Fix warning on suspend errors PM / Hibernate: Add newline to load_image() fail path PM / Hibernate: Fix error handling in save_image() PM / Hibernate: Fix blkdev refleaks PM / yenta: Split resume into early and late parts (rev. 4)
2009-11-03Correct nr_processes() when CPUs have been unpluggedIan Campbell
nr_processes() returns the sum of the per cpu counter process_counts for all online CPUs. This counter is incremented for the current CPU on fork() and decremented for the current CPU on exit(). Since a process does not necessarily fork and exit on the same CPU the process_count for an individual CPU can be either positive or negative and effectively has no meaning in isolation. Therefore calculating the sum of process_counts over only the online CPUs omits the processes which were started or stopped on any CPU which has since been unplugged. Only the sum of process_counts across all possible CPUs has meaning. The only caller of nr_processes() is proc_root_getattr() which calculates the number of links to /proc as stat->nlink = proc_root.nlink + nr_processes(); You don't have to be all that unlucky for the nr_processes() to return a negative value leading to a negative number of links (or rather, an apparently enormous number of links). If this happens then you can get failures where things like "ls /proc" start to fail because they got an -EOVERFLOW from some stat() call. Example with some debugging inserted to show what goes on: # ps haux|wc -l nr_processes: CPU0: 90 nr_processes: CPU1: 1030 nr_processes: CPU2: -900 nr_processes: CPU3: -136 nr_processes: TOTAL: 84 proc_root_getattr. nlink 12 + nr_processes() 84 = 96 84 # echo 0 >/sys/devices/system/cpu/cpu1/online # ps haux|wc -l nr_processes: CPU0: 85 nr_processes: CPU2: -901 nr_processes: CPU3: -137 nr_processes: TOTAL: -953 proc_root_getattr. nlink 12 + nr_processes() -953 = -941 75 # stat /proc/ nr_processes: CPU0: 84 nr_processes: CPU2: -901 nr_processes: CPU3: -137 nr_processes: TOTAL: -954 proc_root_getattr. nlink 12 + nr_processes() -954 = -942 File: `/proc/' Size: 0 Blocks: 0 IO Block: 1024 directory Device: 3h/3d Inode: 1 Links: 4294966354 Access: (0555/dr-xr-xr-x) Uid: ( 0/ root) Gid: ( 0/ root) Access: 2009-11-03 09:06:55.000000000 +0000 Modify: 2009-11-03 09:06:55.000000000 +0000 Change: 2009-11-03 09:06:55.000000000 +0000 I'm not 100% convinced that the per_cpu regions remain valid for offline CPUs, although my testing suggests that they do. If not then I think the correct solution would be to aggregate the process_count for a given CPU into a global base value in cpu_down(). This bug appears to pre-date the transition to git and it looks like it may even have been present in linux-2.6.0-test7-bk3 since it looks like the code Rusty patched in http://lwn.net/Articles/64773/ was already wrong. Signed-off-by: Ian Campbell <ian.campbell@citrix.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-11-03PM / Hibernate: Add newline to load_image() fail pathJiri Slaby
Finish a line by \n when load_image fails in the middle of loading. Signed-off-by: Jiri Slaby <jirislaby@gmail.com> Acked-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2009-11-03PM / Hibernate: Fix error handling in save_image()Jiri Slaby
There are too many retval variables in save_image(). Thus error return value from snapshot_read_next() may be ignored and only part of the snapshot (successfully) written. Remove 'error' variable, invert the condition in the do-while loop and convert the loop to use only 'ret' variable. Switch the rest of the function to consider only 'ret'. Also make sure we end printed line by \n if an error occurs. Signed-off-by: Jiri Slaby <jirislaby@gmail.com> Acked-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2009-11-03PM / Hibernate: Fix blkdev refleaksJiri Slaby
While cruising through the swsusp code I found few blkdev reference leaks of resume_bdev. swsusp_read: remove blkdev_put altogether. Some fail paths do not do that. swsusp_check: make sure we always put a reference on fail paths software_resume: all fail paths between swsusp_check and swsusp_read omit swsusp_close. Add it in those cases. And since swsusp_read doesn't drop the reference anymore, do it here unconditionally. [rjw: Fixed a small coding style issue.] Signed-off-by: Jiri Slaby <jirislaby@gmail.com> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2009-11-03sched: Fix kthread_bind() by moving the body of kthread_bind() to sched.cMike Galbraith
Eric Paris reported that commit f685ceacab07d3f6c236f04803e2f2f0dbcc5afb causes boot time PREEMPT_DEBUG complaints. [ 4.590699] BUG: using smp_processor_id() in preemptible [00000000] code: rmmod/1314 [ 4.593043] caller is task_hot+0x86/0xd0 Since kthread_bind() messes with scheduler internals, move the body to sched.c, and lock the runqueue. Reported-by: Eric Paris <eparis@redhat.com> Signed-off-by: Mike Galbraith <efault@gmx.de> Tested-by: Eric Paris <eparis@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1256813310.7574.3.camel@marge.simson.net> [ v2: fix !SMP build and clean up ] Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-11-02Merge branch 'core-fixes-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: futex: Fix spurious wakeup for requeue_pi really
2009-11-02Merge branch 'perf-fixes-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: perf tools: Remove -Wcast-align perf tools: Fix compatibility with libelf 0.8 and autodetect perf events: Don't generate events for the idle task when exclude_idle is set perf events: Fix swevent hrtimer sampling by keeping track of remaining time when enabling/disabling swevent hrtimers
2009-11-02Merge branch 'tracing-fixes-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'tracing-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: tracing: Remove cpu arg from the rb_time_stamp() function tracing: Fix comment typo and documentation example tracing: Fix trace_seq_printf() return value tracing: Update *ppos instead of filp->f_pos
2009-11-02kprobes: Sanitize struct kretprobe_instance allocationsAnanth N Mavinakayanahalli
For as long as kretprobes have existed, we've allocated NR_CPUS instances of kretprobe_instance structures. With the default value of CONFIG_NR_CPUS increasing on certain architectures, we are potentially wasting kernel memory. See http://sourceware.org/bugzilla/show_bug.cgi?id=10839#c3 for more details. Use a saner num_possible_cpus() instead of NR_CPUS for allocation. Signed-off-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Acked-by: Masami Hiramatsu <mhiramat@redhat.com> Cc: Jim Keniston <jkenisto@us.ibm.com> Cc: fweisbec@gmail.com LKML-Reference: <20091030135310.GA22230@in.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-11-02rcu: Cleanup: balance rcu_irq_enter()/rcu_irq_exit() callsLai Jiangshan
Currently, rcu_irq_exit() is invoked only for CONFIG_NO_HZ, while rcu_irq_enter() is invoked unconditionally. This patch moves rcu_irq_exit() out from under CONFIG_NO_HZ so that the calls are balanced. This patch has no effect on the behavior of the kernel because both rcu_irq_enter() and rcu_irq_exit() are empty for !CONFIG_NO_HZ, but the code is easier to understand if the calls are obviously balanced in all cases. Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <12567428891605-git-send-email-> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-11-02rcu: Fix long-grace-period race between forcing and initializationPaul E. McKenney
Very long RCU read-side critical sections (50 milliseconds or so) can cause a race between force_quiescent_state() and rcu_start_gp() as follows on kernel builds with multi-level rcu_node hierarchies: 1. CPU 0 calls force_quiescent_state(), sees that there is a grace period in progress, and acquires ->fsqlock. 2. CPU 1 detects the end of the grace period, and so cpu_quiet_msk_finish() sets rsp->completed to rsp->gpnum. This operation is carried out under the root rnp->lock, but CPU 0 has not yet acquired that lock. Note that rsp->signaled is still RCU_SAVE_DYNTICK from the last grace period. 3. CPU 1 calls rcu_start_gp(), but no one wants a new grace period, so it drops the root rnp->lock and returns. 4. CPU 0 acquires the root rnp->lock and picks up rsp->completed and rsp->signaled, then drops rnp->lock. It then enters the RCU_SAVE_DYNTICK leg of the switch statement. 5. CPU 2 invokes call_rcu(), and now needs a new grace period. It calls rcu_start_gp(), which acquires the root rnp->lock, sets rsp->signaled to RCU_GP_INIT (too bad that CPU 0 is already in the RCU_SAVE_DYNTICK leg of the switch statement!) and starts initializing the rcu_node hierarchy. If there are multiple levels to the hierarchy, it will drop the root rnp->lock and initialize the lower levels of the hierarchy. 6. CPU 0 notes that rsp->completed has not changed, which permits both CPU 2 and CPU 0 to try updating it concurrently. If CPU 0's update prevails, later calls to force_quiescent_state() can count old quiescent states against the new grace period, which can in turn result in premature ending of grace periods. Not good. This patch adds an RCU_GP_IDLE state for rsp->signaled that is set initially at boot time and any time a grace period ends. This prevents CPU 0 from getting into the workings of force_quiescent_state() in step 4. Additional locking and checks prevent the concurrent update of rsp->signaled in step 6. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <1256742889199-git-send-email-> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-11-02uids: Prevent tear down raceThomas Gleixner
Ingo triggered the following warning: WARNING: at lib/debugobjects.c:255 debug_print_object+0x42/0x50() Hardware name: System Product Name ODEBUG: init active object type: timer_list Modules linked in: Pid: 2619, comm: dmesg Tainted: G W 2.6.32-rc5-tip+ #5298 Call Trace: [<81035443>] warn_slowpath_common+0x6a/0x81 [<8120e483>] ? debug_print_object+0x42/0x50 [<81035498>] warn_slowpath_fmt+0x29/0x2c [<8120e483>] debug_print_object+0x42/0x50 [<8120ec2a>] __debug_object_init+0x279/0x2d7 [<8120ecb3>] debug_object_init+0x13/0x18 [<810409d2>] init_timer_key+0x17/0x6f [<81041526>] free_uid+0x50/0x6c [<8104ed2d>] put_cred_rcu+0x61/0x72 [<81067fac>] rcu_do_batch+0x70/0x121 debugobjects warns about an enqueued timer being initialized. If CONFIG_USER_SCHED=y the user management code uses delayed work to remove the user from the hash table and tear down the sysfs objects. free_uid is called from RCU and initializes/schedules delayed work if the usage count of the user_struct is 0. The init/schedule happens outside of the uidhash_lock protected region which allows a concurrent caller of find_user() to reference the about to be destroyed user_struct w/o preventing the work from being scheduled. If the next free_uid call happens before the work timer expired then the active timer is initialized and the work scheduled again. The race was introduced in commit 5cb350ba (sched: group scheduling, sysfs tunables) and made more prominent by commit 3959214f (sched: delayed cleanup of user_struct) Move the init/schedule_delayed_work inside of the uidhash_lock protected region to prevent the race. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Dhaval Giani <dhaval@linux.vnet.ibm.com> Cc: Paul E. McKenney <paulmck@us.ibm.com> Cc: Kay Sievers <kay.sievers@vrfy.org> Cc: stable@kernel.org
2009-11-02sched: Fix boot crash by zalloc()ing most of the cpu masksRusty Russell
I got a boot crash when forcing cpumasks offstack on 32 bit, because find_new_ilb() returned 3 on my UP system (nohz.cpu_mask wasn't zeroed). AFAICT the others need to be zeroed too: only nohz.ilb_grp_nohz_mask is initialized before use. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Cc: Peter Zijlstra <peterz@infradead.org> LKML-Reference: <200911022037.21282.rusty@rustcorp.com.au> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-11-02tracing: Fix to use __always_unused attributeLi Zefan
____ftrace_check_##name() is used for compile-time check on F_printk() only, so it should be marked as __unused instead of __used. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> LKML-Reference: <4AEE2D01.4010305@cn.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-11-02x86: Fix user return notifier put_cpu_var() invocationStephen Rothwell
Today's linux-next build (x86_64 allmodconfig) failed like this: kernel/user-return-notifier.c: In function 'fire_user_return_notifiers': kernel/user-return-notifier.c:45: error: expected expression before ')' token Introduced by commit 7c68af6e32c73992bad24107311f3433c89016e2 ("core, x86: Add user return notifiers") from the tip and kvm trees but revealed by commit e0fdb0e050eae331046385643618f12452aa7e73 ("percpu: add __percpu for sparse") from the percpu tree. Before that percpu tree commit, "put_cpu_var()" would compile without error (even though it really needs a parameter). Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Avi Kivity <avi@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Tejun Heo <tj@kernel.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Christoph Lameter <cl@linux-foundation.org> LKML-Reference: <20091102161722.eea4358d.sfr@canb.auug.org.au> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-10-29Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu: sched: move rq_weight data array out of .percpu percpu: allow pcpu_alloc() to be called with IRQs off
2009-10-29Merge git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-param-fixesLinus Torvalds
* git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-param-fixes: param: fix setting arrays of bool param: fix NULL comparison on oom param: fix lots of bugs with writing charp params from sysfs, by leaking mem.
2009-10-29Merge branch 'hwpoison-2.6.32' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-mce-2.6 * 'hwpoison-2.6.32' of git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-mce-2.6: HWPOISON: fix invalid page count in printk output HWPOISON: Allow schedule_on_each_cpu() from keventd HWPOISON: fix/proc/meminfo alignment HWPOISON: fix oops on ksm pages HWPOISON: Fix page count leak in hwpoison late kill in do_swap_page HWPOISON: return early on non-LRU pages HWPOISON: Add brief hwpoison description to Documentation HWPOISON: Clean up PR_MCE_KILL interface
2009-10-29Merge branch 'core-fixes-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: futex: Move drop_futex_key_refs out of spinlock'ed region rcu: Fix TREE_PREEMPT_RCU CPU_HOTPLUG bad-luck hang rcu: Stopgap fix for synchronize_rcu_expedited() for TREE_PREEMPT_RCU rcu: Prevent RCU IPI storms in presence of high call_rcu() load futex: Check for NULL keys in match_futex futex: Handle spurious wake up
2009-10-29Merge branch 'perf-fixes-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: perf timechart: Improve the visual appearance of scheduler delays perf timechart: Fix the wakeup-arrows that point to non-visible processes perf top: Fix --delay_secs 0 division by zero perf tools: Bump version to 0.0.2 perf_event: Adjust frequency and unthrottle for non-group-leader events
2009-10-29Merge 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: Do less agressive buddy clearing sched: Disable SD_PREFER_LOCAL for MC/CPU domains
2009-10-29sysctl: fix false positives when PROC_SYSCTL=nAlexey Dobriyan
Having ->procname but not ->proc_handler is valid when PROC_SYSCTL=n, people use such combination to reduce ifdefs with non-standard handlers. Addresses http://bugzilla.kernel.org/show_bug.cgi?id=14408 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Reported-by: Peter Teoh <htmldeveloper@gmail.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-10-29cgroup: fix strstrip() misuseKOSAKI Motohiro
cgroup_write_X64() and cgroup_write_string() ignore the return value of strstrip(). it makes small inconsistent behavior. example: ========================= # cd /mnt/cgroup/hoge # cat memory.swappiness 60 # echo "59 " > memory.swappiness # cat memory.swappiness 59 # echo " 58" > memory.swappiness bash: echo: write error: Invalid argument This patch fixes it. Cc: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Paul Menage <menage@google.com> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-10-29connector: fix regression introduced by sid connectorChristian Borntraeger
Since commit 02b51df1b07b4e9ca823c89284e704cadb323cd1 (proc connector: add event for process becoming session leader) we have the following warning: Badness at kernel/softirq.c:143 [...] Krnl PSW : 0404c00180000000 00000000001481d4 (local_bh_enable+0xb0/0xe0) [...] Call Trace: ([<000000013fe04100>] 0x13fe04100) [<000000000048a946>] sk_filter+0x9a/0xd0 [<000000000049d938>] netlink_broadcast+0x2c0/0x53c [<00000000003ba9ae>] cn_netlink_send+0x272/0x2b0 [<00000000003baef0>] proc_sid_connector+0xc4/0xd4 [<0000000000142604>] __set_special_pids+0x58/0x90 [<0000000000159938>] sys_setsid+0xb4/0xd8 [<00000000001187fe>] sysc_noemu+0x10/0x16 [<00000041616cb266>] 0x41616cb266 The warning is ---> WARN_ON_ONCE(in_irq() || irqs_disabled()); The network code must not be called with disabled interrupts but sys_setsid holds the tasklist_lock with spinlock_irq while calling the connector. After a discussion we agreed that we can move proc_sid_connector from __set_special_pids to sys_setsid. We also agreed that it is sufficient to change the check from task_session(curr) != pid into err > 0, since if we don't change the session, this means we were already the leader and return -EPERM. One last thing: There is also daemonize(), and some people might want to get a notification in that case. Since daemonize() is only needed if a user space does kernel_thread this does not look important (and there seems to be no consensus if this connector should be called in daemonize). If we really want this, we can add proc_sid_connector to daemonize() in an additional patch (Scott?) Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Scott James Remnant <scott@ubuntu.com> Cc: Matt Helsley <matthltc@us.ibm.com> Cc: David S. Miller <davem@davemloft.net> Acked-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Evgeniy Polyakov <zbr@ioremap.net> Acked-by: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-10-29percpu: make percpu symbols in tracer uniqueTejun Heo
This patch updates percpu related symbols in kernel tracer such that percpu symbols are unique and don't clash with local symbols. This serves two purposes of decreasing the possibility of global percpu symbol collision and allowing dropping per_cpu__ prefix from percpu symbols. * kernel/trace/trace.c: s/max_data/max_tr_data/ * kernel/trace/trace_hw_branches: s/tracer/hwb_tracer/, s/buffer/hwb_buffer/ Partly based on Rusty Russell's "alloc_percpu: rename percpu vars which cause name clashes" patch. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@redhat.com>
2009-10-29percpu: make percpu symbols under kernel/ and mm/ uniqueTejun Heo
This patch updates percpu related symbols under kernel/ and mm/ such that percpu symbols are unique and don't clash with local symbols. This serves two purposes of decreasing the possibility of global percpu symbol collision and allowing dropping per_cpu__ prefix from percpu symbols. * kernel/lockdep.c: s/lock_stats/cpu_lock_stats/ * kernel/sched.c: s/init_rq_rt/init_rt_rq_var/ (any better idea?) s/sched_group_cpus/sched_groups/ * kernel/softirq.c: s/ksoftirqd/run_ksoftirqd/a * kernel/softlockup.c: s/(*)_timestamp/softlockup_\1_ts/ s/watchdog_task/softlockup_watchdog/ s/timestamp/ts/ for local variables * kernel/time/timer_stats: s/lookup_lock/tstats_lookup_lock/ * mm/slab.c: s/reap_work/slab_reap_work/ s/reap_node/slab_reap_node/ * mm/vmstat.c: local variable changed to avoid collision with vmstat_work Partly based on Rusty Russell's "alloc_percpu: rename percpu vars which cause name clashes" patch. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: (slab/vmstat) Christoph Lameter <cl@linux-foundation.org> Reviewed-by: Christoph Lameter <cl@linux-foundation.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Ingo Molnar <mingo@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Nick Piggin <npiggin@suse.de>
2009-10-29Merge branch 'tracing/urgent' into tracing/coreIngo Molnar
Merge reason: Pick up fixes and move base from -rc1 to -rc5. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-10-29tracing/filters: Fix to make system filter workLi Zefan
commit fce29d15b59245597f7f320db4a9f2be0f5fb512 ("tracing/filters: Refactor subsystem filter code") broke system filter accidentally. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Tom Zanussi <tzanussi@gmail.com> LKML-Reference: <4AE810BD.3070009@cn.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-10-29kprobe-tracer: Compare both of event-name and event-group to find probeMasami Hiramatsu
Fix find_probe_event() to compare both of event-name and event-group. Without this fix, kprobe-tracer overwrites existing same event-name probe even if its group-name is different. Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Jim Keniston <jkenisto@us.ibm.com> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Frank Ch. Eigler <fche@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jason Baron <jbaron@redhat.com> Cc: K.Prasad <prasad@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> LKML-Reference: <20091027204244.30545.27516.stgit@harusame> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-10-29param: fix setting arrays of boolRusty Russell
We create a dummy struct kernel_param on the stack for parsing each array element, but we didn't initialize the flags word. This matters for arrays of type "bool", where the flag indicates if it really is an array of bools or unsigned int (old-style). Reported-by: Takashi Iwai <tiwai@suse.de> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Cc: stable@kernel.org
2009-10-29param: fix NULL comparison on oomRusty Russell
kp->arg is always true: it's the contents of that pointer we care about. Reported-by: Takashi Iwai <tiwai@suse.de> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Cc: stable@kernel.org