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2013-02-04sched: Fix select_idle_sibling() bouncing cow syndromeMike Galbraith1-14/+7
If the previous CPU is cache affine and idle, select it. The current implementation simply traverses the sd_llc domain, taking the first idle CPU encountered, which walks buddy pairs hand in hand over the package, inflicting excruciating pain. 1 tbench pair (worst case) in a 10 core + SMT package: pre 15.22 MB/sec 1 procs post 252.01 MB/sec 1 procs Signed-off-by: Mike Galbraith <bitbucket@online.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1359371965.5783.127.camel@marge.simpson.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-02-04Merge branch 'rcu/next' of ↵Ingo Molnar10-117/+431
git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu Pull RCU updates from Paul E. McKenney: 1. Changes to rcutorture and to RCU documentation. Posted to LKML at https://lkml.org/lkml/2013/1/26/188. 2. Enhancements to uniprocessor handling in tiny RCU. Posted to LKML at https://lkml.org/lkml/2013/1/27/2. 3. Tag RCU callbacks with grace-period number to simplify callback advancement. Posted to LKML at https://lkml.org/lkml/2013/1/26/203. 4. Miscellaneous fixes. Posted to LKML at https://lkml.org/lkml/2013/1/26/204. Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-02-04irq_work: Remove return value from the irq_work_queue() functionanish kumar1-21/+10
As no one is using the return value of irq_work_queue(), so it is better to just make it void. Signed-off-by: anish kumar <anish198519851985@gmail.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> [ Fix stale comments, remove now unnecessary __irq_work_queue() intermediate function ] Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Link: http://lkml.kernel.org/r/1359925703-24304-1-git-send-email-fweisbec@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-02-04Merge branch 'fortglx/3.9/time' of git://git.linaro.org/people/jstultz/linux ↵Thomas Gleixner4-15/+53
into timers/core Trivial conflict in arch/x86/Kconfig Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2013-02-04switch mips to generic rt_sigsuspend(), make it unconditionalAl Viro1-2/+0
mips was the last architecture not using the generic variant. Both native and compat variants switched to generic, which is made unconditional now. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-02-04new helper: signal_setup_done()Al Viro1-0/+9
usual "call force_sigsegv or signal_delivered" logics. Takes ksignal instead of separate siginfo/k_sigaction. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-02-04convert futex compat syscalls to COMPAT_SYSCALL_DEFINEAl Viro1-9/+10
ppc is stepping into a nasal daemon territory a bit... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-02-04generic sys_sigaction() and compat_sys_sigaction()Al Viro1-0/+78
conditional on OLD_SIGACTION/COMPAT_OLD_SIGACTION Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-02-04generic sys_compat_rt_sigaction()Al Viro1-0/+49
Again, protected by a temporary config symbol (GENERIC_COMPAT_RT_SIGACTION); will be gone by the end of series. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-02-04switch compat_sys_sched_rr_get_interval to COMPAT_SYSCALL_DEFINEAl Viro1-4/+3
... and make it unconditional - we want the sucker on all biarch platforms, really. All kinds of wrappers and private implementations can go now; fortunately, they don't cause name conflicts, so we can do that one first without any bisect hazards. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-02-04switch rt_tgsigqueueinfo to COMPAT_SYSCALL_DEFINEAl Viro2-12/+16
C ABI violations on sparc, ppc and mips Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-02-04switch compat_sys_sigprocmask to COMPAT_SYSCALL_DEFINEAl Viro1-3/+3
In principle, C ABI violation on ppc and mips... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-02-04switch compat_sys_rt_sigtimedwait to COMPAT_SYSCALL_DEFINEAl Viro1-5/+3
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-02-04old sigsuspend variants in kernel/signal.cAl Viro1-0/+17
conditional on OLD_SIGSUSPEND/OLD_SIGSUSPEND3, depending on which variety of that fossil is needed. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-02-04generic compat_sys_rt_sigqueueinfo()Al Viro1-13/+32
conditional on GENERIC_COMPAT_RT_SIGQUEUEINFO; by the end of that series it will become the same thing as COMPAT and conditional will die out. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-02-04generic compat_sys_rt_sigpending()Al Viro1-17/+35
conditional on GENERIC_COMPAT_RT_SIGPENDING; by the end of that series it will become the same thing as COMPAT and conditional will die out. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-02-04generic compat_sys_rt_sigprocmask()Al Viro2-1/+53
conditional on GENERIC_COMPAT_RT_SIGPROCMASK; by the end of that series it will become the same thing as COMPAT and conditional will die out. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-02-04consolidate rt_sigsuspend()Al Viro2-18/+23
* pull compat version alongside with the native one * make little-endian compat variant just call the native * don't bother with separate conditional for compat (both native and compat are going to become unconditional very soon). Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-02-04sanitize rt_sigaction() situation a bitAl Viro1-2/+2
Switch from __ARCH_WANT_SYS_RT_SIGACTION to opposite (!CONFIG_ODD_RT_SIGACTION); the only two architectures that need it are alpha and sparc. The reason for use of CONFIG_... instead of __ARCH_... is that it's needed only kernel-side and doing it that way avoids a mess with include order on many architectures. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-02-04switch compat_sys_[gs]etitimer(2) to COMPAT_SYSCALL_DEFINEAl Viro1-5/+5
again, strictly speaking we are in nasal daemon territory on ppc and mips - we need to sign-extend int arguments. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-02-03sched/rt: Further simplify pick_rt_task()Kirill Tkhai1-2/+1
Function next_prio() has been removed and pull_rt_task() is the only user of pick_next_highest_task_rt() at the moment. pull_rt_task is not interested in p->nr_cpus_allowed, its only interest is the fact that cpu is allowed to execute p. If nr_cpus_allowed == 1, cpu != task_cpu(p) and cpu is allowed then it means that task p is in the middle of the migration techniques; the task waits until it is moved by migration thread. So, lets pull it earlier. Signed-off-by: Kirill V Tkhai <tkhai@yandex.ru> Acked-by: Steven Rostedt <rostedt@goodmis.org> Cc: Peter Zijlstra <peterz@infradead.org> CC: linux-rt-users <linux-rt-users@vger.kernel.org> Link: http://lkml.kernel.org/r/70871359644177@web16d.yandex.ru Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-02-03perf: Fix event group context moveJiri Olsa1-2/+18
When we have group with mixed events (hw/sw) we want to end up with group leader being in hw context. So if group leader is initialy sw event, we move all the events under hw context. The move is done for each event by removing it from its context and adding it back into proper one. As a part of the removal the event is automatically disabled, which is not what we want at this stage of creating groups. The fix is to initialize event state after removal from sw context. This fix resulted from the following discussion: http://thread.gmane.org/gmane.linux.kernel.perf.user/1144 Reported-by: Andreas Hollmann <hollmann@in.tum.de> Signed-off-by: Jiri Olsa <jolsa@redhat.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Stephane Eranian <eranian@google.com> Cc: Vince Weaver <vince@deater.net> Link: http://lkml.kernel.org/r/1359714225-4231-1-git-send-email-jolsa@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-02-03Merge branch 'tip/perf/core' of ↵Ingo Molnar6-61/+200
git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace into perf/core Pull tracing updated from Steve Rostedt. Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-02-02tracing: Init current_trace to nop_trace and remove NULL checksSteven Rostedt (Red Hat)1-18/+12
On early boot up, when the ftrace ring buffer is initialized, the static variable current_trace is initialized to &nop_trace. Before this initialization, current_trace is NULL and will never become NULL again. It is always reassigned to a ftrace tracer. Several places check if current_trace is NULL before it uses it, and this check is frivolous, because at the point in time when the checks are made the only way current_trace could be NULL is if ftrace failed its allocations at boot up, and the paths to these locations would probably not be possible. By initializing current_trace to &nop_trace where it is declared, current_trace will never be NULL, and we can remove all these checks of current_trace being NULL which never needed to be checked in the first place. Cc: Dan Carpenter <dan.carpenter@oracle.com> Cc: Hiraku Toyooka <hiraku.toyooka.gu@hitachi.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-02-01clockevents: Add generic timer broadcast functionMark Rutland2-0/+17
Currently, the timer broadcast mechanism is defined by a function pointer on struct clock_event_device. As the fundamental mechanism for broadcast is architecture-specific, this means that clock_event_device drivers cannot be shared across multiple architectures. This patch adds an (optional) architecture-specific function for timer tick broadcast, allowing drivers which may require broadcast functionality to be shared across multiple architectures. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Reviewed-by: Santosh Shilimkar <santosh.shilimkar@ti.com> Cc: linux-arm-kernel@lists.infradead.org Cc: nico@linaro.org Cc: Will.Deacon@arm.com Cc: Marc.Zyngier@arm.com Cc: john.stultz@linaro.org Link: http://lkml.kernel.org/r/1358183124-28461-3-git-send-email-mark.rutland@arm.com Tested-by: Santosh Shilimkar <santosh.shilimkar@ti.com> Reviewed-by: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2013-02-01clockevents: Add generic timer broadcast receiverMark Rutland1-0/+17
Currently the broadcast mechanism used for timers is abstracted by a function pointer on struct clock_event_device. As the fundamental mechanism for broadcast is architecture-specific, this ties each clock_event_device driver to a single architecture, even where the driver is otherwise generic. This patch adds a standard path for the receipt of timer broadcasts, so drivers and/or architecture backends need not manage redundant lists of timers for the purpose of routing broadcast timer ticks. [tglx: Made the implementation depend on the config switch as well ] Signed-off-by: Mark Rutland <mark.rutland@arm.com> Reviewed-by: Santosh Shilimkar <santosh.shilimkar@ti.com> Cc: linux-arm-kernel@lists.infradead.org Cc: nico@linaro.org Cc: Will.Deacon@arm.com Cc: Marc.Zyngier@arm.com Cc: john.stultz@linaro.org Link: http://lkml.kernel.org/r/1358183124-28461-2-git-send-email-mark.rutland@arm.com Tested-by: Santosh Shilimkar <santosh.shilimkar@ti.com> Reviewed-by: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2013-01-31sched/rt: Do not account zero delta_exec in update_curr_rt()Kirill Tkhai1-2/+2
There are several places of consecutive calls of dequeue_task_rt() and put_prev_task_rt() in the scheduler. For example, function rt_mutex_setprio() does it. The both calls lead to update_curr_rt(), the second of it receives zeroed delta_exec. The only effective action in this case is call of sched_rt_avg_update(), which can change rq->age_stamp and rq->rt_avg. But it is possible in case of ""floating"" rq->clock. This fact is not reasonable to be accounted. Another actions do nothing. Signed-off-by: Kirill V Tkhai <tkhai@yandex.ru> Acked-by: Steven Rostedt <rostedt@goodmis.org> Cc: Peter Zijlstra <peterz@infradead.org> CC: linux-rt-users <linux-rt-users@vger.kernel.org> Link: http://lkml.kernel.org/r/931541359550236@web1g.yandex.ru Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-01-31Merge branch 'x86-urgent-for-linus' of ↵Linus Torvalds1-1/+12
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 fixes from Peter Anvin: "This is a collection of miscellaneous fixes, the most important one is the fix for the Samsung laptop bricking issue (auto-blacklisting the samsung-laptop driver); the efi_enabled() changes you see below are prerequisites for that fix. The other issues fixed are booting on OLPC XO-1.5, an UV fix, NMI debugging, and requiring CAP_SYS_RAWIO for MSR references, just as with I/O port references." * 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: samsung-laptop: Disable on EFI hardware efi: Make 'efi_enabled' a function to query EFI facilities smp: Fix SMP function call empty cpu mask race x86/msr: Add capabilities check x86/dma-debug: Bump PREALLOC_DMA_DEBUG_ENTRIES x86/olpc: Fix olpc-xo1-sci.c build errors arch/x86/platform/uv: Fix incorrect tlb flush all issue x86-64: Fix unwind annotations in recent NMI changes x86-32: Start out cr0 clean, disable paging before modifying cr3/4
2013-01-31Revert "console: implement lockdep support for console_lock"Dave Airlie1-9/+0
This reverts commit daee779718a319ff9f83e1ba3339334ac650bb22. I'll requeue this after the console locking fixes, so lockdep is useful again for people until fbcon is fixed. Signed-off-by: Dave Airlie <airlied@redhat.com>
2013-01-30tracing: Make a snapshot feature available from userspaceHiraku Toyooka3-26/+151
Ftrace has a snapshot feature available from kernel space and latency tracers (e.g. irqsoff) are using it. This patch enables user applictions to take a snapshot via debugfs. Add "snapshot" debugfs file in "tracing" directory. snapshot: This is used to take a snapshot and to read the output of the snapshot. # echo 1 > snapshot This will allocate the spare buffer for snapshot (if it is not allocated), and take a snapshot. # cat snapshot This will show contents of the snapshot. # echo 0 > snapshot This will free the snapshot if it is allocated. Any other positive values will clear the snapshot contents if the snapshot is allocated, or return EINVAL if it is not allocated. Link: http://lkml.kernel.org/r/20121226025300.3252.86850.stgit@liselsia Cc: Jiri Olsa <jolsa@redhat.com> Cc: David Sharp <dhsharp@google.com> Signed-off-by: Hiraku Toyooka <hiraku.toyooka.gu@hitachi.com> [ Fixed irqsoff selftest and also a conflict with a change that fixes the update_max_tr. ] Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-01-30tracing: Replace static old_tracer check of tracer nameHiraku Toyooka1-13/+9
Currently the trace buffer read functions use a static variable "old_tracer" for detecting if the current tracer changes. This was suitable for a single trace file ("trace"), but to add a snapshot feature that will use the same function for its file, a check against a static variable is not sufficient. To use the output functions for two different files, instead of storing the current tracer in a static variable, as the trace iterator descriptor contains a pointer to the original current tracer's name, that pointer can now be used to check if the current tracer has changed between different reads of the trace file. Link: http://lkml.kernel.org/r/20121226025252.3252.9276.stgit@liselsia Signed-off-by: Hiraku Toyooka <hiraku.toyooka.gu@hitachi.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-01-30tracing: Use sched_clock_cpu for trace_clock_globalNamhyung Kim1-1/+1
For systems with an unstable sched_clock, all cpu_clock() does is enable/ disable local irq during the call to sched_clock_cpu(). And for stable systems they are same. trace_clock_global() already disables interrupts, so it can call sched_clock_cpu() directly. Link: http://lkml.kernel.org/r/1356576585-28782-2-git-send-email-namhyung@kernel.org Signed-off-by: Namhyung Kim <namhyung@kernel.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-01-30ring-buffer: Add stats field for amount read from trace ring bufferSteven Rostedt (Red Hat)2-0/+21
Add a stat about the number of events read from the ring buffer: # cat /debug/tracing/per_cpu/cpu0/stats entries: 39869 overrun: 870512 commit overrun: 0 bytes: 1449912 oldest event ts: 6561.368690 now ts: 6565.246426 dropped events: 0 read events: 112 <-- Added Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-01-30x86: Add Crash kernel low reservationYinghai Lu1-5/+29
During kdump kernel's booting stage, it need to find low ram for swiotlb buffer when system does not support intel iommu/dmar remapping. kexed-tools is appending memmap=exactmap and range from /proc/iomem with "Crash kernel", and that range is above 4G for 64bit after boot protocol 2.12. We need to add another range in /proc/iomem like "Crash kernel low", so kexec-tools could find that info and append to kdump kernel command line. Try to reserve some under 4G if the normal "Crash kernel" is above 4G. User could specify the size with crashkernel_low=XX[KMG]. -v2: fix warning that is found by Fengguang's test robot. -v3: move out get_mem_size change to another patch, to solve compiling warning that is found by Borislav Petkov <bp@alien8.de> -v4: user must specify crashkernel_low if system does not support intel or amd iommu. Signed-off-by: Yinghai Lu <yinghai@kernel.org> Link: http://lkml.kernel.org/r/1359058816-7615-31-git-send-email-yinghai@kernel.org Cc: Eric Biederman <ebiederm@xmission.com> Cc: Rob Landley <rob@landley.net> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2013-01-30timekeeping: Switch HAS_PERSISTENT_CLOCK to ALWAYS_USE_PERSISTENT_CLOCKJohn Stultz1-1/+1
Jason pointed out the HAS_PERSISTENT_CLOCK name isn't quite accurate for the config, as some systems may have the persistent_clock in some cases, but not always. So change the config name to the more clear ALWAYS_USE_PERSISTENT_CLOCK. Signed-off-by: John Stultz <john.stultz@linaro.org>
2013-01-30tracing/fgraph: Adjust fgraph depth before calling trace return callbackSteven Rostedt (Red Hat)1-1/+7
While debugging the virtual cputime with the function graph tracer with a max_depth of 1 (most common use of the max_depth so far), I found that I was missing kernel execution because of a race condition. The code for the return side of the function has a slight race: ftrace_pop_return_trace(&trace, &ret, frame_pointer); trace.rettime = trace_clock_local(); ftrace_graph_return(&trace); barrier(); current->curr_ret_stack--; The ftrace_pop_return_trace() initializes the trace structure for the callback. The ftrace_graph_return() uses the trace structure for its own use as that structure is on the stack and is local to this function. Then the curr_ret_stack is decremented which is what the trace.depth is set to. If an interrupt comes in after the ftrace_graph_return() but before the curr_ret_stack, then the called function will get a depth of 2. If max_depth is set to 1 this function will be ignored. The problem is that the trace has already been called, and the timestamp for that trace will not reflect the time the function was about to re-enter userspace. Calls to the interrupt will not be traced because the max_depth has prevented this. To solve this issue, the ftrace_graph_return() can safely be moved after the current->curr_ret_stack has been updated. This way the timestamp for the return callback will reflect the actual time. If an interrupt comes in after the curr_ret_stack update and ftrace_graph_return(), it will be traced. It may look a little confusing to see it within the other function, but at least it will not be lost. Cc: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-01-30Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller10-98/+262
Bring in the 'net' tree so that we can get some ipv4/ipv6 bug fixes that some net-next work will build upon. Signed-off-by: David S. Miller <davem@davemloft.net>
2013-01-29tracing: Remove second iterator initializerJovi Zhang1-4/+1
The trace iterator is already initialized by trace_init_global_iter(), so there is no need to initialize it again. Link: http://lkml.kernel.org/r/CACV3sb+G1YnO6168JhY3dEadmJi58pA5-2cSZT8E0WVHJNFt9Q@mail.gmail.com Signed-off-by: Jovi Zhang <bookjovi@gmail.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-01-29sched: Bail out of yield_to when source and target runqueue has one taskPeter Zijlstra1-6/+19
In case of undercomitted scenarios, especially in large guests yield_to overhead is significantly high. when run queue length of source and target is one, take an opportunity to bail out and return -ESRCH. This return condition can be further exploited to quickly come out of PLE handler. (History: Raghavendra initially worked on break out of kvm ple handler upon seeing source runqueue length = 1, but it had to export rq length). Peter came up with the elegant idea of return -ESRCH in scheduler core. Signed-off-by: Peter Zijlstra <peterz@infradead.org> Raghavendra, Checking the rq length of target vcpu condition added.(thanks Avi) Reviewed-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Signed-off-by: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com> Acked-by: Andrew Jones <drjones@redhat.com> Tested-by: Chegu Vinod <chegu_vinod@hp.com> Signed-off-by: Gleb Natapov <gleb@redhat.com>
2013-01-29Merge branches 'doctorture.2013.01.29a', 'fixes.2013.01.26a', ↵Paul E. McKenney8-100/+370
'tagcb.2013.01.24a' and 'tiny.2013.01.29b' into HEAD doctorture.2013.01.11a: Changes to rcutorture and to RCU documentation. fixes.2013.01.26a: Miscellaneous fixes. tagcb.2013.01.24a: Tag RCU callbacks with grace-period number to simplify callback advancement. tiny.2013.01.29b: Enhancements to uniprocessor handling in tiny RCU.
2013-01-29rcu: Make rcutorture's shuffler task shuffle recently added tasksPaul E. McKenney1-4/+20
A number of kthreads have been added to rcutorture, but the shuffler task was not informed of them, and thus did not shuffle them. This commit therefore adds the requisite shuffling, and, while in the area fixes up some whitespace issues. However, the shuffling is intended to keep randomly selected CPUs idle, which means that the RCU priority boosting kthreads need to avoid waking up every jiffy. This commit also makes that fix. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2013-01-29rcu: Provide RCU CPU stall warnings for tiny RCUPaul E. McKenney6-50/+121
Tiny RCU has historically omitted RCU CPU stall warnings in order to reduce memory requirements, however, lack of these warnings caused Thomas Gleixner some debugging pain recently. Therefore, this commit adds RCU CPU stall warnings to tiny RCU if RCU_TRACE=y. This keeps the memory footprint small, while still enabling CPU stall warnings in kernels built to enable them. Updated to include Josh Triplett's suggested use of RCU_STALL_COMMON config variable to simplify #if expressions. Reported-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2013-01-28smp: Fix SMP function call empty cpu mask raceWang YanQing1-1/+12
I get the following warning every day with v3.7, once or twice a day: [ 2235.186027] WARNING: at /mnt/sda7/kernel/linux/arch/x86/kernel/apic/ipi.c:109 default_send_IPI_mask_logical+0x2f/0xb8() As explained by Linus as well: | | Once we've done the "list_add_rcu()" to add it to the | queue, we can have (another) IPI to the target CPU that can | now see it and clear the mask. | | So by the time we get to actually send the IPI, the mask might | have been cleared by another IPI. | This patch also fixes a system hang problem, if the data->cpumask gets cleared after passing this point: if (WARN_ONCE(!mask, "empty IPI mask")) return; then the problem in commit 83d349f35e1a ("x86: don't send an IPI to the empty set of CPU's") will happen again. Signed-off-by: Wang YanQing <udknight@gmail.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Jan Beulich <jbeulich@suse.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: peterz@infradead.org Cc: mina86@mina86.org Cc: srivatsa.bhat@linux.vnet.ibm.com Cc: <stable@kernel.org> Link: http://lkml.kernel.org/r/20130126075357.GA3205@udknight [ Tidied up the changelog and the comment in the code. ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-01-28Merge tag 'v3.8-rc5' into next/cleanupOlof Johansson16-126/+335
Linux 3.8-rc5 Signed-off-by: Olof Johansson <olof@lixom.net>
2013-01-27cputime: Safely read cputime of full dynticks CPUsFrederic Weisbecker5-16/+211
While remotely reading the cputime of a task running in a full dynticks CPU, the values stored in utime/stime fields of struct task_struct may be stale. Its values may be those of the last kernel <-> user transition time snapshot and we need to add the tickless time spent since this snapshot. To fix this, flush the cputime of the dynticks CPUs on kernel <-> user transition and record the time / context where we did this. Then on top of this snapshot and the current time, perform the fixup on the reader side from task_times() accessors. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Li Zhong <zhong@linux.vnet.ibm.com> Cc: Namhyung Kim <namhyung.kim@lge.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> [fixed kvm module related build errors] Signed-off-by: Sedat Dilek <sedat.dilek@gmail.com>
2013-01-27kvm: Prepare to add generic guest entry/exit callbacksFrederic Weisbecker1-10/+0
Do some ground preparatory work before adding guest_enter() and guest_exit() context tracking callbacks. Those will be later used to read the guest cputime safely when we run in full dynticks mode. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Gleb Natapov <gleb@redhat.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Li Zhong <zhong@linux.vnet.ibm.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Namhyung Kim <namhyung.kim@lge.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de>
2013-01-27cputime: Use accessors to read task cputime statsFrederic Weisbecker8-35/+89
This is in preparation for the full dynticks feature. While remotely reading the cputime of a task running in a full dynticks CPU, we'll need to do some extra-computation. This way we can account the time it spent tickless in userspace since its last cputime snapshot. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Li Zhong <zhong@linux.vnet.ibm.com> Cc: Namhyung Kim <namhyung.kim@lge.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de>
2013-01-27cputime: Allow dynamic switch between tick/virtual based cputime accountingFrederic Weisbecker2-11/+35
Allow to dynamically switch between tick and virtual based cputime accounting. This way we can provide a kind of "on-demand" virtual based cputime accounting. In this mode, the kernel relies on the context tracking subsystem to dynamically probe on kernel boundaries. This is in preparation for being able to stop the timer tick in more places than just the idle state. Doing so will depend on CONFIG_VIRT_CPU_ACCOUNTING_GEN which makes it possible to account the cputime without the tick by hooking on kernel/user boundaries. Depending whether the tick is stopped or not, we can switch between tick and vtime based accounting anytime in order to minimize the overhead associated to user hooks. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Li Zhong <zhong@linux.vnet.ibm.com> Cc: Namhyung Kim <namhyung.kim@lge.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de>
2013-01-27cputime: Generic on-demand virtual cputime accountingFrederic Weisbecker2-6/+61
If we want to stop the tick further idle, we need to be able to account the cputime without using the tick. Virtual based cputime accounting solves that problem by hooking into kernel/user boundaries. However implementing CONFIG_VIRT_CPU_ACCOUNTING require low level hooks and involves more overhead. But we already have a generic context tracking subsystem that is required for RCU needs by archs which plan to shut down the tick outside idle. This patch implements a generic virtual based cputime accounting that relies on these generic kernel/user hooks. There are some upsides of doing this: - This requires no arch code to implement CONFIG_VIRT_CPU_ACCOUNTING if context tracking is already built (already necessary for RCU in full tickless mode). - We can rely on the generic context tracking subsystem to dynamically (de)activate the hooks, so that we can switch anytime between virtual and tick based accounting. This way we don't have the overhead of the virtual accounting when the tick is running periodically. And one downside: - There is probably more overhead than a native virtual based cputime accounting. But this relies on hooks that are already set anyway. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Li Zhong <zhong@linux.vnet.ibm.com> Cc: Namhyung Kim <namhyung.kim@lge.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de>
2013-01-27cputime: Move default nsecs_to_cputime() to jiffies based cputime fileFrederic Weisbecker1-4/+0
If the architecture doesn't provide an implementation of nsecs_to_cputime(), the cputime accounting core uses a default one that converts the nanoseconds to jiffies. However this only makes sense if we use the jiffies based cputime. For now it doesn't matter much because this API is only called on code that uses jiffies based cputime accounting. But the code may evolve and this API may be used more broadly in the future. Keeping this default implementation around is very error prone as it may introduce a bug and hide it on architectures that don't override this API. Fix this by moving this definition to the jiffies based cputime headers as it is the only place where it belongs to. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Li Zhong <zhong@linux.vnet.ibm.com> Cc: Namhyung Kim <namhyung.kim@lge.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de>
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