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* kernel/softirq.c: fix sparse warningH Hartley Sweeten2009-04-171-2/+2
| | | | | | | | | | Fix sparse warning in kernel/softirq.c. warning: do-while statement is not a compound statement Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com> LKML-Reference: <BD79186B4FD85F4B8E60E381CAEE1909015F9033@mi8nycmail19.Mi8.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* Merge branch 'locking-for-linus' of ↵Linus Torvalds2009-04-061-1/+1
|\ | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: lockdep: add stack dumps to asserts hrtimer: fix rq->lock inversion (again)
| * hrtimer: fix rq->lock inversion (again)Peter Zijlstra2009-03-311-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | It appears I inadvertly introduced rq->lock recursion to the hrtimer_start() path when I delegated running already expired timers to softirq context. This patch fixes it by introducing a __hrtimer_start_range_ns() method that will not use raise_softirq_irqoff() but __raise_softirq_irqoff() which avoids the wakeup. It then also changes schedule() to check for pending softirqs and do the wakeup then, I'm not quite sure I like this last bit, nor am I convinced its really needed. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: paulus@samba.org LKML-Reference: <20090313112301.096138802@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | Merge branch 'tracing-for-linus' of ↵Linus Torvalds2009-04-051-3/+25
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'tracing-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (413 commits) tracing, net: fix net tree and tracing tree merge interaction tracing, powerpc: fix powerpc tree and tracing tree interaction ring-buffer: do not remove reader page from list on ring buffer free function-graph: allow unregistering twice trace: make argument 'mem' of trace_seq_putmem() const tracing: add missing 'extern' keywords to trace_output.h tracing: provide trace_seq_reserve() blktrace: print out BLK_TN_MESSAGE properly blktrace: extract duplidate code blktrace: fix memory leak when freeing struct blk_io_trace blktrace: fix blk_probes_ref chaos blktrace: make classic output more classic blktrace: fix off-by-one bug blktrace: fix the original blktrace blktrace: fix a race when creating blk_tree_root in debugfs blktrace: fix timestamp in binary output tracing, Text Edit Lock: cleanup tracing: filter fix for TRACE_EVENT_FORMAT events ftrace: Using FTRACE_WARN_ON() to check "freed record" in ftrace_release() x86: kretprobe-booster interrupt emulation code fix ... Fix up trivial conflicts in arch/parisc/include/asm/ftrace.h include/linux/memory.h kernel/extable.c kernel/module.c
| * | softirq: no need to have SOFTIRQ in softirq nameSteven Rostedt2009-03-131-3/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: clean up It is redundant to have 'SOFTIRQ' in the softirq names. Reported-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Steven Rostedt <srostedt@redhat.com>
| * | tracing: tracepoints for softirq entry/exit - tracepointsJason Baron2009-03-121-1/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Introduce softirq entry/exit tracepoints. These are useful for augmenting existing tracers, and to figure out softirq frequencies and timings. [ s/irq_softirq_/softirq_/ for trace point names and Fixed printf format in TRACE_FORMAT macro - Steven Rostedt ] LKML-Reference: <20090312183603.GC3352@redhat.com> Signed-off-by: Jason Baron <jbaron@redhat.com> Signed-off-by: Steven Rostedt <srostedt@redhat.com>
| * | tracing: tracepoints for softirq entry/exit - add softirq-to-name arrayJason Baron2009-03-121-1/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Create a 'softirq_to_name' array, which is indexed by softirq #, so that we can easily convert between the softirq index # and its name, in order to get more meaningful output messages. LKML-Reference: <20090312183336.GB3352@redhat.com> Signed-off-by: Jason Baron <jbaron@redhat.com> Signed-off-by: Steven Rostedt <srostedt@redhat.com>
| * | Merge branch 'core/locking' into tracing/ftraceIngo Molnar2009-03-131-2/+2
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| *-. \ \ Merge branches 'tracing/doc', 'tracing/ftrace', 'tracing/printk' and 'linus' ↵Ingo Molnar2009-03-101-0/+1
| |\ \ \ \ | | | | | | | | | | | | | | | | | | into tracing/core
| * \ \ \ \ Merge branch 'x86/core' into tracing/texteditIngo Molnar2009-03-061-0/+5
| |\ \ \ \ \ | | |/ / / / | |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Conflicts: arch/x86/Kconfig block/blktrace.c kernel/irq/handle.c Semantic conflict: kernel/trace/blktrace.c Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | | | | trace, lockdep: manual preempt count adding for local_bh_disableSteven Rostedt2009-01-231-1/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: fix to preempt trace triggering lockdep check_flag failure In local_bh_disable, the use of add_preempt_count causes the preempt tracer to start recording the time preemption is off. But because it already modified the preempt_count to show softirqs disabled, and before it called the lockdep code to handle this, it causes a state that lockdep can not handle. The preempt tracer will reset the ring buffer on start of a trace, and the ring buffer reset code does a spin_lock_irqsave. This calls into lockdep and lockdep will fail when it detects the invalid state of having softirqs disabled but the internal current->softirqs_enabled is still set. The fix is to manually add the SOFTIRQ_OFFSET to preempt count and call the preempt tracer code outside the lockdep critical area. Thanks to Peter Zijlstra for suggesting this solution. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | | | | Merge branch 'ipi-for-linus' of ↵Linus Torvalds2009-04-031-1/+1
|\ \ \ \ \ \ | |_|_|_|_|/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'ipi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: s390: remove arch specific smp_send_stop() panic: clean up kernel/panic.c panic, smp: provide smp_send_stop() wrapper on UP too panic: decrease oops_in_progress only after having done the panic generic-ipi: eliminate WARN_ON()s during oops/panic generic-ipi: cleanups generic-ipi: remove CSD_FLAG_WAIT generic-ipi: remove kmalloc() generic IPI: simplify barriers and locking
| * | | | | Merge branch 'x86/core' into core/ipiIngo Molnar2009-03-131-0/+5
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| | *-. \ \ \ \ Merge branches 'x86/apic', 'x86/asm', 'x86/fixmap', 'x86/memtest', 'x86/mm', ↵Ingo Molnar2009-03-101-0/+1
| | |\ \ \ \ \ \ | | | | |/ / / / | | | |/| / / / | | | |_|/ / / | | |/| | / / | | | | |/ / 'x86/urgent', 'linus' and 'core/percpu' into x86/core
| * | | | | Merge branch 'linus' into core/ipiIngo Molnar2009-03-131-0/+1
| |\ \ \ \ \ | | | |_|/ / | | |/| | |
| * | | | | generic-ipi: remove CSD_FLAG_WAITPeter Zijlstra2009-02-251-1/+1
| | |_|/ / | |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Oleg noticed that we don't strictly need CSD_FLAG_WAIT, rework the code so that we can use CSD_FLAG_LOCK for both purposes. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Nick Piggin <npiggin@suse.de> Cc: Jens Axboe <jens.axboe@oracle.com> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | | | Merge branch 'linus' into locking-for-linusIngo Molnar2009-03-311-0/+5
|\ \ \ \ \ | |_|_|_|/ |/| | | | | | | | | | | | | | Conflicts: lib/Kconfig.debug
| * | | | Merge branch 'core/percpu' into percpu-cpumask-x86-for-linus-2Ingo Molnar2009-03-271-0/+5
| |\ \ \ \ | | |_|/ / | |/| | / | | | |/ | | |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Conflicts: arch/parisc/kernel/irq.c arch/x86/include/asm/fixmap_64.h arch/x86/include/asm/setup.h kernel/irq/handle.c Semantic merge: arch/x86/include/asm/fixmap.h Signed-off-by: Ingo Molnar <mingo@elte.hu>
| | * | x86: arch_probe_nr_irqsYinghai Lu2009-01-121-0/+5
| | |/ | | | | | | | | | | | | | | | | | | Impact: save RAM with large NR_CPUS, get smaller nr_irqs Signed-off-by: Yinghai Lu <yinghai@kernel.org> Signed-off-by: Mike Travis <travis@sgi.com>
* | | locking: rename trace_softirq_[enter|exit] => lockdep_softirq_[enter|exit]Ingo Molnar2009-03-131-2/+2
|/ / | | | | | | | | | | | | | | | | | | Impact: cleanup The naming clashes with upcoming softirq tracepoints, so rename the APIs to lockdep_*(). Requested-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | rcu: increment quiescent state counter in ksoftirqd()Eric Dumazet2009-03-041-0/+1
|/ | | | | | | | | | | | | | | | | If a machine is flooded by network frames, a cpu can loop 100% of its time inside ksoftirqd() without calling schedule(). This can delay RCU grace period to insane values. Adding rcu_qsctr_inc() call in ksoftirqd() solves this problem. Paul: "This regression was a result of the recent change from "schedule()" to "cond_resched()", which got rid of that quiescent state in the common case where a reschedule is not needed". Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Reviewed-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>
* Merge branch 'cpus4096-for-linus-3' of ↵Linus Torvalds2009-01-031-1/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'cpus4096-for-linus-3' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (77 commits) x86: setup_per_cpu_areas() cleanup cpumask: fix compile error when CONFIG_NR_CPUS is not defined cpumask: use alloc_cpumask_var_node where appropriate cpumask: convert shared_cpu_map in acpi_processor* structs to cpumask_var_t x86: use cpumask_var_t in acpi/boot.c x86: cleanup some remaining usages of NR_CPUS where s/b nr_cpu_ids sched: put back some stack hog changes that were undone in kernel/sched.c x86: enable cpus display of kernel_max and offlined cpus ia64: cpumask fix for is_affinity_mask_valid() cpumask: convert RCU implementations, fix xtensa: define __fls mn10300: define __fls m32r: define __fls h8300: define __fls frv: define __fls cris: define __fls cpumask: CONFIG_DISABLE_OBSOLETE_CPUMASK_FUNCTIONS cpumask: zero extra bits in alloc_cpumask_var_node cpumask: replace for_each_cpu_mask_nr with for_each_cpu in kernel/time/ cpumask: convert mm/ ...
| * cpumask: remove any_online_cpu() users: kernel/Rusty Russell2009-01-011-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: Remove obsolete API usage any_online_cpu() is a good name, but it takes a cpumask_t, not a pointer. There are several places where any_online_cpu() doesn't really want a mask arg at all. Replace all callers with cpumask_any() and cpumask_any_and(). Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Mike Travis <travis@sgi.com>
* | Merge branch 'irq-fixes-for-linus-4' of ↵Linus Torvalds2008-12-311-0/+20
|\ \ | |/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'irq-fixes-for-linus-4' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: sparseirq: move __weak symbols into separate compilation unit sparseirq: work around __weak alias bug sparseirq: fix hang with !SPARSE_IRQ sparseirq: set lock_class for legacy irq when sparse_irq is selected sparseirq: work around compiler optimizing away __weak functions sparseirq: fix desc->lock init sparseirq: do not printk when migrating IRQ descriptors sparseirq: remove duplicated arch_early_irq_init() irq: simplify for_each_irq_desc() usage proc: remove ifdef CONFIG_SPARSE_IRQ from stat.c irq: for_each_irq_desc() move to irqnr.h hrtimer: remove #include <linux/irq.h>
| * sparseirq: move __weak symbols into separate compilation unitYinghai Lu2008-12-291-0/+20
| | | | | | | | | | | | | | | | | | | | | | | | GCC has a bug with __weak alias functions: if the functions are in the same compilation unit as their call site, GCC can decide to inline them - and thus rob the linker of the opportunity to override the weak alias with the real thing. So move all the IRQ handling related __weak symbols to kernel/irq/chip.c. Signed-off-by: Yinghai Lu <yinghai@kernel.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
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*-. \ Merge branches 'core/debugobjects', 'core/iommu', 'core/locking', ↵Ingo Molnar2008-12-251-16/+3
|\ \ \ | |_|/ |/| | | | | 'core/printk', 'core/rcu', 'core/resources', 'core/softirq' and 'core/stacktrace' into core/core
| | * softirq: remove useless function __local_bh_enableLiming Wang2008-11-281-14/+0
| |/ |/| | | | | | | | | | | | | | | | | | | | | Impact: remove unused code __local_bh_enable has been replaced with _local_bh_enable. As comments says "it always nests inside local_bh_enable() sections" has not been valid now. Also there is no reason to use __local_bh_enable anywhere, so we can remove this useless function. Signed-off-by: Liming Wang <liming.wang@windriver.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * "Tree RCU": scalable classic RCU implementationPaul E. McKenney2008-12-181-2/+3
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch fixes a long-standing performance bug in classic RCU that results in massive internal-to-RCU lock contention on systems with more than a few hundred CPUs. Although this patch creates a separate flavor of RCU for ease of review and patch maintenance, it is intended to replace classic RCU. This patch still handles stress better than does mainline, so I am still calling it ready for inclusion. This patch is against the -tip tree. Nevertheless, experience on an actual 1000+ CPU machine would still be most welcome. Most of the changes noted below were found while creating an rcutiny (which should permit ejecting the current rcuclassic) and while doing detailed line-by-line documentation. Updates from v9 (http://lkml.org/lkml/2008/12/2/334): o Fixes from remainder of line-by-line code walkthrough, including comment spelling, initialization, undesirable narrowing due to type conversion, removing redundant memory barriers, removing redundant local-variable initialization, and removing redundant local variables. I do not believe that any of these fixes address the CPU-hotplug issues that Andi Kleen was seeing, but please do give it a whirl in case the machine is smarter than I am. A writeup from the walkthrough may be found at the following URL, in case you are suffering from terminal insomnia or masochism: http://www.kernel.org/pub/linux/kernel/people/paulmck/tmp/rcutree-walkthrough.2008.12.16a.pdf o Made rcutree tracing use seq_file, as suggested some time ago by Lai Jiangshan. o Added a .csv variant of the rcudata debugfs trace file, to allow people having thousands of CPUs to drop the data into a spreadsheet. Tested with oocalc and gnumeric. Updated documentation to suit. Updates from v8 (http://lkml.org/lkml/2008/11/15/139): o Fix a theoretical race between grace-period initialization and force_quiescent_state() that could occur if more than three jiffies were required to carry out the grace-period initialization. Which it might, if you had enough CPUs. o Apply Ingo's printk-standardization patch. o Substitute local variables for repeated accesses to global variables. o Fix comment misspellings and redundant (but harmless) increments of ->n_rcu_pending (this latter after having explicitly added it). o Apply checkpatch fixes. Updates from v7 (http://lkml.org/lkml/2008/10/10/291): o Fixed a number of problems noted by Gautham Shenoy, including the cpu-stall-detection bug that he was having difficulty convincing me was real. ;-) o Changed cpu-stall detection to wait for ten seconds rather than three in order to reduce false positive, as suggested by Ingo Molnar. o Produced a design document (http://lwn.net/Articles/305782/). The act of writing this document uncovered a number of both theoretical and "here and now" bugs as noted below. o Fix dynticks_nesting accounting confusion, simplify WARN_ON() condition, fix kerneldoc comments, and add memory barriers in dynticks interface functions. o Add more data to tracing. o Remove unused "rcu_barrier" field from rcu_data structure. o Count calls to rcu_pending() from scheduling-clock interrupt to use as a surrogate timebase should jiffies stop counting. o Fix a theoretical race between force_quiescent_state() and grace-period initialization. Yes, initialization does have to go on for some jiffies for this race to occur, but given enough CPUs... Updates from v6 (http://lkml.org/lkml/2008/9/23/448): o Fix a number of checkpatch.pl complaints. o Apply review comments from Ingo Molnar and Lai Jiangshan on the stall-detection code. o Fix several bugs in !CONFIG_SMP builds. o Fix a misspelled config-parameter name so that RCU now announces at boot time if stall detection is configured. o Run tests on numerous combinations of configurations parameters, which after the fixes above, now build and run correctly. Updates from v5 (http://lkml.org/lkml/2008/9/15/92, bad subject line): o Fix a compiler error in the !CONFIG_FANOUT_EXACT case (blew a changeset some time ago, and finally got around to retesting this option). o Fix some tracing bugs in rcupreempt that caused incorrect totals to be printed. o I now test with a more brutal random-selection online/offline script (attached). Probably more brutal than it needs to be on the people reading it as well, but so it goes. o A number of optimizations and usability improvements: o Make rcu_pending() ignore the grace-period timeout when there is no grace period in progress. o Make force_quiescent_state() avoid going for a global lock in the case where there is no grace period in progress. o Rearrange struct fields to improve struct layout. o Make call_rcu() initiate a grace period if RCU was idle, rather than waiting for the next scheduling clock interrupt. o Invoke rcu_irq_enter() and rcu_irq_exit() only when idle, as suggested by Andi Kleen. I still don't completely trust this change, and might back it out. o Make CONFIG_RCU_TRACE be the single config variable manipulated for all forms of RCU, instead of the prior confusion. o Document tracing files and formats for both rcupreempt and rcutree. Updates from v4 for those missing v5 given its bad subject line: o Separated dynticks interface so that NMIs and irqs call separate functions, greatly simplifying it. In particular, this code no longer requires a proof of correctness. ;-) o Separated dynticks state out into its own per-CPU structure, avoiding the duplicated accounting. o The case where a dynticks-idle CPU runs an irq handler that invokes call_rcu() is now correctly handled, forcing that CPU out of dynticks-idle mode. o Review comments have been applied (thank you all!!!). For but one example, fixed the dynticks-ordering issue that Manfred pointed out, saving me much debugging. ;-) o Adjusted rcuclassic and rcupreempt to handle dynticks changes. Attached is an updated patch to Classic RCU that applies a hierarchy, greatly reducing the contention on the top-level lock for large machines. This passes 10-hour concurrent rcutorture and online-offline testing on 128-CPU ppc64 without dynticks enabled, and exposes some timekeeping bugs in presence of dynticks (exciting working on a system where "sleep 1" hangs until interrupted...), which were fixed in the 2.6.27 kernel. It is getting more reliable than mainline by some measures, so the next version will be against -tip for inclusion. See also Manfred Spraul's recent patches (or his earlier work from 2004 at http://marc.info/?l=linux-kernel&m=108546384711797&w=2). We will converge onto a common patch in the fullness of time, but are currently exploring different regions of the design space. That said, I have already gratefully stolen quite a few of Manfred's ideas. This patch provides CONFIG_RCU_FANOUT, which controls the bushiness of the RCU hierarchy. Defaults to 32 on 32-bit machines and 64 on 64-bit machines. If CONFIG_NR_CPUS is less than CONFIG_RCU_FANOUT, there is no hierarchy. By default, the RCU initialization code will adjust CONFIG_RCU_FANOUT to balance the hierarchy, so strongly NUMA architectures may choose to set CONFIG_RCU_FANOUT_EXACT to disable this balancing, allowing the hierarchy to be exactly aligned to the underlying hardware. Up to two levels of hierarchy are permitted (in addition to the root node), allowing up to 16,384 CPUs on 32-bit systems and up to 262,144 CPUs on 64-bit systems. I just know that I am going to regret saying this, but this seems more than sufficient for the foreseeable future. (Some architectures might wish to set CONFIG_RCU_FANOUT=4, which would limit such architectures to 64 CPUs. If this becomes a real problem, additional levels can be added, but I doubt that it will make a significant difference on real hardware.) In the common case, a given CPU will manipulate its private rcu_data structure and the rcu_node structure that it shares with its immediate neighbors. This can reduce both lock and memory contention by multiple orders of magnitude, which should eliminate the need for the strange manipulations that are reported to be required when running Linux on very large systems. Some shortcomings: o More bugs will probably surface as a result of an ongoing line-by-line code inspection. Patches will be provided as required. o There are probably hangs, rcutorture failures, &c. Seems quite stable on a 128-CPU machine, but that is kind of small compared to 4096 CPUs. However, seems to do better than mainline. Patches will be provided as required. o The memory footprint of this version is several KB larger than rcuclassic. A separate UP-only rcutiny patch will be provided, which will reduce the memory footprint significantly, even compared to the old rcuclassic. One such patch passes light testing, and has a memory footprint smaller even than rcuclassic. Initial reaction from various embedded guys was "it is not worth it", so am putting it aside. Credits: o Manfred Spraul for ideas, review comments, and bugs spotted, as well as some good friendly competition. ;-) o Josh Triplett, Ingo Molnar, Peter Zijlstra, Mathieu Desnoyers, Lai Jiangshan, Andi Kleen, Andy Whitcroft, and Andrew Morton for reviews and comments. o Thomas Gleixner for much-needed help with some timer issues (see patches below). o Jon M. Tollefson, Tim Pepper, Andrew Theurer, Jose R. Santos, Andy Whitcroft, Darrick Wong, Nishanth Aravamudan, Anton Blanchard, Dave Kleikamp, and Nathan Lynch for keeping machines alive despite my heavy abuse^Wtesting. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* irq: call __irq_enter() before calling the tick_idle_checkThomas Gleixner2008-11-101-3/+4
| | | | | | | | | | | | | | Impact: avoid spurious ksoftirqd wakeups The tick idle check which is called from irq_enter() was run before the call to __irq_enter() which did not set the in_interrupt() bits in preempt_count. That way the raise of a softirq woke up softirqd for nothing as the softirq was handled on return from interrupt. Call __irq_enter() before calling into the tick idle check code. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
*-. Merge branches 'timers/clocksource', 'timers/hrtimers', 'timers/nohz', ↵Thomas Gleixner2008-10-201-8/+144
|\ \ | | | | | | | | | 'timers/ntp', 'timers/posixtimers' and 'timers/debug' into v28-timers-for-linus
| | * softirq: Add support for triggering softirq work on softirqs.David S. Miller2008-10-171-0/+129
| | | | | | | | | | | | | | | | | | | | | | | | This is basically a genericization of Jens Axboe's block layer remote softirq changes. Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
| * | NOHZ: unify the nohz function calls in irq_enter()Thomas Gleixner2008-10-171-7/+3
| |/ | | | | | | | | | | | | | | We have two separate nohz function calls in irq_enter() for no good reason. Just call a single NOHZ function from irq_enter() and call the bits in the tick code. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * Fix kernel/softirq.c printk format warning properlyLinus Torvalds2008-10-161-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | This fixes the broken 77af7e3403e7314c47b0c07fbc5e4ef21d939532 ("softirq, warning fix: correct a format to avoid a warning") fix correctly. The type of a pointer subtraction is not "int", nor is it "long". It can be either (or something else). It's "ptrdiff_t", and the printk format for it is "%td". Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * softirq, warning fix: correct a format to avoid a warningFrederic Weisbecker2008-10-031-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | Last -tip gives this warning: kernel/softirq.c: Dans la fonction «__do_softirq» : kernel/softirq.c:216: attention : format «%ld» expects type «long int», but argument 2 has type «int» This patch corrects the format type, and a small mistake in the "softirq" word. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * softirqs, debug: preemption checkThomas Gleixner2008-10-021-0/+11
| | | | | | | | | | | | | | | | 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>
| * softirq: allocate less vectorsAlexey Dobriyan2008-09-061-1/+1
|/ | | | | | | | We don't need whole 32 of them, only NR_SOFTIRQS. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* Full conversion to early_initcall() interface, remove old interfaceEduard - Gabriel Munteanu2008-07-261-1/+2
| | | | | | | | | | | | | | | | A previous patch added the early_initcall(), to allow a cleaner hooking of pre-SMP initcalls. Now we remove the older interface, converting all existing users to the new one. [akpm@linux-foundation.org: cleanups] [akpm@linux-foundation.org: build fix] [kosaki.motohiro@jp.fujitsu.com: warning fix] [kosaki.motohiro@jp.fujitsu.com: warning fix] Signed-off-by: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro> Cc: Tom Zanussi <tzanussi@gmail.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>
* Merge branch 'linus' into timers/nohzIngo Molnar2008-07-181-48/+19
|\
| * Merge branch 'generic-ipi' into generic-ipi-for-linusIngo Molnar2008-07-151-2/+2
| |\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Conflicts: arch/powerpc/Kconfig arch/s390/kernel/time.c arch/x86/kernel/apic_32.c arch/x86/kernel/cpu/perfctr-watchdog.c arch/x86/kernel/i8259_64.c arch/x86/kernel/ldt.c arch/x86/kernel/nmi_64.c arch/x86/kernel/smpboot.c arch/x86/xen/smp.c include/asm-x86/hw_irq_32.h include/asm-x86/hw_irq_64.h include/asm-x86/mach-default/irq_vectors.h include/asm-x86/mach-voyager/irq_vectors.h include/asm-x86/smp.h kernel/Makefile Signed-off-by: Ingo Molnar <mingo@elte.hu>
| | * on_each_cpu(): kill unused 'retry' parameterJens Axboe2008-06-261-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | It's not even passed on to smp_call_function() anymore, since that was removed. So kill it. Acked-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
| | * smp_call_function: get rid of the unused nonatomic/retry argumentJens Axboe2008-06-261-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | It's never used and the comments refer to nonatomic and retry interchangably. So get rid of it. Acked-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
| * | Merge branch 'core/softirq' of ↵Linus Torvalds2008-07-141-45/+16
| |\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'core/softirq' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: softirq: remove irqs_disabled warning from local_bh_enable softirq: remove initialization of static per-cpu variable Remove argument from open_softirq which is always NULL
| | * | softirq: remove irqs_disabled warning from local_bh_enableJohannes Berg2008-06-201-37/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There's no need to use local_irq_save() over local_irq_disable() in the local_bh_enable code since it is a bug to call it with irqs disabled and do_softirq will enable irqs if there is any pending work. Consolidate the code from local_bh_enable and ..._ip to avoid having a disconnect between them in the warnings they trigger that is currently there. Also always trigger the warning on in_irq(), not just in the trace-irqflags case. Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Cc: Michael Buesch <mb@bu3sch.de> Cc: David Ellingsworth <david@identd.dyndns.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| | * | softirq: remove initialization of static per-cpu variableVegard Nossum2008-06-181-4/+2
| | | | | | | | | | | | | | | | | | | | Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| | * | Remove argument from open_softirq which is always NULLCarlos R. Mafra2008-05-251-4/+3
| | |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | As git-grep shows, open_softirq() is always called with the last argument being NULL block/blk-core.c: open_softirq(BLOCK_SOFTIRQ, blk_done_softirq, NULL); kernel/hrtimer.c: open_softirq(HRTIMER_SOFTIRQ, run_hrtimer_softirq, NULL); kernel/rcuclassic.c: open_softirq(RCU_SOFTIRQ, rcu_process_callbacks, NULL); kernel/rcupreempt.c: open_softirq(RCU_SOFTIRQ, rcu_process_callbacks, NULL); kernel/sched.c: open_softirq(SCHED_SOFTIRQ, run_rebalance_domains, NULL); kernel/softirq.c: open_softirq(TASKLET_SOFTIRQ, tasklet_action, NULL); kernel/softirq.c: open_softirq(HI_SOFTIRQ, tasklet_hi_action, NULL); kernel/timer.c: open_softirq(TIMER_SOFTIRQ, run_timer_softirq, NULL); net/core/dev.c: open_softirq(NET_TX_SOFTIRQ, net_tx_action, NULL); net/core/dev.c: open_softirq(NET_RX_SOFTIRQ, net_rx_action, NULL); This observation has already been made by Matthew Wilcox in June 2002 (http://www.cs.helsinki.fi/linux/linux-kernel/2002-25/0687.html) "I notice that none of the current softirq routines use the data element passed to them." and the situation hasn't changed since them. So it appears we can safely remove that extra argument to save 128 (54) bytes of kernel data (text). Signed-off-by: Carlos R. Mafra <crmafra@ift.unesp.br> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | sched: add new API sched_setscheduler_nocheck: add a flag to control access ↵Rusty Russell2008-06-231-1/+1
| |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | checks Hidehiro Kawai noticed that sched_setscheduler() can fail in stop_machine: it calls sched_setscheduler() from insmod, which can have CAP_SYS_MODULE without CAP_SYS_NICE. Two cases could have failed, so are changed to sched_setscheduler_nocheck: kernel/softirq.c:cpu_callback() - CPU hotplug callback kernel/stop_machine.c:__stop_machine_run() - Called from various places, including modprobe() Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: linux-mm@kvack.org Cc: sugita <yumiko.sugita.yf@hitachi.com> Cc: Satoshi OSHIMA <satoshi.oshima.fk@hitachi.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | nohz: prevent tick stop outside of the idle loopThomas Gleixner2008-07-181-1/+1
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Jack Ren and Eric Miao tracked down the following long standing problem in the NOHZ code: scheduler switch to idle task enable interrupts Window starts here ----> interrupt happens (does not set NEED_RESCHED) irq_exit() stops the tick ----> interrupt happens (does set NEED_RESCHED) return from schedule() cpu_idle(): preempt_disable(); Window ends here The interrupts can happen at any point inside the race window. The first interrupt stops the tick, the second one causes the scheduler to rerun and switch away from idle again and we end up with the tick disabled. The fact that it needs two interrupts where the first one does not set NEED_RESCHED and the second one does made the bug obscure and extremly hard to reproduce and analyse. Kudos to Jack and Eric. Solution: Limit the NOHZ functionality to the idle loop to make sure that we can not run into such a situation ever again. cpu_idle() { preempt_disable(); while(1) { tick_nohz_stop_sched_tick(1); <- tell NOHZ code that we are in the idle loop while (!need_resched()) halt(); tick_nohz_restart_sched_tick(); <- disables NOHZ mode preempt_enable_no_resched(); schedule(); preempt_disable(); } } In hindsight we should have done this forever, but ... /me grabs a large brown paperbag. Debugged-by: Jack Ren <jack.ren@marvell.com>, Debugged-by: eric miao <eric.y.miao@gmail.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* Fix cpu hotplug problem in softirq codeChristian Borntraeger2008-05-011-8/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | currently cpu hotplug (unplug) seems broken on s390 and likely others. On cpu unplug the system starts to behave very strange and hangs. I bisected the problem to the following commit: commit 48f20a9a9488c432fc86df1ff4b7f4fa895d1183 Author: Olof Johansson <olof@lixom.net> Date: Tue Mar 4 15:23:25 2008 -0800 tasklets: execute tasklets in the same order they were queued Reverting this patch seems to fix the problem. I looked into takeover_tasklet and it seems that there is a way to corrupt the tail pointer of the current cpu. If the tasklet list of the frozen cpu is empty, the tail pointer of the current cpu points to the address of the head pointer of the stopped cpu and not to the next pointer of a tasklet_struct. This patch avoids the list splice of the list is empty and cpu hotplug seems to work as the tail pointer is not corrupted. Olof, can you look into that patch and ACK/NACK it so Andrew can push this to Linus, if appropriate? Please note that some lines are longer than 80 chars, but line-wrapping looked worse that this version. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Acked-by: Olof Johansson <olof@lixom.net> Acked-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* tasklets: execute tasklets in the same order they were queuedOlof Johansson2008-04-191-22/+41
| | | | | | | | | | | | | | | | | I noticed this when looking at an openswan issue. Openswan (ab?)uses the tasklet API to defer processing of packets in some situations, with one packet per tasklet_action(). I started noticing sequences of backwards-ordered sequence numbers coming over the wire, since new tasklets are always queued at the head of the list but processed sequentially. Convert it to instead append new entries to the tail of the list. As an extra bonus, the splicing code in takeover_tasklets() no longer has to iterate over the list. Signed-off-by: Olof Johansson <olof@lixom.net> Cc: "David S. Miller" <davem@davemloft.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* rcu: add support for dynamic ticks and preempt rcuSteven Rostedt2008-02-291-0/+1
| | | | | | | | | | | | | | | The PREEMPT-RCU can get stuck if a CPU goes idle and NO_HZ is set. The idle CPU will not progress the RCU through its grace period and a synchronize_rcu my get stuck. Without this patch I have a box that will not boot when PREEMPT_RCU and NO_HZ are set. That same box boots fine with this patch. This patch comes from the -rt kernel where it has been tested for several months. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
generated by cgit v1.1 at 2024-10-31 14:25:11 +0000