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* tracing: Kernel TracepointsMathieu Desnoyers2008-10-143-1/+542
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Implementation of kernel tracepoints. Inspired from the Linux Kernel Markers. Allows complete typing verification by declaring both tracing statement inline functions and probe registration/unregistration static inline functions within the same macro "DEFINE_TRACE". No format string is required. See the tracepoint Documentation and Samples patches for usage examples. Taken from the documentation patch : "A tracepoint placed in code provides a hook to call a function (probe) that you can provide at runtime. A tracepoint can be "on" (a probe is connected to it) or "off" (no probe is attached). When a tracepoint is "off" it has no effect, except for adding a tiny time penalty (checking a condition for a branch) and space penalty (adding a few bytes for the function call at the end of the instrumented function and adds a data structure in a separate section). When a tracepoint is "on", the function you provide is called each time the tracepoint is executed, in the execution context of the caller. When the function provided ends its execution, it returns to the caller (continuing from the tracepoint site). You can put tracepoints at important locations in the code. They are lightweight hooks that can pass an arbitrary number of parameters, which prototypes are described in a tracepoint declaration placed in a header file." Addition and removal of tracepoints is synchronized by RCU using the scheduler (and preempt_disable) as guarantees to find a quiescent state (this is really RCU "classic"). The update side uses rcu_barrier_sched() with call_rcu_sched() and the read/execute side uses "preempt_disable()/preempt_enable()". We make sure the previous array containing probes, which has been scheduled for deletion by the rcu callback, is indeed freed before we proceed to the next update. It therefore limits the rate of modification of a single tracepoint to one update per RCU period. The objective here is to permit fast batch add/removal of probes on _different_ tracepoints. Changelog : - Use #name ":" #proto as string to identify the tracepoint in the tracepoint table. This will make sure not type mismatch happens due to connexion of a probe with the wrong type to a tracepoint declared with the same name in a different header. - Add tracepoint_entry_free_old. - Change __TO_TRACE to get rid of the 'i' iterator. Masami Hiramatsu <mhiramat@redhat.com> : Tested on x86-64. Performance impact of a tracepoint : same as markers, except that it adds about 70 bytes of instructions in an unlikely branch of each instrumented function (the for loop, the stack setup and the function call). It currently adds a memory read, a test and a conditional branch at the instrumentation site (in the hot path). Immediate values will eventually change this into a load immediate, test and branch, which removes the memory read which will make the i-cache impact smaller (changing the memory read for a load immediate removes 3-4 bytes per site on x86_32 (depending on mov prefixes), or 7-8 bytes on x86_64, it also saves the d-cache hit). About the performance impact of tracepoints (which is comparable to markers), even without immediate values optimizations, tests done by Hideo Aoki on ia64 show no regression. His test case was using hackbench on a kernel where scheduler instrumentation (about 5 events in code scheduler code) was added. Quoting Hideo Aoki about Markers : I evaluated overhead of kernel marker using linux-2.6-sched-fixes git tree, which includes several markers for LTTng, using an ia64 server. While the immediate trace mark feature isn't implemented on ia64, there is no major performance regression. So, I think that we don't have any issues to propose merging marker point patches into Linus's tree from the viewpoint of performance impact. I prepared two kernels to evaluate. The first one was compiled without CONFIG_MARKERS. The second one was enabled CONFIG_MARKERS. I downloaded the original hackbench from the following URL: http://devresources.linux-foundation.org/craiger/hackbench/src/hackbench.c I ran hackbench 5 times in each condition and calculated the average and difference between the kernels. The parameter of hackbench: every 50 from 50 to 800 The number of CPUs of the server: 2, 4, and 8 Below is the results. As you can see, major performance regression wasn't found in any case. Even if number of processes increases, differences between marker-enabled kernel and marker- disabled kernel doesn't increase. Moreover, if number of CPUs increases, the differences doesn't increase either. Curiously, marker-enabled kernel is better than marker-disabled kernel in more than half cases, although I guess it comes from the difference of memory access pattern. * 2 CPUs Number of | without | with | diff | diff | processes | Marker [Sec] | Marker [Sec] | [Sec] | [%] | -------------------------------------------------------------- 50 | 4.811 | 4.872 | +0.061 | +1.27 | 100 | 9.854 | 10.309 | +0.454 | +4.61 | 150 | 15.602 | 15.040 | -0.562 | -3.6 | 200 | 20.489 | 20.380 | -0.109 | -0.53 | 250 | 25.798 | 25.652 | -0.146 | -0.56 | 300 | 31.260 | 30.797 | -0.463 | -1.48 | 350 | 36.121 | 35.770 | -0.351 | -0.97 | 400 | 42.288 | 42.102 | -0.186 | -0.44 | 450 | 47.778 | 47.253 | -0.526 | -1.1 | 500 | 51.953 | 52.278 | +0.325 | +0.63 | 550 | 58.401 | 57.700 | -0.701 | -1.2 | 600 | 63.334 | 63.222 | -0.112 | -0.18 | 650 | 68.816 | 68.511 | -0.306 | -0.44 | 700 | 74.667 | 74.088 | -0.579 | -0.78 | 750 | 78.612 | 79.582 | +0.970 | +1.23 | 800 | 85.431 | 85.263 | -0.168 | -0.2 | -------------------------------------------------------------- * 4 CPUs Number of | without | with | diff | diff | processes | Marker [Sec] | Marker [Sec] | [Sec] | [%] | -------------------------------------------------------------- 50 | 2.586 | 2.584 | -0.003 | -0.1 | 100 | 5.254 | 5.283 | +0.030 | +0.56 | 150 | 8.012 | 8.074 | +0.061 | +0.76 | 200 | 11.172 | 11.000 | -0.172 | -1.54 | 250 | 13.917 | 14.036 | +0.119 | +0.86 | 300 | 16.905 | 16.543 | -0.362 | -2.14 | 350 | 19.901 | 20.036 | +0.135 | +0.68 | 400 | 22.908 | 23.094 | +0.186 | +0.81 | 450 | 26.273 | 26.101 | -0.172 | -0.66 | 500 | 29.554 | 29.092 | -0.461 | -1.56 | 550 | 32.377 | 32.274 | -0.103 | -0.32 | 600 | 35.855 | 35.322 | -0.533 | -1.49 | 650 | 39.192 | 38.388 | -0.804 | -2.05 | 700 | 41.744 | 41.719 | -0.025 | -0.06 | 750 | 45.016 | 44.496 | -0.520 | -1.16 | 800 | 48.212 | 47.603 | -0.609 | -1.26 | -------------------------------------------------------------- * 8 CPUs Number of | without | with | diff | diff | processes | Marker [Sec] | Marker [Sec] | [Sec] | [%] | -------------------------------------------------------------- 50 | 2.094 | 2.072 | -0.022 | -1.07 | 100 | 4.162 | 4.273 | +0.111 | +2.66 | 150 | 6.485 | 6.540 | +0.055 | +0.84 | 200 | 8.556 | 8.478 | -0.078 | -0.91 | 250 | 10.458 | 10.258 | -0.200 | -1.91 | 300 | 12.425 | 12.750 | +0.325 | +2.62 | 350 | 14.807 | 14.839 | +0.032 | +0.22 | 400 | 16.801 | 16.959 | +0.158 | +0.94 | 450 | 19.478 | 19.009 | -0.470 | -2.41 | 500 | 21.296 | 21.504 | +0.208 | +0.98 | 550 | 23.842 | 23.979 | +0.137 | +0.57 | 600 | 26.309 | 26.111 | -0.198 | -0.75 | 650 | 28.705 | 28.446 | -0.259 | -0.9 | 700 | 31.233 | 31.394 | +0.161 | +0.52 | 750 | 34.064 | 33.720 | -0.344 | -1.01 | 800 | 36.320 | 36.114 | -0.206 | -0.57 | -------------------------------------------------------------- Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Acked-by: Masami Hiramatsu <mhiramat@redhat.com> Acked-by: 'Peter Zijlstra' <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* tty: Fix abusers of current->sighand->ttyAlan Cox2008-10-132-6/+5
| | | | | | | | Various people outside the tty layer still stick their noses in behind the scenes. We need to make sure they also obey the locking and referencing rules. Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* tty: Move tty_write_message out of kernel/printkAlan Cox2008-10-131-16/+0
| | | | | | | | This is pure tty code so put it in the tty layer where it can be with the locking relevant material it uses Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* tty: Add a kref countAlan Cox2008-10-132-4/+5
| | | | | | | | Introduce a kref to the tty structure and use it to protect the tty->signal tty references. For now we don't introduce it for anything else. Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'master' of ↵David S. Miller2008-10-1126-468/+900
|\ | | | | | | | | | | | | | | master.kernel.org:/pub/scm/linux/kernel/git/torvalds/linux-2.6 Conflicts: sound/core/memalloc.c
| * Merge phase #4 (X2APIC, APIC unification, CPU identification unification) of ↵Linus Torvalds2008-10-112-1/+76
| |\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'x86-v28-for-linus-phase4-D' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (186 commits) x86, debug: print more information about unknown CPUs x86 setup: handle more than 8 CPU flag words x86: cpuid, fix typo x86: move transmeta cap read to early_init_transmeta() x86: identify_cpu_without_cpuid v2 x86: extended "flags" to show virtualization HW feature in /proc/cpuinfo x86: move VMX MSRs to msr-index.h x86: centaur_64.c remove duplicated setting of CONSTANT_TSC x86: intel.c put workaround for old cpus together x86: let intel 64-bit use intel.c x86: make intel_64.c the same as intel.c x86: make intel.c have 64-bit support code x86: little clean up of intel.c/intel_64.c x86: make 64 bit to use amd.c x86: make amd_64 have 32 bit code x86: make amd.c have 64bit support code x86: merge header in amd_64.c x86: add srat_detect_node for amd64 x86: remove duplicated force_mwait x86: cpu make amd.c more like amd_64.c v2 ...
| | * Merge branch 'x86/unify-cpu-detect' into x86-v28-for-linus-phase4-DIngo Molnar2008-10-111-0/+68
| | |\ | | | | | | | | | | | | | | | | | | | | | | | | Conflicts: arch/x86/kernel/cpu/common.c arch/x86/kernel/signal_64.c include/asm-x86/cpufeature.h
| | | * Merge commit 'v2.6.27-rc6' into x86/unify-cpu-detectIngo Molnar2008-09-1010-168/+361
| | | |\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Conflicts: arch/x86/kernel/cpu/amd.c arch/x86/kernel/cpu/common.c arch/x86/kernel/cpu/common_64.c arch/x86/kernel/cpu/feature_names.c include/asm-x86/cpufeature.h Signed-off-by: Ingo Molnar <mingo@elte.hu>
| | | * \ Merge branch 'x86/core' into x86/unify-cpu-detectIngo Molnar2008-09-052-1/+76
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| | | | * \ Merge branch 'core/resources' into x86/coreIngo Molnar2008-09-041-0/+68
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| | | | | * | IO resources: add reserve_region_with_split()Yinghai Lu2008-09-041-0/+68
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | add reserve_region_with_split() to not lose e820 reserved entries if they overlap with existing IO regions: with test case by extend 0xe0000000 - 0xeffffff to 0xdd800000 - we get: e0000000-efffffff : PCI MMCONFIG 0 e0000000-efffffff : reserved and in /proc/iomem we get: found conflict for reserved [dd800000, efffffff], try to reserve with split __reserve_region_with_split: (PCI Bus #80) [dd000000, ddffffff], res: (reserved) [dd800000, efffffff] __reserve_region_with_split: (PCI Bus #00) [de000000, dfffffff], res: (reserved) [de000000, efffffff] initcall pci_subsys_init+0x0/0x121 returned 0 after 381 msecs in dmesg various fixes and improvements suggested by Linus. Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| | | | * | | Merge branch 'linus' into x86/coreH. Peter Anvin2008-09-0413-157/+173
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| | | | * | | Merge branch 'x86/cpu' into x86/coreH. Peter Anvin2008-09-0420-88/+135
| | | | |\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Conflicts: arch/x86/kernel/cpu/feature_names.c include/asm-x86/cpufeature.h
| | * | | \ \ \ Merge branch 'x86/apic' into x86-v28-for-linus-phase4-BIngo Molnar2008-10-111-1/+8
| | |\ \ \ \ \ \ | | | | |/ / / / | | | |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Conflicts: arch/x86/kernel/apic_32.c arch/x86/kernel/apic_64.c arch/x86/kernel/setup.c drivers/pci/intel-iommu.c include/asm-x86/cpufeature.h include/asm-x86/dma-mapping.h
| | | * | | | | Merge branch 'linus' into x86/coreIngo Molnar2008-08-1434-441/+724
| | | |\ \ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Conflicts: arch/x86/kernel/genapic_64.c include/asm-x86/kvm_host.h Signed-off-by: Ingo Molnar <mingo@elte.hu>
| | | * \ \ \ \ \ Merge commit 'v2.6.27-rc1' into x86/coreIngo Molnar2008-07-3032-480/+962
| | | |\ \ \ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Conflicts: include/asm-x86/dma-mapping.h include/asm-x86/namei.h include/asm-x86/uaccess.h Signed-off-by: Ingo Molnar <mingo@elte.hu>
| | | * \ \ \ \ \ \ Merge branch 'x86/x2apic' into x86/coreIngo Molnar2008-07-261-1/+8
| | | |\ \ \ \ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Conflicts: include/asm-x86/i8259.h include/asm-x86/msidef.h Signed-off-by: Ingo Molnar <mingo@elte.hu>
| | | | * \ \ \ \ \ \ Merge branch 'linus' into x86/x2apicIngo Molnar2008-07-2536-685/+1125
| | | | |\ \ \ \ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Conflicts: drivers/pci/dmar.c Signed-off-by: Ingo Molnar <mingo@elte.hu>
| | | | * \ \ \ \ \ \ \ Merge branch 'linus' into x86/x2apicIngo Molnar2008-07-221-1/+1
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| | | | * \ \ \ \ \ \ \ \ Merge branch 'linus' into x86/x2apicIngo Molnar2008-07-1863-1140/+11466
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| | | | * | | | | | | | | | x64, x2apic/intr-remap: generic irq migration support from process contextSuresh Siddha2008-07-121-1/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Generic infrastructure for migrating the irq from the process context in the presence of CONFIG_GENERIC_PENDING_IRQ. This will be used later for migrating irq in the presence of interrupt-remapping. Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> Cc: akpm@linux-foundation.org Cc: arjan@linux.intel.com Cc: andi@firstfloor.org Cc: ebiederm@xmission.com Cc: jbarnes@virtuousgeek.org Cc: steiner@sgi.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | | | | | | | | | | | | Merge phase #3 (IOMMU) of ↵Linus Torvalds2008-10-111-0/+2
| |\ \ \ \ \ \ \ \ \ \ \ \ \ | | |/ / / / / / / / / / / / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'x86-v28-for-linus-phase3-B' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (74 commits) AMD IOMMU: use iommu_device_max_index, fix AMD IOMMU: use iommu_device_max_index x86: add PCI IDs for AMD Barcelona PCI devices x86/iommu: use __GFP_ZERO instead of memset for GART x86/iommu: convert GART need_flush to bool x86/iommu: make GART driver checkpatch clean x86 gart: remove unnecessary initialization x86: restore old GART alloc_coherent behavior revert "x86: make GART to respect device's dma_mask about virtual mappings" x86: export pci-nommu's alloc_coherent iommu: remove fullflush and nofullflush in IOMMU generic option x86: remove set_bit_string() iommu: export iommu_area_reserve helper function AMD IOMMU: use coherent_dma_mask in alloc_coherent add AMD IOMMU tree to MAINTAINERS file AMD IOMMU: use cmd_buf_size when freeing the command buffer AMD IOMMU: calculate IVHD size with a function AMD IOMMU: remove unnecessary cast to u64 in the init code AMD IOMMU: free domain bitmap with its allocation order AMD IOMMU: simplify dma_mask_to_pages ...
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| | *---. \ \ \ \ \ \ \ \ \ \ \ Merge branches 'core/iommu', 'x86/amd-iommu' and 'x86/iommu' into ↵Ingo Molnar2008-10-101-0/+2
| | |\ \ \ \ \ \ \ \ \ \ \ \ \ \ | | | | | |_|_|_|_|_|_|/ / / / / | | | | |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | x86-v28-for-linus-phase3-B Conflicts: arch/x86/kernel/pci-gart_64.c include/asm-x86/dma-mapping.h
| | | | | * | | | | | | | | | | Merge branch 'linus' into x86/iommuIngo Molnar2008-09-141-22/+15
| | | | | |\ \ \ \ \ \ \ \ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Conflicts: lib/swiotlb.c Signed-off-by: Ingo Molnar <mingo@elte.hu>
| | | | | * \ \ \ \ \ \ \ \ \ \ \ Merge commit 'v2.6.27-rc6' into x86/iommuIngo Molnar2008-09-1033-341/+556
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| | | | | * | | | | | | | | | | | dma-coherent: export dma_[alloc|release]_from_coherent methodsIngo Molnar2008-08-221-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | fixes modular builds: ERROR: "dma_alloc_from_coherent" [sound/core/snd-page-alloc.ko] undefined! ERROR: "dma_release_from_coherent" [sound/core/snd-page-alloc.ko] undefined! Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | | | | | | | | | | | | | | | Merge branch 'next' of ↵Linus Torvalds2008-10-111-1/+10
| |\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/davej/cpufreq * 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/davej/cpufreq: [CPUFREQ] Fix BUG: using smp_processor_id() in preemptible code [CPUFREQ] Don't export governors for default governor [CPUFREQ][6/6] cpufreq: Add idle microaccounting in ondemand governor [CPUFREQ][5/6] cpufreq: Changes to get_cpu_idle_time_us(), used by ondemand governor [CPUFREQ][4/6] cpufreq_ondemand: Parameterize down differential [CPUFREQ][3/6] cpufreq: get_cpu_idle_time() changes in ondemand for idle-microaccounting [CPUFREQ][2/6] cpufreq: Change load calculation in ondemand for software coordination [CPUFREQ][1/6] cpufreq: Add cpu number parameter to __cpufreq_driver_getavg() [CPUFREQ] use deferrable delayed work init in conservative governor [CPUFREQ] drivers/cpufreq/cpufreq.c: Adjust error handling code involving cpufreq_cpu_put [CPUFREQ] add error handling for cpufreq_register_governor() error [CPUFREQ] acpi-cpufreq: add error handling for cpufreq_register_driver() error [CPUFREQ] Coding style fixes to arch/x86/kernel/cpu/cpufreq/powernow-k6.c [CPUFREQ] Coding style fixes to arch/x86/kernel/cpu/cpufreq/elanfreq.c
| | * | | | | | | | | | | | | | | | [CPUFREQ][5/6] cpufreq: Changes to get_cpu_idle_time_us(), used by ondemand ↵venkatesh.pallipadi@intel.com2008-10-091-1/+10
| | |/ / / / / / / / / / / / / / / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | governor export get_cpu_idle_time_us() for it to be used in ondemand governor. Last update time can be current time when the CPU is currently non-idle, accounting for the busy time since last idle. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Dave Jones <davej@redhat.com>
| * | | | | | | | | | | | | | | | Merge branch 'rcu-v28-for-linus' of ↵Linus Torvalds2008-10-103-95/+257
| |\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'rcu-v28-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (21 commits) rcu: RCU-based detection of stalled CPUs for Classic RCU, fix rcu: RCU-based detection of stalled CPUs for Classic RCU rcu: add rcu_read_lock_sched() / rcu_read_unlock_sched() rcu: fix sparse shadowed variable warning doc/RCU: fix pseudocode in rcuref.txt rcuclassic: fix compiler warning rcu: use irq-safe locks rcuclassic: fix compilation NG rcu: fix locking cleanup fallout rcu: remove redundant ACCESS_ONCE definition from rcupreempt.c rcu: fix classic RCU locking cleanup lockdep problem rcu: trace fix possible mem-leak rcu: just rename call_rcu_bh instead of making it a macro rcu: remove list_for_each_rcu() rcu: fixes to include/linux/rcupreempt.h rcu: classic RCU locking and memory-barrier cleanups rcu: prevent console flood when one CPU sees another AWOL via RCU rcu, debug: detect stalled grace periods, cleanups rcu, debug: detect stalled grace periods rcu classic: new algorithm for callbacks-processing(v2) ...
| | * \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ Merge branch 'linus' into core/rcuIngo Molnar2008-10-097-17/+97
| | |\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ | | | |/ / / / / / / / / / / / / / /
| | * | | | | | | | | | | | | | | | rcu: RCU-based detection of stalled CPUs for Classic RCU, fixIngo Molnar2008-10-031-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | fix the !CONFIG_RCU_CPU_STALL_DETECTOR path: kernel/rcuclassic.c: In function '__rcu_pending': kernel/rcuclassic.c:609: error: too few arguments to function 'check_cpu_stall' Signed-off-by: Ingo Molnar <mingo@elte.hu>
| | * | | | | | | | | | | | | | | | rcu: RCU-based detection of stalled CPUs for Classic RCUPaul E. McKenney2008-10-031-80/+86
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch adds stalled-CPU detection to Classic RCU. This capability is enabled by a new config variable CONFIG_RCU_CPU_STALL_DETECTOR, which defaults disabled. This is a debugging feature to detect infinite loops in kernel code, not something that non-kernel-hackers would be expected to care about. This feature can detect looping CPUs in !PREEMPT builds and looping CPUs with preemption disabled in PREEMPT builds. This is essentially a port of this functionality from the treercu patch, replacing the stall debug patch that is already in tip/core/rcu (commit 67182ae1c4). The changes from the patch in tip/core/rcu include making the config variable name match that in treercu, changing from seconds to jiffies to avoid spurious warnings, and printing a boot message when this feature is enabled. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| | * | | | | | | | | | | | | | | | Merge commit 'v2.6.27-rc8' into core/rcuIngo Molnar2008-10-0312-51/+97
| | |\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \
| | * | | | | | | | | | | | | | | | | rcu: fix sparse shadowed variable warningHarvey Harrison2008-09-231-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | kernel/rcuclassic.c:564:18: warning: symbol 'flags' shadows an earlier one kernel/rcuclassic.c:527:16: originally declared here Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| | * | | | | | | | | | | | | | | | | Merge commit 'v2.6.27-rc6' into core/rcuIngo Molnar2008-09-1046-707/+1133
| | |\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ | | | | |_|_|_|_|/ / / / / / / / / / / | | | |/| | | | | | | | | | | | | | |
| | * | | | | | | | | | | | | | | | | rcuclassic: fix compiler warningHiroshi Shimamoto2008-08-271-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | CC kernel/rcuclassic.o kernel/rcuclassic.c: In function 'rcu_init_percpu_data': kernel/rcuclassic.c:705: warning: comparison of distinct pointer types lacks a cast kernel/rcuclassic.c:713: warning: comparison of distinct pointer types lacks a cast flags should be unsigned long. Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| | * | | | | | | | | | | | | | | | | rcu: use irq-safe locksPaul E. McKenney2008-08-211-6/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Some earlier tip/core/rcu patches caused RCU to incorrectly enable irqs too early in boot. This caused Yinghai's repeated-kexec testing to hit oopses, presumably due to so that device interrupts left over from the prior kernel instance (which would oops the newly booting kernel before it got a chance to reset said devices). This patch therefore converts all the local_irq_disable()s in rcuclassic.c to local_irq_save(). Besides, I never did like local_irq_disable() anyway. ;-) Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| | * | | | | | | | | | | | | | | | | rcuclassic: fix compilation NGHiroshi Shimamoto2008-08-191-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | fix: CC kernel/rcuclassic.o kernel/rcuclassic.c: In function '__rcu_process_callbacks': kernel/rcuclassic.c:561: error: 'flags' undeclared (first use in this function) kernel/rcuclassic.c:561: error: (Each undeclared identifier is reported only once kernel/rcuclassic.c:561: error: for each function it appears in.) Declare missing variable flags. Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| | * | | | | | | | | | | | | | | | | rcu: fix locking cleanup falloutPaul E. McKenney2008-08-191-14/+22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Given that the rcp->lock is now acquired from call_rcu(), which can be invoked from irq-disable regions, all acquisitions need to disable irqs. The following patch fixes this. Although I don't have any reason to believe that this is the cause of Yinghai's oops, it does need to be fixed. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Yinghai Lu <yhlu.kernel@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| | * | | | | | | | | | | | | | | | | rcu: remove redundant ACCESS_ONCE definition from rcupreempt.cPaul E. McKenney2008-08-181-8/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Remove the redundant definition of ACCESS_ONCE() from rcupreempt.c in favor of the one in compiler.h. Also merge the comment header from rcupreempt.c's definition into that in compiler.h. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| | * | | | | | | | | | | | | | | | | rcu: fix classic RCU locking cleanup lockdep problemPaul E. McKenney2008-08-171-2/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | On Fri, Aug 15, 2008 at 04:24:30PM +0200, Ingo Molnar wrote: > > Paul, > > one of your two recent RCU patches caused this lockdep splat in -tip > testing: > > -------------------> > Brought up 2 CPUs > Total of 2 processors activated (6850.87 BogoMIPS). > PM: Adding info for No Bus:platform > khelper used greatest stack depth: 3124 bytes left > > ================================= > [ INFO: inconsistent lock state ] > 2.6.27-rc3-tip #1 > --------------------------------- > inconsistent {softirq-on-W} -> {in-softirq-W} usage. > ksoftirqd/0/4 [HC0[0]:SC1[1]:HE1:SE0] takes: > (&rcu_ctrlblk.lock){-+..}, at: [<c016d91c>] __rcu_process_callbacks+0x1ac/0x1f0 > {softirq-on-W} state was registered at: > [<c01528e4>] __lock_acquire+0x3f4/0x5b0 > [<c0152b29>] lock_acquire+0x89/0xc0 > [<c076142b>] _spin_lock+0x3b/0x70 > [<c016d649>] rcu_init_percpu_data+0x29/0x80 > [<c075e43f>] rcu_cpu_notify+0xaf/0xd0 > [<c076458d>] notifier_call_chain+0x2d/0x60 > [<c0145ede>] __raw_notifier_call_chain+0x1e/0x30 > [<c075db29>] _cpu_up+0x79/0x110 > [<c075dc0d>] cpu_up+0x4d/0x70 > [<c0a769e1>] kernel_init+0xb1/0x200 > [<c01048a3>] kernel_thread_helper+0x7/0x10 > [<ffffffff>] 0xffffffff > irq event stamp: 14 > hardirqs last enabled at (14): [<c01534db>] trace_hardirqs_on+0xb/0x10 > hardirqs last disabled at (13): [<c014dbeb>] trace_hardirqs_off+0xb/0x10 > softirqs last enabled at (0): [<c012b186>] copy_process+0x276/0x1190 > softirqs last disabled at (11): [<c0105c0a>] call_on_stack+0x1a/0x30 > > other info that might help us debug this: > no locks held by ksoftirqd/0/4. > > stack backtrace: > Pid: 4, comm: ksoftirqd/0 Not tainted 2.6.27-rc3-tip #1 > [<c01504dc>] print_usage_bug+0x16c/0x1b0 > [<c0152455>] mark_lock+0xa75/0xb10 > [<c0108b75>] ? sched_clock+0x15/0x30 > [<c015289d>] __lock_acquire+0x3ad/0x5b0 > [<c0152b29>] lock_acquire+0x89/0xc0 > [<c016d91c>] ? __rcu_process_callbacks+0x1ac/0x1f0 > [<c076142b>] _spin_lock+0x3b/0x70 > [<c016d91c>] ? __rcu_process_callbacks+0x1ac/0x1f0 > [<c016d91c>] __rcu_process_callbacks+0x1ac/0x1f0 > [<c016d986>] rcu_process_callbacks+0x26/0x50 > [<c0132305>] __do_softirq+0x95/0x120 > [<c0132270>] ? __do_softirq+0x0/0x120 > [<c0105c0a>] call_on_stack+0x1a/0x30 > [<c0132426>] ? ksoftirqd+0x96/0x110 > [<c0132390>] ? ksoftirqd+0x0/0x110 > [<c01411f7>] ? kthread+0x47/0x80 > [<c01411b0>] ? kthread+0x0/0x80 > [<c01048a3>] ? kernel_thread_helper+0x7/0x10 > ======================= > calling init_cpufreq_transition_notifier_list+0x0/0x20 > initcall init_cpufreq_transition_notifier_list+0x0/0x20 returned 0 after 0 msecs > calling net_ns_init+0x0/0x190 > net_namespace: 676 bytes > initcall net_ns_init+0x0/0x190 returned 0 after 0 msecs > calling cpufreq_tsc+0x0/0x20 > initcall cpufreq_tsc+0x0/0x20 returned 0 after 0 msecs > calling reboot_init+0x0/0x20 > initcall reboot_init+0x0/0x20 returned 0 after 0 msecs > calling print_banner+0x0/0x10 > Booting paravirtualized kernel on bare hardware > > <----------------------- > > my guess is on: > > commit 1f7b94cd3d564901f9e04a8bc5832ae7bfd690a0 > Author: Paul E. McKenney <paulmck@linux.vnet.ibm.com> > Date: Tue Aug 5 09:21:44 2008 -0700 > > rcu: classic RCU locking and memory-barrier cleanups > > Ingo Fixes a problem detected by lockdep in which rcu->lock was acquired both in irq context and in process context, but without disabling from process context. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| | * | | | | | | | | | | | | | | | | rcu: trace fix possible mem-leakSteven Rostedt2008-08-151-1/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In the initialization of the RCU trace module, if rcupreempt_debugfs_init() fails, we never free the the trace buffer. This patch frees the trace buffer in case the debugfs fails. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Reviewed-by: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| | * | | | | | | | | | | | | | | | | rcu: classic RCU locking and memory-barrier cleanupsPaul E. McKenney2008-08-151-10/+41
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch simplifies the locking and memory-barrier usage in the Classic RCU grace-period-detection mechanism, incorporating Lai Jiangshan's feedback from the earlier version (http://lkml.org/lkml/2008/8/1/400 and http://lkml.org/lkml/2008/8/3/43). Passed 10 hours of rcutorture concurrent with CPUs being put online and taken offline on a 128-hardware-thread Power machine. My apologies to whoever in the Eastern Hemisphere was planning to use this machine over the Western Hemisphere night, but it was sitting idle and... So this is ready for tip/core/rcu. This patch is in preparation for moving to a hierarchical algorithm to allow the very large SMP machines -- requested by some people at OLS, and there seem to have been a few recent patches in the 4096-CPU direction as well. The general idea is to move to a much more conservative concurrency design, then apply a hierarchy to reduce contention on the global lock by a few orders of magnitude (larger machines would see greater reductions). The reason for taking a conservative approach is that this code isn't on any fast path. Prototype in progress. This patch is against the linux-tip git tree (tip/core/rcu). If you wish to test this against 2.6.26, use the following set of patches: http://www.rdrop.com/users/paulmck/patches/2.6.26-ljsimp-1.patch http://www.rdrop.com/users/paulmck/patches/2.6.26-ljsimpfix-3.patch The first patch combines commits 5127bed588a2f8f3a1f732de2a8a190b7df5dce3 and 3cac97cbb14aed00d83eb33d4613b0fe3aaea863 from Lai Jiangshan <laijs@cn.fujitsu.com>, and the second patch contains my changes. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| | * | | | | | | | | | | | | | | | | rcu: prevent console flood when one CPU sees another AWOL via RCUPaul E. McKenney2008-08-151-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | One small change needed to keep from flooding the console when one CPU notices that another is AWOL. Unless I am missing something subtle. Otherwise the cleanups look good! Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| | * | | | | | | | | | | | | | | | | rcu, debug: detect stalled grace periods, cleanupsIngo Molnar2008-08-111-13/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | small cleanups. Signed-off-by: Ingo Molnar <mingo@elte.hu>
| | * | | | | | | | | | | | | | | | | rcu, debug: detect stalled grace periodsPaul E. McKenney2008-08-111-0/+80
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | this is a diagnostic patch for Classic RCU. The approach is to record a timestamp at the beginning of the grace period (in rcu_start_batch()), then have rcu_check_callbacks() complain if: 1. it is running on a CPU that has holding up grace periods for a long time (say one second). This will identify the culprit assuming that the culprit has not disabled hardware irqs, instruction execution, or some such. 2. it is running on a CPU that is not holding up grace periods, but grace periods have been held up for an even longer time (say two seconds). It is enabled via the default-off CONFIG_DEBUG_RCU_STALL kernel parameter. Rather than exponential backoff, it backs off to once per 30 seconds. My feeling upon thinking on it was that if you have stalled RCU grace periods for that long, a few extra printk() messages are probably the least of your worries... Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Yinghai Lu <yhlu.kernel@gmail.com> Cc: David Witbrodt <dawitbro@sbcglobal.net> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| | * | | | | | | | | | | | | | | | | Merge branch 'linus' into core/rcuIngo Molnar2008-08-1173-1897/+3112
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| | * | | | | | | | | | | | | | | | | | rcu classic: new algorithm for callbacks-processing(v2)Lai Jiangshan2008-07-181-60/+97
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This is v2, it's a little deference from v1 that I had send to lkml. use ACCESS_ONCE use rcu_batch_after/rcu_batch_before for batch # comparison. rcutorture test result: (hotplugs: do cpu-online/offline once per second) No CONFIG_NO_HZ: OK, 12hours No CONFIG_NO_HZ, hotplugs: OK, 12hours CONFIG_NO_HZ=y: OK, 24hours CONFIG_NO_HZ=y, hotplugs: Failed. (Failed also without my patch applied, exactly the same bug occurred, http://lkml.org/lkml/2008/7/3/24) v1's email thread: http://lkml.org/lkml/2008/6/2/539 v1's description: The code/algorithm of the implement of current callbacks-processing is very efficient and technical. But when I studied it and I found a disadvantage: In multi-CPU systems, when a new RCU callback is being queued(call_rcu[_bh]), this callback will be invoked after the grace period for the batch with batch number = rcp->cur+2 has completed very very likely in current implement. Actually, this callback can be invoked after the grace period for the batch with batch number = rcp->cur+1 has completed. The delay of invocation means that latency of synchronize_rcu() is extended. But more important thing is that the callbacks usually free memory, and these works are delayed too! it's necessary for reclaimer to free memory as soon as possible when left memory is few. A very simple way can solve this problem: a field(struct rcu_head::batch) is added to record the batch number for the RCU callback. And when a new RCU callback is being queued, we determine the batch number for this callback(head->batch = rcp->cur+1) and we move this callback to rdp->donelist if we find that head->batch <= rcp->completed when we process callbacks. This simple way reduces the wait time for invocation a lot. (about 2.5Grace Period -> 1.5Grace Period in average in multi-CPU systems) This is my algorithm. But I do not add any field for struct rcu_head in my implement. We just need to memorize the last 2 batches and their batch number, because these 2 batches include all entries that for whom the grace period hasn't completed. So we use a special linked-list rather than add a field. Please see the comment of struct rcu_data. Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Dipankar Sarma <dipankar@in.ibm.com> Cc: Gautham Shenoy <ego@in.ibm.com> Cc: Dhaval Giani <dhaval@linux.vnet.ibm.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| | * | | | | | | | | | | | | | | | | | rcu classic: simplify the next pending batchLai Jiangshan2008-07-181-14/+8
| | | |_|_|_|_|_|_|_|_|_|/ / / / / / / | | |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | use a batch number(rcp->pending) instead of a flag(rcp->next_pending) rcu_start_batch() need to change this flag, so mb()s is needed for memory-access safe. but(after this patch applied) rcu_start_batch() do not change this batch number(rcp->pending), rcp->pending is managed by __rcu_process_callbacks only, and troublesome mb()s are eliminated. And codes look simpler and clearer. Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Dipankar Sarma <dipankar@in.ibm.com> Cc: Gautham Shenoy <ego@in.ibm.com> Cc: Dhaval Giani <dhaval@linux.vnet.ibm.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | | | | | | | | | | | | | | | | | sched debug: add name to sched_domain sysctl entriesIngo Molnar2008-10-091-2/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | add /proc/sys/kernel/sched_domain/cpu0/domain0/name, to make it easier to see which specific scheduler domain remained at that entry. Since we process the scheduler domain tree and simplify it, it's not always immediately clear during debugging which domain came from where. depends on CONFIG_SCHED_DEBUG=y. Signed-off-by: Ingo Molnar <mingo@elte.hu>
generated by cgit v1.1 at 2025-01-30 00:48:21 +0000