summaryrefslogtreecommitdiffstats
path: root/include/trace
Commit message (Collapse)AuthorAgeFilesLines
* Merge tag 'device-for-3.4' of ↵Linus Torvalds2012-03-243-3/+3
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux Pull <linux/device.h> avoidance patches from Paul Gortmaker: "Nearly every subsystem has some kind of header with a proto like: void foo(struct device *dev); and yet there is no reason for most of these guys to care about the sub fields within the device struct. This allows us to significantly reduce the scope of headers including headers. For this instance, a reduction of about 40% is achieved by replacing the include with the simple fact that the device is some kind of a struct. Unlike the much larger module.h cleanup, this one is simply two commits. One to fix the implicit <linux/device.h> users, and then one to delete the device.h includes from the linux/include/ dir wherever possible." * tag 'device-for-3.4' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux: device.h: audit and cleanup users in main include dir device.h: cleanup users outside of linux/include (C files)
| * device.h: audit and cleanup users in main include dirPaul Gortmaker2012-03-163-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The <linux/device.h> header includes a lot of stuff, and it in turn gets a lot of use just for the basic "struct device" which appears so often. Clean up the users as follows: 1) For those headers only needing "struct device" as a pointer in fcn args, replace the include with exactly that. 2) For headers not really using anything from device.h, simply delete the include altogether. 3) For headers relying on getting device.h implicitly before being included themselves, now explicitly include device.h 4) For files in which doing #1 or #2 uncovers an implicit dependency on some other header, fix by explicitly adding the required header(s). Any C files that were implicitly relying on device.h to be present have already been dealt with in advance. Total removals from #1 and #2: 51. Total additions coming from #3: 9. Total other implicit dependencies from #4: 7. As of 3.3-rc1, there were 110, so a net removal of 42 gives about a 38% reduction in device.h presence in include/* Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
* | Merge tag 'nfs-for-3.4-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfsLinus Torvalds2012-03-231-0/+177
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull NFS client updates for Linux 3.4 from Trond Myklebust: "New features include: - Add NFS client support for containers. This should enable most of the necessary functionality, including lockd support, and support for rpc.statd, NFSv4 idmapper and RPCSEC_GSS upcalls into the correct network namespace from which the mount system call was issued. - NFSv4 idmapper scalability improvements Base the idmapper cache on the keyring interface to allow concurrent access to idmapper entries. Start the process of migrating users from the single-threaded daemon-based approach to the multi-threaded request-key based approach. - NFSv4.1 implementation id. Allows the NFSv4.1 client and server to mutually identify each other for logging and debugging purposes. - Support the 'vers=4.1' mount option for mounting NFSv4.1 instead of having to use the more counterintuitive 'vers=4,minorversion=1'. - SUNRPC tracepoints. Start the process of adding tracepoints in order to improve debugging of the RPC layer. - pNFS object layout support for autologin. Important bugfixes include: - Fix a bug in rpc_wake_up/rpc_wake_up_status that caused them to fail to wake up all tasks when applied to priority waitqueues. - Ensure that we handle read delegations correctly, when we try to truncate a file. - A number of fixes for NFSv4 state manager loops (mostly to do with delegation recovery)." * tag 'nfs-for-3.4-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs: (224 commits) NFS: fix sb->s_id in nfs debug prints xprtrdma: Remove assumption that each segment is <= PAGE_SIZE xprtrdma: The transport should not bug-check when a dup reply is received pnfs-obj: autologin: Add support for protocol autologin NFS: Remove nfs4_setup_sequence from generic rename code NFS: Remove nfs4_setup_sequence from generic unlink code NFS: Remove nfs4_setup_sequence from generic read code NFS: Remove nfs4_setup_sequence from generic write code NFS: Fix more NFS debug related build warnings SUNRPC/LOCKD: Fix build warnings when CONFIG_SUNRPC_DEBUG is undefined nfs: non void functions must return a value SUNRPC: Kill compiler warning when RPC_DEBUG is unset SUNRPC/NFS: Add Kbuild dependencies for NFS_DEBUG/RPC_DEBUG NFS: Use cond_resched_lock() to reduce latencies in the commit scans NFSv4: It is not safe to dereference lsp->ls_state in release_lockowner NFS: ncommit count is being double decremented SUNRPC: We must not use list_for_each_entry_safe() in rpc_wake_up() Try using machine credentials for RENEW calls NFSv4.1: Fix a few issues in filelayout_commit_pagelist NFSv4.1: Clean ups and bugfixes for the pNFS read/writeback/commit code ...
| * | SUNRPC: Adding status trace pointsSteve Dickson2012-02-061-0/+53
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch adds three trace points to the status routines in the sunrpc state machine. The goal of these trace points is to give an Admin the ability to check on binding status or connection status to see if there is a potential problem. Signed-off-by: Steve Dickson <steved@redhat.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
| * | SUNRPC: Fix up sunrpc trace eventsTrond Myklebust2012-02-061-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | The reporting of the RPC queue name needs to use the __string() event interface. Reported-by: Neil Horman <nhorman@redhat.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
| * | SUNRPC: Add trace events to the sunrpc subsystemTrond Myklebust2012-01-311-0/+124
| |/ | | | | | | | | | | | | Add declarations to allow tracing of RPC call creation, running, sleeping, and destruction. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
* | Merge tag 'regmap-3.4' of ↵Linus Torvalds2012-03-221-0/+36
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regmap Pull regmap updates from Mark Brown: "Things are really quieting down with the regmap API, while we're still seeing a trickle of new features coming in they're getting much smaller than they were. It's also nice to have some features which support other subsystems building infrastructure on top of regmap. Highlights include: - Support for padding between the register and the value when interacting with the device, sometimes needed for fast interfaces. - Support for applying register updates to the device when restoring the register state. This is intended to be used to apply updates supplied by manufacturers for tuning the performance of the device (many of which are to undocumented registers which aren't otherwise covered). - Support for multi-register operations on cached registers. - Support for syncing only part of the register cache. - Stubs and parameter query functions intended to make it easier for other subsystems to build infrastructure on top of the regmap API. plus a few driver updates making use of the new features which it was easier to merge via this tree." * tag 'regmap-3.4' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regmap: (41 commits) regmap: Fix future missing prototype of devres_alloc() and friends regmap: Rejig struct declarations for stubbed API regmap: Fix rbtree block base in sync regcache: Make sure we sync register 0 in an rbtree cache regmap: delete unused module.h from drivers/base/regmap files regmap: Add stub for regcache_sync_region() mfd: Improve performance of later WM1811 revisions regmap: Fix x86_64 breakage regmap: Allow drivers to sync only part of the register cache regmap: Supply ranges to the sync operations regmap: Add tracepoints for cache only and cache bypass regmap: Mark the cache as clean after a successful sync regmap: Remove default cache sync implementation regmap: Skip hardware defaults for LZO caches regmap: Expose the driver name in debugfs mfd: wm8400: Convert to devm_regmap_init_i2c() mfd: wm831x: Convert to devm_regmap_init() mfd: wm8994: Convert to devm_regmap_init() mfd/ASoC: Convert WM8994 driver to use regmap patches mfd: Add __devinit and __devexit annotations in wm8994 ...
| * \ Merge remote-tracking branch 'regmap/topic/drivers' into regmap-nextMark Brown2012-03-141-2/+5
| |\ \ | | | | | | | | | | | | | | | | | | | | Resolved simple add/add conflicts: drivers/base/regmap/internal.h drivers/base/regmap/regmap.c
| * | | regmap: Add tracepoints for cache only and cache bypassMark Brown2012-02-231-0/+36
| | |/ | |/| | | | | | | | | | | | | Useful for figuring out where the hardware interaction went or came from. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
* | | Merge branch 'for-linus' of ↵Linus Torvalds2012-03-201-1/+0
|\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial Pull trivial tree from Jiri Kosina: "It's indeed trivial -- mostly documentation updates and a bunch of typo fixes from Masanari. There are also several linux/version.h include removals from Jesper." * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (101 commits) kcore: fix spelling in read_kcore() comment constify struct pci_dev * in obvious cases Revert "char: Fix typo in viotape.c" init: fix wording error in mm_init comment usb: gadget: Kconfig: fix typo for 'different' Revert "power, max8998: Include linux/module.h just once in drivers/power/max8998_charger.c" writeback: fix fn name in writeback_inodes_sb_nr_if_idle() comment header writeback: fix typo in the writeback_control comment Documentation: Fix multiple typo in Documentation tpm_tis: fix tis_lock with respect to RCU Revert "media: Fix typo in mixer_drv.c and hdmi_drv.c" Doc: Update numastat.txt qla4xxx: Add missing spaces to error messages compiler.h: Fix typo security: struct security_operations kerneldoc fix Documentation: broken URL in libata.tmpl Documentation: broken URL in filesystems.tmpl mtd: simplify return logic in do_map_probe() mm: fix comment typo of truncate_inode_pages_range power: bq27x00: Fix typos in comment ...
| * | | Remove incorrect comment from include/trace/events/power.hJesper Juhl2012-02-051-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The code is not going to be removed, so remove the comment stating that it will be. Signed-off-by: Jesper Juhl <jj@chaosbits.net> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
| * | | Merge branch 'master' into for-nextJiri Kosina2012-02-038-16/+336
| |\ \ \ | | |/ / | | | | | | | | | | | | Sync with Linus' tree to be able to apply patch to a newer code (namely drivers/gpu/drm/gma500/psb_intel_lvds.c)
| * | | Fix up version number reference in include/trace/events/power.hJesper Juhl2012-02-031-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | What was originally going to be 2.6.41 became 3.1 . Signed-off-by: Jesper Juhl <jj@chaosbits.net> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
* | | | Merge branch 'perf-core-for-linus' of ↵Linus Torvalds2012-03-204-63/+92
|\ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull perf events changes for v3.4 from Ingo Molnar: - New "hardware based branch profiling" feature both on the kernel and the tooling side, on CPUs that support it. (modern x86 Intel CPUs with the 'LBR' hardware feature currently.) This new feature is basically a sophisticated 'magnifying glass' for branch execution - something that is pretty difficult to extract from regular, function histogram centric profiles. The simplest mode is activated via 'perf record -b', and the result looks like this in perf report: $ perf record -b any_call,u -e cycles:u branchy $ perf report -b --sort=symbol 52.34% [.] main [.] f1 24.04% [.] f1 [.] f3 23.60% [.] f1 [.] f2 0.01% [k] _IO_new_file_xsputn [k] _IO_file_overflow 0.01% [k] _IO_vfprintf_internal [k] _IO_new_file_xsputn 0.01% [k] _IO_vfprintf_internal [k] strchrnul 0.01% [k] __printf [k] _IO_vfprintf_internal 0.01% [k] main [k] __printf This output shows from/to branch columns and shows the highest percentage (from,to) jump combinations - i.e. the most likely taken branches in the system. "branches" can also include function calls and any other synchronous and asynchronous transitions of the instruction pointer that are not 'next instruction' - such as system calls, traps, interrupts, etc. This feature comes with (hopefully intuitive) flat ascii and TUI support in perf report. - Various 'perf annotate' visual improvements for us assembly junkies. It will now recognize function calls in the TUI and by hitting enter you can follow the call (recursively) and back, amongst other improvements. - Multiple threads/processes recording support in perf record, perf stat, perf top - which is activated via a comma-list of PIDs: perf top -p 21483,21485 perf stat -p 21483,21485 -ddd perf record -p 21483,21485 - Support for per UID views, via the --uid paramter to perf top, perf report, etc. For example 'perf top --uid mingo' will only show the tasks that I am running, excluding other users, root, etc. - Jump label restructurings and improvements - this includes the factoring out of the (hopefully much clearer) include/linux/static_key.h generic facility: struct static_key key = STATIC_KEY_INIT_FALSE; ... if (static_key_false(&key)) do unlikely code else do likely code ... static_key_slow_inc(); ... static_key_slow_inc(); ... The static_key_false() branch will be generated into the code with as little impact to the likely code path as possible. the static_key_slow_*() APIs flip the branch via live kernel code patching. This facility can now be used more widely within the kernel to micro-optimize hot branches whose likelihood matches the static-key usage and fast/slow cost patterns. - SW function tracer improvements: perf support and filtering support. - Various hardenings of the perf.data ABI, to make older perf.data's smoother on newer tool versions, to make new features integrate more smoothly, to support cross-endian recording/analyzing workflows better, etc. - Restructuring of the kprobes code, the splitting out of 'optprobes', and a corner case bugfix. - Allow the tracing of kernel console output (printk). - Improvements/fixes to user-space RDPMC support, allowing user-space self-profiling code to extract PMU counts without performing any system calls, while playing nice with the kernel side. - 'perf bench' improvements - ... and lots of internal restructurings, cleanups and fixes that made these features possible. And, as usual this list is incomplete as there were also lots of other improvements * 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (120 commits) perf report: Fix annotate double quit issue in branch view mode perf report: Remove duplicate annotate choice in branch view mode perf/x86: Prettify pmu config literals perf report: Enable TUI in branch view mode perf report: Auto-detect branch stack sampling mode perf record: Add HEADER_BRANCH_STACK tag perf record: Provide default branch stack sampling mode option perf tools: Make perf able to read files from older ABIs perf tools: Fix ABI compatibility bug in print_event_desc() perf tools: Enable reading of perf.data files from different ABI rev perf: Add ABI reference sizes perf report: Add support for taken branch sampling perf record: Add support for sampling taken branch perf tools: Add code to support PERF_SAMPLE_BRANCH_STACK x86/kprobes: Split out optprobe related code to kprobes-opt.c x86/kprobes: Fix a bug which can modify kernel code permanently x86/kprobes: Fix instruction recovery on optimized path perf: Add callback to flush branch_stack on context switch perf: Disable PERF_SAMPLE_BRANCH_* when not supported perf/x86: Add LBR software filter support for Intel CPUs ...
| * \ \ \ Merge branch 'perf/urgent' into perf/coreIngo Molnar2012-03-052-52/+5
| |\ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Conflicts: tools/perf/builtin-record.c tools/perf/builtin-top.c tools/perf/perf.h tools/perf/util/top.h Merge reason: resolve these cherry-picking conflicts. Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | | | | tracepoint, vfs, sched: Add exec() tracepointDavid Smith2012-02-231-0/+27
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Added a minimal exec tracepoint. Exec is an important major event in the life of a task, like fork(), clone() or exit(), all of which we already trace. [ We also do scheduling re-balancing during exec() - so it's useful from a scheduler instrumentation POV as well. ] If you want to watch a task start up, when it gets exec'ed is a good place to start. With the addition of this tracepoint, exec's can be monitored and better picture of general system activity can be obtained. This tracepoint will also enable better process life tracking, allowing you to answer questions like "what process keeps starting up binary X?". This tracepoint can also be useful in ftrace filtering and trigger conditions: i.e. starting or stopping filtering when exec is called. Signed-off-by: David Smith <dsmith@redhat.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Christoph Hellwig <hch@infradead.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/4F314D19.7030504@redhat.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | | | | printk/tracing: Add console output tracingJohannes Berg2012-02-131-0/+41
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add a printk.console trace point to record any printk messages into the trace, regardless of the current console loglevel. This can help correlate (existing) printk debugging with other tracing. Link: http://lkml.kernel.org/r/1322161388.5366.54.camel@jlt3.sipsolutions.net Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Ingo Molnar <mingo@redhat.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * | | | | x86/tracing: Denote the power and cpuidle tracepoints as _rcuidle()Steven Rostedt2012-02-131-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The power and cpuidle tracepoints are called within a rcu_idle_exit() section, and must be denoted with the _rcuidle() version of the tracepoint. Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * | | | | Merge branch 'sigtrace' of git://github.com/utrace/linux into perf/coreIngo Molnar2012-01-261-63/+22
| |\ \ \ \ \ | | |_|_|/ / | |/| | | |
| | * | | | tracing: let trace_signal_generate() report more info, kill ↵Oleg Nesterov2012-01-131-63/+22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | overflow_fail/lose_info __send_signal()->trace_signal_generate() doesn't report enough info. The users want to know was the signal actually delivered or not, and they also need the shared/private info. The patch moves trace_signal_generate() at the end of __send_signal() and adds the 2 additional arguments. This also allows us to kill trace_signal_overflow_fail/lose_info, we can simply add the appropriate TRACE_SIGNAL_ "result" codes. Reported-by: Seiji Aguchi <saguchi@redhat.com> Reviewed-by: Seiji Aguchi <seiji.aguchi@hds.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Oleg Nesterov <oleg@redhat.com>
* | | | | | Merge branch 'rcu/next' of ↵Ingo Molnar2012-02-281-24/+39
|\ \ \ \ \ \ | |_|_|/ / / |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu The major features of this series are: - making RCU more aggressive about entering dyntick-idle mode in order to improve energy efficiency - converting a few more call_rcu()s to kfree_rcu()s - applying a number of rcutree fixes and cleanups to rcutiny - removing CONFIG_SMP #ifdefs from treercu - allowing RCU CPU stall times to be set via sysfs - adding CPU-stall capability to rcutorture - adding more RCU-abuse diagnostics - updating documentation - fixing yet more issues located by the still-ongoing top-to-bottom inspection of RCU, this time with a special focus on the CPU-hotplug code path. Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | | | | rcu: Avoid waking up CPUs having only kfree_rcu() callbacksPaul E. McKenney2012-02-211-24/+39
| | |_|_|/ | |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When CONFIG_RCU_FAST_NO_HZ is enabled, RCU will allow a given CPU to enter dyntick-idle mode even if it still has RCU callbacks queued. RCU avoids system hangs in this case by scheduling a timer for several jiffies in the future. However, if all of the callbacks on that CPU are from kfree_rcu(), there is no reason to wake the CPU up, as it is not a problem to defer freeing of memory. This commit therefore tracks the number of callbacks on a given CPU that are from kfree_rcu(), and avoids scheduling the timer if all of a given CPU's callbacks are from kfree_rcu(). Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* | | | | sched/events: Revert trace_sched_stat_sleeptime()Peter Zijlstra2012-02-221-50/+0
|/ / / / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit 1ac9bc69 ("sched/tracing: Add a new tracepoint for sleeptime") added a new sched:sched_stat_sleeptime tracepoint. It's broken: the first sample we get on a task might be bad because of a stale sleep_start value that wasn't reset at the last task switch because the tracepoint was not active. It also breaks the existing schedstat samples due to the side effects of: - se->statistics.sleep_start = 0; ... - se->statistics.block_start = 0; Nor do I see means to fix it without adding overhead to the scheduler fast path, which I'm not willing to for the sake of redundant instrumentation. Most importantly, sleep time information can already be constructed by tracing context switches and wakeups, and taking the timestamp difference between the schedule-out, the wakeup and the schedule-in. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Andrew Vagin <avagin@openvz.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Link: http://lkml.kernel.org/n/tip-pc4c9qhl8q6vg3bs4j6k0rbd@git.kernel.org Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | | writeback: fix dereferencing NULL bdi->dev on trace_writeback_queueWu Fengguang2012-02-061-1/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When a SD card is hot removed without umount, del_gendisk() will call bdi_unregister() without destroying/freeing it. This leaves the bdi in the bdi->dev = NULL, bdi->wb.task = NULL, bdi->bdi_list removed state. When sync(2) gets the bdi before bdi_unregister() and calls bdi_queue_work() after the unregister, trace_writeback_queue will be dereferencing the NULL bdi->dev. Fix it with a simple test for NULL. LKML-reference: http://lkml.org/lkml/2012/1/18/346 Cc: stable@kernel.org Reported-by: Rabin Vincent <rabin@rab.in> Tested-by: Namjae Jeon <linkinjeon@gmail.com> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
* | | | writeback: fix NULL bdi->dev in trace writeback_single_inodeWu Fengguang2012-02-011-1/+1
|/ / / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | bdi_prune_sb() resets sb->s_bdi to default_backing_dev_info when the tearing down the original bdi. Fix trace_writeback_single_inode to use sb->s_bdi=default_backing_dev_info rather than bdi->dev=NULL for a teared down bdi. Cc: <stable@kernel.org> Reported-by: Rabin Vincent <rabin@rab.in> Tested-by: Rabin Vincent <rabin@rab.in> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
* | | Merge branch 'for-linus' of ↵Linus Torvalds2012-01-171-0/+203
|\ \ \ | |/ / |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs: (62 commits) Btrfs: use larger system chunks Btrfs: add a delalloc mutex to inodes for delalloc reservations Btrfs: space leak tracepoints Btrfs: protect orphan block rsv with spin_lock Btrfs: add allocator tracepoints Btrfs: don't call btrfs_throttle in file write Btrfs: release space on error in page_mkwrite Btrfs: fix btrfsck error 400 when truncating a compressed Btrfs: do not use btrfs_end_transaction_throttle everywhere Btrfs: add balance progress reporting Btrfs: allow for resuming restriper after it was paused Btrfs: allow for canceling restriper Btrfs: allow for pausing restriper Btrfs: add skip_balance mount option Btrfs: recover balance on mount Btrfs: save balance parameters to disk Btrfs: soft profile changing mode (aka soft convert) Btrfs: implement online profile changing Btrfs: do not reduce profile in do_chunk_alloc() Btrfs: virtual address space subset filter ... Fix up trivial conflict in fs/btrfs/ioctl.c due to the use of the new mnt_drop_write_file() helper.
| * | Btrfs: space leak tracepointsJosef Bacik2012-01-161-0/+30
| | | | | | | | | | | | | | | | | | | | | This in addition to a script in my btrfs-tracing tree will help track down space leaks when we're getting space left over in block groups on umount. Thanks, Signed-off-by: Josef Bacik <josef@redhat.com>
| * | Btrfs: add allocator tracepointsJosef Bacik2012-01-161-0/+173
| | | | | | | | | | | | | | | | | | | | | I used these tracepoints when figuring out what the cluster stuff was doing, so add them to mainline in case we need to profile this stuff again. Thanks, Signed-off-by: Josef Bacik <josef@redhat.com>
* | | vmscan/trace: Add 'file' info to trace_mm_vmscan_lru_isolate()Tao Ma2012-01-121-8/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In trace_mm_vmscan_lru_isolate(), we don't output 'file' information to the trace event and it is a bit inconvenient for the user to get the real information(like pasted below). mm_vmscan_lru_isolate: isolate_mode=2 order=0 nr_requested=32 nr_scanned=32 nr_taken=32 contig_taken=0 contig_dirty=0 contig_failed=0 'active' can be obtained by analyzing mode(Thanks go to Minchan and Mel), So this patch adds 'file' to the trace event and it now looks like: mm_vmscan_lru_isolate: isolate_mode=2 order=0 nr_requested=32 nr_scanned=32 nr_taken=32 contig_taken=0 contig_dirty=0 contig_failed=0 file=0 Signed-off-by: Tao Ma <boyu.mt@taobao.com> Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Mel Gorman <mel@csn.ul.ie> Reviewed-by: Minchan Kim <minchan@kernel.org> Cc: Rik van Riel <riel@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | Merge branch 'writeback-for-linus' of ↵Linus Torvalds2012-01-101-3/+11
|\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/wfg/linux * 'writeback-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/wfg/linux: writeback: move MIN_WRITEBACK_PAGES to fs-writeback.c writeback: balanced_rate cannot exceed write bandwidth writeback: do strict bdi dirty_exceeded writeback: avoid tiny dirty poll intervals writeback: max, min and target dirty pause time writeback: dirty ratelimit - think time compensation btrfs: fix dirtied pages accounting on sub-page writes writeback: fix dirtied pages accounting on redirty writeback: fix dirtied pages accounting on sub-page writes writeback: charge leaked page dirties to active tasks writeback: Include all dirty inodes in background writeback
| * | | writeback: dirty ratelimit - think time compensationWu Fengguang2011-12-181-3/+11
| |/ / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Compensate the task's think time when computing the final pause time, so that ->dirty_ratelimit can be executed accurately. think time := time spend outside of balance_dirty_pages() In the rare case that the task slept longer than the 200ms period time (result in negative pause time), the sleep time will be compensated in the following periods, too, if it's less than 1 second. Accumulated errors are carefully avoided as long as the max pause area is not hitted. Pseudo code: period = pages_dirtied / task_ratelimit; think = jiffies - dirty_paused_when; pause = period - think; 1) normal case: period > think pause = period - think dirty_paused_when = jiffies + pause nr_dirtied = 0 period time |===============================>| think time pause time |===============>|==============>| ------|----------------|---------------|------------------------ dirty_paused_when jiffies 2) no pause case: period <= think don't pause; reduce future pause time by: dirty_paused_when += period nr_dirtied = 0 period time |===============================>| think time |===================================================>| ------|--------------------------------+-------------------|---- dirty_paused_when jiffies Acked-by: Jan Kara <jack@suse.cz> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
* | | Merge branch 'akpm' (aka "Andrew's patch-bomb")Linus Torvalds2012-01-103-2/+96
|\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Andrew elucidates: - First installmeant of MM. We have a HUGE number of MM patches this time. It's crazy. - MAINTAINERS updates - backlight updates - leds - checkpatch updates - misc ELF stuff - rtc updates - reiserfs - procfs - some misc other bits * akpm: (124 commits) user namespace: make signal.c respect user namespaces workqueue: make alloc_workqueue() take printf fmt and args for name procfs: add hidepid= and gid= mount options procfs: parse mount options procfs: introduce the /proc/<pid>/map_files/ directory procfs: make proc_get_link to use dentry instead of inode signal: add block_sigmask() for adding sigmask to current->blocked sparc: make SA_NOMASK a synonym of SA_NODEFER reiserfs: don't lock root inode searching reiserfs: don't lock journal_init() reiserfs: delay reiserfs lock until journal initialization reiserfs: delete comments referring to the BKL drivers/rtc/interface.c: fix alarm rollover when day or month is out-of-range drivers/rtc/rtc-twl.c: add DT support for RTC inside twl4030/twl6030 drivers/rtc/: remove redundant spi driver bus initialization drivers/rtc/rtc-jz4740.c: make jz4740_rtc_driver static drivers/rtc/rtc-mc13xxx.c: make mc13xxx_rtc_idtable static rtc: convert drivers/rtc/* to use module_platform_driver() drivers/rtc/rtc-wm831x.c: convert to devm_kzalloc() drivers/rtc/rtc-wm831x.c: remove unused period IRQ handler ...
| * | | tracepoint: add tracepoints for debugging oom_score_adjKAMEZAWA Hiroyuki2012-01-102-0/+94
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | oom_score_adj is used for guarding processes from OOM-Killer. One of problem is that it's inherited at fork(). When a daemon set oom_score_adj and make children, it's hard to know where the value is set. This patch adds some tracepoints useful for debugging. This patch adds 3 trace points. - creating new task - renaming a task (exec) - set oom_score_adj To debug, users need to enable some trace pointer. Maybe filtering is useful as # EVENT=/sys/kernel/debug/tracing/events/task/ # echo "oom_score_adj != 0" > $EVENT/task_newtask/filter # echo "oom_score_adj != 0" > $EVENT/task_rename/filter # echo 1 > $EVENT/enable # EVENT=/sys/kernel/debug/tracing/events/oom/ # echo 1 > $EVENT/enable output will be like this. # grep oom /sys/kernel/debug/tracing/trace bash-7699 [007] d..3 5140.744510: oom_score_adj_update: pid=7699 comm=bash oom_score_adj=-1000 bash-7699 [007] ...1 5151.818022: task_newtask: pid=7729 comm=bash clone_flags=1200011 oom_score_adj=-1000 ls-7729 [003] ...2 5151.818504: task_rename: pid=7729 oldcomm=bash newcomm=ls oom_score_adj=-1000 bash-7699 [002] ...1 5175.701468: task_newtask: pid=7730 comm=bash clone_flags=1200011 oom_score_adj=-1000 grep-7730 [007] ...2 5175.701993: task_rename: pid=7730 oldcomm=bash newcomm=grep oom_score_adj=-1000 Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Acked-by: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | | mm-tracepoint: rename page-free eventsKonstantin Khlebnikov2012-01-101-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Rename mm_page_free_direct into mm_page_free and mm_pagevec_free into mm_page_free_batched Since v2.6.33-5426-gc475dab the kernel triggers mm_page_free_direct for all freed pages, not only for directly freed. So, let's name it properly. For pages freed via page-list we also trigger mm_page_free_batched event. Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org> Cc: Mel Gorman <mel@csn.ul.ie> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | | Merge branch 'for_linus' into for_linus_mergedTheodore Ts'o2012-01-101-3/+3
|\ \ \ \ | |/ / / |/| | | | | | | | | | | Conflicts: fs/ext4/ioctl.c
| * | | ext4: do not reference pa_inode from group_paYongqiang Yang2011-12-181-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | pa_inode in group_pa is set NULL in ext4_mb_new_group_pa, so pa_inode should be not referenced. Reported-by: Wu Fengguang <fengguang.wu@intel.com> Signed-off-by: Yongqiang Yang <xiaoqiangnk@gmail.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
* | | | Merge branch 'for-linus' of ↵Linus Torvalds2012-01-081-0/+9
|\ \ \ \ | |_|_|/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regmap * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regmap: (36 commits) mfd: Clearing events requires event registers to be writable for da9052-core mfd: Fix annotations in da9052-core gpiolib: Mark da9052 driver broken mfd: Declare da9052_regmap_config for the bus drivers MFD: DA9052/53 MFD core module add SPI support v2 MFD: DA9052/53 MFD core module regmap: Add irq_base accessor to regmap_irq regmap: Allow drivers to reinitialise the register cache at runtime regmap: Add trace event for successful cache reads regmap: Allow regmap_update_bits() users to detect changes regmap: Report if we actually handled an interrupt in regmap-irq regmap: Fix rbtreee build when not using debugfs regmap: Provide debugfs dump of the rbtree cache data regmap: Do debugfs init before cache init regmap: Suppress noop writes in regmap_update_bits() regmap: Remove indexed cache type regmap: Drop check whether a register is readable in regcache_read regmap: Properly round cache_word_size regmap: Add support for 10/14 register formating regmap: Try cached read before checking if a hardware read is possible ...
| * | | regmap: Add trace event for successful cache readsMark Brown2011-11-301-0/+9
| |/ / | | | | | | | | | | | | | | | | | | Currently we only trace physical reads, there's no instrumentation if the read is satisfied from cache. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
* | | Merge branch 'sched-core-for-linus' of ↵Linus Torvalds2012-01-061-0/+57
|\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip * 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (40 commits) sched/tracing: Add a new tracepoint for sleeptime sched: Disable scheduler warnings during oopses sched: Fix cgroup movement of waking process sched: Fix cgroup movement of newly created process sched: Fix cgroup movement of forking process sched: Remove cfs bandwidth period check in tg_set_cfs_period() sched: Fix load-balance lock-breaking sched: Replace all_pinned with a generic flags field sched: Only queue remote wakeups when crossing cache boundaries sched: Add missing rcu_dereference() around ->real_parent usage [S390] fix cputime overflow in uptime_proc_show [S390] cputime: add sparse checking and cleanup sched: Mark parent and real_parent as __rcu sched, nohz: Fix missing RCU read lock sched, nohz: Set the NOHZ_BALANCE_KICK flag for idle load balancer sched, nohz: Fix the idle cpu check in nohz_idle_balance sched: Use jump_labels for sched_feat sched/accounting: Fix parameter passing in task_group_account_field sched/accounting: Fix user/system tick double accounting sched/accounting: Re-use scheduler statistics for the root cgroup ... Fix up conflicts in - arch/ia64/include/asm/cputime.h, include/asm-generic/cputime.h usecs_to_cputime64() vs the sparse cleanups - kernel/sched/fair.c, kernel/time/tick-sched.c scheduler changes in multiple branches
| * | | sched/tracing: Add a new tracepoint for sleeptimeArun Sharma2011-12-231-0/+50
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If CONFIG_SCHEDSTATS is defined, the kernel maintains information about how long the task was sleeping or in the case of iowait, blocking in the kernel before getting woken up. This will be useful for sleep time profiling. Note: this information is only provided for sched_fair. Other scheduling classes may choose to provide this in the future. Note: the delay includes the time spent on the runqueue as well. Signed-off-by: Arun Sharma <asharma@fb.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Arnaldo Carvalho de Melo <acme@infradead.org> Cc: Andrew Vagin <avagin@openvz.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Link: http://lkml.kernel.org/r/1324512940-32060-2-git-send-email-asharma@fb.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | | events, sched: Add tracepoint for accounting blocked timeAndrew Vagin2011-12-061-0/+7
| |/ / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This tracepoint shows how long a task is sleeping in uninterruptible state. E.g. it may show how long and where a mutex is waited for. Signed-off-by: Andrew Vagin <avagin@openvz.org> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1322471015-107825-8-git-send-email-avagin@openvz.org Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | Merge branch 'core-rcu-for-linus' of ↵Linus Torvalds2012-01-061-13/+109
|\ \ \ | |_|/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip * 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (64 commits) cpu: Export cpu_up() rcu: Apply ACCESS_ONCE() to rcu_boost() return value Revert "rcu: Permit rt_mutex_unlock() with irqs disabled" docs: Additional LWN links to RCU API rcu: Augment rcu_batch_end tracing for idle and callback state rcu: Add rcutorture tests for srcu_read_lock_raw() rcu: Make rcutorture test for hotpluggability before offlining CPUs driver-core/cpu: Expose hotpluggability to the rest of the kernel rcu: Remove redundant rcu_cpu_stall_suppress declaration rcu: Adaptive dyntick-idle preparation rcu: Keep invoking callbacks if CPU otherwise idle rcu: Irq nesting is always 0 on rcu_enter_idle_common rcu: Don't check irq nesting from rcu idle entry/exit rcu: Permit dyntick-idle with callbacks pending rcu: Document same-context read-side constraints rcu: Identify dyntick-idle CPUs on first force_quiescent_state() pass rcu: Remove dynticks false positives and RCU failures rcu: Reduce latency of rcu_prepare_for_idle() rcu: Eliminate RCU_FAST_NO_HZ grace-period hang rcu: Avoid needlessly IPIing CPUs at GP end ...
| * | rcu: Augment rcu_batch_end tracing for idle and callback statePaul E. McKenney2011-12-111-9/+29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The current rcu_batch_end event trace records only the name of the RCU flavor and the total number of callbacks that remain queued on the current CPU. This is insufficient for testing and tuning the new dyntick-idle RCU_FAST_NO_HZ code, so this commit adds idle state along with whether or not any of the callbacks that were ready to invoke at the beginning of rcu_do_batch() are still queued. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
| * | rcu: Permit dyntick-idle with callbacks pendingPaul E. McKenney2011-12-111-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The current implementation of RCU_FAST_NO_HZ prevents CPUs from entering dyntick-idle state if they have RCU callbacks pending. Unfortunately, this has the side-effect of often preventing them from entering this state, especially if at least one other CPU is not in dyntick-idle state. However, the resulting per-tick wakeup is wasteful in many cases: if the CPU has already fully responded to the current RCU grace period, there will be nothing for it to do until this grace period ends, which will frequently take several jiffies. This commit therefore permits a CPU that has done everything that the current grace period has asked of it (rcu_pending() == 0) even if it still as RCU callbacks pending. However, such a CPU posts a timer to wake it up several jiffies later (6 jiffies, based on experience with grace-period lengths). This wakeup is required to handle situations that can result in all CPUs being in dyntick-idle mode, thus failing to ever complete the current grace period. If a CPU wakes up before the timer goes off, then it cancels that timer, thus avoiding spurious wakeups. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
| * | rcu: Eliminate RCU_FAST_NO_HZ grace-period hangPaul E. McKenney2011-12-111-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | With the new implementation of RCU_FAST_NO_HZ, it was possible to hang RCU grace periods as follows: o CPU 0 attempts to go idle, cycles several times through the rcu_prepare_for_idle() loop, then goes dyntick-idle when RCU needs nothing more from it, while still having at least on RCU callback pending. o CPU 1 goes idle with no callbacks. Both CPUs can then stay in dyntick-idle mode indefinitely, preventing the RCU grace period from ever completing, possibly hanging the system. This commit therefore prevents CPUs that have RCU callbacks from entering dyntick-idle mode. This approach also eliminates the need for the end-of-grace-period IPIs used previously. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
| * | rcu: Add tracing for RCU_FAST_NO_HZPaul E. McKenney2011-12-111-0/+37
| | | | | | | | | | | | | | | | | | | | | | | | | | | This commit adds trace_rcu_prep_idle(), which is invoked from rcu_prepare_for_idle() and rcu_wake_cpu() to trace attempts on the part of RCU to force CPUs into dyntick-idle mode. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
| * | rcu: Update trace_rcu_dyntick() header commentPaul E. McKenney2011-12-111-2/+10
| | | | | | | | | | | | | | | | | | | | | | | | This commit updates the trace_rcu_dyntick() header comment to reflect events added by commit 4b4f421. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
| * | rcu: Deconfuse dynticks entry-exit tracingPaul E. McKenney2011-12-111-6/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The trace_rcu_dyntick() trace event did not print both the old and the new value of the nesting level, and furthermore printed only the low-order 32 bits of it. This could result in some confusion when interpreting trace-event dumps, so this commit prints both the old and the new value, prints the full 64 bits, and also selects the process-entry/exit increment to print nicely in hexadecimal. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
| * | rcu: Add failure tracing to rcutorturePaul E. McKenney2011-12-111-0/+26
| | | | | | | | | | | | | | | | | | | | | | | | | | | Trace the rcutorture RCU accesses and dump the trace buffer when the first failure is detected. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
| * | rcu: Track idleness independent of idle tasksPaul E. McKenney2011-12-111-4/+6
| |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Earlier versions of RCU used the scheduling-clock tick to detect idleness by checking for the idle task, but handled idleness differently for CONFIG_NO_HZ=y. But there are now a number of uses of RCU read-side critical sections in the idle task, for example, for tracing. A more fine-grained detection of idleness is therefore required. This commit presses the old dyntick-idle code into full-time service, so that rcu_idle_enter(), previously known as rcu_enter_nohz(), is always invoked at the beginning of an idle loop iteration. Similarly, rcu_idle_exit(), previously known as rcu_exit_nohz(), is always invoked at the end of an idle-loop iteration. This allows the idle task to use RCU everywhere except between consecutive rcu_idle_enter() and rcu_idle_exit() calls, in turn allowing architecture maintainers to specify exactly where in the idle loop that RCU may be used. Because some of the userspace upcall uses can result in what looks to RCU like half of an interrupt, it is not possible to expect that the irq_enter() and irq_exit() hooks will give exact counts. This patch therefore expands the ->dynticks_nesting counter to 64 bits and uses two separate bitfields to count process/idle transitions and interrupt entry/exit transitions. It is presumed that userspace upcalls do not happen in the idle loop or from usermode execution (though usermode might do a system call that results in an upcall). The counter is hard-reset on each process/idle transition, which avoids the interrupt entry/exit error from accumulating. Overflow is avoided by the 64-bitness of the ->dyntick_nesting counter. This commit also adds warnings if a non-idle task asks RCU to enter idle state (and these checks will need some adjustment before applying Frederic's OS-jitter patches (http://lkml.org/lkml/2011/10/7/246). In addition, validation of ->dynticks and ->dynticks_nesting is added. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
OpenPOWER on IntegriCloud