summaryrefslogtreecommitdiffstats
path: root/kernel/lockdep.c
Commit message (Collapse)AuthorAgeFilesLines
...
| | * lockdep: Move lock events under lockdep recursion protectionFrederic Weisbecker2010-03-101-6/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There are rcu locked read side areas in the path where we submit a trace event. And these rcu_read_(un)lock() trigger lock events, which create recursive events. One pair in do_perf_sw_event: __lock_acquire | |--96.11%-- lock_acquire | | | |--27.21%-- do_perf_sw_event | | perf_tp_event | | | | | |--49.62%-- ftrace_profile_lock_release | | | lock_release | | | | | | | |--33.85%-- _raw_spin_unlock Another pair in perf_output_begin/end: __lock_acquire |--23.40%-- perf_output_begin | | __perf_event_overflow | | perf_swevent_overflow | | perf_swevent_add | | perf_swevent_ctx_event | | do_perf_sw_event | | perf_tp_event | | | | | |--55.37%-- ftrace_profile_lock_acquire | | | lock_acquire | | | | | | | |--37.31%-- _raw_spin_lock The problem is not that much the trace recursion itself, as we have a recursion protection already (though it's always wasteful to recurse). But the trace events are outside the lockdep recursion protection, then each lockdep event triggers a lock trace, which will trigger two other lockdep events. Here the recursive lock trace event won't be taken because of the trace recursion, so the recursion stops there but lockdep will still analyse these new events: To sum up, for each lockdep events we have: lock_*() | trace lock_acquire | ----- rcu_read_lock() | | | lock_acquire() | | | trace_lock_acquire() (stopped) | | | lockdep analyze | ----- rcu_read_unlock() | lock_release | trace_lock_release() (stopped) | lockdep analyze And you can repeat the above two times as we have two rcu read side sections when we submit an event. This is fixed in this patch by moving the lock trace event under the lockdep recursion protection. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Hitoshi Mitake <mitake@dcl.info.waseda.ac.jp> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Lai Jiangshan <laijs@cn.fujitsu.com> Cc: Masami Hiramatsu <mhiramat@redhat.com> Cc: Jens Axboe <jens.axboe@oracle.com>
| * | rcu: Add control variables to lockdep_rcu_dereference() diagnosticsPaul E. McKenney2010-03-041-0/+1
| |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add the values of rcu_scheduler_active() and debug_locks() to the lockdep_rcu_dereference() output to help diagnose RCU lockdep splats that occur shortly after the scheduler starts. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <1267631219-8713-4-git-send-email-paulmck@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | lockstat: Make lockstat counting per cpuFrederic Weisbecker2010-04-061-30/+17
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Locking statistics are implemented using global atomic variables. This is usually fine unless some path write them very often. This is the case for the function and function graph tracers that disable irqs for each entry saved (except if the function tracer is in preempt disabled only mode). And calls to local_irq_save/restore() increment hardirqs_on_events and hardirqs_off_events stats (or similar stats for redundant versions). Incrementing these global vars for each function ends up in too much cache bouncing if lockstats are enabled. To solve this, implement the debug_atomic_*() operations using per cpu vars. -v2: Use per_cpu() instead of get_cpu_var() to fetch the desired cpu vars on debug_atomic_read() -v3: Store the stats in a structure. No need for local_t as we are NMI/irq safe. -v4: Fix tons of build errors. I thought I had tested it but I probably forgot to select the relevant config. Suggested-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1270505417-8144-1-git-send-regression-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Steven Rostedt <rostedt@goodmis.org>
* rcu: Make lockdep_rcu_dereference() message less alarmistPaul E. McKenney2010-02-261-3/+3
| | | | | | | | | | | | | | | | | | | | Change from "unsafe" to "suspicious", given that there will be false alarms. Suggested-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <1267135607-7056-1-git-send-email-paulmck@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* rcu: Integrate rcu_dereference_check() message into lockdepPaul E. McKenney2010-02-251-0/+18
| | | | | | | | | | | | | | | | | | | Make rcu_dereference_check() print the list of held locks in addition to the stack dump to ease debugging. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <1266887105-1528-3-git-send-email-paulmck@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* lockdep: Fix check_usage_backwards() error messageOleg Nesterov2010-01-271-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Lockdep has found the real bug, but the output doesn't look right to me: > ========================================================= > [ INFO: possible irq lock inversion dependency detected ] > 2.6.33-rc5 #77 > --------------------------------------------------------- > emacs/1609 just changed the state of lock: > (&(&tty->ctrl_lock)->rlock){+.....}, at: [<ffffffff8127c648>] tty_fasync+0xe8/0x190 > but this lock took another, HARDIRQ-unsafe lock in the past: > (&(&sighand->siglock)->rlock){-.....} "HARDIRQ-unsafe" and "this lock took another" looks wrong, afaics. > ... key at: [<ffffffff81c054a4>] __key.46539+0x0/0x8 > ... acquired at: > [<ffffffff81089af6>] __lock_acquire+0x1056/0x15a0 > [<ffffffff8108a0df>] lock_acquire+0x9f/0x120 > [<ffffffff81423012>] _raw_spin_lock_irqsave+0x52/0x90 > [<ffffffff8127c1be>] __proc_set_tty+0x3e/0x150 > [<ffffffff8127e01d>] tty_open+0x51d/0x5e0 The stack-trace shows that this lock (ctrl_lock) was taken under ->siglock (which is hopefully irq-safe). This is a clear typo in check_usage_backwards() where we tell the print a fancy routine we're forwards. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <20100126181641.GA10460@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* locking: Convert __raw_spin* functions to arch_spin*Thomas Gleixner2009-12-141-9/+9
| | | | | | | | | | Name space cleanup. No functional change. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra <peterz@infradead.org> Acked-by: David S. Miller <davem@davemloft.net> Acked-by: Ingo Molnar <mingo@elte.hu> Cc: linux-arch@vger.kernel.org
* locking: Rename __RAW_SPIN_LOCK_UNLOCKED to __ARCH_SPIN_LOCK_UNLOCKEDThomas Gleixner2009-12-141-1/+1
| | | | | | | | | | Further name space cleanup. No functional change Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra <peterz@infradead.org> Acked-by: David S. Miller <davem@davemloft.net> Acked-by: Ingo Molnar <mingo@elte.hu> Cc: linux-arch@vger.kernel.org
* locking: Convert raw_spinlock to arch_spinlockThomas Gleixner2009-12-141-1/+1
| | | | | | | | | | | | | | | | | | | The raw_spin* namespace was taken by lockdep for the architecture specific implementations. raw_spin_* would be the ideal name space for the spinlocks which are not converted to sleeping locks in preempt-rt. Linus suggested to convert the raw_ to arch_ locks and cleanup the name space instead of using an artifical name like core_spin, atomic_spin or whatever No functional change. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra <peterz@infradead.org> Acked-by: David S. Miller <davem@davemloft.net> Acked-by: Ingo Molnar <mingo@elte.hu> Cc: linux-arch@vger.kernel.org
* Merge branch 'for-linus' of ↵Linus Torvalds2009-12-141-5/+6
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu: (34 commits) m68k: rename global variable vmalloc_end to m68k_vmalloc_end percpu: add missing per_cpu_ptr_to_phys() definition for UP percpu: Fix kdump failure if booted with percpu_alloc=page percpu: make misc percpu symbols unique percpu: make percpu symbols in ia64 unique percpu: make percpu symbols in powerpc unique percpu: make percpu symbols in x86 unique percpu: make percpu symbols in xen unique percpu: make percpu symbols in cpufreq unique percpu: make percpu symbols in oprofile unique percpu: make percpu symbols in tracer unique percpu: make percpu symbols under kernel/ and mm/ unique percpu: remove some sparse warnings percpu: make alloc_percpu() handle array types vmalloc: fix use of non-existent percpu variable in put_cpu_var() this_cpu: Use this_cpu_xx in trace_functions_graph.c this_cpu: Use this_cpu_xx for ftrace this_cpu: Use this_cpu_xx in nmi handling this_cpu: Use this_cpu operations in RCU this_cpu: Use this_cpu ops for VM statistics ... Fix up trivial (famous last words) global per-cpu naming conflicts in arch/x86/kvm/svm.c mm/slab.c
| * percpu: make percpu symbols under kernel/ and mm/ uniqueTejun Heo2009-10-291-5/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch updates percpu related symbols under kernel/ and mm/ such that percpu symbols are unique and don't clash with local symbols. This serves two purposes of decreasing the possibility of global percpu symbol collision and allowing dropping per_cpu__ prefix from percpu symbols. * kernel/lockdep.c: s/lock_stats/cpu_lock_stats/ * kernel/sched.c: s/init_rq_rt/init_rt_rq_var/ (any better idea?) s/sched_group_cpus/sched_groups/ * kernel/softirq.c: s/ksoftirqd/run_ksoftirqd/a * kernel/softlockup.c: s/(*)_timestamp/softlockup_\1_ts/ s/watchdog_task/softlockup_watchdog/ s/timestamp/ts/ for local variables * kernel/time/timer_stats: s/lookup_lock/tstats_lookup_lock/ * mm/slab.c: s/reap_work/slab_reap_work/ s/reap_node/slab_reap_node/ * mm/vmstat.c: local variable changed to avoid collision with vmstat_work Partly based on Rusty Russell's "alloc_percpu: rename percpu vars which cause name clashes" patch. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: (slab/vmstat) Christoph Lameter <cl@linux-foundation.org> Reviewed-by: Christoph Lameter <cl@linux-foundation.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Ingo Molnar <mingo@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Nick Piggin <npiggin@suse.de>
* | lockdep: Avoid out of bounds array reference in save_trace()Luck, Tony2009-12-101-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | ia64 found this the hard way (because we currently have a stub for save_stack_trace() that does nothing). But it would be a good idea to be cautious in case a real save_stack_trace() bailed out with an error before it set trace->nr_entries. Signed-off-by: Tony Luck <tony.luck@intel.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: luming.yu@intel.com LKML-Reference: <4b2024d085302c2a2@agluck-desktop.sc.intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | lockstat: Fix min, max times in /proc/lock_statsFrank Rowand2009-12-061-3/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Fix min, max times in /proc/lock_stats (1) When collecting lock hold and wait times, if the current minimum time is zero, it will be replaced by the next time. (2) When aggregating minimum and maximum lock hold and wait times accross cpus, the values are added, instead of selecting the minimum and maximum. Signed-off-by: Frank Rowand <frank.rowand@am.sony.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <4B05BBAE.2050005@am.sony.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | tracing: Rename 'lockdep' event subsystem into 'lock'Frederic Weisbecker2009-11-131-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Lockdep events subsystem gathers various locking related events such as a request, release, contention or acquisition of a lock. The name of this event subsystem is a bit of a misnomer since these events are not quite related to lockdep but more generally to locking, ie: these events are not reporting lock dependencies or possible deadlock scenario but pure locking events. Hence this rename. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Peter Zijlstra <peterz@infradead.org> Acked-by: Hitoshi Mitake <mitake@dcl.info.waseda.ac.jp> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Li Zefan <lizf@cn.fujitsu.com> LKML-Reference: <1258103194-843-1-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | lockdep: Use cpu_clock() for lockstatPeter Zijlstra2009-10-091-8/+12
|/ | | | | | | | | | | | | | Some tracepoint magic (TRACE_EVENT(lock_acquired)) relies on the fact that lock hold times are positive and uses div64 on that. That triggered a build warning on MIPS, and probably causes bad output in certain circumstances as well. Make it truly positive. Reported-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1254818502.21044.112.camel@laptop> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* lockdep: use new arch_is_kernel_data()Mike Frysinger2009-09-231-0/+3
| | | | | | | | | | | | | | This allows lockdep to locate symbols that are in arch-specific data sections (such as data in Blackfin on-chip SRAM regions). Signed-off-by: Mike Frysinger <vapier@gentoo.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Robin Getz <rgetz@blackfin.uclinux.org> Cc: Sam Ravnborg <sam@ravnborg.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* lockdep: Remove recursion stattisticsMing Lei2009-08-291-4/+0
| | | | | | | | | | Since lockdep has introduced BFS to avoid recursion, statistics for recursion does not make any sense now. So remove them. Signed-off-by: Ming Lei <tom.leiming@gmail.com> Cc: a.p.zijlstra@chello.nl LKML-Reference: <1251542879-5211-1-git-send-email-tom.leiming@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* lockdep: Fix memory usage info of BFSMing Lei2009-08-021-1/+2
| | | | | | | | | | | | | | The unit is KB, so sizeof(struct circular_queue) should be divided by 1024. Signed-off-by: Ming Lei <tom.leiming@gmail.com> Cc: akpm@linux-foundation.org Cc: torvalds@linux-foundation.org Cc: davem@davemloft.net Cc: Ming Lei <tom.leiming@gmail.com> Cc: a.p.zijlstra@chello.nl LKML-Reference: <1249220616-7190-1-git-send-email-tom.leiming@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* lockdep: Reintroduce generation count to make BFS fasterMing Lei2009-08-021-5/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We still can apply DaveM's generation count optimization to BFS, based on the following idea: - before doing each BFS, increase the global generation id by 1 - if one node in the graph has been visited, mark it as visited by storing the current global generation id into the node's dep_gen_id field - so we can decide if one node has been visited already, by comparing the node's dep_gen_id with the global generation id. By applying DaveM's generation count optimization to current implementation of BFS, we gain the following advantages: - we save MAX_LOCKDEP_ENTRIES/8 bytes memory; - we remove the bitmap_zero(bfs_accessed, MAX_LOCKDEP_ENTRIES); in each BFS, which is very time-consuming since MAX_LOCKDEP_ENTRIES may be very large.(16384UL) Signed-off-by: Ming Lei <tom.leiming@gmail.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: "David S. Miller" <davem@davemloft.net> LKML-Reference: <1248274089-6358-1-git-send-email-tom.leiming@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* lockdep: Deal with many similar locksPeter Zijlstra2009-08-021-12/+77
| | | | | | | | | | | | | | | | | | | | | | | | | | | spin_lock_nest_lock() allows to take many instances of the same class, this can easily lead to overflow of MAX_LOCK_DEPTH. To avoid this overflow, we'll stop accounting instances but start reference counting the class in the held_lock structure. [ We could maintain a list of instances, if we'd move the hlock stuff into __lock_acquired(), but that would require significant modifications to the current code. ] We restrict this mode to spin_lock_nest_lock() only, because it degrades the lockdep quality due to lost of instance. For lockstat this means we don't track lock statistics for any but the first lock in the series. Currently nesting is limited to 11 bits because that was the spare space available in held_lock. This yields a 2048 instances maximium. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* lockdep: Introduce lockdep_assert_held()Peter Zijlstra2009-08-021-0/+33
| | | | | | | | Add a lockdep helper to validate that we indeed are the owner of a lock. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* lockdep: Fix style nitsPeter Zijlstra2009-08-021-3/+8
| | | | | | | fixes a few comments and whitespaces that annoyed me. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* lockdep: Fix backtracesPeter Zijlstra2009-08-021-1/+11
| | | | | | | | Truncate stupid -1 entries in backtraces. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1248096665.15751.8816.camel@twins> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* lockdep: BFS cleanupPeter Zijlstra2009-07-241-114/+170
| | | | | | | | | | | | | | Some cleanups of the lockdep code after the BFS series: - Remove the last traces of the generation id - Fixup comment style - Move the bfs routines into lockdep.c - Cleanup the bfs routines [ tom.leiming@gmail.com: Fix crash ] Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1246201486-7308-11-git-send-email-tom.leiming@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* lockdep: Add statistics info for max bfs queue depthMing Lei2009-07-241-1/+5
| | | | | | | | | Add BFS statistics to the existing lockdep stats. Signed-off-by: Ming Lei <tom.leiming@gmail.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1246201486-7308-10-git-send-email-tom.leiming@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* lockdep: Update memory usage introduced by BFSMing Lei2009-07-241-1/+5
| | | | | | | | | | Also account the BFS memory usage. Signed-off-by: Ming Lei <tom.leiming@gmail.com> [ fix build for !PROVE_LOCKING ] Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1246201486-7308-9-git-send-email-tom.leiming@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* lockdep: Implement lockdep_count_*ward_deps by BFSMing Lei2009-07-241-27/+25
| | | | | | | | | Implement lockdep_count_{for,back}ward using BFS. Signed-off-by: Ming Lei <tom.leiming@gmail.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1246201486-7308-8-git-send-email-tom.leiming@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* lockdep: Introduce print_shortest_lock_dependenciesMing Lei2009-07-241-26/+67
| | | | | | | | | | Since the shortest lock dependencies' path may be obtained by BFS, we print the shortest one by print_shortest_lock_dependencies(). Signed-off-by: Ming Lei <tom.leiming@gmail.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1246201486-7308-7-git-send-email-tom.leiming@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* lockdep: Implement find_usage_*wards by BFSMing Lei2009-07-241-108/+72
| | | | | | | | | | This patch uses BFS to implement find_usage_*wards(),which was originally writen by DFS. Signed-off-by: Ming Lei <tom.leiming@gmail.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1246201486-7308-6-git-send-email-tom.leiming@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* lockdep: Implement check_noncircular() by BFSMing Lei2009-07-241-52/+37
| | | | | | | | | | This patch uses BFS to implement check_noncircular() and prints the generated shortest circle if exists. Signed-off-by: Ming Lei <tom.leiming@gmail.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1246201486-7308-5-git-send-email-tom.leiming@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* lockdep: Introduce match function to BFSMing Lei2009-07-241-17/+26
| | | | | | | | | | | | 1,introduce match() to BFS in order to make it usable to match different pattern; 2,also rename some functions to make them more suitable. Signed-off-by: Ming Lei <tom.leiming@gmail.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1246201486-7308-4-git-send-email-tom.leiming@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* lockdep: Improve implementation of BFSMing Lei2009-07-241-7/+16
| | | | | | | | | | | | | 1,replace %MAX_CIRCULAR_QUE_SIZE with &(MAX_CIRCULAR_QUE_SIZE-1) since we define MAX_CIRCULAR_QUE_SIZE as power of 2; 2,use bitmap to mark if a lock is accessed in BFS in order to clear it quickly, because we may search a graph many times. Signed-off-by: Ming Lei <tom.leiming@gmail.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1246201486-7308-3-git-send-email-tom.leiming@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* lockdep: Print the shortest dependency chain if finding a circleMing Lei2009-07-241-9/+106
| | | | | | | | | | | | | | | | | | | | | Currently lockdep will print the 1st circle detected if it exists when acquiring a new (next) lock. This patch prints the shortest path from the next lock to be acquired to the previous held lock if a circle is found. The patch still uses the current method to check circle, and once the circle is found, breadth-first search algorithem is used to compute the shortest path from the next lock to the previous lock in the forward lock dependency graph. Printing the shortest path will shorten the dependency chain, and make troubleshooting for possible circular locking easier. Signed-off-by: Ming Lei <tom.leiming@gmail.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1246201486-7308-2-git-send-email-tom.leiming@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* Merge branch 'linus' into tracing/coreIngo Molnar2009-05-071-8/+14
|\ | | | | | | | | | | | | Merge reason: tracing/core was on a .30-rc1 base and was missing out on on a handful of tracing fixes present in .30-rc5-almost. Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * lockdep: more robust lockdep_map init sequencePeter Zijlstra2009-04-171-8/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Steven Rostedt reported: > OK, I think I figured this bug out. This is a lockdep issue with respect > to tracepoints. > > The trace points in lockdep are called all the time. Outside the lockdep > logic. But if lockdep were to trigger an error / warning (which this run > did) we might be in trouble. For new locks, like the dentry->d_lock, that > are created, they will not get a name: > > void lockdep_init_map(struct lockdep_map *lock, const char *name, > struct lock_class_key *key, int subclass) > { > if (unlikely(!debug_locks)) > return; > > When a problem is found by lockdep, debug_locks becomes false. Thus we > stop allocating names for locks. This dentry->d_lock I had, now has no > name. Worse yet, I have CONFIG_DEBUG_VM set, that scrambles non > initialized memory. Thus, when the trace point was hit, it had junk for > the lock->name, and the machine crashed. Ah, nice catch. I think we should put at least the name in regardless. Ensure we at least initialize the trivial entries of the depmap so that they can be relied upon, even when lockdep itself decided to pack up and go home. [ Impact: fix lock tracing after lockdep warnings. ] Reported-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Steven Rostedt <rostedt@goodmis.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <1239954049.23397.4156.camel@laptop> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | tracing/events: move trace point headers into include/trace/eventsSteven Rostedt2009-04-141-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: clean up Create a sub directory in include/trace called events to keep the trace point headers in their own separate directory. Only headers that declare trace points should be defined in this directory. Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Neil Horman <nhorman@tuxdriver.com> Cc: Zhao Lei <zhaolei@cn.fujitsu.com> Cc: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* | tracing: create automated trace definesSteven Rostedt2009-04-141-9/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch lowers the number of places a developer must modify to add new tracepoints. The current method to add a new tracepoint into an existing system is to write the trace point macro in the trace header with one of the macros TRACE_EVENT, TRACE_FORMAT or DECLARE_TRACE, then they must add the same named item into the C file with the macro DEFINE_TRACE(name) and then add the trace point. This change cuts out the needing to add the DEFINE_TRACE(name). Every file that uses the tracepoint must still include the trace/<type>.h file, but the one C file must also add a define before the including of that file. #define CREATE_TRACE_POINTS #include <trace/mytrace.h> This will cause the trace/mytrace.h file to also produce the C code necessary to implement the trace point. Note, if more than one trace/<type>.h is used to create the C code it is best to list them all together. #define CREATE_TRACE_POINTS #include <trace/foo.h> #include <trace/bar.h> #include <trace/fido.h> Thanks to Mathieu Desnoyers and Christoph Hellwig for coming up with the cleaner solution of the define above the includes over my first design to have the C code include a "special" header. This patch converts sched, irq and lockdep and skb to use this new method. Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Neil Horman <nhorman@tuxdriver.com> Cc: Zhao Lei <zhaolei@cn.fujitsu.com> Cc: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* | tracing/lockdep: report the time waited for a lockFrederic Weisbecker2009-04-101-4/+4
|/ | | | | | | | | | | | | | | | | | | | | | | | | While trying to optimize the new lock on reiserfs to replace the bkl, I find the lock tracing very useful though it lacks something important for performance (and latency) instrumentation: the time a task waits for a lock. That's what this patch implements: bash-4816 [000] 202.652815: lock_contended: lock_contended: &sb->s_type->i_mutex_key bash-4816 [000] 202.652819: lock_acquired: &rq->lock (0.000 us) <...>-4787 [000] 202.652825: lock_acquired: &rq->lock (0.000 us) <...>-4787 [000] 202.652829: lock_acquired: &rq->lock (0.000 us) bash-4816 [000] 202.652833: lock_acquired: &sb->s_type->i_mutex_key (16.005 us) As shown above, the "lock acquired" field is followed by the time it has been waiting for the lock. Usually, a lock contended entry is followed by a near lock_acquired entry with a non-zero time waited. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1238975373-15739-1-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* Merge branch 'locking-for-linus' of ↵Linus Torvalds2009-04-061-0/+5
|\ | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: lockdep: add stack dumps to asserts hrtimer: fix rq->lock inversion (again)
| * lockdep: add stack dumps to assertsPeter Zijlstra2009-03-311-0/+5
| | | | | | | | | | | | | | | | | | | | Have a better idea about exactly which loc causes a lockdep limit overflow. Often it's a bug or inefficiency in that subsystem. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1237376327.5069.253.camel@laptop> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * Merge branch 'linus' into locking-for-linusIngo Molnar2009-03-311-2/+19
| |\ | | | | | | | | | | | | Conflicts: lib/Kconfig.debug
* | \ Merge branch 'tracing/core-v2' into tracing-for-linusIngo Molnar2009-04-021-11/+22
|\ \ \ | |_|/ |/| | | | | | | | | | | | | | | | | Conflicts: include/linux/slub_def.h lib/Kconfig.debug mm/slob.c mm/slub.c
| * | Merge branch 'core/locking' into tracing/ftraceIngo Molnar2009-03-131-7/+0
| |\ \ | | |/
| | * lockdep: remove duplicate CONFIG_DEBUG_LOCKDEP definitionsDavid Rientjes2009-03-051-7/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: cleanup The atomic debug modifiers are already defined in kernel/lockdep_internals.h. Signed-off-by: David Rientjes <rientjes@google.com> Acked-by: Peter Zijlstra <peterz@infradead.org> LKML-Reference: <alpine.DEB.2.00.0903050222160.30401@chino.kir.corp.google.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | tracing: add lockdep tracepoints for lock acquire/releasePeter Zijlstra2009-03-041-0/+17
| |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Augment the traces with lock names when lockdep is available: 1) | down_read_trylock() { 1) | _spin_lock_irqsave() { 1) | /* lock_acquire: &sem->wait_lock */ 1) 4.201 us | } 1) | _spin_unlock_irqrestore() { 1) | /* lock_release: &sem->wait_lock */ 1) 3.523 us | } 1) | /* lock_acquire: try read &mm->mmap_sem */ 1) + 13.386 us | } 1) 1.635 us | find_vma(); 1) | handle_mm_fault() { 1) | __do_fault() { 1) | filemap_fault() { 1) | find_lock_page() { 1) | find_get_page() { 1) | /* lock_acquire: read rcu_read_lock */ 1) | /* lock_release: rcu_read_lock */ 1) 5.697 us | } 1) 8.158 us | } 1) + 11.079 us | } 1) | _spin_lock() { 1) | /* lock_acquire: __pte_lockptr(page) */ 1) 3.949 us | } 1) 1.460 us | page_add_file_rmap(); 1) | _spin_unlock() { 1) | /* lock_release: __pte_lockptr(page) */ 1) 3.115 us | } 1) | unlock_page() { 1) 1.421 us | page_waitqueue(); 1) 1.220 us | __wake_up_bit(); 1) 6.519 us | } 1) + 34.328 us | } 1) + 37.452 us | } 1) | up_read() { 1) | /* lock_release: &mm->mmap_sem */ 1) | _spin_lock_irqsave() { 1) | /* lock_acquire: &sem->wait_lock */ 1) 3.865 us | } 1) | _spin_unlock_irqrestore() { 1) | /* lock_release: &sem->wait_lock */ 1) 8.562 us | } 1) + 17.370 us | } Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: =?ISO-8859-1?Q?T=F6r=F6k?= Edwin <edwintorok@gmail.com> Cc: Jason Baron <jbaron@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <1236166375.5330.7209.camel@laptop> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * lockdep: remove extra "irq" stringPeter Zijlstra2009-03-041-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: clarify lockdep printk text print_irq_inversion_bug() gets handed state strings of the form "HARDIRQ", "SOFTIRQ", "RECLAIM_FS" and appends "-irq-{un,}safe" to them, which is either redudant for *IRQ or confusing in the RECLAIM_FS case. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1236175192.5330.7585.camel@laptop> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * lockdep: fix incorrect state namePeter Zijlstra2009-03-041-2/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | In the recent mark_lock_irq() rework a bug snuck in that would report the state of write locks causing irq inversion under a read lock as a read lock. Fix this by masking the read bit of the state when validating write dependencies. Reported-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1236172646.5330.7450.camel@laptop> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | lockdep: fix deadlock in lockdep_trace_allocPeter Zijlstra2009-03-301-2/+19
|/ | | | | | | | | | | | | Heiko reported that we grab the graph lock with irqs enabled. Fix this by providng the same wrapper as all other lockdep entry functions have. Reported-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Nick Piggin <npiggin@suse.de> LKML-Reference: <1237544000.24626.52.camel@twins> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* lockdep: build fix for !PROVE_LOCKINGPeter Zijlstra2009-02-151-0/+4
| | | | | | | | The __GFP_FS annotations fail to build with CONFIG_LOCKDEP=y, CONFIG_PROVE_LOCKING=n, ammend that. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* lockdep: use stringify.hPeter Zijlstra2009-02-141-9/+7
| | | | | | | | Arnd pointed out we have the stringify macro magic already in-kernel. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> CC: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
OpenPOWER on IntegriCloud