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* 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>
* lockdep: simplify check_prev_add_irq()Peter Zijlstra2009-02-141-93/+61
| | | | | | | Remove the manual state iteration thingy. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* lockdep: get_user_chars() redoPeter Zijlstra2009-02-141-12/+12
| | | | | | | Generic, states independent, get_user_chars(). Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* lockdep: simplify get_user_chars()Peter Zijlstra2009-02-141-41/+24
| | | | | | | there's too much repetition of code.. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* lockdep: add comments to mark_lock_irq()Peter Zijlstra2009-02-141-7/+30
| | | | | | | re-add some of the comments that got lost in the refactoring. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* lockdep: remove macro usage from mark_held_locks()Peter Zijlstra2009-02-141-15/+5
| | | | | | | | Now that we have nice numerical relations for the states, remove the macro magics. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* lockdep: fully reduce mark_lock_irq()Peter Zijlstra2009-02-141-78/+8
| | | | | | | Now what its only two functions, they again look rather similar. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* lockdep: merge the !_READ mark_lock_irq() helpersPeter Zijlstra2009-02-141-43/+15
| | | | | | | These two are also remakably similar Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* lockdep: merge the _READ mark_lock_irq() helpersPeter Zijlstra2009-02-141-38/+23
| | | | | | | The _READ helpers show remarkable similarity, merge them. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* lockdep: simplify mark_lock_irq() helpers #3Peter Zijlstra2009-02-141-38/+27
| | | | | | | Kill another argument Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* lockdep: further simplify mark_lock_irq() helpersPeter Zijlstra2009-02-141-16/+31
| | | | | | | take away another parameter Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* lockdep: simplify the mark_lock_irq() helpersPeter Zijlstra2009-02-141-16/+44
| | | | | | | In order to unify them, take some arguments away Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* lockdep: split up mark_lock_irq()Peter Zijlstra2009-02-141-225/+147
| | | | | | | split mark_lock_irq() into 4 simple helper functions Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* lockdep: generate usage stringsPeter Zijlstra2009-02-141-13/+13
| | | | | | | | | generate the usage strings XXX capital invasion :-( Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* lockdep: simplify mark_lock()Peter Zijlstra2009-02-141-12/+7
| | | | | | | remove the state iteration Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* lockdep: simplify mark_held_locksPeter Zijlstra2009-02-141-24/+14
| | | | | | | remove the explicit state iteration Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* lockdep: sanitize reclaim bit namesPeter Zijlstra2009-02-141-19/+19
| | | | | | | | | s/HELD_OVER/ENABLED/g so that its similar to the hard and soft-irq names. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* lockdep: sanitize bit namesPeter Zijlstra2009-02-141-42/+42
| | | | | | | | | s/\(LOCKF\?_ENABLED_[^ ]*\)S\(_READ\)\?\>/\1\2/g So that the USED_IN and ENABLED have the same names. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* lockdep: annotate reclaim context (__GFP_NOFS)Nick Piggin2009-02-141-12/+217
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Here is another version, with the incremental patch rolled up, and added reclaim context annotation to kswapd, and allocation tracing to slab allocators (which may only ever reach the page allocator in rare cases, so it is good to put annotations here too). Haven't tested this version as such, but it should be getting closer to merge worthy ;) -- After noticing some code in mm/filemap.c accidentally perform a __GFP_FS allocation when it should not have been, I thought it might be a good idea to try to catch this kind of thing with lockdep. I coded up a little idea that seems to work. Unfortunately the system has to actually be in __GFP_FS page reclaim, then take the lock, before it will mark it. But at least that might still be some orders of magnitude more common (and more debuggable) than an actual deadlock condition, so we have some improvement I hope (the concept is no less complete than discovery of a lock's interrupt contexts). I guess we could even do the same thing with __GFP_IO (normal reclaim), and even GFP_NOIO locks too... but filesystems will have the most locks and fiddly code paths, so let's start there and see how it goes. It *seems* to work. I did a quick test. ================================= [ INFO: inconsistent lock state ] 2.6.28-rc6-00007-ged31348-dirty #26 --------------------------------- inconsistent {in-reclaim-W} -> {ov-reclaim-W} usage. modprobe/8526 [HC0[0]:SC0[0]:HE1:SE1] takes: (testlock){--..}, at: [<ffffffffa0020055>] brd_init+0x55/0x216 [brd] {in-reclaim-W} state was registered at: [<ffffffff80267bdb>] __lock_acquire+0x75b/0x1a60 [<ffffffff80268f71>] lock_acquire+0x91/0xc0 [<ffffffff8070f0e1>] mutex_lock_nested+0xb1/0x310 [<ffffffffa002002b>] brd_init+0x2b/0x216 [brd] [<ffffffff8020903b>] _stext+0x3b/0x170 [<ffffffff80272ebf>] sys_init_module+0xaf/0x1e0 [<ffffffff8020c3fb>] system_call_fastpath+0x16/0x1b [<ffffffffffffffff>] 0xffffffffffffffff irq event stamp: 3929 hardirqs last enabled at (3929): [<ffffffff8070f2b5>] mutex_lock_nested+0x285/0x310 hardirqs last disabled at (3928): [<ffffffff8070f089>] mutex_lock_nested+0x59/0x310 softirqs last enabled at (3732): [<ffffffff8061f623>] sk_filter+0x83/0xe0 softirqs last disabled at (3730): [<ffffffff8061f5b6>] sk_filter+0x16/0xe0 other info that might help us debug this: 1 lock held by modprobe/8526: #0: (testlock){--..}, at: [<ffffffffa0020055>] brd_init+0x55/0x216 [brd] stack backtrace: Pid: 8526, comm: modprobe Not tainted 2.6.28-rc6-00007-ged31348-dirty #26 Call Trace: [<ffffffff80265483>] print_usage_bug+0x193/0x1d0 [<ffffffff80266530>] mark_lock+0xaf0/0xca0 [<ffffffff80266735>] mark_held_locks+0x55/0xc0 [<ffffffffa0020000>] ? brd_init+0x0/0x216 [brd] [<ffffffff802667ca>] trace_reclaim_fs+0x2a/0x60 [<ffffffff80285005>] __alloc_pages_internal+0x475/0x580 [<ffffffff8070f29e>] ? mutex_lock_nested+0x26e/0x310 [<ffffffffa0020000>] ? brd_init+0x0/0x216 [brd] [<ffffffffa002006a>] brd_init+0x6a/0x216 [brd] [<ffffffffa0020000>] ? brd_init+0x0/0x216 [brd] [<ffffffff8020903b>] _stext+0x3b/0x170 [<ffffffff8070f8b9>] ? mutex_unlock+0x9/0x10 [<ffffffff8070f83d>] ? __mutex_unlock_slowpath+0x10d/0x180 [<ffffffff802669ec>] ? trace_hardirqs_on_caller+0x12c/0x190 [<ffffffff80272ebf>] sys_init_module+0xaf/0x1e0 [<ffffffff8020c3fb>] system_call_fastpath+0x16/0x1b Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* Merge branch 'core-for-linus' of ↵Linus Torvalds2008-12-301-28/+32
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (63 commits) stacktrace: provide save_stack_trace_tsk() weak alias rcu: provide RCU options on non-preempt architectures too printk: fix discarding message when recursion_bug futex: clean up futex_(un)lock_pi fault handling "Tree RCU": scalable classic RCU implementation futex: rename field in futex_q to clarify single waiter semantics x86/swiotlb: add default swiotlb_arch_range_needs_mapping x86/swiotlb: add default phys<->bus conversion x86: unify pci iommu setup and allow swiotlb to compile for 32 bit x86: add swiotlb allocation functions swiotlb: consolidate swiotlb info message printing swiotlb: support bouncing of HighMem pages swiotlb: factor out copy to/from device swiotlb: add arch hook to force mapping swiotlb: allow architectures to override phys<->bus<->phys conversions swiotlb: add comment where we handle the overflow of a dma mask on 32 bit rcu: fix rcutorture behavior during reboot resources: skip sanity check of busy resources swiotlb: move some definitions to header swiotlb: allow architectures to override swiotlb pool allocation ... Fix up trivial conflicts in arch/x86/kernel/Makefile arch/x86/mm/init_32.c include/linux/hardirq.h as per Ingo's suggestions.
| * lockdep: change a held lock's classPeter Zijlstra2008-12-041-15/+9
| | | | | | | | | | | | | | | | | | | | | | | | Impact: introduce new lockdep API Allow to change a held lock's class. Basically the same as the existing code to change a subclass therefore reuse all that. The XFS code will be able to use this to annotate their inode locking. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * Merge commit 'v2.6.28-rc7' into core/lockingIngo Molnar2008-12-041-2/+2
| |\
| * | lockdep: fix unused function warning in kernel/lockdep.cIngo Molnar2008-11-251-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: fix build warning this warning: kernel/lockdep.c:584: warning: ‘print_lock_dependencies’ defined but not used triggers because print_lock_dependencies() is only used if both CONFIG_TRACE_IRQFLAGS and CONFIG_PROVE_LOCKING are enabled. But adding #ifdefs is not an option here - it would spread out to 4-5 other helper functions and uglify the file. So mark this function as __used - it's static and the compiler can eliminate it just fine. Signed-off-by: Ingo Molnar <mingo@elte.hu>
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