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* Merge branch 'locking-core-for-linus' of ↵Linus Torvalds2019-05-0614-766/+858
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull locking updates from Ingo Molnar: "Here are the locking changes in this cycle: - rwsem unification and simpler micro-optimizations to prepare for more intrusive (and more lucrative) scalability improvements in v5.3 (Waiman Long) - Lockdep irq state tracking flag usage cleanups (Frederic Weisbecker) - static key improvements (Jakub Kicinski, Peter Zijlstra) - misc updates, cleanups and smaller fixes" * 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (26 commits) locking/lockdep: Remove unnecessary unlikely() locking/static_key: Don't take sleeping locks in __static_key_slow_dec_deferred() locking/static_key: Factor out the fast path of static_key_slow_dec() locking/static_key: Add support for deferred static branches locking/lockdep: Test all incompatible scenarios at once in check_irq_usage() locking/lockdep: Avoid bogus Clang warning locking/lockdep: Generate LOCKF_ bit composites locking/lockdep: Use expanded masks on find_usage_*() functions locking/lockdep: Map remaining magic numbers to lock usage mask names locking/lockdep: Move valid_state() inside CONFIG_TRACE_IRQFLAGS && CONFIG_PROVE_LOCKING locking/rwsem: Prevent unneeded warning during locking selftest locking/rwsem: Optimize rwsem structure for uncontended lock acquisition locking/rwsem: Enable lock event counting locking/lock_events: Don't show pvqspinlock events on bare metal locking/lock_events: Make lock_events available for all archs & other locks locking/qspinlock_stat: Introduce generic lockevent_*() counting APIs locking/rwsem: Enhance DEBUG_RWSEMS_WARN_ON() macro locking/rwsem: Add debug check for __down_read*() locking/rwsem: Micro-optimize rwsem_try_read_lock_unqueued() locking/rwsem: Move rwsem internal function declarations to rwsem-xadd.h ...
| * locking/lockdep: Remove unnecessary unlikely()zhengbin2019-04-291-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | DEBUG_LOCKS_WARN_ON() already contains an unlikely(), there is no need for another one. Signed-off-by: zhengbin <zhengbin13@huawei.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will.deacon@arm.com> Cc: houtao1@huawei.com Link: http://lkml.kernel.org/r/1556540791-23110-1-git-send-email-zhengbin13@huawei.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * locking/lockdep: Test all incompatible scenarios at once in check_irq_usage()Frederic Weisbecker2019-04-292-67/+167
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | check_prev_add_irq() tests all incompatible scenarios one after the other while adding a lock (@next) to a tree dependency (@prev): LOCK_USED_IN_HARDIRQ vs LOCK_ENABLED_HARDIRQ LOCK_USED_IN_HARDIRQ_READ vs LOCK_ENABLED_HARDIRQ LOCK_USED_IN_SOFTIRQ vs LOCK_ENABLED_SOFTIRQ LOCK_USED_IN_SOFTIRQ_READ vs LOCK_ENABLED_SOFTIRQ Also for these four scenarios, we must at least iterate the @prev backward dependency. Then if it matches the relevant LOCK_USED_* bit, we must also iterate the @next forward dependency. Therefore in the best case we iterate 4 times, in the worst case 8 times. A different approach can let us divide the number of branch iterations by 4: 1) Iterate through @prev backward dependencies and accumulate all the IRQ uses in a single mask. In the best case where the current lock hasn't been used in IRQ, we stop here. 2) Iterate through @next forward dependencies and try to find a lock whose usage is exclusive to the accumulated usages gathered in the previous step. If we find one (call it @lockA), we have found an incompatible use, otherwise we stop here. Only bad locking scenario go further. So a sane verification stop here. 3) Iterate again through @prev backward dependency and find the lock whose usage matches @lockA in term of incompatibility. Call that lock @lockB. 4) Report the incompatible usages of @lockA and @lockB If no incompatible use is found, the verification never goes beyond step 2 which means at most two iterations. The following compares the execution measurements of the function check_prev_add_irq(): Number of calls | Avg (ns) | Stdev (ns) | Total time (ns) ------------------------------------------------------------------------ Mainline 8452 | 2652 | 11962 | 22415143 This patch 8452 | 1518 | 7090 | 12835602 Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will.deacon@arm.com> Link: https://lkml.kernel.org/r/20190402160244.32434-5-frederic@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * locking/lockdep: Generate LOCKF_ bit compositesPeter Zijlstra2019-04-181-6/+22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Instead of open-coding the bitmasks, generate them using the lockdep_states.h header. This prepares for additional states, which would make the manual masks tedious and error prone. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * locking/lockdep: Use expanded masks on find_usage_*() functionsFrederic Weisbecker2019-04-181-10/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In order to optimize check_irq_usage() and factorize all the IRQ usage validations we'll need to be able to check multiple lock usage bits at once. Prepare the low level usage mask check functions for that purpose. Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will.deacon@arm.com> Link: https://lkml.kernel.org/r/20190402160244.32434-4-frederic@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * locking/lockdep: Map remaining magic numbers to lock usage mask namesFrederic Weisbecker2019-04-181-4/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Clarify the code with mapping some more constant numbers that haven't been named after their corresponding LOCK_USAGE_* symbol. Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will.deacon@arm.com> Link: https://lkml.kernel.org/r/20190402160244.32434-3-frederic@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * locking/lockdep: Move valid_state() inside CONFIG_TRACE_IRQFLAGS && ↵Frederic Weisbecker2019-04-181-4/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | CONFIG_PROVE_LOCKING valid_state() and print_usage_bug*() functions are not used beyond irq locking correctness checks under CONFIG_TRACE_IRQFLAGS && CONFIG_PROVE_LOCKING. Sadly the "unused function" warning wouldn't fire because valid_state() is inline so the unused case has remained unseen until now. So move them inside the appropriate CONFIG_TRACE_IRQFLAGS && CONFIG_PROVE_LOCKING section. Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will.deacon@arm.com> Link: https://lkml.kernel.org/r/20190402160244.32434-2-frederic@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * locking/rwsem: Prevent unneeded warning during locking selftestWaiman Long2019-04-141-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Disable the DEBUG_RWSEMS check when locking selftest is running with debug_locks_silent flag set. Signed-off-by: Waiman Long <longman@redhat.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tim Chen <tim.c.chen@linux.intel.com> Cc: Will Deacon <will.deacon@arm.com> Cc: huang ying <huang.ying.caritas@gmail.com> Link: http://lkml.kernel.org/r/20190413172259.2740-2-longman@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * locking/rwsem: Enable lock event countingWaiman Long2019-04-103-0/+32
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add lock event counting calls so that we can track the number of lock events happening in the rwsem code. With CONFIG_LOCK_EVENT_COUNTS on and booting a 4-socket 112-thread x86-64 system, the rwsem counts after system bootup were as follows: rwsem_opt_fail=261 rwsem_opt_wlock=50636 rwsem_rlock=445 rwsem_rlock_fail=0 rwsem_rlock_fast=22 rwsem_rtrylock=810144 rwsem_sleep_reader=441 rwsem_sleep_writer=310 rwsem_wake_reader=355 rwsem_wake_writer=2335 rwsem_wlock=261 rwsem_wlock_fail=0 rwsem_wtrylock=20583 It can be seen that most of the lock acquisitions in the slowpath were write-locks in the optimistic spinning code path with no sleeping at all. For this system, over 97% of the locks are acquired via optimistic spinning. It illustrates the importance of optimistic spinning in improving the performance of rwsem. Signed-off-by: Waiman Long <longman@redhat.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Davidlohr Bueso <dbueso@suse.de> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tim Chen <tim.c.chen@linux.intel.com> Cc: Will Deacon <will.deacon@arm.com> Link: http://lkml.kernel.org/r/20190404174320.22416-11-longman@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * locking/lock_events: Don't show pvqspinlock events on bare metalWaiman Long2019-04-101-1/+27
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | On bare metal, the pvqspinlock event counts will always be 0. So there is no point in showing their corresponding debugfs files. So they are skipped in this case. Signed-off-by: Waiman Long <longman@redhat.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Davidlohr Bueso <dbueso@suse.de> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tim Chen <tim.c.chen@linux.intel.com> Cc: Will Deacon <will.deacon@arm.com> Link: http://lkml.kernel.org/r/20190404174320.22416-10-longman@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * locking/lock_events: Make lock_events available for all archs & other locksWaiman Long2019-04-104-132/+173
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The QUEUED_LOCK_STAT option to report queued spinlocks event counts was previously allowed only on x86 architecture. To make the locking event counting code more useful, it is now renamed to a more generic LOCK_EVENT_COUNTS config option. This new option will be available to all the architectures that use qspinlock at the moment. Other locking code can now start to use the generic locking event counting code by including lock_events.h and put the new locking event names into the lock_events_list.h header file. My experience with lock event counting is that it gives valuable insight on how the locking code works and what can be done to make it better. I would like to extend this benefit to other locking code like mutex and rwsem in the near future. The PV qspinlock specific code will stay in qspinlock_stat.h. The locking event counters will now reside in the <debugfs>/lock_event_counts directory. Signed-off-by: Waiman Long <longman@redhat.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Davidlohr Bueso <dbueso@suse.de> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tim Chen <tim.c.chen@linux.intel.com> Cc: Will Deacon <will.deacon@arm.com> Link: http://lkml.kernel.org/r/20190404174320.22416-9-longman@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * locking/qspinlock_stat: Introduce generic lockevent_*() counting APIsWaiman Long2019-04-105-114/+181
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The percpu event counts used by qspinlock code can be useful for other locking code as well. So a new set of lockevent_* counting APIs is introduced with the lock event names extracted out into the new lock_events_list.h header file for easier addition in the future. The existing qstat_inc() calls are replaced by either lockevent_inc() or lockevent_cond_inc() calls. The qstat_hop() call is renamed to lockevent_pv_hop(). The "reset_counters" debugfs file is also renamed to ".reset_counts". Signed-off-by: Waiman Long <longman@redhat.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Davidlohr Bueso <dbueso@suse.de> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tim Chen <tim.c.chen@linux.intel.com> Cc: Will Deacon <will.deacon@arm.com> Link: http://lkml.kernel.org/r/20190404174320.22416-8-longman@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * locking/rwsem: Enhance DEBUG_RWSEMS_WARN_ON() macroWaiman Long2019-04-102-8/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, the DEBUG_RWSEMS_WARN_ON() macro just dumps a stack trace when the rwsem isn't in the right state. It does not show the actual states of the rwsem. This may not be that helpful in the debugging process. Enhance the DEBUG_RWSEMS_WARN_ON() macro to also show the current content of the rwsem count and owner fields to give more information about what is wrong with the rwsem. The debug_locks_off() function is called as is done inside DEBUG_LOCKS_WARN_ON(). Signed-off-by: Waiman Long <longman@redhat.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Davidlohr Bueso <dbueso@suse.de> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tim Chen <tim.c.chen@linux.intel.com> Cc: Will Deacon <will.deacon@arm.com> Link: http://lkml.kernel.org/r/20190404174320.22416-7-longman@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * locking/rwsem: Add debug check for __down_read*()Waiman Long2019-04-102-5/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When rwsem_down_read_failed*() return, the read lock is acquired indirectly by others. So debug checks are added in __down_read() and __down_read_killable() to make sure the rwsem is really reader-owned. The other debug check calls in kernel/locking/rwsem.c except the one in up_read_non_owner() are also moved over to rwsem-xadd.h. Signed-off-by: Waiman Long <longman@redhat.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Davidlohr Bueso <dbueso@suse.de> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tim Chen <tim.c.chen@linux.intel.com> Cc: Will Deacon <will.deacon@arm.com> Link: http://lkml.kernel.org/r/20190404174320.22416-6-longman@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * locking/rwsem: Micro-optimize rwsem_try_read_lock_unqueued()Waiman Long2019-04-101-10/+5Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The atomic_long_cmpxchg_acquire() in rwsem_try_read_lock_unqueued() is replaced by atomic_long_try_cmpxchg_acquire() to simpify the code and generate slightly better assembly code. There is no functional change. Signed-off-by: Waiman Long <longman@redhat.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Will Deacon <will.deacon@arm.com> Acked-by: Davidlohr Bueso <dbueso@suse.de> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tim Chen <tim.c.chen@linux.intel.com> Link: http://lkml.kernel.org/r/20190404174320.22416-5-longman@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * locking/rwsem: Move rwsem internal function declarations to rwsem-xadd.hWaiman Long2019-04-101-0/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We don't need to expose rwsem internal functions which are not supposed to be called directly from other kernel code. Signed-off-by: Waiman Long <longman@redhat.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Will Deacon <will.deacon@arm.com> Acked-by: Davidlohr Bueso <dbueso@suse.de> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tim Chen <tim.c.chen@linux.intel.com> Link: http://lkml.kernel.org/r/20190404174320.22416-4-longman@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * locking/rwsem: Move owner setting code from rwsem.c to rwsem.hWaiman Long2019-04-103-22/+20Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Move all the owner setting code closer to the rwsem-xadd fast paths directly within rwsem.h file as well as in the slowpaths where owner setting is done after acquring the lock. This will enable us to add DEBUG_RWSEMS check in a later patch to make sure that read lock is really acquired when rwsem_down_read_failed() returns, for instance. Signed-off-by: Waiman Long <longman@redhat.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Davidlohr Bueso <dbueso@suse.de> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tim Chen <tim.c.chen@linux.intel.com> Cc: Will Deacon <will.deacon@arm.com> Link: http://lkml.kernel.org/r/20190404174320.22416-3-longman@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * locking/rwsem: Relocate rwsem_down_read_failed()Waiman Long2019-04-101-86/+86
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The rwsem_down_read_failed*() functions were relocated from above the optimistic spinning section to below that section. This enables the reader functions to use optimisitic spinning in future patches. There is no code change. Signed-off-by: Waiman Long <longman@redhat.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Will Deacon <will.deacon@arm.com> Acked-by: Davidlohr Bueso <dbueso@suse.de> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tim Chen <tim.c.chen@linux.intel.com> Link: http://lkml.kernel.org/r/20190404174320.22416-2-longman@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * locking/rwsem: Optimize down_read_trylock()Waiman Long2019-04-031-5/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Modify __down_read_trylock() to optimize for an unlocked rwsem and make it generate slightly better code. Before this patch, down_read_trylock: 0x0000000000000000 <+0>: callq 0x5 <down_read_trylock+5> 0x0000000000000005 <+5>: jmp 0x18 <down_read_trylock+24> 0x0000000000000007 <+7>: lea 0x1(%rdx),%rcx 0x000000000000000b <+11>: mov %rdx,%rax 0x000000000000000e <+14>: lock cmpxchg %rcx,(%rdi) 0x0000000000000013 <+19>: cmp %rax,%rdx 0x0000000000000016 <+22>: je 0x23 <down_read_trylock+35> 0x0000000000000018 <+24>: mov (%rdi),%rdx 0x000000000000001b <+27>: test %rdx,%rdx 0x000000000000001e <+30>: jns 0x7 <down_read_trylock+7> 0x0000000000000020 <+32>: xor %eax,%eax 0x0000000000000022 <+34>: retq 0x0000000000000023 <+35>: mov %gs:0x0,%rax 0x000000000000002c <+44>: or $0x3,%rax 0x0000000000000030 <+48>: mov %rax,0x20(%rdi) 0x0000000000000034 <+52>: mov $0x1,%eax 0x0000000000000039 <+57>: retq After patch, down_read_trylock: 0x0000000000000000 <+0>: callq 0x5 <down_read_trylock+5> 0x0000000000000005 <+5>: xor %eax,%eax 0x0000000000000007 <+7>: lea 0x1(%rax),%rdx 0x000000000000000b <+11>: lock cmpxchg %rdx,(%rdi) 0x0000000000000010 <+16>: jne 0x29 <down_read_trylock+41> 0x0000000000000012 <+18>: mov %gs:0x0,%rax 0x000000000000001b <+27>: or $0x3,%rax 0x000000000000001f <+31>: mov %rax,0x20(%rdi) 0x0000000000000023 <+35>: mov $0x1,%eax 0x0000000000000028 <+40>: retq 0x0000000000000029 <+41>: test %rax,%rax 0x000000000000002c <+44>: jns 0x7 <down_read_trylock+7> 0x000000000000002e <+46>: xor %eax,%eax 0x0000000000000030 <+48>: retq By using a rwsem microbenchmark, the down_read_trylock() rate (with a load of 10 to lengthen the lock critical section) on a x86-64 system before and after the patch were: Before Patch After Patch # of Threads rlock rlock ------------ ----- ----- 1 14,496 14,716 2 8,644 8,453 4 6,799 6,983 8 5,664 7,190 On a ARM64 system, the performance results were: Before Patch After Patch # of Threads rlock rlock ------------ ----- ----- 1 23,676 24,488 2 7,697 9,502 4 4,945 3,440 8 2,641 1,603 For the uncontended case (1 thread), the new down_read_trylock() is a little bit faster. For the contended cases, the new down_read_trylock() perform pretty well in x86-64, but performance degrades at high contention level on ARM64. Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tim Chen <tim.c.chen@linux.intel.com> Cc: Will Deacon <will.deacon@arm.com> Cc: linux-arm-kernel@lists.infradead.org Cc: linux-c6x-dev@linux-c6x.org Cc: linux-m68k@lists.linux-m68k.org Cc: linux-riscv@lists.infradead.org Cc: linux-um@lists.infradead.org Cc: linux-xtensa@linux-xtensa.org Cc: linuxppc-dev@lists.ozlabs.org Cc: nios2-dev@lists.rocketboards.org Cc: openrisc@lists.librecores.org Cc: uclinux-h8-devel@lists.sourceforge.jp Link: https://lkml.kernel.org/r/20190322143008.21313-4-longman@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * locking/rwsem: Remove rwsem-spinlock.c & use rwsem-xadd.c for all archsWaiman Long2019-04-033-345/+1Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, we have two different implementation of rwsem: 1) CONFIG_RWSEM_GENERIC_SPINLOCK (rwsem-spinlock.c) 2) CONFIG_RWSEM_XCHGADD_ALGORITHM (rwsem-xadd.c) As we are going to use a single generic implementation for rwsem-xadd.c and no architecture-specific code will be needed, there is no point in keeping two different implementations of rwsem. In most cases, the performance of rwsem-spinlock.c will be worse. It also doesn't get all the performance tuning and optimizations that had been implemented in rwsem-xadd.c over the years. For simplication, we are going to remove rwsem-spinlock.c and make all architectures use a single implementation of rwsem - rwsem-xadd.c. All references to RWSEM_GENERIC_SPINLOCK and RWSEM_XCHGADD_ALGORITHM in the code are removed. Suggested-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tim Chen <tim.c.chen@linux.intel.com> Cc: Will Deacon <will.deacon@arm.com> Cc: linux-arm-kernel@lists.infradead.org Cc: linux-c6x-dev@linux-c6x.org Cc: linux-m68k@lists.linux-m68k.org Cc: linux-riscv@lists.infradead.org Cc: linux-um@lists.infradead.org Cc: linux-xtensa@linux-xtensa.org Cc: linuxppc-dev@lists.ozlabs.org Cc: nios2-dev@lists.rocketboards.org Cc: openrisc@lists.librecores.org Cc: uclinux-h8-devel@lists.sourceforge.jp Link: https://lkml.kernel.org/r/20190322143008.21313-3-longman@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * locking/rwsem: Remove arch specific rwsem filesWaiman Long2019-04-032-0/+132
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | As the generic rwsem-xadd code is using the appropriate acquire and release versions of the atomic operations, the arch specific rwsem.h files will not be that much faster than the generic code as long as the atomic functions are properly implemented. So we can remove those arch specific rwsem.h and stop building asm/rwsem.h to reduce maintenance effort. Currently, only x86, alpha and ia64 have implemented architecture specific fast paths. I don't have access to alpha and ia64 systems for testing, but they are legacy systems that are not likely to be updated to the latest kernel anyway. By using a rwsem microbenchmark, the total locking rates on a 4-socket 56-core 112-thread x86-64 system before and after the patch were as follows (mixed means equal # of read and write locks): Before Patch After Patch # of Threads wlock rlock mixed wlock rlock mixed ------------ ----- ----- ----- ----- ----- ----- 1 29,201 30,143 29,458 28,615 30,172 29,201 2 6,807 13,299 1,171 7,725 15,025 1,804 4 6,504 12,755 1,520 7,127 14,286 1,345 8 6,762 13,412 764 6,826 13,652 726 16 6,693 15,408 662 6,599 15,938 626 32 6,145 15,286 496 5,549 15,487 511 64 5,812 15,495 60 5,858 15,572 60 There were some run-to-run variations for the multi-thread tests. For x86-64, using the generic C code fast path seems to be a little bit faster than the assembly version with low lock contention. Looking at the assembly version of the fast paths, there are assembly to/from C code wrappers that save and restore all the callee-clobbered registers (7 registers on x86-64). The assembly generated from the generic C code doesn't need to do that. That may explain the slight performance gain here. The generic asm rwsem.h can also be merged into kernel/locking/rwsem.h with no code change as no other code other than those under kernel/locking needs to access the internal rwsem macros and functions. Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tim Chen <tim.c.chen@linux.intel.com> Cc: Will Deacon <will.deacon@arm.com> Cc: linux-arm-kernel@lists.infradead.org Cc: linux-c6x-dev@linux-c6x.org Cc: linux-m68k@lists.linux-m68k.org Cc: linux-riscv@lists.infradead.org Cc: linux-um@lists.infradead.org Cc: linux-xtensa@linux-xtensa.org Cc: linuxppc-dev@lists.ozlabs.org Cc: nios2-dev@lists.rocketboards.org Cc: openrisc@lists.librecores.org Cc: uclinux-h8-devel@lists.sourceforge.jp Link: https://lkml.kernel.org/r/20190322143008.21313-2-longman@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | Merge branch 'core-stacktrace-for-linus' of ↵Linus Torvalds2019-05-061-49/+38Star
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull stack trace updates from Ingo Molnar: "So Thomas looked at the stacktrace code recently and noticed a few weirdnesses, and we all know how such stories of crummy kernel code meeting German engineering perfection end: a 45-patch series to clean it all up! :-) Here's the changes in Thomas's words: 'Struct stack_trace is a sinkhole for input and output parameters which is largely pointless for most usage sites. In fact if embedded into other data structures it creates indirections and extra storage overhead for no benefit. Looking at all usage sites makes it clear that they just require an interface which is based on a storage array. That array is either on stack, global or embedded into some other data structure. Some of the stack depot usage sites are outright wrong, but fortunately the wrongness just causes more stack being used for nothing and does not have functional impact. Another oddity is the inconsistent termination of the stack trace with ULONG_MAX. It's pointless as the number of entries is what determines the length of the stored trace. In fact quite some call sites remove the ULONG_MAX marker afterwards with or without nasty comments about it. Not all architectures do that and those which do, do it inconsistenly either conditional on nr_entries == 0 or unconditionally. The following series cleans that up by: 1) Removing the ULONG_MAX termination in the architecture code 2) Removing the ULONG_MAX fixups at the call sites 3) Providing plain storage array based interfaces for stacktrace and stackdepot. 4) Cleaning up the mess at the callsites including some related cleanups. 5) Removing the struct stack_trace based interfaces This is not changing the struct stack_trace interfaces at the architecture level, but it removes the exposure to the generic code'" * 'core-stacktrace-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (45 commits) x86/stacktrace: Use common infrastructure stacktrace: Provide common infrastructure lib/stackdepot: Remove obsolete functions stacktrace: Remove obsolete functions livepatch: Simplify stack trace retrieval tracing: Remove the last struct stack_trace usage tracing: Simplify stack trace retrieval tracing: Make ftrace_trace_userstack() static and conditional tracing: Use percpu stack trace buffer more intelligently tracing: Simplify stacktrace retrieval in histograms lockdep: Simplify stack trace handling lockdep: Remove save argument from check_prev_add() lockdep: Remove unused trace argument from print_circular_bug() drm: Simplify stacktrace handling dm persistent data: Simplify stack trace handling dm bufio: Simplify stack trace retrieval btrfs: ref-verify: Simplify stack trace retrieval dma/debug: Simplify stracktrace retrieval fault-inject: Simplify stacktrace retrieval mm/page_owner: Simplify stack trace handling ...
| * | lockdep: Simplify stack trace handlingThomas Gleixner2019-04-291-27/+28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Replace the indirection through struct stack_trace by using the storage array based interfaces and storing the information is a small lockdep specific data structure. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Alexander Potapenko <glider@google.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: linux-mm@kvack.org Cc: David Rientjes <rientjes@google.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: kasan-dev@googlegroups.com Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: Akinobu Mita <akinobu.mita@gmail.com> Cc: Christoph Hellwig <hch@lst.de> Cc: iommu@lists.linux-foundation.org Cc: Robin Murphy <robin.murphy@arm.com> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Cc: Johannes Thumshirn <jthumshirn@suse.de> Cc: David Sterba <dsterba@suse.com> Cc: Chris Mason <clm@fb.com> Cc: Josef Bacik <josef@toxicpanda.com> Cc: linux-btrfs@vger.kernel.org Cc: dm-devel@redhat.com Cc: Mike Snitzer <snitzer@redhat.com> Cc: Alasdair Kergon <agk@redhat.com> Cc: Daniel Vetter <daniel@ffwll.ch> Cc: intel-gfx@lists.freedesktop.org Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Cc: dri-devel@lists.freedesktop.org Cc: David Airlie <airlied@linux.ie> Cc: Jani Nikula <jani.nikula@linux.intel.com> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com> Cc: Tom Zanussi <tom.zanussi@linux.intel.com> Cc: Miroslav Benes <mbenes@suse.cz> Cc: linux-arch@vger.kernel.org Link: https://lkml.kernel.org/r/20190425094802.891724020@linutronix.de
| * | lockdep: Remove save argument from check_prev_add()Thomas Gleixner2019-04-291-8/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There is only one caller which hands in save_trace as function pointer. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Alexander Potapenko <glider@google.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: linux-mm@kvack.org Cc: David Rientjes <rientjes@google.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: kasan-dev@googlegroups.com Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: Akinobu Mita <akinobu.mita@gmail.com> Cc: Christoph Hellwig <hch@lst.de> Cc: iommu@lists.linux-foundation.org Cc: Robin Murphy <robin.murphy@arm.com> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Cc: Johannes Thumshirn <jthumshirn@suse.de> Cc: David Sterba <dsterba@suse.com> Cc: Chris Mason <clm@fb.com> Cc: Josef Bacik <josef@toxicpanda.com> Cc: linux-btrfs@vger.kernel.org Cc: dm-devel@redhat.com Cc: Mike Snitzer <snitzer@redhat.com> Cc: Alasdair Kergon <agk@redhat.com> Cc: Daniel Vetter <daniel@ffwll.ch> Cc: intel-gfx@lists.freedesktop.org Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Cc: dri-devel@lists.freedesktop.org Cc: David Airlie <airlied@linux.ie> Cc: Jani Nikula <jani.nikula@linux.intel.com> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com> Cc: Tom Zanussi <tom.zanussi@linux.intel.com> Cc: Miroslav Benes <mbenes@suse.cz> Cc: linux-arch@vger.kernel.org Link: https://lkml.kernel.org/r/20190425094802.803362058@linutronix.de
| * | lockdep: Remove unused trace argument from print_circular_bug()Thomas Gleixner2019-04-291-5/+4Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Alexander Potapenko <glider@google.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: linux-mm@kvack.org Cc: David Rientjes <rientjes@google.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: kasan-dev@googlegroups.com Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: Akinobu Mita <akinobu.mita@gmail.com> Cc: Christoph Hellwig <hch@lst.de> Cc: iommu@lists.linux-foundation.org Cc: Robin Murphy <robin.murphy@arm.com> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Cc: Johannes Thumshirn <jthumshirn@suse.de> Cc: David Sterba <dsterba@suse.com> Cc: Chris Mason <clm@fb.com> Cc: Josef Bacik <josef@toxicpanda.com> Cc: linux-btrfs@vger.kernel.org Cc: dm-devel@redhat.com Cc: Mike Snitzer <snitzer@redhat.com> Cc: Alasdair Kergon <agk@redhat.com> Cc: Daniel Vetter <daniel@ffwll.ch> Cc: intel-gfx@lists.freedesktop.org Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Cc: dri-devel@lists.freedesktop.org Cc: David Airlie <airlied@linux.ie> Cc: Jani Nikula <jani.nikula@linux.intel.com> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com> Cc: Tom Zanussi <tom.zanussi@linux.intel.com> Cc: Miroslav Benes <mbenes@suse.cz> Cc: linux-arch@vger.kernel.org Link: https://lkml.kernel.org/r/20190425094802.716274532@linutronix.de
| * | lockdep: Remove the ULONG_MAX stack trace hackeryThomas Gleixner2019-04-141-11/+0Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | No architecture terminates the stack trace with ULONG_MAX anymore. Remove the cruft. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Alexander Potapenko <glider@google.com> Cc: Will Deacon <will.deacon@arm.com> Link: https://lkml.kernel.org/r/20190410103644.485737321@linutronix.de
* | | Merge branch 'core-rcu-for-linus' of ↵Linus Torvalds2019-05-061-0/+2
|\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull RCU updates from Ingo Molnar: "This cycles's RCU changes include: - a couple of straggling RCU flavor consolidation updates - SRCU updates - RCU CPU stall-warning updates - torture-test updates - an LKMM commit adding support for synchronize_srcu_expedited() - documentation updates - miscellaneous fixes" * 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (57 commits) net/ipv4/netfilter: Update comment from call_rcu_bh() to call_rcu() tools/memory-model: Add support for synchronize_srcu_expedited() doc/kprobes: Update obsolete RCU update functions torture: Suppress false-positive CONFIG_INITRAMFS_SOURCE complaint locktorture: NULL cxt.lwsa and cxt.lrsa to allow bad-arg detection rcuperf: Fix cleanup path for invalid perf_type strings rcutorture: Fix cleanup path for invalid torture_type strings rcutorture: Fix expected forward progress duration in OOM notifier rcutorture: Remove ->ext_irq_conflict field rcutorture: Make rcutorture_extend_mask() comment match the code tools/.../rcutorture: Convert to SPDX license identifier torture: Don't try to offline the last CPU rcu: Fix nohz status in stall warning rcu: Move forward-progress checkers into tree_stall.h rcu: Move irq-disabled stall-warning checking to tree_stall.h rcu: Organize functions in tree_stall.h rcu: Move FAST_NO_HZ stall-warning code to tree_stall.h rcu: Inline RCU stall-warning info helper functions rcu: Move rcu_print_task_exp_stall() to tree_exp.h rcu: Inline RCU task stall-warning helper functions ...
| * \ \ Merge branch 'for-mingo' of ↵Ingo Molnar2019-04-181-0/+2
| |\ \ \ | | |/ / | |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu Pull RCU and LKMM commits from Paul E. McKenney: - An LKMM commit adding support for synchronize_srcu_expedited() - A couple of straggling RCU flavor consolidation updates - Documentation updates. - Miscellaneous fixes - SRCU updates - RCU CPU stall-warning updates - Torture-test updates Signed-off-by: Ingo Molnar <mingo@kernel.org>
| | * | locktorture: NULL cxt.lwsa and cxt.lrsa to allow bad-arg detectionPaul E. McKenney2019-03-261-0/+2
| | |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, lock_torture_cleanup() uses the values of cxt.lwsa and cxt.lrsa to detect bad parameters that prevented locktorture from initializing, let alone running. In this case, lock_torture_cleanup() does no cleanup aside from invoking torture_cleanup_begin() and torture_cleanup_end(), as required to permit future torture tests to run. However, this heuristic fails if the run with bad parameters was preceded by a previous run that actually ran: In this case, both cxt.lwsa and cxt.lrsa will remain non-zero, which means that the current lock_torture_cleanup() invocation will be unable to detect the fact that it should skip cleanup, which can result in charming outcomes such as double frees. This commit therefore NULLs out both cxt.lwsa and cxt.lrsa at the end of any run that actually ran. Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Josh Triplett <josh@joshtriplett.org>
* | / locking/lockdep: Make lockdep_unregister_key() honor 'debug_locks' againBart Van Assche2019-04-161-4/+5
|/ / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If lockdep_register_key() and lockdep_unregister_key() are called with debug_locks == false then the following warning is reported: WARNING: CPU: 2 PID: 15145 at kernel/locking/lockdep.c:4920 lockdep_unregister_key+0x1ad/0x240 That warning is reported because lockdep_unregister_key() ignores the value of 'debug_locks' and because the behavior of lockdep_register_key() depends on whether or not 'debug_locks' is set. Fix this inconsistency by making lockdep_unregister_key() take 'debug_locks' again into account. Signed-off-by: Bart Van Assche <bvanassche@acm.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Waiman Long <longman@redhat.com> Cc: Will Deacon <will.deacon@arm.com> Cc: shenghui <shhuiw@foxmail.com> Fixes: 90c1cba2b3b3 ("locking/lockdep: Zap lock classes even with lock debugging disabled") Link: http://lkml.kernel.org/r/20190415170538.23491-1-bvanassche@acm.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* / locking/lockdep: Zap lock classes even with lock debugging disabledBart Van Assche2019-04-101-17/+12Star
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The following commit: a0b0fd53e1e6 ("locking/lockdep: Free lock classes that are no longer in use") changed the behavior of lockdep_free_key_range() from unconditionally zapping lock classes into only zapping lock classes if debug_lock == true. Not zapping lock classes if debug_lock == false leaves dangling pointers in several lockdep datastructures, e.g. lock_class::name in the all_lock_classes list. The shell command "cat /proc/lockdep" causes the kernel to iterate the all_lock_classes list. Hence the "unable to handle kernel paging request" cash that Shenghui encountered by running cat /proc/lockdep. Since the new behavior can cause cat /proc/lockdep to crash, restore the pre-v5.1 behavior. This patch avoids that cat /proc/lockdep triggers the following crash with debug_lock == false: BUG: unable to handle kernel paging request at fffffbfff40ca448 RIP: 0010:__asan_load1+0x28/0x50 Call Trace: string+0xac/0x180 vsnprintf+0x23e/0x820 seq_vprintf+0x82/0xc0 seq_printf+0x92/0xb0 print_name+0x34/0xb0 l_show+0x184/0x200 seq_read+0x59e/0x6c0 proc_reg_read+0x11f/0x170 __vfs_read+0x4d/0x90 vfs_read+0xc5/0x1f0 ksys_read+0xab/0x130 __x64_sys_read+0x43/0x50 do_syscall_64+0x71/0x210 entry_SYSCALL_64_after_hwframe+0x49/0xbe Reported-by: shenghui <shhuiw@foxmail.com> Signed-off-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Waiman Long <longman@redhat.com> Cc: Will Deacon <will.deacon@arm.com> Fixes: a0b0fd53e1e6 ("locking/lockdep: Free lock classes that are no longer in use") # v5.1-rc1. Link: https://lkml.kernel.org/r/20190403233552.124673-1-bvanassche@acm.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* locking/lockdep: Only call init_rcu_head() after RCU has been initializedBart Van Assche2019-03-091-4/+11
| | | | | | | | | | | | | | | | | | | | | | | init_data_structures_once() is called for the first time before RCU has been initialized. Make sure that init_rcu_head() is called before the RCU head is used and after RCU has been initialized. Signed-off-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@surriel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will.deacon@arm.com> Cc: longman@redhat.com Link: https://lkml.kernel.org/r/c20aa0f0-42ab-a884-d931-7d4ec2bf0cdc@acm.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* locking/lockdep: Avoid a Clang warningArnd Bergmann2019-03-091-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Clang warns about a tentative array definition without a length: kernel/locking/lockdep.c:845:12: error: tentative array definition assumed to have one element [-Werror] There is no real reason to do this here, so just set the same length as in the real definition later in the same file. It has to be hidden in an #ifdef or annotated __maybe_unused though, to avoid the unused-variable warning if CONFIG_PROVE_LOCKING is disabled. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Bart Van Assche <bvanassche@acm.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Frederic Weisbecker <frederic@kernel.org> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Joel Fernandes (Google) <joel@joelfernandes.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@surriel.com> Cc: Stephane Eranian <eranian@google.com> Cc: Steven Rostedt (VMware) <rostedt@goodmis.org> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> Cc: Waiman Long <longman@redhat.com> Cc: Will Deacon <will.deacon@arm.com> Link: https://lkml.kernel.org/r/20190307075222.3424524-1-arnd@arndb.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
* Merge branch 'perf-core-for-linus' of ↵Linus Torvalds2019-03-061-1/+6
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull perf updates from Ingo Molnar: "Lots of tooling updates - too many to list, here's a few highlights: - Various subcommand updates to 'perf trace', 'perf report', 'perf record', 'perf annotate', 'perf script', 'perf test', etc. - CPU and NUMA topology and affinity handling improvements, - HW tracing and HW support updates: - Intel PT updates - ARM CoreSight updates - vendor HW event updates - BPF updates - Tons of infrastructure updates, both on the build system and the library support side - Documentation updates. - ... and lots of other changes, see the changelog for details. Kernel side updates: - Tighten up kprobes blacklist handling, reduce the number of places where developers can install a kprobe and hang/crash the system. - Fix/enhance vma address filter handling. - Various PMU driver updates, small fixes and additions. - refcount_t conversions - BPF updates - error code propagation enhancements - misc other changes" * 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (238 commits) perf script python: Add Python3 support to syscall-counts-by-pid.py perf script python: Add Python3 support to syscall-counts.py perf script python: Add Python3 support to stat-cpi.py perf script python: Add Python3 support to stackcollapse.py perf script python: Add Python3 support to sctop.py perf script python: Add Python3 support to powerpc-hcalls.py perf script python: Add Python3 support to net_dropmonitor.py perf script python: Add Python3 support to mem-phys-addr.py perf script python: Add Python3 support to failed-syscalls-by-pid.py perf script python: Add Python3 support to netdev-times.py perf tools: Add perf_exe() helper to find perf binary perf script: Handle missing fields with -F +.. perf data: Add perf_data__open_dir_data function perf data: Add perf_data__(create_dir|close_dir) functions perf data: Fail check_backup in case of error perf data: Make check_backup work over directories perf tools: Add rm_rf_perf_data function perf tools: Add pattern name checking to rm_rf perf tools: Add depth checking to rm_rf perf data: Add global path holder ...
| * Merge branch 'linus' into perf/core, to pick up fixesIngo Molnar2019-02-281-5/+32
| |\ | | | | | | | | | Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | kprobes: Prohibit probing on lockdep functionsMasami Hiramatsu2019-02-131-1/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Some lockdep functions can be involved in breakpoint handling and probing on those functions can cause a breakpoint recursion. Prohibit probing on those functions by blacklist. Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Andrea Righi <righi.andrea@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/154998810578.31052.1680977921449292812.stgit@devbox Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | | Merge branch 'locking-core-for-linus' of ↵Linus Torvalds2019-03-066-174/+857
|\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull locking updates from Ingo Molnar: "The biggest part of this tree is the new auto-generated atomics API wrappers by Mark Rutland. The primary motivation was to allow instrumentation without uglifying the primary source code. The linecount increase comes from adding the auto-generated files to the Git space as well: include/asm-generic/atomic-instrumented.h | 1689 ++++++++++++++++-- include/asm-generic/atomic-long.h | 1174 ++++++++++--- include/linux/atomic-fallback.h | 2295 +++++++++++++++++++++++++ include/linux/atomic.h | 1241 +------------ I preferred this approach, so that the full call stack of the (already complex) locking APIs is still fully visible in 'git grep'. But if this is excessive we could certainly hide them. There's a separate build-time mechanism to determine whether the headers are out of date (they should never be stale if we do our job right). Anyway, nothing from this should be visible to regular kernel developers. Other changes: - Add support for dynamic keys, which removes a source of false positives in the workqueue code, among other things (Bart Van Assche) - Updates to tools/memory-model (Andrea Parri, Paul E. McKenney) - qspinlock, wake_q and lockdep micro-optimizations (Waiman Long) - misc other updates and enhancements" * 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (48 commits) locking/lockdep: Shrink struct lock_class_key locking/lockdep: Add module_param to enable consistency checks lockdep/lib/tests: Test dynamic key registration lockdep/lib/tests: Fix run_tests.sh kernel/workqueue: Use dynamic lockdep keys for workqueues locking/lockdep: Add support for dynamic keys locking/lockdep: Verify whether lock objects are small enough to be used as class keys locking/lockdep: Check data structure consistency locking/lockdep: Reuse lock chains that have been freed locking/lockdep: Fix a comment in add_chain_cache() locking/lockdep: Introduce lockdep_next_lockchain() and lock_chain_count() locking/lockdep: Reuse list entries that are no longer in use locking/lockdep: Free lock classes that are no longer in use locking/lockdep: Update two outdated comments locking/lockdep: Make it easy to detect whether or not inside a selftest locking/lockdep: Split lockdep_free_key_range() and lockdep_reset_lock() locking/lockdep: Initialize the locks_before and locks_after lists earlier locking/lockdep: Make zap_class() remove all matching lock order entries locking/lockdep: Reorder struct lock_class members locking/lockdep: Avoid that add_chain_cache() adds an invalid chain to the cache ...
| * | | locking/lockdep: Add module_param to enable consistency checksPeter Zijlstra2019-02-281-13/+33
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | And move the whole lot under CONFIG_DEBUG_LOCKDEP. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | locking/lockdep: Add support for dynamic keysBart Van Assche2019-02-281-8/+113
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | A shortcoming of the current lockdep implementation is that it requires lock keys to be allocated statically. That forces all instances of lock objects that occur in a given data structure to share a lock key. Since lock dependency analysis groups lock objects per key sharing lock keys can cause false positive lockdep reports. Make it possible to avoid such false positive reports by allowing lock keys to be allocated dynamically. Require that dynamically allocated lock keys are registered before use by calling lockdep_register_key(). Complain about attempts to register the same lock key pointer twice without calling lockdep_unregister_key() between successive registration calls. The purpose of the new lock_keys_hash[] data structure that keeps track of all dynamic keys is twofold: - Verify whether the lockdep_register_key() and lockdep_unregister_key() functions are used correctly. - Avoid that lockdep_init_map() complains when encountering a dynamically allocated key. Signed-off-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Johannes Berg <johannes@sipsolutions.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Waiman Long <longman@redhat.com> Cc: Will Deacon <will.deacon@arm.com> Cc: johannes.berg@intel.com Cc: tj@kernel.org Link: https://lkml.kernel.org/r/20190214230058.196511-19-bvanassche@acm.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | locking/lockdep: Verify whether lock objects are small enough to be used as ↵Bart Van Assche2019-02-281-0/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | class keys Signed-off-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Johannes Berg <johannes@sipsolutions.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Waiman Long <longman@redhat.com> Cc: Will Deacon <will.deacon@arm.com> Cc: johannes.berg@intel.com Cc: tj@kernel.org Link: https://lkml.kernel.org/r/20190214230058.196511-18-bvanassche@acm.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | locking/lockdep: Check data structure consistencyBart Van Assche2019-02-281-0/+167
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Debugging lockdep data structure inconsistencies is challenging. Add code that verifies data structure consistency at runtime. That code is disabled by default because it is very CPU intensive. Signed-off-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Johannes Berg <johannes@sipsolutions.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Waiman Long <longman@redhat.com> Cc: Will Deacon <will.deacon@arm.com> Cc: johannes.berg@intel.com Cc: tj@kernel.org Link: https://lkml.kernel.org/r/20190214230058.196511-17-bvanassche@acm.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | locking/lockdep: Reuse lock chains that have been freedBart Van Assche2019-02-281-20/+37
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | A previous patch introduced a lock chain leak. Fix that leak by reusing lock chains that have been freed. Signed-off-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Johannes Berg <johannes@sipsolutions.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Waiman Long <longman@redhat.com> Cc: Will Deacon <will.deacon@arm.com> Cc: johannes.berg@intel.com Cc: tj@kernel.org Link: https://lkml.kernel.org/r/20190214230058.196511-16-bvanassche@acm.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | locking/lockdep: Fix a comment in add_chain_cache()Bart Van Assche2019-02-281-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Reflect that add_chain_cache() is always called with the graph lock held. Signed-off-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Johannes Berg <johannes@sipsolutions.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Waiman Long <longman@redhat.com> Cc: Will Deacon <will.deacon@arm.com> Cc: johannes.berg@intel.com Cc: tj@kernel.org Link: https://lkml.kernel.org/r/20190214230058.196511-15-bvanassche@acm.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | locking/lockdep: Introduce lockdep_next_lockchain() and lock_chain_count()Bart Van Assche2019-02-283-8/+23
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch does not change any functionality but makes the next patch in this series easier to read. Signed-off-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Johannes Berg <johannes@sipsolutions.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Waiman Long <longman@redhat.com> Cc: Will Deacon <will.deacon@arm.com> Cc: johannes.berg@intel.com Cc: tj@kernel.org Link: https://lkml.kernel.org/r/20190214230058.196511-14-bvanassche@acm.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | locking/lockdep: Reuse list entries that are no longer in useBart Van Assche2019-02-281-8/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Instead of abandoning elements of list_entries[] that are no longer in use, make alloc_list_entry() reuse array elements that have been freed. Signed-off-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Johannes Berg <johannes@sipsolutions.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Waiman Long <longman@redhat.com> Cc: Will Deacon <will.deacon@arm.com> Cc: johannes.berg@intel.com Cc: tj@kernel.org Link: https://lkml.kernel.org/r/20190214230058.196511-13-bvanassche@acm.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | locking/lockdep: Free lock classes that are no longer in useBart Van Assche2019-02-281-48/+348
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Instead of leaving lock classes that are no longer in use in the lock_classes array, reuse entries from that array that are no longer in use. Maintain a linked list of free lock classes with list head 'free_lock_class'. Only add freed lock classes to the free_lock_classes list after a grace period to avoid that a lock_classes[] element would be reused while an RCU reader is accessing it. Since the lockdep selftests run in a context where sleeping is not allowed and since the selftests require that lock resetting/zapping works with debug_locks off, make the behavior of lockdep_free_key_range() and lockdep_reset_lock() depend on whether or not these are called from the context of the lockdep selftests. Thanks to Peter for having shown how to modify get_pending_free() such that that function does not have to sleep. Signed-off-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Johannes Berg <johannes@sipsolutions.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Waiman Long <longman@redhat.com> Cc: Will Deacon <will.deacon@arm.com> Cc: johannes.berg@intel.com Cc: tj@kernel.org Link: https://lkml.kernel.org/r/20190214230058.196511-12-bvanassche@acm.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | locking/lockdep: Update two outdated commentsBart Van Assche2019-02-281-5/+3Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | synchronize_sched() has been removed recently. Update the comments that refer to synchronize_sched(). Signed-off-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Johannes Berg <johannes@sipsolutions.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Waiman Long <longman@redhat.com> Cc: Will Deacon <will.deacon@arm.com> Cc: johannes.berg@intel.com Cc: tj@kernel.org Fixes: 51959d85f32d ("lockdep: Replace synchronize_sched() with synchronize_rcu()") # v5.0-rc1 Link: https://lkml.kernel.org/r/20190214230058.196511-11-bvanassche@acm.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | locking/lockdep: Make it easy to detect whether or not inside a selftestBart Van Assche2019-02-281-0/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The patch that frees unused lock classes will modify the behavior of lockdep_free_key_range() and lockdep_reset_lock() depending on whether or not these functions are called from the context of the lockdep selftests. Hence make it easy to detect whether or not lockdep code is called from the context of a lockdep selftest. Signed-off-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Johannes Berg <johannes@sipsolutions.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Waiman Long <longman@redhat.com> Cc: Will Deacon <will.deacon@arm.com> Cc: johannes.berg@intel.com Cc: tj@kernel.org Link: https://lkml.kernel.org/r/20190214230058.196511-10-bvanassche@acm.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | locking/lockdep: Split lockdep_free_key_range() and lockdep_reset_lock()Bart Van Assche2019-02-281-36/+36
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch does not change the behavior of these functions but makes the patch that frees unused lock classes easier to read. Signed-off-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Johannes Berg <johannes@sipsolutions.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Waiman Long <longman@redhat.com> Cc: Will Deacon <will.deacon@arm.com> Cc: johannes.berg@intel.com Cc: tj@kernel.org Link: https://lkml.kernel.org/r/20190214230058.196511-9-bvanassche@acm.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | locking/lockdep: Initialize the locks_before and locks_after lists earlierBart Van Assche2019-02-281-2/+27
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch does not change any functionality. A later patch will reuse lock classes that have been freed. In combination with that patch this patch wil have the effect of initializing lock class order lists once instead of every time a lock class structure is reinitialized. Signed-off-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Johannes Berg <johannes@sipsolutions.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Waiman Long <longman@redhat.com> Cc: Will Deacon <will.deacon@arm.com> Cc: johannes.berg@intel.com Cc: tj@kernel.org Link: https://lkml.kernel.org/r/20190214230058.196511-8-bvanassche@acm.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
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