* [PATCH v4 0/1] blktrace: switch trace spinlock to a raw spinlock @ 2021-12-20 13:03 Wander Lairson Costa 2021-12-20 13:03 ` [PATCH v4 1/1] " Wander Lairson Costa 0 siblings, 1 reply; 3+ messages in thread From: Wander Lairson Costa @ 2021-12-20 13:03 UTC (permalink / raw) To: linux-kernel, Jens Axboe, Steven Rostedt, Ingo Molnar, open list:BLOCK LAYER Cc: Thomas Gleixner, Sebastian Andrzej Siewior, Wander Lairson Costa This version only changes the commit message as suggested by Sebastian. Wander Lairson Costa (1): blktrace: switch trace spinlock to a raw spinlock kernel/trace/blktrace.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) -- 2.27.0 ^ permalink raw reply [flat|nested] 3+ messages in thread
* [PATCH v4 1/1] blktrace: switch trace spinlock to a raw spinlock 2021-12-20 13:03 [PATCH v4 0/1] blktrace: switch trace spinlock to a raw spinlock Wander Lairson Costa @ 2021-12-20 13:03 ` Wander Lairson Costa 2021-12-20 18:14 ` kernel test robot 0 siblings, 1 reply; 3+ messages in thread From: Wander Lairson Costa @ 2021-12-20 13:03 UTC (permalink / raw) To: linux-kernel, Jens Axboe, Steven Rostedt, Ingo Molnar, open list:BLOCK LAYER Cc: Thomas Gleixner, Sebastian Andrzej Siewior, Wander Lairson Costa The running_trace_lock protects running_trace_list and is acquired within the tracepoint which implies disabled preemption. The spinlock_t typed lock can not be acquired with disabled preemption on PREEMPT_RT because it becomes a sleeping lock. The runtime of the tracepoint depends on the number of entries in running_trace_list and has no limit. The blk-tracer is considered debug code and higher latencies here are okay. Make running_trace_lock a raw_spinlock_t. Signed-off-by: Wander Lairson Costa <wander@redhat.com> --- kernel/trace/blktrace.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c index c221e4c3f625..0ce1fadce078 100644 --- a/kernel/trace/blktrace.c +++ b/kernel/trace/blktrace.c @@ -34,7 +34,7 @@ static struct trace_array *blk_tr; static bool blk_tracer_enabled __read_mostly; static LIST_HEAD(running_trace_list); -static __cacheline_aligned_in_smp DEFINE_SPINLOCK(running_trace_lock); +static __cacheline_aligned_in_smp DEFINE_RAW_SPINLOCK(running_trace_lock); /* Select an alternative, minimalistic output than the original one */ #define TRACE_BLK_OPT_CLASSIC 0x1 @@ -121,12 +121,12 @@ static void trace_note_tsk(struct task_struct *tsk) struct blk_trace *bt; tsk->btrace_seq = blktrace_seq; - spin_lock_irqsave(&running_trace_lock, flags); + raw_spin_lock_irqsave(&running_trace_lock, flags); list_for_each_entry(bt, &running_trace_list, running_list) { trace_note(bt, tsk->pid, BLK_TN_PROCESS, tsk->comm, sizeof(tsk->comm), 0); } - spin_unlock_irqrestore(&running_trace_lock, flags); + raw_spin_unlock_irqrestore(&running_trace_lock, flags); } static void trace_note_time(struct blk_trace *bt) @@ -666,9 +666,9 @@ static int __blk_trace_startstop(struct request_queue *q, int start) blktrace_seq++; smp_mb(); bt->trace_state = Blktrace_running; - spin_lock_irq(&running_trace_lock); + raw_spin_lock_irq(&running_trace_lock); list_add(&bt->running_list, &running_trace_list); - spin_unlock_irq(&running_trace_lock); + raw_spin_unlock_irq(&running_trace_lock); trace_note_time(bt); ret = 0; @@ -676,9 +676,9 @@ static int __blk_trace_startstop(struct request_queue *q, int start) } else { if (bt->trace_state == Blktrace_running) { bt->trace_state = Blktrace_stopped; - spin_lock_irq(&running_trace_lock); + raw_spin_lock_irq(&running_trace_lock); list_del_init(&bt->running_list); - spin_unlock_irq(&running_trace_lock); + raw_spin_unlock_irq(&running_trace_lock); relay_flush(bt->rchan); ret = 0; } -- 2.27.0 ^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH v4 1/1] blktrace: switch trace spinlock to a raw spinlock 2021-12-20 13:03 ` [PATCH v4 1/1] " Wander Lairson Costa @ 2021-12-20 18:14 ` kernel test robot 0 siblings, 0 replies; 3+ messages in thread From: kernel test robot @ 2021-12-20 18:14 UTC (permalink / raw) To: Wander Lairson Costa, linux-kernel, Jens Axboe, Steven Rostedt, Ingo Molnar, linux-block Cc: llvm, kbuild-all, Thomas Gleixner, Sebastian Andrzej Siewior, Wander Lairson Costa Hi Wander, Thank you for the patch! Yet something to improve: [auto build test ERROR on axboe-block/for-next] [also build test ERROR on linux/master linus/master v5.16-rc6 next-20211220] [If your patch is applied to the wrong git tree, kindly drop us a note. And when submitting patch, we suggest to use '--base' as documented in https://git-scm.com/docs/git-format-patch] url: https://github.com/0day-ci/linux/commits/Wander-Lairson-Costa/blktrace-switch-trace-spinlock-to-a-raw-spinlock/20211220-210538 base: https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git for-next config: hexagon-randconfig-r045-20211220 (https://download.01.org/0day-ci/archive/20211221/202112210258.y6u1AZpZ-lkp@intel.com/config) compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project 555eacf75f21cd1dfc6363d73ad187b730349543) reproduce (this is a W=1 build): wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # https://github.com/0day-ci/linux/commit/b270731108ecba0d77a6db93d057290406c51a20 git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Wander-Lairson-Costa/blktrace-switch-trace-spinlock-to-a-raw-spinlock/20211220-210538 git checkout b270731108ecba0d77a6db93d057290406c51a20 # save the config file to linux build tree mkdir build_dir COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=hexagon SHELL=/bin/bash drivers/gpu/drm/ kernel/trace/ If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp@intel.com> All errors (new ones prefixed by >>): kernel/trace/blktrace.c:148:63: warning: parameter 'blkcg' set but not used [-Wunused-but-set-parameter] void __trace_note_message(struct blk_trace *bt, struct blkcg *blkcg, ^ >> kernel/trace/blktrace.c:1611:17: error: incompatible pointer types passing 'raw_spinlock_t *' (aka 'struct raw_spinlock *') to parameter of type 'spinlock_t *' (aka 'struct spinlock *') [-Werror,-Wincompatible-pointer-types] spin_lock_irq(&running_trace_lock); ^~~~~~~~~~~~~~~~~~~ include/linux/spinlock.h:372:55: note: passing argument to parameter 'lock' here static __always_inline void spin_lock_irq(spinlock_t *lock) ^ kernel/trace/blktrace.c:1613:19: error: incompatible pointer types passing 'raw_spinlock_t *' (aka 'struct raw_spinlock *') to parameter of type 'spinlock_t *' (aka 'struct spinlock *') [-Werror,-Wincompatible-pointer-types] spin_unlock_irq(&running_trace_lock); ^~~~~~~~~~~~~~~~~~~ include/linux/spinlock.h:397:57: note: passing argument to parameter 'lock' here static __always_inline void spin_unlock_irq(spinlock_t *lock) ^ 1 warning and 2 errors generated. vim +1611 kernel/trace/blktrace.c c71a896154119f block/blktrace.c Arnaldo Carvalho de Melo 2009-01-23 1599 c71a896154119f block/blktrace.c Arnaldo Carvalho de Melo 2009-01-23 1600 static int blk_trace_remove_queue(struct request_queue *q) c71a896154119f block/blktrace.c Arnaldo Carvalho de Melo 2009-01-23 1601 { c71a896154119f block/blktrace.c Arnaldo Carvalho de Melo 2009-01-23 1602 struct blk_trace *bt; c71a896154119f block/blktrace.c Arnaldo Carvalho de Melo 2009-01-23 1603 c3dbe541ef7775 kernel/trace/blktrace.c Jan Kara 2020-06-05 1604 bt = rcu_replace_pointer(q->blk_trace, NULL, 85e0cbbb8a7953 kernel/trace/blktrace.c Luis Chamberlain 2020-06-19 1605 lockdep_is_held(&q->debugfs_mutex)); c71a896154119f block/blktrace.c Arnaldo Carvalho de Melo 2009-01-23 1606 if (bt == NULL) c71a896154119f block/blktrace.c Arnaldo Carvalho de Melo 2009-01-23 1607 return -EINVAL; c71a896154119f block/blktrace.c Arnaldo Carvalho de Melo 2009-01-23 1608 5afedf670caf30 kernel/trace/blktrace.c Zhihao Cheng 2021-09-23 1609 if (bt->trace_state == Blktrace_running) { 5afedf670caf30 kernel/trace/blktrace.c Zhihao Cheng 2021-09-23 1610 bt->trace_state = Blktrace_stopped; 5afedf670caf30 kernel/trace/blktrace.c Zhihao Cheng 2021-09-23 @1611 spin_lock_irq(&running_trace_lock); 5afedf670caf30 kernel/trace/blktrace.c Zhihao Cheng 2021-09-23 1612 list_del_init(&bt->running_list); 5afedf670caf30 kernel/trace/blktrace.c Zhihao Cheng 2021-09-23 1613 spin_unlock_irq(&running_trace_lock); 5afedf670caf30 kernel/trace/blktrace.c Zhihao Cheng 2021-09-23 1614 relay_flush(bt->rchan); 5afedf670caf30 kernel/trace/blktrace.c Zhihao Cheng 2021-09-23 1615 } 5afedf670caf30 kernel/trace/blktrace.c Zhihao Cheng 2021-09-23 1616 a6da0024ffc19e kernel/trace/blktrace.c Jens Axboe 2017-11-05 1617 put_probe_ref(); c780e86dd48ef6 kernel/trace/blktrace.c Jan Kara 2020-02-06 1618 synchronize_rcu(); ad5dd5493a55e4 kernel/trace/blktrace.c Li Zefan 2009-03-27 1619 blk_trace_free(bt); c71a896154119f block/blktrace.c Arnaldo Carvalho de Melo 2009-01-23 1620 return 0; c71a896154119f block/blktrace.c Arnaldo Carvalho de Melo 2009-01-23 1621 } c71a896154119f block/blktrace.c Arnaldo Carvalho de Melo 2009-01-23 1622 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org ^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2021-12-20 18:15 UTC | newest] Thread overview: 3+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2021-12-20 13:03 [PATCH v4 0/1] blktrace: switch trace spinlock to a raw spinlock Wander Lairson Costa 2021-12-20 13:03 ` [PATCH v4 1/1] " Wander Lairson Costa 2021-12-20 18:14 ` kernel test robot
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