From: Thomas Gleixner <[email protected]> The scheduler added NEED_RESCHED_LAZY scheduling. Record this state as part of trace flags and expose it in the need_resched field.
Record and expose NEED_RESCHED_LAZY. [bigeasy: Commit description, documentation bits.] Reviewed-by: Ankur Arora <[email protected]> Reviewed-by: Steven Rostedt (Google) <[email protected]> Signed-off-by: Thomas Gleixner <[email protected]> Signed-off-by: Sebastian Andrzej Siewior <[email protected]> --- Documentation/trace/ftrace.rst | 4 ++++ include/linux/trace_events.h | 1 + kernel/trace/trace.c | 2 ++ kernel/trace/trace_output.c | 14 +++++++++++++- 4 files changed, 20 insertions(+), 1 deletion(-) --- a/Documentation/trace/ftrace.rst +++ b/Documentation/trace/ftrace.rst @@ -1036,9 +1036,13 @@ explains which is which. be printed here. need-resched: + - 'B' all, TIF_NEED_RESCHED, PREEMPT_NEED_RESCHED and TIF_RESCHED_LAZY is set, - 'N' both TIF_NEED_RESCHED and PREEMPT_NEED_RESCHED is set, - 'n' only TIF_NEED_RESCHED is set, - 'p' only PREEMPT_NEED_RESCHED is set, + - 'L' borg PREEMPT_NEED_RESCHED and TIF_RESCHED_LAZY is set, + - 'b' borg TIF_NEED_RESCHED and TIF_RESCHED_LAZY is set, + - 'l' only TIF_RESCHED_LAZY is set - '.' otherwise. hardirq/softirq: --- a/include/linux/trace_events.h +++ b/include/linux/trace_events.h @@ -185,6 +185,7 @@ unsigned int tracing_gen_ctx_irq_test(un enum trace_flag_type { TRACE_FLAG_IRQS_OFF = 0x01, TRACE_FLAG_NEED_RESCHED = 0x02, + TRACE_FLAG_NEED_RESCHED_LAZY = 0x04, TRACE_FLAG_HARDIRQ = 0x08, TRACE_FLAG_SOFTIRQ = 0x10, TRACE_FLAG_PREEMPT_RESCHED = 0x20, --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -2544,6 +2544,8 @@ unsigned int tracing_gen_ctx_irq_test(un trace_flags |= TRACE_FLAG_NEED_RESCHED; if (test_preempt_need_resched()) trace_flags |= TRACE_FLAG_PREEMPT_RESCHED; + if (IS_ENABLED(CONFIG_ARCH_HAS_PREEMPT_LAZY) && tif_test_bit(TIF_NEED_RESCHED_LAZY)) + trace_flags |= TRACE_FLAG_NEED_RESCHED_LAZY; return (trace_flags << 16) | (min_t(unsigned int, pc & 0xff, 0xf)) | (min_t(unsigned int, migration_disable_value(), 0xf)) << 4; } --- a/kernel/trace/trace_output.c +++ b/kernel/trace/trace_output.c @@ -463,17 +463,29 @@ int trace_print_lat_fmt(struct trace_seq !IS_ENABLED(CONFIG_TRACE_IRQFLAGS_SUPPORT) ? 'X' : '.'; - switch (entry->flags & (TRACE_FLAG_NEED_RESCHED | + switch (entry->flags & (TRACE_FLAG_NEED_RESCHED | TRACE_FLAG_NEED_RESCHED_LAZY | TRACE_FLAG_PREEMPT_RESCHED)) { + case TRACE_FLAG_NEED_RESCHED | TRACE_FLAG_NEED_RESCHED_LAZY | TRACE_FLAG_PREEMPT_RESCHED: + need_resched = 'B'; + break; case TRACE_FLAG_NEED_RESCHED | TRACE_FLAG_PREEMPT_RESCHED: need_resched = 'N'; break; + case TRACE_FLAG_NEED_RESCHED_LAZY | TRACE_FLAG_PREEMPT_RESCHED: + need_resched = 'L'; + break; + case TRACE_FLAG_NEED_RESCHED | TRACE_FLAG_NEED_RESCHED_LAZY: + need_resched = 'b'; + break; case TRACE_FLAG_NEED_RESCHED: need_resched = 'n'; break; case TRACE_FLAG_PREEMPT_RESCHED: need_resched = 'p'; break; + case TRACE_FLAG_NEED_RESCHED_LAZY: + need_resched = 'l'; + break; default: need_resched = '.'; break;
