Re: [PATCH 2/3] tracing: Record task flag NEED_RESCHED_LAZY.

[Sebastian Andrzej Siewior]

On 2024-10-09 11:49:41 [-0700], Ankur Arora wrote:
> > So this should be:
> >
> >     if (IS_ENABLED(CONFIG_ARCH_HAS_PREEMPT_LAZY) &&
> >         tif_test_bit(TIF_NEED_RESCHED_LAZY))
> >
> > ?
> 
> Yeah, exactly that.

Okay, this makes sense, this is what I ended up with:

diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h
index d5c0fcf20f024..4cae6f2581379 100644
--- a/include/linux/trace_events.h
+++ b/include/linux/trace_events.h
@@ -185,6 +185,7 @@ unsigned int tracing_gen_ctx_irq_test(unsigned int 
irqs_status);
 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,
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 1c69ca1f10886..fb839d00aad12 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -2544,6 +2544,8 @@ unsigned int tracing_gen_ctx_irq_test(unsigned int 
irqs_status)
                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;
 }
diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
index 829daa0764dd9..23ca2155306b1 100644
--- a/kernel/trace/trace_output.c
+++ b/kernel/trace/trace_output.c
@@ -463,17 +463,29 @@ int trace_print_lat_fmt(struct trace_seq *s, struct 
trace_entry *entry)
                !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;
-- 
2.45.2


Sebastian