diff mbox series

[RFC,46/86] tracing: handle lazy resched

Message ID 20231107215742.363031-47-ankur.a.arora@oracle.com (mailing list archive)
State New
Headers show
Series Make the kernel preemptible | expand

Commit Message

Ankur Arora Nov. 7, 2023, 9:57 p.m. UTC 
Tracing support.

Note: this is quite incomplete.

Originally-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ankur Arora <ankur.a.arora@oracle.com>
---
 include/linux/trace_events.h |  6 +++---
 kernel/trace/trace.c         |  2 ++
 kernel/trace/trace_output.c  | 16 ++++++++++++++--
 3 files changed, 19 insertions(+), 5 deletions(-)

Comments

Steven Rostedt Nov. 8, 2023, 12:19 a.m. UTC | #1 
On Tue,  7 Nov 2023 13:57:32 -0800
Ankur Arora <ankur.a.arora@oracle.com> wrote:

> Tracing support.
> 
> Note: this is quite incomplete.

What's not complete? The removal of the IRQS_NOSUPPORT?

Really, that's only for alpha, m68k and nios2. I think setting 'X' is not
needed anymore, and we can use that bit for this, and for those archs, have
0 for interrupts disabled.

-- Steve


> 
> Originally-by: Thomas Gleixner <tglx@linutronix.de>
> Signed-off-by: Ankur Arora <ankur.a.arora@oracle.com>
> ---
>  include/linux/trace_events.h |  6 +++---
>  kernel/trace/trace.c         |  2 ++
>  kernel/trace/trace_output.c  | 16 ++++++++++++++--
>  3 files changed, 19 insertions(+), 5 deletions(-)
> 
> diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h
> index 21ae37e49319..355d25d5e398 100644
> --- a/include/linux/trace_events.h
> +++ b/include/linux/trace_events.h
> @@ -178,7 +178,7 @@ unsigned int tracing_gen_ctx_irq_test(unsigned int irqs_status);
>  
>  enum trace_flag_type {
>  	TRACE_FLAG_IRQS_OFF		= 0x01,
> -	TRACE_FLAG_IRQS_NOSUPPORT	= 0x02,
> +	TRACE_FLAG_NEED_RESCHED_LAZY    = 0x02,
>  	TRACE_FLAG_NEED_RESCHED		= 0x04,
>  	TRACE_FLAG_HARDIRQ		= 0x08,
>  	TRACE_FLAG_SOFTIRQ		= 0x10,
> @@ -205,11 +205,11 @@ static inline unsigned int tracing_gen_ctx(void)
>  
>  static inline unsigned int tracing_gen_ctx_flags(unsigned long irqflags)
>  {
> -	return tracing_gen_ctx_irq_test(TRACE_FLAG_IRQS_NOSUPPORT);
> +	return tracing_gen_ctx_irq_test(0);
>  }
>  static inline unsigned int tracing_gen_ctx(void)
>  {
> -	return tracing_gen_ctx_irq_test(TRACE_FLAG_IRQS_NOSUPPORT);
> +	return tracing_gen_ctx_irq_test(0);
>  }
>  #endif
>  
> diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
> index 7f067ad9cf50..0776dba32c2d 100644
> --- a/kernel/trace/trace.c
> +++ b/kernel/trace/trace.c
> @@ -2722,6 +2722,8 @@ unsigned int tracing_gen_ctx_irq_test(unsigned int irqs_status)
>  
>  	if (tif_need_resched(RESCHED_eager))
>  		trace_flags |= TRACE_FLAG_NEED_RESCHED;
> +	if (tif_need_resched(RESCHED_lazy))
> +		trace_flags |= TRACE_FLAG_NEED_RESCHED_LAZY;
>  	if (test_preempt_need_resched())
>  		trace_flags |= TRACE_FLAG_PREEMPT_RESCHED;
>  	return (trace_flags << 16) | (min_t(unsigned int, pc & 0xff, 0xf)) |
> diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
> index db575094c498..c251a44ad8ac 100644
> --- a/kernel/trace/trace_output.c
> +++ b/kernel/trace/trace_output.c
> @@ -460,17 +460,29 @@ int trace_print_lat_fmt(struct trace_seq *s, struct trace_entry *entry)
>  		(entry->flags & TRACE_FLAG_IRQS_OFF && bh_off) ? 'D' :
>  		(entry->flags & TRACE_FLAG_IRQS_OFF) ? 'd' :
>  		bh_off ? 'b' :
> -		(entry->flags & TRACE_FLAG_IRQS_NOSUPPORT) ? 'X' :
> +		!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_NEED_RESCHED_LAZY:
> +		need_resched = 'l';
> +		break;
>  	case TRACE_FLAG_PREEMPT_RESCHED:
>  		need_resched = 'p';
>  		break;
Ankur Arora Nov. 8, 2023, 9:24 a.m. UTC | #2 
Steven Rostedt <rostedt@goodmis.org> writes:

> On Tue,  7 Nov 2023 13:57:32 -0800
> Ankur Arora <ankur.a.arora@oracle.com> wrote:
>
>> Tracing support.
>>
>> Note: this is quite incomplete.
>
> What's not complete? The removal of the IRQS_NOSUPPORT?
>
> Really, that's only for alpha, m68k and nios2. I think setting 'X' is not
> needed anymore, and we can use that bit for this, and for those archs, have
> 0 for interrupts disabled.

Right, that makes sense. I wasn't worried about the IRQS_NOSUPPORT.
I think I just misread the code and thought that some other tracers might
need separate support as well.

Will fix the commit message.

Thanks
Ankur

>>
>> Originally-by: Thomas Gleixner <tglx@linutronix.de>
>> Signed-off-by: Ankur Arora <ankur.a.arora@oracle.com>
>> ---
>>  include/linux/trace_events.h |  6 +++---
>>  kernel/trace/trace.c         |  2 ++
>>  kernel/trace/trace_output.c  | 16 ++++++++++++++--
>>  3 files changed, 19 insertions(+), 5 deletions(-)
>>
>> diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h
>> index 21ae37e49319..355d25d5e398 100644
>> --- a/include/linux/trace_events.h
>> +++ b/include/linux/trace_events.h
>> @@ -178,7 +178,7 @@ unsigned int tracing_gen_ctx_irq_test(unsigned int irqs_status);
>>
>>  enum trace_flag_type {
>>  	TRACE_FLAG_IRQS_OFF		= 0x01,
>> -	TRACE_FLAG_IRQS_NOSUPPORT	= 0x02,
>> +	TRACE_FLAG_NEED_RESCHED_LAZY    = 0x02,
>>  	TRACE_FLAG_NEED_RESCHED		= 0x04,
>>  	TRACE_FLAG_HARDIRQ		= 0x08,
>>  	TRACE_FLAG_SOFTIRQ		= 0x10,
>> @@ -205,11 +205,11 @@ static inline unsigned int tracing_gen_ctx(void)
>>
>>  static inline unsigned int tracing_gen_ctx_flags(unsigned long irqflags)
>>  {
>> -	return tracing_gen_ctx_irq_test(TRACE_FLAG_IRQS_NOSUPPORT);
>> +	return tracing_gen_ctx_irq_test(0);
>>  }
>>  static inline unsigned int tracing_gen_ctx(void)
>>  {
>> -	return tracing_gen_ctx_irq_test(TRACE_FLAG_IRQS_NOSUPPORT);
>> +	return tracing_gen_ctx_irq_test(0);
>>  }
>>  #endif
>>
>> diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
>> index 7f067ad9cf50..0776dba32c2d 100644
>> --- a/kernel/trace/trace.c
>> +++ b/kernel/trace/trace.c
>> @@ -2722,6 +2722,8 @@ unsigned int tracing_gen_ctx_irq_test(unsigned int irqs_status)
>>
>>  	if (tif_need_resched(RESCHED_eager))
>>  		trace_flags |= TRACE_FLAG_NEED_RESCHED;
>> +	if (tif_need_resched(RESCHED_lazy))
>> +		trace_flags |= TRACE_FLAG_NEED_RESCHED_LAZY;
>>  	if (test_preempt_need_resched())
>>  		trace_flags |= TRACE_FLAG_PREEMPT_RESCHED;
>>  	return (trace_flags << 16) | (min_t(unsigned int, pc & 0xff, 0xf)) |
>> diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
>> index db575094c498..c251a44ad8ac 100644
>> --- a/kernel/trace/trace_output.c
>> +++ b/kernel/trace/trace_output.c
>> @@ -460,17 +460,29 @@ int trace_print_lat_fmt(struct trace_seq *s, struct trace_entry *entry)
>>  		(entry->flags & TRACE_FLAG_IRQS_OFF && bh_off) ? 'D' :
>>  		(entry->flags & TRACE_FLAG_IRQS_OFF) ? 'd' :
>>  		bh_off ? 'b' :
>> -		(entry->flags & TRACE_FLAG_IRQS_NOSUPPORT) ? 'X' :
>> +		!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_NEED_RESCHED_LAZY:
>> +		need_resched = 'l';
>> +		break;
>>  	case TRACE_FLAG_PREEMPT_RESCHED:
>>  		need_resched = 'p';
>>  		break;


--
ankur
diff mbox series

Patch

diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h
index 21ae37e49319..355d25d5e398 100644
--- a/include/linux/trace_events.h
+++ b/include/linux/trace_events.h
@@ -178,7 +178,7 @@  unsigned int tracing_gen_ctx_irq_test(unsigned int irqs_status);
 
 enum trace_flag_type {
 	TRACE_FLAG_IRQS_OFF		= 0x01,
-	TRACE_FLAG_IRQS_NOSUPPORT	= 0x02,
+	TRACE_FLAG_NEED_RESCHED_LAZY    = 0x02,
 	TRACE_FLAG_NEED_RESCHED		= 0x04,
 	TRACE_FLAG_HARDIRQ		= 0x08,
 	TRACE_FLAG_SOFTIRQ		= 0x10,
@@ -205,11 +205,11 @@  static inline unsigned int tracing_gen_ctx(void)
 
 static inline unsigned int tracing_gen_ctx_flags(unsigned long irqflags)
 {
-	return tracing_gen_ctx_irq_test(TRACE_FLAG_IRQS_NOSUPPORT);
+	return tracing_gen_ctx_irq_test(0);
 }
 static inline unsigned int tracing_gen_ctx(void)
 {
-	return tracing_gen_ctx_irq_test(TRACE_FLAG_IRQS_NOSUPPORT);
+	return tracing_gen_ctx_irq_test(0);
 }
 #endif
 
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 7f067ad9cf50..0776dba32c2d 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -2722,6 +2722,8 @@  unsigned int tracing_gen_ctx_irq_test(unsigned int irqs_status)
 
 	if (tif_need_resched(RESCHED_eager))
 		trace_flags |= TRACE_FLAG_NEED_RESCHED;
+	if (tif_need_resched(RESCHED_lazy))
+		trace_flags |= TRACE_FLAG_NEED_RESCHED_LAZY;
 	if (test_preempt_need_resched())
 		trace_flags |= TRACE_FLAG_PREEMPT_RESCHED;
 	return (trace_flags << 16) | (min_t(unsigned int, pc & 0xff, 0xf)) |
diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
index db575094c498..c251a44ad8ac 100644
--- a/kernel/trace/trace_output.c
+++ b/kernel/trace/trace_output.c
@@ -460,17 +460,29 @@  int trace_print_lat_fmt(struct trace_seq *s, struct trace_entry *entry)
 		(entry->flags & TRACE_FLAG_IRQS_OFF && bh_off) ? 'D' :
 		(entry->flags & TRACE_FLAG_IRQS_OFF) ? 'd' :
 		bh_off ? 'b' :
-		(entry->flags & TRACE_FLAG_IRQS_NOSUPPORT) ? 'X' :
+		!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_NEED_RESCHED_LAZY:
+		need_resched = 'l';
+		break;
 	case TRACE_FLAG_PREEMPT_RESCHED:
 		need_resched = 'p';
 		break;