* Re: [RFC PATCH 46/86] tracing: handle lazy resched
[not found] ` <20231107215742.363031-47-ankur.a.arora@oracle.com>
@ 2023-11-08 0:19 ` Steven Rostedt
2023-11-08 9:24 ` Ankur Arora
0 siblings, 1 reply; 2+ messages in thread
From: Steven Rostedt @ 2023-11-08 0:19 UTC (permalink / raw)
To: Ankur Arora
Cc: linux-kernel, tglx, peterz, torvalds, paulmck, linux-mm, x86,
akpm, luto, bp, dave.hansen, hpa, mingo, juri.lelli,
vincent.guittot, willy, mgorman, jon.grimm, bharata,
raghavendra.kt, boris.ostrovsky, konrad.wilk, jgross,
andrew.cooper3, mingo, bristot, mathieu.desnoyers, geert,
glaubitz, anton.ivanov, mattst88, krypton, David.Laight, richard,
mjguzik, Richard Henderson, Ivan Kokshaysky, Matt Turner,
linux-alpha, Geert Uytterhoeven, linux-m68k, Dinh Nguyen
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;
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [RFC PATCH 46/86] tracing: handle lazy resched
2023-11-08 0:19 ` [RFC PATCH 46/86] tracing: handle lazy resched Steven Rostedt
@ 2023-11-08 9:24 ` Ankur Arora
0 siblings, 0 replies; 2+ messages in thread
From: Ankur Arora @ 2023-11-08 9:24 UTC (permalink / raw)
To: Steven Rostedt
Cc: Ankur Arora, linux-kernel, tglx, peterz, torvalds, paulmck,
linux-mm, x86, akpm, luto, bp, dave.hansen, hpa, mingo,
juri.lelli, vincent.guittot, willy, mgorman, jon.grimm, bharata,
raghavendra.kt, boris.ostrovsky, konrad.wilk, jgross,
andrew.cooper3, mingo, bristot, mathieu.desnoyers, glaubitz,
anton.ivanov, krypton, David.Laight, richard, mjguzik,
Richard Henderson, Ivan Kokshaysky, Matt Turner, linux-alpha,
Geert Uytterhoeven, linux-m68k, Dinh Nguyen
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
^ permalink raw reply [flat|nested] 2+ messages in thread
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[not found] ` <20231107215742.363031-47-ankur.a.arora@oracle.com>
2023-11-08 0:19 ` [RFC PATCH 46/86] tracing: handle lazy resched Steven Rostedt
2023-11-08 9:24 ` Ankur Arora
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