* [PATCH v3] smp: Fix the comments of smp_call_function_many()
@ 2021-12-15 12:29 Zhen Lei
2021-12-16 1:01 ` Randy Dunlap
0 siblings, 1 reply; 3+ messages in thread
From: Zhen Lei @ 2021-12-15 12:29 UTC (permalink / raw)
To: Ingo Molnar, Randy Dunlap, Peter Zijlstra, linux-kernel
Cc: Zhen Lei, Nadav Amit, Dave Hansen
As commit a32a4d8a815c ("smp: Run functions concurrently in
smp_call_function_many_cond()") itself says:
"Keep other smp_call_function_many() semantic as it is
today for backward compatibility: the called function is not executed in
this case locally."
It's clear that, the function header comments of smp_call_function_many()
does not need to be changed.
So move the comment about 'scf_flags' to smp_call_function_many_cond(),
and restore the original comments of smp_call_function_many(). The
comments have been simplified slightly to avoid duplication. And the
description of other parameters of smp_call_function_many_cond() is added.
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
---
kernel/smp.c | 24 +++++++++++++++++-------
1 file changed, 17 insertions(+), 7 deletions(-)
v2 --> v3:
Add the descrition of other parameters of smp_call_function_many_cond().
v1 --> v2:
Delete some duplicate comments.
diff --git a/kernel/smp.c b/kernel/smp.c
index 01a7c1706a58b1d..46ef41d6b6f197e 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -853,14 +853,26 @@ int smp_call_function_any(const struct cpumask *mask,
EXPORT_SYMBOL_GPL(smp_call_function_any);
/*
- * Flags to be used as scf_flags argument of smp_call_function_many_cond().
- *
* %SCF_WAIT: Wait until function execution is completed
* %SCF_RUN_LOCAL: Run also locally if local cpu is set in cpumask
*/
#define SCF_WAIT (1U << 0)
#define SCF_RUN_LOCAL (1U << 1)
+/**
+ * smp_call_function_many_cond(): Run a function on a set of CPUs.
+ * @mask: The set of cpus to run on (only runs on online subset).
+ * Whether to allow execution on the local CPU is also controlled
+ * by @scf_flags.
+ * @func: The function to run on all applicable CPUs.
+ * @info: An arbitrary pointer to pass to @func.
+ * @scf_flags: Bitmask that controls the operation. Such as SCF_WAIT,
+ * SCF_RUN_LOCAL.
+ * @cond_func: A callback function that is passed a cpu id and the info
+ * parameter. The function should return a blooean value
+ * indicating whether @func will be executed on the specified CPU.
+ * If @cond_func is NULL, that means unconditional, always true.
+ */
static void smp_call_function_many_cond(const struct cpumask *mask,
smp_call_func_t func, void *info,
unsigned int scf_flags,
@@ -972,14 +984,12 @@ static void smp_call_function_many_cond(const struct cpumask *mask,
}
/**
- * smp_call_function_many(): Run a function on a set of CPUs.
+ * smp_call_function_many(): Run a function on a set of other CPUs.
* @mask: The set of cpus to run on (only runs on online subset).
* @func: The function to run. This must be fast and non-blocking.
* @info: An arbitrary pointer to pass to the function.
- * @wait: Bitmask that controls the operation. If %SCF_WAIT is set, wait
- * (atomically) until function has completed on other CPUs. If
- * %SCF_RUN_LOCAL is set, the function will also be run locally
- * if the local CPU is set in the @cpumask.
+ * @wait: If true, wait (atomically) until function has completed
+ * on other CPUs.
*
* If @wait is true, then returns once @func has returned.
*
--
2.25.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH v3] smp: Fix the comments of smp_call_function_many()
2021-12-15 12:29 [PATCH v3] smp: Fix the comments of smp_call_function_many() Zhen Lei
@ 2021-12-16 1:01 ` Randy Dunlap
2021-12-16 1:54 ` Leizhen (ThunderTown)
0 siblings, 1 reply; 3+ messages in thread
From: Randy Dunlap @ 2021-12-16 1:01 UTC (permalink / raw)
To: Zhen Lei, Ingo Molnar, Peter Zijlstra, linux-kernel
Cc: Nadav Amit, Dave Hansen
Hi,
On 12/15/21 04:29, Zhen Lei wrote:
> As commit a32a4d8a815c ("smp: Run functions concurrently in
> smp_call_function_many_cond()") itself says:
> "Keep other smp_call_function_many() semantic as it is
> today for backward compatibility: the called function is not executed in
> this case locally."
>
> It's clear that, the function header comments of smp_call_function_many()
> does not need to be changed.
>
> So move the comment about 'scf_flags' to smp_call_function_many_cond(),
> and restore the original comments of smp_call_function_many(). The
> comments have been simplified slightly to avoid duplication. And the
> description of other parameters of smp_call_function_many_cond() is added.
>
> Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
> ---
> kernel/smp.c | 24 +++++++++++++++++-------
> 1 file changed, 17 insertions(+), 7 deletions(-)
>
> v2 --> v3:
> Add the descrition of other parameters of smp_call_function_many_cond().
description
OK, this patch works (that is, scripts/kernel-doc does not complain).
However:
>
> v1 --> v2:
> Delete some duplicate comments.
>
> diff --git a/kernel/smp.c b/kernel/smp.c
> index 01a7c1706a58b1d..46ef41d6b6f197e 100644
> --- a/kernel/smp.c
> +++ b/kernel/smp.c
> @@ -853,14 +853,26 @@ int smp_call_function_any(const struct cpumask *mask,
> EXPORT_SYMBOL_GPL(smp_call_function_any);
>
> /*
> - * Flags to be used as scf_flags argument of smp_call_function_many_cond().
> - *
> * %SCF_WAIT: Wait until function execution is completed
> * %SCF_RUN_LOCAL: Run also locally if local cpu is set in cpumask
> */
> #define SCF_WAIT (1U << 0)
> #define SCF_RUN_LOCAL (1U << 1)
>
> +/**
> + * smp_call_function_many_cond(): Run a function on a set of CPUs.
The documented character to use after a function name is '-', not ':'. So
* smp_call_function_many_cond() - Run a function on a set of CPUs
and
> + * @mask: The set of cpus to run on (only runs on online subset).
> + * Whether to allow execution on the local CPU is also controlled
> + * by @scf_flags.
> + * @func: The function to run on all applicable CPUs.
> + * @info: An arbitrary pointer to pass to @func.
> + * @scf_flags: Bitmask that controls the operation. Such as SCF_WAIT,
> + * SCF_RUN_LOCAL.
> + * @cond_func: A callback function that is passed a cpu id and the info
> + * parameter. The function should return a blooean value
> + * indicating whether @func will be executed on the specified CPU.
> + * If @cond_func is NULL, that means unconditional, always true.
> + */
> static void smp_call_function_many_cond(const struct cpumask *mask,
> smp_call_func_t func, void *info,
> unsigned int scf_flags,
> @@ -972,14 +984,12 @@ static void smp_call_function_many_cond(const struct cpumask *mask,
> }
>
> /**
> - * smp_call_function_many(): Run a function on a set of CPUs.
> + * smp_call_function_many(): Run a function on a set of other CPUs.
* smp_call_function_many() - Run a function on a set of other CPUs.
are preferable.
> * @mask: The set of cpus to run on (only runs on online subset).
> * @func: The function to run. This must be fast and non-blocking.
> * @info: An arbitrary pointer to pass to the function.
> - * @wait: Bitmask that controls the operation. If %SCF_WAIT is set, wait
> - * (atomically) until function has completed on other CPUs. If
> - * %SCF_RUN_LOCAL is set, the function will also be run locally
> - * if the local CPU is set in the @cpumask.
> + * @wait: If true, wait (atomically) until function has completed
> + * on other CPUs.
> *
> * If @wait is true, then returns once @func has returned.
> *
>
thanks.
--
~Randy
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH v3] smp: Fix the comments of smp_call_function_many()
2021-12-16 1:01 ` Randy Dunlap
@ 2021-12-16 1:54 ` Leizhen (ThunderTown)
0 siblings, 0 replies; 3+ messages in thread
From: Leizhen (ThunderTown) @ 2021-12-16 1:54 UTC (permalink / raw)
To: Randy Dunlap, Ingo Molnar, Peter Zijlstra, linux-kernel
Cc: Nadav Amit, Dave Hansen
On 2021/12/16 9:01, Randy Dunlap wrote:
> Hi,
>
> On 12/15/21 04:29, Zhen Lei wrote:
>> As commit a32a4d8a815c ("smp: Run functions concurrently in
>> smp_call_function_many_cond()") itself says:
>> "Keep other smp_call_function_many() semantic as it is
>> today for backward compatibility: the called function is not executed in
>> this case locally."
>>
>> It's clear that, the function header comments of smp_call_function_many()
>> does not need to be changed.
>>
>> So move the comment about 'scf_flags' to smp_call_function_many_cond(),
>> and restore the original comments of smp_call_function_many(). The
>> comments have been simplified slightly to avoid duplication. And the
>> description of other parameters of smp_call_function_many_cond() is added.
>>
>> Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
>> ---
>> kernel/smp.c | 24 +++++++++++++++++-------
>> 1 file changed, 17 insertions(+), 7 deletions(-)
>>
>> v2 --> v3:
>> Add the descrition of other parameters of smp_call_function_many_cond().
>
> description
>
> OK, this patch works (that is, scripts/kernel-doc does not complain).
> However:
>
>>
>> v1 --> v2:
>> Delete some duplicate comments.
>>
>> diff --git a/kernel/smp.c b/kernel/smp.c
>> index 01a7c1706a58b1d..46ef41d6b6f197e 100644
>> --- a/kernel/smp.c
>> +++ b/kernel/smp.c
>> @@ -853,14 +853,26 @@ int smp_call_function_any(const struct cpumask *mask,
>> EXPORT_SYMBOL_GPL(smp_call_function_any);
>>
>> /*
>> - * Flags to be used as scf_flags argument of smp_call_function_many_cond().
>> - *
>> * %SCF_WAIT: Wait until function execution is completed
>> * %SCF_RUN_LOCAL: Run also locally if local cpu is set in cpumask
>> */
>> #define SCF_WAIT (1U << 0)
>> #define SCF_RUN_LOCAL (1U << 1)
>>
>> +/**
>> + * smp_call_function_many_cond(): Run a function on a set of CPUs.
>
> The documented character to use after a function name is '-', not ':'. So
>
> * smp_call_function_many_cond() - Run a function on a set of CPUs
OK, I'll modify it, and change ":" to "-" for other functions in kernel/smp.c
with a new patch.
>
> and
>
>> + * @mask: The set of cpus to run on (only runs on online subset).
>> + * Whether to allow execution on the local CPU is also controlled
>> + * by @scf_flags.
>> + * @func: The function to run on all applicable CPUs.
>> + * @info: An arbitrary pointer to pass to @func.
>> + * @scf_flags: Bitmask that controls the operation. Such as SCF_WAIT,
>> + * SCF_RUN_LOCAL.
>> + * @cond_func: A callback function that is passed a cpu id and the info
>> + * parameter. The function should return a blooean value
>> + * indicating whether @func will be executed on the specified CPU.
>> + * If @cond_func is NULL, that means unconditional, always true.
>> + */
>> static void smp_call_function_many_cond(const struct cpumask *mask,
>> smp_call_func_t func, void *info,
>> unsigned int scf_flags,
>> @@ -972,14 +984,12 @@ static void smp_call_function_many_cond(const struct cpumask *mask,
>> }
>>
>> /**
>> - * smp_call_function_many(): Run a function on a set of CPUs.
>> + * smp_call_function_many(): Run a function on a set of other CPUs.
>
> * smp_call_function_many() - Run a function on a set of other CPUs.
>
> are preferable.
>
>> * @mask: The set of cpus to run on (only runs on online subset).
>> * @func: The function to run. This must be fast and non-blocking.
>> * @info: An arbitrary pointer to pass to the function.
>> - * @wait: Bitmask that controls the operation. If %SCF_WAIT is set, wait
>> - * (atomically) until function has completed on other CPUs. If
>> - * %SCF_RUN_LOCAL is set, the function will also be run locally
>> - * if the local CPU is set in the @cpumask.
>> + * @wait: If true, wait (atomically) until function has completed
>> + * on other CPUs.
>> *
>> * If @wait is true, then returns once @func has returned.
>> *
>>
>
> thanks.
>
^ permalink raw reply [flat|nested] 3+ messages in thread
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2021-12-16 1:01 ` Randy Dunlap
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