2020-02-23 19:30:48

by Qais Yousef

Subject: [PATCH v3 13/15] torture: Replace cpu_up/down with add/remove_cpu

The core device API performs extra housekeeping bits that are missing
from directly calling cpu_up/down.

See commit a6717c01ddc2 ("powerpc/rtas: use device model APIs and
serialization during LPM") for an example description of what might go
wrong.

This also prepares to make cpu_up/down a private interface for anything
but the cpu subsystem.

Signed-off-by: Qais Yousef <[email protected]>
CC: Davidlohr Bueso <[email protected]>
CC: "Paul E. McKenney" <[email protected]>
CC: Josh Triplett <[email protected]>
CC: [email protected]
---
kernel/torture.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/kernel/torture.c b/kernel/torture.c
index 7c13f5558b71..a479689eac73 100644
--- a/kernel/torture.c
+++ b/kernel/torture.c
@@ -97,7 +97,7 @@ bool torture_offline(int cpu, long *n_offl_attempts, long *n_offl_successes,
torture_type, cpu);
starttime = jiffies;
(*n_offl_attempts)++;
- ret = cpu_down(cpu);
+ ret = remove_cpu(cpu);
if (ret) {
if (verbose)
pr_alert("%s" TORTURE_FLAG
@@ -148,7 +148,7 @@ bool torture_online(int cpu, long *n_onl_attempts, long *n_onl_successes,
torture_type, cpu);
starttime = jiffies;
(*n_onl_attempts)++;
- ret = cpu_up(cpu);
+ ret = add_cpu(cpu);
if (ret) {
if (verbose)
pr_alert("%s" TORTURE_FLAG
@@ -192,17 +192,18 @@ torture_onoff(void *arg)
for_each_online_cpu(cpu)
maxcpu = cpu;
WARN_ON(maxcpu < 0);
- if (!IS_MODULE(CONFIG_TORTURE_TEST))
+ if (!IS_MODULE(CONFIG_TORTURE_TEST)) {
for_each_possible_cpu(cpu) {
if (cpu_online(cpu))
continue;
- ret = cpu_up(cpu);
+ ret = add_cpu(cpu);
if (ret && verbose) {
pr_alert("%s" TORTURE_FLAG
"%s: Initial online %d: errno %d\n",
__func__, torture_type, cpu, ret);
}
}
+ }

if (maxcpu == 0) {
VERBOSE_TOROUT_STRING("Only one CPU, so CPU-hotplug testing is disabled");
--
2.17.1

2020-02-24 02:53:46

by Paul E. McKenney

Subject: Re: [PATCH v3 13/15] torture: Replace cpu_up/down with add/remove_cpu

On Sun, Feb 23, 2020 at 07:29:40PM +0000, Qais Yousef wrote:
> The core device API performs extra housekeeping bits that are missing
> from directly calling cpu_up/down.
>
> See commit a6717c01ddc2 ("powerpc/rtas: use device model APIs and
> serialization during LPM") for an example description of what might go
> wrong.
>
> This also prepares to make cpu_up/down a private interface for anything
> but the cpu subsystem.
>
> Signed-off-by: Qais Yousef <[email protected]>
> CC: Davidlohr Bueso <[email protected]>
> CC: "Paul E. McKenney" <[email protected]>
> CC: Josh Triplett <[email protected]>
> CC: [email protected]

From a torture-test perspective:

Acked-by: Paul E. McKenney <[email protected]>

> ---
> kernel/torture.c | 9 +++++----
> 1 file changed, 5 insertions(+), 4 deletions(-)
>
> diff --git a/kernel/torture.c b/kernel/torture.c
> index 7c13f5558b71..a479689eac73 100644
> --- a/kernel/torture.c
> +++ b/kernel/torture.c
> @@ -97,7 +97,7 @@ bool torture_offline(int cpu, long *n_offl_attempts, long *n_offl_successes,
> torture_type, cpu);
> starttime = jiffies;
> (*n_offl_attempts)++;
> - ret = cpu_down(cpu);
> + ret = remove_cpu(cpu);
> if (ret) {
> if (verbose)
> pr_alert("%s" TORTURE_FLAG
> @@ -148,7 +148,7 @@ bool torture_online(int cpu, long *n_onl_attempts, long *n_onl_successes,
> torture_type, cpu);
> starttime = jiffies;
> (*n_onl_attempts)++;
> - ret = cpu_up(cpu);
> + ret = add_cpu(cpu);
> if (ret) {
> if (verbose)
> pr_alert("%s" TORTURE_FLAG
> @@ -192,17 +192,18 @@ torture_onoff(void *arg)
> for_each_online_cpu(cpu)
> maxcpu = cpu;
> WARN_ON(maxcpu < 0);
> - if (!IS_MODULE(CONFIG_TORTURE_TEST))
> + if (!IS_MODULE(CONFIG_TORTURE_TEST)) {
> for_each_possible_cpu(cpu) {
> if (cpu_online(cpu))
> continue;
> - ret = cpu_up(cpu);
> + ret = add_cpu(cpu);
> if (ret && verbose) {
> pr_alert("%s" TORTURE_FLAG
> "%s: Initial online %d: errno %d\n",
> __func__, torture_type, cpu, ret);
> }
> }
> + }
>
> if (maxcpu == 0) {
> VERBOSE_TOROUT_STRING("Only one CPU, so CPU-hotplug testing is disabled");
> --
> 2.17.1
>