On 22/06/25 00:49, Madadi Vineeth Reddy wrote:
> Previously, running "chrt --pid <pid>" with no policy options
> would display the process’s current scheduling attributes, but
> specifying a policy without a priority (e.g. chrt --rr --pid <pid>)
> would silently fallback to displaying the same info. This was
> confusing, since a policy option normally implies an intent to
> change something.
>
> This patch changes the behavior so that
> chrt --pid <pid> continues to show the current settings:
>
> chrt --pid 10862
> pid 10862's current scheduling policy: SCHED_OTHER
> pid 10862's current scheduling priority: 0
> pid 10862's current runtime parameter: 2800000
>
> If a policy is specified but no priority follows, chrt now
> errors out:
>
> chrt --rr --pid 10862
> chrt: policy SCHED_RR requires a priority argument
>
> Verbose output (-v) still prints the current settings when a
> valid policy+priority is provided.
>
> Signed-off-by: Madadi Vineeth Reddy <vineethr@xxxxxxxxxxxxx>
> ---
> schedutils/chrt.c | 25 +++++++++++++++++++++----
> 1 file changed, 21 insertions(+), 4 deletions(-)
>
> diff --git a/schedutils/chrt.c b/schedutils/chrt.c
> index 8fe748f43..40a006040 100644
> --- a/schedutils/chrt.c
> +++ b/schedutils/chrt.c
> @@ -64,7 +64,7 @@ static void __attribute__((__noreturn__)) usage(void)
> " chrt [options] --pid <priority> <pid>\n"), out);
> fputs(USAGE_SEPARATOR, out);
> fputs(_("Get policy:\n"
> - " chrt [options] --pid <pid>\n"), out);
> + " chrt --pid <pid>\n"), out);
>
> fputs(USAGE_SEPARATOR, out);
> fputs(_("Policy options:\n"), out);
> @@ -399,6 +399,7 @@ int main(int argc, char **argv)
> {
> struct chrt_ctl _ctl = { .pid = -1, .policy = SCHED_RR }, *ctl = &_ctl;
> int c;
> + bool policy_given = false;
>
> static const struct option longopts[] = {
> { "all-tasks", no_argument, NULL, 'a' },
> @@ -435,21 +436,25 @@ int main(int argc, char **argv)
> case 'b':
> #ifdef SCHED_BATCH
> ctl->policy = SCHED_BATCH;
> + policy_given = true;
> #endif
> break;
>
> case 'd':
> #ifdef SCHED_DEADLINE
> ctl->policy = SCHED_DEADLINE;
> + policy_given = true;
> #endif
> break;
> case 'e':
> #ifdef SCHED_EXT
> ctl->policy = SCHED_EXT;
> + policy_given = true;
> #endif
> break;
> case 'f':
> ctl->policy = SCHED_FIFO;
> + policy_given = true;
> break;
> case 'R':
> ctl->reset_on_fork = 1;
> @@ -457,6 +462,7 @@ int main(int argc, char **argv)
> case 'i':
> #ifdef SCHED_IDLE
> ctl->policy = SCHED_IDLE;
> + policy_given = true;
> #endif
> break;
> case 'm':
> @@ -464,6 +470,7 @@ int main(int argc, char **argv)
> return EXIT_SUCCESS;
> case 'o':
> ctl->policy = SCHED_OTHER;
> + policy_given = true;
> break;
> case 'p':
> errno = 0;
> @@ -472,6 +479,7 @@ int main(int argc, char **argv)
> break;
> case 'r':
> ctl->policy = SCHED_RR;
> + policy_given = true;
> break;
> case 'v':
> ctl->verbose = 1;
> @@ -501,12 +509,21 @@ int main(int argc, char **argv)
> errtryhelp(EXIT_FAILURE);
> }
>
> - if ((ctl->pid > -1) && (ctl->verbose || argc - optind == 1)) {
> + /*pid exists but priority not given*/
Missed spacing in the comment. Ignore this v3. Please refer to v4.
> + if (ctl->pid > -1 && argc - optind == 1) {
> + /* Error if a policy was specified but no priority given */
> + if (policy_given)
> + errx(EXIT_FAILURE, ("policy %s requires a priority argument"),
> + get_policy_name(ctl->policy));
> +
> + /* If no policy specified, show current settings */
> show_sched_info(ctl);
> - if (argc - optind == 1)
> - return EXIT_SUCCESS;
> + return EXIT_SUCCESS;
> }
>
> + if (ctl->verbose)
> + show_sched_info(ctl);
> +
> errno = 0;
> ctl->priority = strtos32_or_err(argv[optind], _("invalid priority argument"));
>
