kernel/time/clocksource.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-)
Simplify the procedure of CPU random selection under
"clocksource_verify_choose_cpus()" with "cpumask_next_wrap()". The
logic is still the same but with this change it can shrink the code size
by 18 bytes and increase readability.
$ ./scripts/bloat-o-meter vmlinux_old vmlinux_new
add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-18 (-18)
Function old new delta
clocksource_verify_percpu 1064 1046 -18
Signed-off-by: I Hsin Cheng <richard120310@gmail.com>
---
kernel/time/clocksource.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)
diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
index bb48498ebb5a..ab580873408b 100644
--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -343,9 +343,7 @@ static void clocksource_verify_choose_cpus(void)
*/
for (i = 1; i < n; i++) {
cpu = get_random_u32_below(nr_cpu_ids);
- cpu = cpumask_next(cpu - 1, cpu_online_mask);
- if (cpu >= nr_cpu_ids)
- cpu = cpumask_first(cpu_online_mask);
+ cpu = cpumask_next_wrap(cpu - 1, cpu_online_mask);
if (!WARN_ON_ONCE(cpu >= nr_cpu_ids))
cpumask_set_cpu(cpu, &cpus_chosen);
}
--
2.43.0On Wed, Jun 11, 2025 at 3:45 AM I Hsin Cheng <richard120310@gmail.com> wrote:
>
> Simplify the procedure of CPU random selection under
> "clocksource_verify_choose_cpus()" with "cpumask_next_wrap()". The
> logic is still the same but with this change it can shrink the code size
> by 18 bytes and increase readability.
>
> $ ./scripts/bloat-o-meter vmlinux_old vmlinux_new
> add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-18 (-18)
> Function old new delta
> clocksource_verify_percpu 1064 1046 -18
>
> Signed-off-by: I Hsin Cheng <richard120310@gmail.com>
> ---
> kernel/time/clocksource.c | 4 +---
> 1 file changed, 1 insertion(+), 3 deletions(-)
>
> diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
> index bb48498ebb5a..ab580873408b 100644
> --- a/kernel/time/clocksource.c
> +++ b/kernel/time/clocksource.c
> @@ -343,9 +343,7 @@ static void clocksource_verify_choose_cpus(void)
> */
> for (i = 1; i < n; i++) {
> cpu = get_random_u32_below(nr_cpu_ids);
> - cpu = cpumask_next(cpu - 1, cpu_online_mask);
> - if (cpu >= nr_cpu_ids)
> - cpu = cpumask_first(cpu_online_mask);
> + cpu = cpumask_next_wrap(cpu - 1, cpu_online_mask);
> if (!WARN_ON_ONCE(cpu >= nr_cpu_ids))
> cpumask_set_cpu(cpu, &cpus_chosen);
> }
I think Yury submitted the same change here recently:
https://lore.kernel.org/lkml/20250607141106.563924-3-yury.norov@gmail.com/
Though, I think he has another iteration needed as Thomas had feedback
on the subject line.
The bloat-o-meter data is a nice inclusion here!
Yury: Would you be open to adapting I Hsin Cheng's commit message into
yours and adding them as co-author via the Co-developed-by: tag?
(Assuming I Hsin Cheng agrees - See
Documentation/process/submitting-patches.rst for how to do this
properly).
thanks
-john
On Wed, Jun 11, 2025 at 11:35:13AM -0700, John Stultz wrote:
> On Wed, Jun 11, 2025 at 3:45 AM I Hsin Cheng <richard120310@gmail.com> wrote:
> >
> > Simplify the procedure of CPU random selection under
> > "clocksource_verify_choose_cpus()" with "cpumask_next_wrap()". The
> > logic is still the same but with this change it can shrink the code size
> > by 18 bytes and increase readability.
> >
> > $ ./scripts/bloat-o-meter vmlinux_old vmlinux_new
> > add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-18 (-18)
> > Function old new delta
> > clocksource_verify_percpu 1064 1046 -18
> >
> > Signed-off-by: I Hsin Cheng <richard120310@gmail.com>
> > ---
> > kernel/time/clocksource.c | 4 +---
> > 1 file changed, 1 insertion(+), 3 deletions(-)
> >
> > diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
> > index bb48498ebb5a..ab580873408b 100644
> > --- a/kernel/time/clocksource.c
> > +++ b/kernel/time/clocksource.c
> > @@ -343,9 +343,7 @@ static void clocksource_verify_choose_cpus(void)
> > */
> > for (i = 1; i < n; i++) {
> > cpu = get_random_u32_below(nr_cpu_ids);
> > - cpu = cpumask_next(cpu - 1, cpu_online_mask);
> > - if (cpu >= nr_cpu_ids)
> > - cpu = cpumask_first(cpu_online_mask);
> > + cpu = cpumask_next_wrap(cpu - 1, cpu_online_mask);
> > if (!WARN_ON_ONCE(cpu >= nr_cpu_ids))
> > cpumask_set_cpu(cpu, &cpus_chosen);
> > }
>
> I think Yury submitted the same change here recently:
> https://lore.kernel.org/lkml/20250607141106.563924-3-yury.norov@gmail.com/
>
> Though, I think he has another iteration needed as Thomas had feedback
> on the subject line.
>
> The bloat-o-meter data is a nice inclusion here!
>
> Yury: Would you be open to adapting I Hsin Cheng's commit message into
> yours and adding them as co-author via the Co-developed-by: tag?
> (Assuming I Hsin Cheng agrees - See
> Documentation/process/submitting-patches.rst for how to do this
> properly).
Yeah, bloat-o-meter report is good enough to add co-developed-by tag.
I Hsin, do you agree?
On Wed, Jun 11, 2025 at 03:04:42PM -0400, Yury Norov wrote:
> On Wed, Jun 11, 2025 at 11:35:13AM -0700, John Stultz wrote:
> > On Wed, Jun 11, 2025 at 3:45 AM I Hsin Cheng <richard120310@gmail.com> wrote:
> > >
> > > Simplify the procedure of CPU random selection under
> > > "clocksource_verify_choose_cpus()" with "cpumask_next_wrap()". The
> > > logic is still the same but with this change it can shrink the code size
> > > by 18 bytes and increase readability.
> > >
> > > $ ./scripts/bloat-o-meter vmlinux_old vmlinux_new
> > > add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-18 (-18)
> > > Function old new delta
> > > clocksource_verify_percpu 1064 1046 -18
> > >
> > > Signed-off-by: I Hsin Cheng <richard120310@gmail.com>
> > > ---
> > > kernel/time/clocksource.c | 4 +---
> > > 1 file changed, 1 insertion(+), 3 deletions(-)
> > >
> > > diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
> > > index bb48498ebb5a..ab580873408b 100644
> > > --- a/kernel/time/clocksource.c
> > > +++ b/kernel/time/clocksource.c
> > > @@ -343,9 +343,7 @@ static void clocksource_verify_choose_cpus(void)
> > > */
> > > for (i = 1; i < n; i++) {
> > > cpu = get_random_u32_below(nr_cpu_ids);
> > > - cpu = cpumask_next(cpu - 1, cpu_online_mask);
> > > - if (cpu >= nr_cpu_ids)
> > > - cpu = cpumask_first(cpu_online_mask);
> > > + cpu = cpumask_next_wrap(cpu - 1, cpu_online_mask);
> > > if (!WARN_ON_ONCE(cpu >= nr_cpu_ids))
> > > cpumask_set_cpu(cpu, &cpus_chosen);
> > > }
> >
> > I think Yury submitted the same change here recently:
> > https://lore.kernel.org/lkml/20250607141106.563924-3-yury.norov@gmail.com/
> >
> > Though, I think he has another iteration needed as Thomas had feedback
> > on the subject line.
> >
> > The bloat-o-meter data is a nice inclusion here!
> >
> > Yury: Would you be open to adapting I Hsin Cheng's commit message into
> > yours and adding them as co-author via the Co-developed-by: tag?
> > (Assuming I Hsin Cheng agrees - See
> > Documentation/process/submitting-patches.rst for how to do this
> > properly).
>
> Yeah, bloat-o-meter report is good enough to add co-developed-by tag.
> I Hsin, do you agree?
Sure thing, so do I need to apply the tag myself or we'll follow Yury's
patch work?
Best regards,
I Hsin Cheng
On Thu, Jun 12, 2025 at 03:45:36PM +0800, I Hsin Cheng wrote:
> On Wed, Jun 11, 2025 at 03:04:42PM -0400, Yury Norov wrote:
> > On Wed, Jun 11, 2025 at 11:35:13AM -0700, John Stultz wrote:
> > > On Wed, Jun 11, 2025 at 3:45 AM I Hsin Cheng <richard120310@gmail.com> wrote:
> > > >
> > > > Simplify the procedure of CPU random selection under
> > > > "clocksource_verify_choose_cpus()" with "cpumask_next_wrap()". The
> > > > logic is still the same but with this change it can shrink the code size
> > > > by 18 bytes and increase readability.
> > > >
> > > > $ ./scripts/bloat-o-meter vmlinux_old vmlinux_new
> > > > add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-18 (-18)
> > > > Function old new delta
> > > > clocksource_verify_percpu 1064 1046 -18
> > > >
> > > > Signed-off-by: I Hsin Cheng <richard120310@gmail.com>
> > > > ---
> > > > kernel/time/clocksource.c | 4 +---
> > > > 1 file changed, 1 insertion(+), 3 deletions(-)
> > > >
> > > > diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
> > > > index bb48498ebb5a..ab580873408b 100644
> > > > --- a/kernel/time/clocksource.c
> > > > +++ b/kernel/time/clocksource.c
> > > > @@ -343,9 +343,7 @@ static void clocksource_verify_choose_cpus(void)
> > > > */
> > > > for (i = 1; i < n; i++) {
> > > > cpu = get_random_u32_below(nr_cpu_ids);
> > > > - cpu = cpumask_next(cpu - 1, cpu_online_mask);
> > > > - if (cpu >= nr_cpu_ids)
> > > > - cpu = cpumask_first(cpu_online_mask);
> > > > + cpu = cpumask_next_wrap(cpu - 1, cpu_online_mask);
> > > > if (!WARN_ON_ONCE(cpu >= nr_cpu_ids))
> > > > cpumask_set_cpu(cpu, &cpus_chosen);
> > > > }
> > >
> > > I think Yury submitted the same change here recently:
> > > https://lore.kernel.org/lkml/20250607141106.563924-3-yury.norov@gmail.com/
> > >
> > > Though, I think he has another iteration needed as Thomas had feedback
> > > on the subject line.
> > >
> > > The bloat-o-meter data is a nice inclusion here!
> > >
> > > Yury: Would you be open to adapting I Hsin Cheng's commit message into
> > > yours and adding them as co-author via the Co-developed-by: tag?
> > > (Assuming I Hsin Cheng agrees - See
> > > Documentation/process/submitting-patches.rst for how to do this
> > > properly).
> >
> > Yeah, bloat-o-meter report is good enough to add co-developed-by tag.
> > I Hsin, do you agree?
>
> Sure thing, so do I need to apply the tag myself or we'll follow Yury's
> patch work?
I'll send v2 and include your results.
> > > > I think Yury submitted the same change here recently: > > > > https://lore.kernel.org/lkml/20250607141106.563924-3-yury.norov@gmail.com/ > > > > > > > > Though, I think he has another iteration needed as Thomas had feedback > > > > on the subject line. > > > > > > > > The bloat-o-meter data is a nice inclusion here! > > > > > > > > Yury: Would you be open to adapting I Hsin Cheng's commit message into > > > > yours and adding them as co-author via the Co-developed-by: tag? > > > > (Assuming I Hsin Cheng agrees - See > > > > Documentation/process/submitting-patches.rst for how to do this > > > > properly). > > > > > > Yeah, bloat-o-meter report is good enough to add co-developed-by tag. > > > I Hsin, do you agree? > > > > Sure thing, so do I need to apply the tag myself or we'll follow Yury's > > patch work? > > I'll send v2 and include your results. John, FYI. I Hsing submitted another patch that duplicates this series. You're in CC, but just in case: https://lore.kernel.org/all/20250613033447.3531709-1-richard120310@gmail.com/ I think it's pretty disgusting. I will not make him co-author, and will not give any credit for this work. Thanks, Yury
On Fri, Jun 13, 2025 at 01:13:38AM -0400, Yury Norov wrote: > > > > > I think Yury submitted the same change here recently: > > > > > https://lore.kernel.org/lkml/20250607141106.563924-3-yury.norov@gmail.com/ > > > > > > > > > > Though, I think he has another iteration needed as Thomas had feedback > > > > > on the subject line. > > > > > > > > > > The bloat-o-meter data is a nice inclusion here! > > > > > > > > > > Yury: Would you be open to adapting I Hsin Cheng's commit message into > > > > > yours and adding them as co-author via the Co-developed-by: tag? > > > > > (Assuming I Hsin Cheng agrees - See > > > > > Documentation/process/submitting-patches.rst for how to do this > > > > > properly). > > > > > > > > Yeah, bloat-o-meter report is good enough to add co-developed-by tag. > > > > I Hsin, do you agree? > > > > > > Sure thing, so do I need to apply the tag myself or we'll follow Yury's > > > patch work? > > > > I'll send v2 and include your results. > > John, FYI. > > I Hsing submitted another patch that duplicates this series. You're in > CC, but just in case: > > https://lore.kernel.org/all/20250613033447.3531709-1-richard120310@gmail.com/ > > I think it's pretty disgusting. I will not make him co-author, and > will not give any credit for this work. > > Thanks, > Yury I just realized your patch series already does that, I didn't check on other patches, I'm sorry, I should've been more careful on that, not just looking at the only patch in the link. Hope you can forgive me, I really have no offense on that and didn't mean to do it. Best regards, I Hsin Cheng
On Fri, Jun 13, 2025 at 01:13:38AM -0400, Yury Norov wrote: > > > > > I think Yury submitted the same change here recently: > > > > > https://lore.kernel.org/lkml/20250607141106.563924-3-yury.norov@gmail.com/ > > > > > > > > > > Though, I think he has another iteration needed as Thomas had feedback > > > > > on the subject line. > > > > > > > > > > The bloat-o-meter data is a nice inclusion here! > > > > > > > > > > Yury: Would you be open to adapting I Hsin Cheng's commit message into > > > > > yours and adding them as co-author via the Co-developed-by: tag? > > > > > (Assuming I Hsin Cheng agrees - See > > > > > Documentation/process/submitting-patches.rst for how to do this > > > > > properly). > > > > > > > > Yeah, bloat-o-meter report is good enough to add co-developed-by tag. > > > > I Hsin, do you agree? > > > > > > Sure thing, so do I need to apply the tag myself or we'll follow Yury's > > > patch work? > > > > I'll send v2 and include your results. > > John, FYI. > > I Hsing submitted another patch that duplicates this series. You're in > CC, but just in case: > > https://lore.kernel.org/all/20250613033447.3531709-1-richard120310@gmail.com/ > > I think it's pretty disgusting. I will not make him co-author, and > will not give any credit for this work. > > Thanks, > Yury I'm really sorry for this, I really didn't notice others have already send the patches. I didn't mean to copy others work on purpose, I am very sorry. Thanks, I Hsin Cheng.
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