| Message ID | 20240207171020.41036-2-yoann.congal@smile.fr (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | printk: CONFIG_BASE_SMALL fix for LOG_CPU_MAX_BUF_SHIFT and removal of CONFIG_BASE_FULL | expand |
On Thu, Feb 8, 2024 at 2:10 AM Yoann Congal <yoann.congal@smile.fr> wrote: > > LOG_CPU_MAX_BUF_SHIFT default value depends on BASE_SMALL: > config LOG_CPU_MAX_BUF_SHIFT > default 12 if !BASE_SMALL > default 0 if BASE_SMALL > But, BASE_SMALL is a config of type int and "!BASE_SMALL" is always > evaluated to true whatever is the value of BASE_SMALL. > > This patch fixes this by using the correct conditional operator for int > type : BASE_SMALL != 0. > > Note: This changes CONFIG_LOG_CPU_MAX_BUF_SHIFT=12 to > CONFIG_LOG_CPU_MAX_BUF_SHIFT=0 for BASE_SMALL defconfigs, but that will > not be a big impact due to this code in kernel/printk/printk.c: > /* by default this will only continue through for large > 64 CPUs */ > if (cpu_extra <= __LOG_BUF_LEN / 2) > return; > Systems using CONFIG_BASE_SMALL and having 64+ CPUs should be quite > rare. > > John Ogness <john.ogness@linutronix.de> (printk reviewer) wrote: > > For printk this will mean that BASE_SMALL systems were probably > > previously allocating/using the dynamic ringbuffer and now they will > > just continue to use the static ringbuffer. Which is fine and saves > > memory (as it should). > > Petr Mladek <pmladek@suse.com> (printk maintainer) wrote: > > More precisely, it allocated the buffer dynamically when the sum > > of per-CPU-extra space exceeded half of the default static ring > > buffer. This happened for systems with more than 64 CPUs with > > the default config values. > > Signed-off-by: Yoann Congal <yoann.congal@smile.fr> > Reported-by: Geert Uytterhoeven <geert@linux-m68k.org> > Closes: https://lore.kernel.org/all/CAMuHMdWm6u1wX7efZQf=2XUAHascps76YQac6rdnQGhc8nop_Q@mail.gmail.com/ > Reported-by: Vegard Nossum <vegard.nossum@oracle.com> > Closes: https://lore.kernel.org/all/f6856be8-54b7-0fa0-1d17-39632bf29ada@oracle.com/ > Fixes: 4e244c10eab3 ("kconfig: remove unneeded symbol_empty variable") > All the Reviewed-by tags are dropped every time, annoyingly. This is equivalent to v4, which had these tags: Reviewed-by: Petr Mladek <pmladek@suse.com> Reviewed-by: Masahiro Yamada <masahiroy@kernel.org> > --- > v3->v4: > * Fix BASE_SMALL usage instead of switching to BASE_FULL because > BASE_FULL will be removed in the next patches of this series. > --- > init/Kconfig | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/init/Kconfig b/init/Kconfig > index deda3d14135bb..d50ebd2a2ce42 100644 > --- a/init/Kconfig > +++ b/init/Kconfig > @@ -734,8 +734,8 @@ config LOG_CPU_MAX_BUF_SHIFT > int "CPU kernel log buffer size contribution (13 => 8 KB, 17 => 128KB)" > depends on SMP > range 0 21 > - default 12 if !BASE_SMALL > - default 0 if BASE_SMALL > + default 0 if BASE_SMALL != 0 > + default 12 > depends on PRINTK > help > This option allows to increase the default ring buffer size > -- > 2.39.2 > > -- Best Regards Masahiro Yamada
Le 11/02/2024 à 00:41, Masahiro Yamada a écrit : > On Thu, Feb 8, 2024 at 2:10 AM Yoann Congal <yoann.congal@smile.fr> wrote: >> >> LOG_CPU_MAX_BUF_SHIFT default value depends on BASE_SMALL: >> config LOG_CPU_MAX_BUF_SHIFT >> default 12 if !BASE_SMALL >> default 0 if BASE_SMALL >> But, BASE_SMALL is a config of type int and "!BASE_SMALL" is always >> evaluated to true whatever is the value of BASE_SMALL. >> >> This patch fixes this by using the correct conditional operator for int >> type : BASE_SMALL != 0. >> >> Note: This changes CONFIG_LOG_CPU_MAX_BUF_SHIFT=12 to >> CONFIG_LOG_CPU_MAX_BUF_SHIFT=0 for BASE_SMALL defconfigs, but that will >> not be a big impact due to this code in kernel/printk/printk.c: >> /* by default this will only continue through for large > 64 CPUs */ >> if (cpu_extra <= __LOG_BUF_LEN / 2) >> return; >> Systems using CONFIG_BASE_SMALL and having 64+ CPUs should be quite >> rare. >> >> John Ogness <john.ogness@linutronix.de> (printk reviewer) wrote: >>> For printk this will mean that BASE_SMALL systems were probably >>> previously allocating/using the dynamic ringbuffer and now they will >>> just continue to use the static ringbuffer. Which is fine and saves >>> memory (as it should). >> >> Petr Mladek <pmladek@suse.com> (printk maintainer) wrote: >>> More precisely, it allocated the buffer dynamically when the sum >>> of per-CPU-extra space exceeded half of the default static ring >>> buffer. This happened for systems with more than 64 CPUs with >>> the default config values. >> >> Signed-off-by: Yoann Congal <yoann.congal@smile.fr> >> Reported-by: Geert Uytterhoeven <geert@linux-m68k.org> >> Closes: https://lore.kernel.org/all/CAMuHMdWm6u1wX7efZQf=2XUAHascps76YQac6rdnQGhc8nop_Q@mail.gmail.com/ >> Reported-by: Vegard Nossum <vegard.nossum@oracle.com> >> Closes: https://lore.kernel.org/all/f6856be8-54b7-0fa0-1d17-39632bf29ada@oracle.com/ >> Fixes: 4e244c10eab3 ("kconfig: remove unneeded symbol_empty variable") >> > > > > All the Reviewed-by tags are dropped every time, annoyingly. Hi! Was I supposed to gather these tags from patch version N to patch version N+1? In that case, I'm sorry, I did not know that :-/ Patch 1/3 is exactly the same but patch 2/3 is equivalent but different. Is there a rule written somewhere about when carrying the tags across revision and when not? (I could not find it) > This is equivalent to v4, which had these tags: > > Reviewed-by: Petr Mladek <pmladek@suse.com> > Reviewed-by: Masahiro Yamada <masahiroy@kernel.org> Thanks a lot! > >> --- >> v3->v4: >> * Fix BASE_SMALL usage instead of switching to BASE_FULL because >> BASE_FULL will be removed in the next patches of this series. >> --- >> init/Kconfig | 4 ++-- >> 1 file changed, 2 insertions(+), 2 deletions(-) >> >> diff --git a/init/Kconfig b/init/Kconfig >> index deda3d14135bb..d50ebd2a2ce42 100644 >> --- a/init/Kconfig >> +++ b/init/Kconfig >> @@ -734,8 +734,8 @@ config LOG_CPU_MAX_BUF_SHIFT >> int "CPU kernel log buffer size contribution (13 => 8 KB, 17 => 128KB)" >> depends on SMP >> range 0 21 >> - default 12 if !BASE_SMALL >> - default 0 if BASE_SMALL >> + default 0 if BASE_SMALL != 0 >> + default 12 >> depends on PRINTK >> help >> This option allows to increase the default ring buffer size >> -- >> 2.39.2 >> >> > > > -- > Best Regards > Masahiro Yamada
On Tue, Feb 13, 2024 at 4:01 AM Yoann Congal <yoann.congal@smile.fr> wrote: > > > > Le 11/02/2024 à 00:41, Masahiro Yamada a écrit : > > On Thu, Feb 8, 2024 at 2:10 AM Yoann Congal <yoann.congal@smile.fr> wrote: > >> > >> LOG_CPU_MAX_BUF_SHIFT default value depends on BASE_SMALL: > >> config LOG_CPU_MAX_BUF_SHIFT > >> default 12 if !BASE_SMALL > >> default 0 if BASE_SMALL > >> But, BASE_SMALL is a config of type int and "!BASE_SMALL" is always > >> evaluated to true whatever is the value of BASE_SMALL. > >> > >> This patch fixes this by using the correct conditional operator for int > >> type : BASE_SMALL != 0. > >> > >> Note: This changes CONFIG_LOG_CPU_MAX_BUF_SHIFT=12 to > >> CONFIG_LOG_CPU_MAX_BUF_SHIFT=0 for BASE_SMALL defconfigs, but that will > >> not be a big impact due to this code in kernel/printk/printk.c: > >> /* by default this will only continue through for large > 64 CPUs */ > >> if (cpu_extra <= __LOG_BUF_LEN / 2) > >> return; > >> Systems using CONFIG_BASE_SMALL and having 64+ CPUs should be quite > >> rare. > >> > >> John Ogness <john.ogness@linutronix.de> (printk reviewer) wrote: > >>> For printk this will mean that BASE_SMALL systems were probably > >>> previously allocating/using the dynamic ringbuffer and now they will > >>> just continue to use the static ringbuffer. Which is fine and saves > >>> memory (as it should). > >> > >> Petr Mladek <pmladek@suse.com> (printk maintainer) wrote: > >>> More precisely, it allocated the buffer dynamically when the sum > >>> of per-CPU-extra space exceeded half of the default static ring > >>> buffer. This happened for systems with more than 64 CPUs with > >>> the default config values. > >> > >> Signed-off-by: Yoann Congal <yoann.congal@smile.fr> > >> Reported-by: Geert Uytterhoeven <geert@linux-m68k.org> > >> Closes: https://lore.kernel.org/all/CAMuHMdWm6u1wX7efZQf=2XUAHascps76YQac6rdnQGhc8nop_Q@mail.gmail.com/ > >> Reported-by: Vegard Nossum <vegard.nossum@oracle.com> > >> Closes: https://lore.kernel.org/all/f6856be8-54b7-0fa0-1d17-39632bf29ada@oracle.com/ > >> Fixes: 4e244c10eab3 ("kconfig: remove unneeded symbol_empty variable") > >> > > > > > > > > All the Reviewed-by tags are dropped every time, annoyingly. > > Hi! > > Was I supposed to gather these tags from patch version N to patch version N+1? > In that case, I'm sorry, I did not know that :-/ > Patch 1/3 is exactly the same but patch 2/3 is equivalent but different. Is there a rule written somewhere about when carrying the tags across revision and when not? (I could not find it) I do not know any written rules either. In my experience, people carry tags when changes since the previous version are small.
diff --git a/init/Kconfig b/init/Kconfig index deda3d14135bb..d50ebd2a2ce42 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -734,8 +734,8 @@ config LOG_CPU_MAX_BUF_SHIFT int "CPU kernel log buffer size contribution (13 => 8 KB, 17 => 128KB)" depends on SMP range 0 21 - default 12 if !BASE_SMALL - default 0 if BASE_SMALL + default 0 if BASE_SMALL != 0 + default 12 depends on PRINTK help This option allows to increase the default ring buffer size
LOG_CPU_MAX_BUF_SHIFT default value depends on BASE_SMALL: config LOG_CPU_MAX_BUF_SHIFT default 12 if !BASE_SMALL default 0 if BASE_SMALL But, BASE_SMALL is a config of type int and "!BASE_SMALL" is always evaluated to true whatever is the value of BASE_SMALL. This patch fixes this by using the correct conditional operator for int type : BASE_SMALL != 0. Note: This changes CONFIG_LOG_CPU_MAX_BUF_SHIFT=12 to CONFIG_LOG_CPU_MAX_BUF_SHIFT=0 for BASE_SMALL defconfigs, but that will not be a big impact due to this code in kernel/printk/printk.c: /* by default this will only continue through for large > 64 CPUs */ if (cpu_extra <= __LOG_BUF_LEN / 2) return; Systems using CONFIG_BASE_SMALL and having 64+ CPUs should be quite rare. John Ogness <john.ogness@linutronix.de> (printk reviewer) wrote: > For printk this will mean that BASE_SMALL systems were probably > previously allocating/using the dynamic ringbuffer and now they will > just continue to use the static ringbuffer. Which is fine and saves > memory (as it should). Petr Mladek <pmladek@suse.com> (printk maintainer) wrote: > More precisely, it allocated the buffer dynamically when the sum > of per-CPU-extra space exceeded half of the default static ring > buffer. This happened for systems with more than 64 CPUs with > the default config values. Signed-off-by: Yoann Congal <yoann.congal@smile.fr> Reported-by: Geert Uytterhoeven <geert@linux-m68k.org> Closes: https://lore.kernel.org/all/CAMuHMdWm6u1wX7efZQf=2XUAHascps76YQac6rdnQGhc8nop_Q@mail.gmail.com/ Reported-by: Vegard Nossum <vegard.nossum@oracle.com> Closes: https://lore.kernel.org/all/f6856be8-54b7-0fa0-1d17-39632bf29ada@oracle.com/ Fixes: 4e244c10eab3 ("kconfig: remove unneeded symbol_empty variable") --- v3->v4: * Fix BASE_SMALL usage instead of switching to BASE_FULL because BASE_FULL will be removed in the next patches of this series. --- init/Kconfig | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)