Le 11/02/2024 à 00:41, Masahiro Yamada a écrit : > On Thu, Feb 8, 2024 at 2:10 AM Yoann Congal <yoann.congal@xxxxxxxx> 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@xxxxxxxxxxxxx> (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@xxxxxxxx> (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@xxxxxxxx> >> Reported-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> >> Closes: https://lore.kernel.org/all/CAMuHMdWm6u1wX7efZQf=2XUAHascps76YQac6rdnQGhc8nop_Q@xxxxxxxxxxxxxx/ >> Reported-by: Vegard Nossum <vegard.nossum@xxxxxxxxxx> >> Closes: https://lore.kernel.org/all/f6856be8-54b7-0fa0-1d17-39632bf29ada@xxxxxxxxxx/ >> 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@xxxxxxxx> > Reviewed-by: Masahiro Yamada <masahiroy@xxxxxxxxxx> 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 -- Yoann Congal Smile ECS - Tech Expert
