From: Libo Chen <libo.chen@oracle.com> To: Randy Dunlap <rdunlap@infradead.org>, gregkh@linuxfoundation.org, masahiroy@kernel.org, tglx@linutronix.de, peterz@infradead.org, mingo@kernel.org, vbabka@suse.cz, akpm@linux-foundation.org Cc: linux-kernel@vger.kernel.org, linux-kbuild@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-arch@vger.kernel.org Subject: Re: [PATCH RESEND 1/1] lib/Kconfig: remove DEBUG_PER_CPU_MAPS dependency for CPUMASK_OFFSTACK Date: Tue, 12 Apr 2022 18:35:27 -0700 [thread overview] Message-ID: <157cb46a-d134-2e72-4a65-14e378dd2b8e@oracle.com> (raw) In-Reply-To: <c7d26e9d-8c70-86a6-cdab-b180a365804f@infradead.org> Hi Randy, On 4/12/22 17:18, Randy Dunlap wrote: > Hi-- > > On 4/12/22 16:15, Libo Chen wrote: >> Forcing CPUMASK_OFFSTACK to be conditoned on DEBUG_PER_CPU_MAPS doesn't >> make a lot of sense nowaday. Even the original patch dating back to 2008, >> aab46da0520a ("cpumask: Add CONFIG_CPUMASK_OFFSTACK") didn't give any >> rationale for such dependency. >> >> Nowhere in the code supports the presumption that DEBUG_PER_CPU_MAPS is >> necessary for CONFIG_CPUMASK_OFFSTACK. Make no mistake, it's good to >> have DEBUG_PER_CPU_MAPS for debugging purpose or precaution, but it's >> simply not a hard requirement for CPUMASK_OFFSTACK. Moreover, x86 Kconfig >> already can set CPUMASK_OFFSTACK=y without DEBUG_PER_CPU_MAPS=y. >> There is no reason other architectures cannot given the fact that they >> have even fewer, if any, arch-specific CONFIG_DEBUG_PER_CPU_MAPS code than >> x86. >> >> Signed-off-by: Libo Chen <libo.chen@oracle.com> >> --- >> lib/Kconfig | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/lib/Kconfig b/lib/Kconfig >> index 087e06b4cdfd..7209039dfb59 100644 >> --- a/lib/Kconfig >> +++ b/lib/Kconfig >> @@ -511,7 +511,7 @@ config CHECK_SIGNATURE >> bool >> >> config CPUMASK_OFFSTACK >> - bool "Force CPU masks off stack" if DEBUG_PER_CPU_MAPS > This "if" dependency only controls whether the Kconfig symbol's prompt is > displayed (presented) in kconfig tools. Removing it makes the prompt always > be displayed. > > Any architecture could select (should be able to) CPUMASK_OFFSTACK independently > of DEBUG_PER_CPU_MAPS. Do you mean changing arch/xxxx/Kconfig to select CPUMASK_OFFSTACK under some config xxx? That will work but it requires code changes for each architecture. But if you are talking about setting CONFIG_CPUMASK_OFFSTACK=y without CONFIG_DEBUG_PER_CPU_MAPS directly in config file, I have tried, it doesn't work. Libo > Is there another problem here? > >> + bool "Force CPU masks off stack" >> help >> Use dynamic allocation for cpumask_var_t, instead of putting >> them on the stack. This is a bit more expensive, but avoids
WARNING: multiple messages have this Message-ID (diff)
From: Libo Chen <libo.chen@oracle.com> To: Randy Dunlap <rdunlap@infradead.org>, gregkh@linuxfoundation.org, masahiroy@kernel.org, tglx@linutronix.de, peterz@infradead.org, mingo@kernel.org, vbabka@suse.cz, akpm@linux-foundation.org Cc: linux-kernel@vger.kernel.org, linux-kbuild@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-arch@vger.kernel.org Subject: Re: [PATCH RESEND 1/1] lib/Kconfig: remove DEBUG_PER_CPU_MAPS dependency for CPUMASK_OFFSTACK Date: Tue, 12 Apr 2022 18:35:27 -0700 [thread overview] Message-ID: <157cb46a-d134-2e72-4a65-14e378dd2b8e@oracle.com> (raw) In-Reply-To: <c7d26e9d-8c70-86a6-cdab-b180a365804f@infradead.org> Hi Randy, On 4/12/22 17:18, Randy Dunlap wrote: > Hi-- > > On 4/12/22 16:15, Libo Chen wrote: >> Forcing CPUMASK_OFFSTACK to be conditoned on DEBUG_PER_CPU_MAPS doesn't >> make a lot of sense nowaday. Even the original patch dating back to 2008, >> aab46da0520a ("cpumask: Add CONFIG_CPUMASK_OFFSTACK") didn't give any >> rationale for such dependency. >> >> Nowhere in the code supports the presumption that DEBUG_PER_CPU_MAPS is >> necessary for CONFIG_CPUMASK_OFFSTACK. Make no mistake, it's good to >> have DEBUG_PER_CPU_MAPS for debugging purpose or precaution, but it's >> simply not a hard requirement for CPUMASK_OFFSTACK. Moreover, x86 Kconfig >> already can set CPUMASK_OFFSTACK=y without DEBUG_PER_CPU_MAPS=y. >> There is no reason other architectures cannot given the fact that they >> have even fewer, if any, arch-specific CONFIG_DEBUG_PER_CPU_MAPS code than >> x86. >> >> Signed-off-by: Libo Chen <libo.chen@oracle.com> >> --- >> lib/Kconfig | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/lib/Kconfig b/lib/Kconfig >> index 087e06b4cdfd..7209039dfb59 100644 >> --- a/lib/Kconfig >> +++ b/lib/Kconfig >> @@ -511,7 +511,7 @@ config CHECK_SIGNATURE >> bool >> >> config CPUMASK_OFFSTACK >> - bool "Force CPU masks off stack" if DEBUG_PER_CPU_MAPS > This "if" dependency only controls whether the Kconfig symbol's prompt is > displayed (presented) in kconfig tools. Removing it makes the prompt always > be displayed. > > Any architecture could select (should be able to) CPUMASK_OFFSTACK independently > of DEBUG_PER_CPU_MAPS. Do you mean changing arch/xxxx/Kconfig to select CPUMASK_OFFSTACK under some config xxx? That will work but it requires code changes for each architecture. But if you are talking about setting CONFIG_CPUMASK_OFFSTACK=y without CONFIG_DEBUG_PER_CPU_MAPS directly in config file, I have tried, it doesn't work. Libo > Is there another problem here? > >> + bool "Force CPU masks off stack" >> help >> Use dynamic allocation for cpumask_var_t, instead of putting >> them on the stack. This is a bit more expensive, but avoids _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2022-04-13 1:36 UTC|newest] Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-04-12 23:15 [PATCH RESEND 0/1] lib/Kconfig: remove DEBUG_PER_CPU_MAPS dependency for CPUMASK_OFFSTACK Libo Chen 2022-04-12 23:15 ` Libo Chen 2022-04-12 23:15 ` [PATCH RESEND 1/1] " Libo Chen 2022-04-12 23:15 ` Libo Chen 2022-04-13 0:18 ` Randy Dunlap 2022-04-13 0:18 ` Randy Dunlap 2022-04-13 1:35 ` Libo Chen [this message] 2022-04-13 1:35 ` Libo Chen 2022-04-13 2:13 ` Randy Dunlap 2022-04-13 2:13 ` Randy Dunlap 2022-04-13 2:34 ` Libo Chen 2022-04-13 2:34 ` Libo Chen 2022-04-13 5:54 ` Randy Dunlap 2022-04-13 5:54 ` Randy Dunlap 2022-04-13 6:56 ` Libo Chen 2022-04-13 6:56 ` Libo Chen 2022-04-13 8:37 ` Masahiro Yamada 2022-04-13 8:37 ` Masahiro Yamada 2022-04-13 15:41 ` Randy Dunlap 2022-04-13 15:41 ` Randy Dunlap 2022-04-13 19:28 ` Libo Chen 2022-04-13 19:28 ` Libo Chen 2022-04-13 20:52 ` Arnd Bergmann 2022-04-13 20:52 ` Arnd Bergmann 2022-04-13 21:50 ` Libo Chen 2022-04-13 21:50 ` Libo Chen 2022-04-14 1:20 ` Randy Dunlap 2022-04-14 1:20 ` Randy Dunlap 2022-04-14 11:41 ` Arnd Bergmann 2022-04-14 11:41 ` Arnd Bergmann 2022-04-14 18:01 ` Libo Chen 2022-04-14 18:01 ` Libo Chen 2022-04-13 13:11 ` kernel test robot 2022-04-13 13:11 ` kernel test robot 2022-04-13 14:33 ` kernel test robot 2022-04-13 14:33 ` kernel test robot
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