| Message ID | 20220908104337.11940-7-lukas.bulwahn@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | Remove CONFIG_EMBEDDED | expand |
On Thu, Sep 8, 2022 at 7:44 PM Lukas Bulwahn <lukas.bulwahn@gmail.com> wrote: > > Commit 6a108a14fa35 ("kconfig: rename CONFIG_EMBEDDED to CONFIG_EXPERT") > introduces CONFIG_EXPERT to carry the previous intent of CONFIG_EMBEDDED > and just gives that intent a much better name. That has been clearly a good > and long overdue renaming, and it is clearly an improvement to the kernel > build configuration that has shown to help managing the kernel build > configuration in the last decade. > > However, rather than bravely and radically just deleting CONFIG_EMBEDDED, > this commit gives CONFIG_EMBEDDED a new intended semantics, but keeps it > open for future contributors to implement that intended semantics: > > A new CONFIG_EMBEDDED option is added that automatically selects > CONFIG_EXPERT when enabled and can be used in the future to isolate > options that should only be considered for embedded systems (RISC > architectures, SLOB, etc). > > Since then, this CONFIG_EMBEDDED implicitly had two purposes: > > - It can make even more options visible beyond what CONFIG_EXPERT makes > visible. In other words, it may introduce another level of enabling the > visibility of configuration options: always visible, visible with > CONFIG_EXPERT and visible with CONFIG_EMBEDDED. > > - Set certain default values of some configurations differently, > following the assumption that configuring a kernel build for an > embedded system generally starts with a different set of default values > compared to kernel builds for all other kind of systems. > > Considering the first purpose, at the point in time where CONFIG_EMBEDDED > was renamed to CONFIG_EXPERT, CONFIG_EXPERT already made 130 more options > become visible throughout all different menus for the kernel configuration. > Over the last decade, this has gradually increased, so that currently, with > CONFIG_EXPERT, roughly 170 more options become visible throughout all > different menus for the kernel configuration. In comparison, currently with > CONFIG_EMBEDDED enabled, just seven more options are visible, one in x86, > one in arm, and five for the ChipIdea Highspeed Dual Role Controller. > > As the numbers suggest, these two levels of enabling the visibility of even > more configuration options---beyond what CONFIG_EXPERT enables---never > evolved to a good solution in the last decade. In other words, this > additional level of visibility of configuration option with CONFIG_EMBEDDED > compared to CONFIG_EXPERT has since its introduction never become really > valuable. It requires quite some investigation to actually understand what > is additionally visible and it does not differ significantly in complexity > compared to just enabling CONFIG_EXPERT. This CONFIG_EMBEDDED---or any > other config to show more detailed options beyond CONFIG_EXPERT---is > unlikely to be valuable unless somebody puts significant effort in > identifying how such visibility options can be properly split and creating > clear criteria, when some config option is visible with CONFIG_EXPERT and > when some config option is visible only with some further option enabled > beyond CONFIG_EXPERT, such as CONFIG_EMBEDDED attempted to do. For now, it > is much more reasonable to simply make those additional seven options that > visible with CONFIG_EMBEDDED, visible with CONFIG_EXPERT, and then remove > CONFIG_EMBEDDED. If anyone spends significant effort in structuring the > visibility of config options, they may re-introduce suitable new config > options simply as they see fit. > > Hence, all uses of CONFIG_EMBEDDED have been replaced with CONFIG_EXPERT. > > Considering the second purpose, note that already probably arguing that a > kernel build for an embedded system would choose some values differently is > already tricky: the set of embedded systems with Linux kernels is already > quite diverse. Many embedded system have powerful CPUs and it would not be > clear that all embedded systems just optimize towards one specific aspect, > e.g., a smaller kernel image size. So, it is unclear if starting with "one > set of default configuration" that is induced by CONFIG_EMBEDDED is a good > offer for developers configuring their kernels. > > Also, the differences of needed user-space features in an embedded system > compared to a non-embedded system are probably difficult or even impossible > to name in some generic way. > > So it is not surprising that in the last decade hardly anyone has > contributed changes to make something default differently in case of > CONFIG_EMBEDDED=y. > > In v6.0-rc4, SECRETMEM is the only config switched off if > CONFIG_EMBEDDED=y. That one use was removed as well, SECRETMEM was made > configurable at build time by experts using menuconfig instead. > > As there are no further uses of CONFIG_EMBEDDED and CONFIG_EMBEDDED never > lived up to its intended purpose defined above, simply delete this > confusing CONFIG_EMBEDDED. > > Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com> > --- > init/Kconfig | 8 -------- > 1 file changed, 8 deletions(-) > > diff --git a/init/Kconfig b/init/Kconfig > index 9e3fd79b089c..d7429e0b8cae 100644 > --- a/init/Kconfig > +++ b/init/Kconfig > @@ -1818,14 +1818,6 @@ config DEBUG_RSEQ > > If unsure, say N. > > -config EMBEDDED > - bool "Embedded system" > - select EXPERT > - help > - This option should be enabled if compiling the kernel for > - an embedded system so certain expert options are available > - for configuration. > - > config HAVE_PERF_EVENTS > bool > help > -- > 2.17.1 > So, I am supposed to pick this up after 01-05 land. (please ping me if I forget about it). For now, Reviewed-by: Masahiro Yamada <masahiroy@kernel.org>
+ linuxppc-dev Le 08/09/2022 à 12:43, Lukas Bulwahn a écrit : > Commit 6a108a14fa35 ("kconfig: rename CONFIG_EMBEDDED to CONFIG_EXPERT") > introduces CONFIG_EXPERT to carry the previous intent of CONFIG_EMBEDDED > and just gives that intent a much better name. That has been clearly a good > and long overdue renaming, and it is clearly an improvement to the kernel > build configuration that has shown to help managing the kernel build > configuration in the last decade. > > However, rather than bravely and radically just deleting CONFIG_EMBEDDED, > this commit gives CONFIG_EMBEDDED a new intended semantics, but keeps it > open for future contributors to implement that intended semantics: > > A new CONFIG_EMBEDDED option is added that automatically selects > CONFIG_EXPERT when enabled and can be used in the future to isolate > options that should only be considered for embedded systems (RISC > architectures, SLOB, etc). > > Since then, this CONFIG_EMBEDDED implicitly had two purposes: > > - It can make even more options visible beyond what CONFIG_EXPERT makes > visible. In other words, it may introduce another level of enabling the > visibility of configuration options: always visible, visible with > CONFIG_EXPERT and visible with CONFIG_EMBEDDED. > > - Set certain default values of some configurations differently, > following the assumption that configuring a kernel build for an > embedded system generally starts with a different set of default values > compared to kernel builds for all other kind of systems. > > Considering the first purpose, at the point in time where CONFIG_EMBEDDED > was renamed to CONFIG_EXPERT, CONFIG_EXPERT already made 130 more options > become visible throughout all different menus for the kernel configuration. > Over the last decade, this has gradually increased, so that currently, with > CONFIG_EXPERT, roughly 170 more options become visible throughout all > different menus for the kernel configuration. In comparison, currently with > CONFIG_EMBEDDED enabled, just seven more options are visible, one in x86, > one in arm, and five for the ChipIdea Highspeed Dual Role Controller. > > As the numbers suggest, these two levels of enabling the visibility of even > more configuration options---beyond what CONFIG_EXPERT enables---never > evolved to a good solution in the last decade. In other words, this > additional level of visibility of configuration option with CONFIG_EMBEDDED > compared to CONFIG_EXPERT has since its introduction never become really > valuable. It requires quite some investigation to actually understand what > is additionally visible and it does not differ significantly in complexity > compared to just enabling CONFIG_EXPERT. This CONFIG_EMBEDDED---or any > other config to show more detailed options beyond CONFIG_EXPERT---is > unlikely to be valuable unless somebody puts significant effort in > identifying how such visibility options can be properly split and creating > clear criteria, when some config option is visible with CONFIG_EXPERT and > when some config option is visible only with some further option enabled > beyond CONFIG_EXPERT, such as CONFIG_EMBEDDED attempted to do. For now, it > is much more reasonable to simply make those additional seven options that > visible with CONFIG_EMBEDDED, visible with CONFIG_EXPERT, and then remove > CONFIG_EMBEDDED. If anyone spends significant effort in structuring the > visibility of config options, they may re-introduce suitable new config > options simply as they see fit. > > Hence, all uses of CONFIG_EMBEDDED have been replaced with CONFIG_EXPERT. > > Considering the second purpose, note that already probably arguing that a > kernel build for an embedded system would choose some values differently is > already tricky: the set of embedded systems with Linux kernels is already > quite diverse. Many embedded system have powerful CPUs and it would not be > clear that all embedded systems just optimize towards one specific aspect, > e.g., a smaller kernel image size. So, it is unclear if starting with "one > set of default configuration" that is induced by CONFIG_EMBEDDED is a good > offer for developers configuring their kernels. > > Also, the differences of needed user-space features in an embedded system > compared to a non-embedded system are probably difficult or even impossible > to name in some generic way. > > So it is not surprising that in the last decade hardly anyone has > contributed changes to make something default differently in case of > CONFIG_EMBEDDED=y. > > In v6.0-rc4, SECRETMEM is the only config switched off if > CONFIG_EMBEDDED=y. That one use was removed as well, SECRETMEM was made > configurable at build time by experts using menuconfig instead. > > As there are no further uses of CONFIG_EMBEDDED and CONFIG_EMBEDDED never > lived up to its intended purpose defined above, simply delete this > confusing CONFIG_EMBEDDED. > > Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com> > --- > init/Kconfig | 8 -------- > 1 file changed, 8 deletions(-) > > diff --git a/init/Kconfig b/init/Kconfig > index 9e3fd79b089c..d7429e0b8cae 100644 > --- a/init/Kconfig > +++ b/init/Kconfig > @@ -1818,14 +1818,6 @@ config DEBUG_RSEQ > > If unsure, say N. > > -config EMBEDDED > - bool "Embedded system" > - select EXPERT > - help > - This option should be enabled if compiling the kernel for > - an embedded system so certain expert options are available > - for configuration. > - > config HAVE_PERF_EVENTS > bool > help That's fine, but what happens to existing defconfigs then ? $ git grep -w CONFIG_EMBEDDED arch/powerpc/ arch/powerpc/configs/40x/klondike_defconfig:CONFIG_EMBEDDED=y arch/powerpc/configs/44x/fsp2_defconfig:CONFIG_EMBEDDED=y arch/powerpc/configs/52xx/tqm5200_defconfig:CONFIG_EMBEDDED=y arch/powerpc/configs/mgcoge_defconfig:CONFIG_EMBEDDED=y arch/powerpc/configs/microwatt_defconfig:CONFIG_EMBEDDED=y arch/powerpc/configs/ps3_defconfig:CONFIG_EMBEDDED=y They need to get converted to selecting CONFIG_EXPERT instead. And that needs to be done before you remove CONFIG_EMBEDDED. Christophe
> > init/Kconfig | 8 -------- > > 1 file changed, 8 deletions(-) > > > > diff --git a/init/Kconfig b/init/Kconfig > > index 9e3fd79b089c..d7429e0b8cae 100644 > > --- a/init/Kconfig > > +++ b/init/Kconfig > > @@ -1818,14 +1818,6 @@ config DEBUG_RSEQ > > > > If unsure, say N. > > > > -config EMBEDDED > > - bool "Embedded system" > > - select EXPERT > > - help > > - This option should be enabled if compiling the kernel for > > - an embedded system so certain expert options are available > > - for configuration. > > - > > config HAVE_PERF_EVENTS > > bool > > help > > That's fine, but what happens to existing defconfigs then ? > > $ git grep -w CONFIG_EMBEDDED arch/powerpc/ > arch/powerpc/configs/40x/klondike_defconfig:CONFIG_EMBEDDED=y > arch/powerpc/configs/44x/fsp2_defconfig:CONFIG_EMBEDDED=y > arch/powerpc/configs/52xx/tqm5200_defconfig:CONFIG_EMBEDDED=y > arch/powerpc/configs/mgcoge_defconfig:CONFIG_EMBEDDED=y > arch/powerpc/configs/microwatt_defconfig:CONFIG_EMBEDDED=y > arch/powerpc/configs/ps3_defconfig:CONFIG_EMBEDDED=y > > They need to get converted to selecting CONFIG_EXPERT instead. > > And that needs to be done before you remove CONFIG_EMBEDDED. > Agree. Let us get the first five patches included. Then adjust the configs for all architectures and then delete the CONFIG_EMBEDDED. Lukas
diff --git a/init/Kconfig b/init/Kconfig index 9e3fd79b089c..d7429e0b8cae 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -1818,14 +1818,6 @@ config DEBUG_RSEQ If unsure, say N. -config EMBEDDED - bool "Embedded system" - select EXPERT - help - This option should be enabled if compiling the kernel for - an embedded system so certain expert options are available - for configuration. - config HAVE_PERF_EVENTS bool help
Commit 6a108a14fa35 ("kconfig: rename CONFIG_EMBEDDED to CONFIG_EXPERT") introduces CONFIG_EXPERT to carry the previous intent of CONFIG_EMBEDDED and just gives that intent a much better name. That has been clearly a good and long overdue renaming, and it is clearly an improvement to the kernel build configuration that has shown to help managing the kernel build configuration in the last decade. However, rather than bravely and radically just deleting CONFIG_EMBEDDED, this commit gives CONFIG_EMBEDDED a new intended semantics, but keeps it open for future contributors to implement that intended semantics: A new CONFIG_EMBEDDED option is added that automatically selects CONFIG_EXPERT when enabled and can be used in the future to isolate options that should only be considered for embedded systems (RISC architectures, SLOB, etc). Since then, this CONFIG_EMBEDDED implicitly had two purposes: - It can make even more options visible beyond what CONFIG_EXPERT makes visible. In other words, it may introduce another level of enabling the visibility of configuration options: always visible, visible with CONFIG_EXPERT and visible with CONFIG_EMBEDDED. - Set certain default values of some configurations differently, following the assumption that configuring a kernel build for an embedded system generally starts with a different set of default values compared to kernel builds for all other kind of systems. Considering the first purpose, at the point in time where CONFIG_EMBEDDED was renamed to CONFIG_EXPERT, CONFIG_EXPERT already made 130 more options become visible throughout all different menus for the kernel configuration. Over the last decade, this has gradually increased, so that currently, with CONFIG_EXPERT, roughly 170 more options become visible throughout all different menus for the kernel configuration. In comparison, currently with CONFIG_EMBEDDED enabled, just seven more options are visible, one in x86, one in arm, and five for the ChipIdea Highspeed Dual Role Controller. As the numbers suggest, these two levels of enabling the visibility of even more configuration options---beyond what CONFIG_EXPERT enables---never evolved to a good solution in the last decade. In other words, this additional level of visibility of configuration option with CONFIG_EMBEDDED compared to CONFIG_EXPERT has since its introduction never become really valuable. It requires quite some investigation to actually understand what is additionally visible and it does not differ significantly in complexity compared to just enabling CONFIG_EXPERT. This CONFIG_EMBEDDED---or any other config to show more detailed options beyond CONFIG_EXPERT---is unlikely to be valuable unless somebody puts significant effort in identifying how such visibility options can be properly split and creating clear criteria, when some config option is visible with CONFIG_EXPERT and when some config option is visible only with some further option enabled beyond CONFIG_EXPERT, such as CONFIG_EMBEDDED attempted to do. For now, it is much more reasonable to simply make those additional seven options that visible with CONFIG_EMBEDDED, visible with CONFIG_EXPERT, and then remove CONFIG_EMBEDDED. If anyone spends significant effort in structuring the visibility of config options, they may re-introduce suitable new config options simply as they see fit. Hence, all uses of CONFIG_EMBEDDED have been replaced with CONFIG_EXPERT. Considering the second purpose, note that already probably arguing that a kernel build for an embedded system would choose some values differently is already tricky: the set of embedded systems with Linux kernels is already quite diverse. Many embedded system have powerful CPUs and it would not be clear that all embedded systems just optimize towards one specific aspect, e.g., a smaller kernel image size. So, it is unclear if starting with "one set of default configuration" that is induced by CONFIG_EMBEDDED is a good offer for developers configuring their kernels. Also, the differences of needed user-space features in an embedded system compared to a non-embedded system are probably difficult or even impossible to name in some generic way. So it is not surprising that in the last decade hardly anyone has contributed changes to make something default differently in case of CONFIG_EMBEDDED=y. In v6.0-rc4, SECRETMEM is the only config switched off if CONFIG_EMBEDDED=y. That one use was removed as well, SECRETMEM was made configurable at build time by experts using menuconfig instead. As there are no further uses of CONFIG_EMBEDDED and CONFIG_EMBEDDED never lived up to its intended purpose defined above, simply delete this confusing CONFIG_EMBEDDED. Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com> --- init/Kconfig | 8 -------- 1 file changed, 8 deletions(-)