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References: <20230105003759.GA1769545@paulmck-ThinkPad-P17-Gen-1>
 <20230105003813.1770367-22-paulmck@kernel.org> <CAKwvOdmt7mnP_dfCMO_YUV792Zgtirk=NFqe8XH0z88-b0e23A@mail.gmail.com>
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From:   Nick Desaulniers <ndesaulniers@google.com>
Date:   Mon, 9 Jan 2023 16:05:10 -0800
Message-ID: <CAKwvOdnQX1H9-8QnsUiXi+eK4udGdO34isHZ-PEzNDZwJbJ41w@mail.gmail.com>
Subject: Re: [PATCH rcu 22/27] init: Remove "select SRCU"
To:     "Paul E. McKenney" <paulmck@kernel.org>
Cc:     rcu@vger.kernel.org, linux-kernel@vger.kernel.org,
        kernel-team@meta.com, rostedt@goodmis.org,
        Andrew Morton <akpm@linux-foundation.org>,
        Masahiro Yamada <masahiroy@kernel.org>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Vlastimil Babka <vbabka@suse.cz>,
        Nathan Chancellor <nathan@kernel.org>,
        Arnd Bergmann <arnd@arndb.de>, Miguel Ojeda <ojeda@kernel.org>,
        Masami Hiramatsu <mhiramat@kernel.org>,
        Dmitry Torokhov <dmitry.torokhov@gmail.com>,
        Aaron Tomlin <atomlin@redhat.com>, Tejun Heo <tj@kernel.org>,
        Christophe Leroy <christophe.leroy@csgroup.eu>
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On Mon, Jan 9, 2023 at 4:02 PM Nick Desaulniers <ndesaulniers@google.com> wrote:
>
> On Wed, Jan 4, 2023 at 4:38 PM Paul E. McKenney <paulmck@kernel.org> wrote:
> >
> > Now that the SRCU Kconfig option is unconditionally selected, there is
> > no longer any point in selecting it.  Therefore, remove the "select SRCU"
> > Kconfig statements.
>
> Looks like that's the case as of
> commit 0cd7e350abc4 ("rcu: Make SRCU mandatory")
> in v6.2-rc1.
>
> >
> > Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
> > Cc: Andrew Morton <akpm@linux-foundation.org>
> > Cc: Nick Desaulniers <ndesaulniers@google.com>
> > Cc: Masahiro Yamada <masahiroy@kernel.org>
> > Cc: Johannes Weiner <hannes@cmpxchg.org>
> > Cc: Vlastimil Babka <vbabka@suse.cz>
> > Cc: Nathan Chancellor <nathan@kernel.org>
> > Cc: Arnd Bergmann <arnd@arndb.de>
> > Cc: Miguel Ojeda <ojeda@kernel.org>
> > Cc: Masami Hiramatsu <mhiramat@kernel.org>
> > Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
> > Cc: Aaron Tomlin <atomlin@redhat.com>
> > Cc: Tejun Heo <tj@kernel.org>
> > Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
>
> Patch LGTM
> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
>
> Note that there's quite a few more of these though. Perhaps best to
> remove them all together? Or perhaps you already have individual
> patches out already for all of these?

Ah indeed, I missed that this was part of such a series:
https://lore.kernel.org/lkml/20230105003759.GA1769545@paulmck-ThinkPad-P17-Gen-1/


>
> $ grep -rn 'select SRCU'
> mm/Kconfig:670: select SRCU
> kernel/power/Kconfig:121: select SRCU
> arch/mips/kvm/Kconfig:29: select SRCU
> arch/riscv/kvm/Kconfig:30: select SRCU
> arch/s390/kvm/Kconfig:34: select SRCU
> arch/powerpc/kvm/Kconfig:25: select SRCU
> arch/x86/kvm/Kconfig:49: select SRCU
> arch/x86/Kconfig:286: select SRCU
> arch/x86/Kconfig:1941: select SRCU
> arch/arm64/kvm/Kconfig:31: select SRCU
> init/Kconfig:1868: select SRCU
> security/tomoyo/Kconfig:9: select SRCU
> fs/btrfs/Kconfig:20: select SRCU
> fs/dlm/Kconfig:7: select SRCU
> fs/quota/Kconfig:9: select SRCU
> fs/notify/Kconfig:4: select SRCU
> drivers/md/Kconfig:9: select SRCU
> drivers/clk/Kconfig:26: select SRCU
> drivers/dax/Kconfig:4: select SRCU
> drivers/devfreq/Kconfig:4: select SRCU
> drivers/net/Kconfig:337: select SRCU
> drivers/hwtracing/stm/Kconfig:5: select SRCU
> drivers/cpufreq/Kconfig:6: select SRCU
> drivers/opp/Kconfig:4: select SRCU
>
> > ---
> >  init/Kconfig | 1 -
> >  1 file changed, 1 deletion(-)
> >
> > diff --git a/init/Kconfig b/init/Kconfig
> > index 7e5c3ddc341de..af511c726d695 100644
> > --- a/init/Kconfig
> > +++ b/init/Kconfig
> > @@ -1865,7 +1865,6 @@ config PERF_EVENTS
> >         default y if PROFILING
> >         depends on HAVE_PERF_EVENTS
> >         select IRQ_WORK
> > -       select SRCU
> >         help
> >           Enable kernel support for various performance events provided
> >           by software and hardware.
> > --
> > 2.31.1.189.g2e36527f23
> >
>
>
> --
> Thanks,
> ~Nick Desaulniers


-- 
Thanks,
~Nick Desaulniers