From: Charalampos Mitrodimas <charmitro@posteo.net>
To: I Hsin Cheng <richard120310@gmail.com>
Cc: rostedt@goodmis.org, paulmck@kernel.org, frederic@kernel.org,
neeraj.upadhyay@kernel.org, joel@joelfernandes.org,
josh@joshtriplett.org, boqun.feng@gmail.com, urezki@gmail.com,
mathieu.desnoyers@efficios.com, jiangshanlai@gmail.com,
qiang.zhang1211@gmail.com, ojeda@kernel.org,
alex.gaynor@gmail.com, gary@garyguo.net,
bjorn3_gh@protonmail.com, benno.lossin@proton.me,
a.hindborg@kernel.org, aliceryhl@google.com, tmgross@umich.edu,
dakr@kernel.org, rcu@vger.kernel.org,
rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org,
skhan@linuxfoundation.org, jserv@ccns.ncku.edu.tw
Subject: Re: [PATCH] rust: sync: rcu: Mark Guard methods as inline
Date: Wed, 12 Mar 2025 12:20:27 +0000 [thread overview]
Message-ID: <m2h63ycues.fsf@Mac.home> (raw)
In-Reply-To: <20250312101723.149135-1-richard120310@gmail.com> (I. Hsin Cheng's message of "Wed, 12 Mar 2025 18:17:23 +0800")
I Hsin Cheng <richard120310@gmail.com> writes:
> Currenyly the implementation of "Guard" methods are basically wrappers
"Currenyly" -> "Currently".
> around rcu's function within kernel. Building the kernel with llvm
> 18.1.8 on x86_64 machine will generate the following symbols:
>
> $ nm vmlinux | grep ' _R'.*Guard | rustfilt
> ffffffff817b6c90 T <kernel::sync::rcu::Guard>::new
> ffffffff817b6cb0 T <kernel::sync::rcu::Guard>::unlock
> ffffffff817b6cd0 T <kernel::sync::rcu::Guard as core::ops::drop::Drop>::drop
> ffffffff817b6c90 T <kernel::sync::rcu::Guard as core::default::Default>::default
>
> These Rust symbols are basically wrappers around functions
> "rcu_read_lock" and "rcu_read_unlock". Marking them as inline can
> reduce the generation of these symbols, and saves the size of code
> generation for 100 bytes.
>
> $ ./scripts/bloat-o-meter vmlinux_old vmlinux_new
> add/remove: 0/8 grow/shrink: 0/0 up/down: 0/-100 (-100)
> Function old new delta
> _RNvXs_NtNtCsaYBeKL739Xz_6kernel4sync3rcuNtB4_5GuardNtNtCsdaXADs8PRFB_4core7default7Default7default 9 - -9
> _RNvXs0_NtNtCsaYBeKL739Xz_6kernel4sync3rcuNtB5_5GuardNtNtNtCsdaXADs8PRFB_4core3ops4drop4Drop4drop 9 - -9
> _RNvMNtNtCsaYBeKL739Xz_6kernel4sync3rcuNtB2_5Guard6unlock 9 - -9
> _RNvMNtNtCsaYBeKL739Xz_6kernel4sync3rcuNtB2_5Guard3new 9 - -9
> __pfx__RNvXs_NtNtCsaYBeKL739Xz_6kernel4sync3rcuNtB4_5GuardNtNtCsdaXADs8PRFB_4core7default7Default7default 16 - -16
> __pfx__RNvXs0_NtNtCsaYBeKL739Xz_6kernel4sync3rcuNtB5_5GuardNtNtNtCsdaXADs8PRFB_4core3ops4drop4Drop4drop 16 - -16
> __pfx__RNvMNtNtCsaYBeKL739Xz_6kernel4sync3rcuNtB2_5Guard6unlock 16 - -16
> __pfx__RNvMNtNtCsaYBeKL739Xz_6kernel4sync3rcuNtB2_5Guard3new 16 - -16
> Total: Before=23385830, After=23385730, chg -0.00%
>
> Link: https://github.com/Rust-for-Linux/linux/issues/1145
> Signed-off-by: I Hsin Cheng <richard120310@gmail.com>
Reviewed-by: Charalampos Mitrodimas <charmitro@posteo.net>
next prev parent reply other threads:[~2025-03-12 12:20 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-03-12 10:17 [PATCH] rust: sync: rcu: Mark Guard methods as inline I Hsin Cheng
2025-03-12 11:48 ` Benno Lossin
2025-03-12 12:20 ` Charalampos Mitrodimas [this message]
2025-03-13 4:30 ` Joel Fernandes
2025-03-14 14:43 ` Miguel Ojeda
2025-03-15 6:29 ` I Hsin Cheng
2025-03-13 19:41 ` Christian Schrefl
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