On Wed Mar 12, 2025 at 11:17 AM CET, I Hsin Cheng wrote: > Currenyly the implementation of "Guard" methods are basically wrappers > 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@xxxxxxxxx> Reviewed-by: Benno Lossin <benno.lossin@xxxxxxxxx> --- Cheers, Benno
