net: force inlining of netif_tx_start/stop_queue, sock_hold, __sock_put
Sometimes gcc mysteriously doesn't inline
very small functions we expect to be inlined. See
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66122
Arguably, gcc should do better, but gcc people aren't willing
to invest time into it, asking to use __always_inline instead.
With this .config:
http://busybox.net/~vda/kernel_config_OPTIMIZE_INLINING_and_Os,
the following functions get deinlined many times.
netif_tx_stop_queue: 207 copies, 590 calls:
55 push %rbp
48 89 e5 mov %rsp,%rbp
f0 80 8f e0 01 00 00 01 lock orb $0x1,0x1e0(%rdi)
5d pop %rbp
c3 retq
netif_tx_start_queue: 47 copies, 111 calls
55 push %rbp
48 89 e5 mov %rsp,%rbp
f0 80 a7 e0 01 00 00 fe lock andb $0xfe,0x1e0(%rdi)
5d pop %rbp
c3 retq
sock_hold: 39 copies, 124 calls
55 push %rbp
48 89 e5 mov %rsp,%rbp
f0 ff 87 80 00 00 00 lock incl 0x80(%rdi)
5d pop %rbp
c3 retq
__sock_put: 6 copies, 13 calls
55 push %rbp
48 89 e5 mov %rsp,%rbp
f0 ff 8f 80 00 00 00 lock decl 0x80(%rdi)
5d pop %rbp
c3 retq
This patch fixes this via s/inline/__always_inline/.
Code size decrease after the patch is ~2.5k:
text data bss dec hex filename
56719876 56364551 36196352 149280779 8e5d80b vmlinux_before
56717440 56364551 36196352 149278343 8e5ce87 vmlinux
Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
CC: David S. Miller <davem@davemloft.net>
CC: linux-kernel@vger.kernel.org
CC: netdev@vger.kernel.org
CC: netfilter-devel@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>
2 files changed