Hello Zheng,
The third paragraph of the commit description still mentions the .bss
segment.
Wednesday, April 7, 2021, 7:50:00 PM, you wrote:
> mutex lock can be initialized automatically with DEFINE_MUTEX() rather
> than explicitly calling mutex_init().
> this patch will reduce the size of bcache.ko about 16 bytes, the reason
> as follows:
> though this patch will increase the size of .data segment about 32 bytes,
> it will also reduce the size of .init.text and .rodata.str1.1(at x86_64),
> .rodata_str1.8(at arm64) and .bss segment total about 48 bytes which reduce
> the size more than .data segment;
> here is the statistics:
> Sections: (arm64 platform)
> Idx name size
> -.init.text 00000240
> +.init.text 00000228
> -.rodata.str1.8 000012cd
> +.rodata.str1.8 000012b5
> -.data 00000c60
> +.data 00000c80
> Sections: (x86 platform)
> Idx name size
> -.init.text 000001d9
> +.init.text 000001bf
> -.rodata.str1.1 00000c80
> +.rodata.str1.1 00000c6d
> -.data 00000cc0
> +.data 00000ce0
> Reported-by: Hulk Robot <hulkci@xxxxxxxxxx>
> Signed-off-by: Zheng Yongjun <zhengyongjun3@xxxxxxxxxx>
> ---
> v3:
> - change commit log, delete statistic about .bss segment.
> v2:
> - add commit log about the reason why bcache.ko size reduced.
> drivers/md/bcache/super.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
> diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
> index 03e1fe4de53d..3635f454309e 100644
> --- a/drivers/md/bcache/super.c
> +++ b/drivers/md/bcache/super.c
> @@ -40,7 +40,7 @@ static const char invalid_uuid[] = {
> };
>
> static struct kobject *bcache_kobj;
> -struct mutex bch_register_lock;
> +DEFINE_MUTEX(bch_register_lock);
> bool bcache_is_reboot;
> LIST_HEAD(bch_cache_sets);
> static LIST_HEAD(uncached_devices);
> @@ -2869,7 +2869,6 @@ static int __init bcache_init(void)
>
> check_module_parameters();
>
> - mutex_init(&bch_register_lock);
> init_waitqueue_head(&unregister_wait);
> register_reboot_notifier(&reboot);
>
Pavel Goran
