在 2022年05月12日 23:29, Muchun Song 写道: > On Thu, May 12, 2022 at 04:26:37PM +0800, liqiong wrote: >> "char bdi_unknown_nam[]" string form declares a single variable. >> It is better then "char *bdi_unknown_name" which creates two >> variables. >> > Sorry, I do not understand what you are saying here. Creating > two variables means what? > > Thanks. Hi there， The string form of "char *" creates two variables in the final assembly output, a static string, and a char pointer to the static string. Use "objdump -S -D *.o", can find out the static string occurring at "Contents of section .rodata". > >> Signed-off-by: liqiong <liqiong@xxxxxxxxxxxx> >> --- >> mm/backing-dev.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/mm/backing-dev.c b/mm/backing-dev.c >> index 7176af65b103..4982ccc63536 100644 >> --- a/mm/backing-dev.c >> +++ b/mm/backing-dev.c >> @@ -20,7 +20,7 @@ struct backing_dev_info noop_backing_dev_info; >> EXPORT_SYMBOL_GPL(noop_backing_dev_info); >> >> static struct class *bdi_class; >> -static const char *bdi_unknown_name = "(unknown)"; >> +static const char bdi_unknown_name[] = "(unknown)"; >> >> /* >> * bdi_lock protects bdi_tree and updates to bdi_list. bdi_list has RCU >> -- >> 2.11.0 >> >> -- 李力琼 <13524287433> 上海市浦东新区海科路99号中科院上海高等研究院3号楼3楼
