>+++ zhouchuangao [30/03/21 05:07 -0700]:
>>It can be optimized at compile time.
>>
>>Signed-off-by: zhouchuangao <zhouchuan...@vivo.com>
>
>Hi,
>
>Could you please provide a more descriptive changelog? I.e., Is this
>a fix for a cocinelle warning? What are the optimization(s)?
>
>Thanks,
>
First,
This patch comes from cocinelle warning.
Second,
#define BUG_ON(condition) do { if (unlikely(condition)) BUG(); } while (0)
BUG_ON uses unlikely in if(). Through disassembly, we can see that
brk #0x800 is compiled to the end of the function.
As you can see below:
......
ffffff8008660bec: d65f03c0 ret
ffffff8008660bf0: d4210000 brk #0x800
Usually, the condition in if () is not satisfied. For the multi-stage pipeline,
we do not need to perform fetch decode and excute operation on brk
instruction.
In my opinion, this can improve the efficiency of the multi-stage pipeline.
Thanks,
zhouchuangao
>Jessica
>
>>---
>> kernel/module.c | 4 ++--
>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>
>>diff --git a/kernel/module.c b/kernel/module.c
>>index 3047935..f46fc4f 100644
>>--- a/kernel/module.c
>>+++ b/kernel/module.c
>>@@ -1014,8 +1014,8 @@ void __symbol_put(const char *symbol)
>> };
>>
>> preempt_disable();
>>- if (!find_symbol(&fsa))
>>- BUG();
>>+ BUG_ON(!find_symbol(&fsa));
>>+
>> module_put(fsa.owner);
>> preempt_enable();
>> }
>>--
>>2.7.4
>>
