2019-09-26 09:33:34

by Greg Kroah-Hartman

Subject: Re: [PATCH] async: Let kfree() out of the critical area of the lock

On Wed, Sep 25, 2019 at 08:52:26PM +0800, Yunfeng Ye wrote:
> It's not necessary to put kfree() in the critical area of the lock, so
> let it out.
>
> Signed-off-by: Yunfeng Ye <[email protected]>
> ---
> kernel/async.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/kernel/async.c b/kernel/async.c
> index 4f9c1d6..1de270d 100644
> --- a/kernel/async.c
> +++ b/kernel/async.c
> @@ -135,12 +135,12 @@ static void async_run_entry_fn(struct work_struct *work)
> list_del_init(&entry->domain_list);
> list_del_init(&entry->global_list);
>
> - /* 3) free the entry */
> - kfree(entry);
> atomic_dec(&entry_count);
> -
> spin_unlock_irqrestore(&async_lock, flags);
>
> + /* 3) free the entry */
> + kfree(entry);
> +
> /* 4) wake up any waiters */
> wake_up(&async_done);
> }
> --
> 2.7.4
>

Does this result any any measurable performance changes?

thanks,

greg k-h

2019-09-26 10:54:39

by Yunfeng Ye

Subject: Re: [PATCH] async: Let kfree() out of the critical area of the lock

On 2019/9/25 21:38, [email protected] wrote:
> On Wed, Sep 25, 2019 at 08:52:26PM +0800, Yunfeng Ye wrote:
>> It's not necessary to put kfree() in the critical area of the lock, so
>> let it out.
>>
>> Signed-off-by: Yunfeng Ye <[email protected]>
>> ---
>> kernel/async.c | 6 +++---
>> 1 file changed, 3 insertions(+), 3 deletions(-)
>>
>> diff --git a/kernel/async.c b/kernel/async.c
>> index 4f9c1d6..1de270d 100644
>> --- a/kernel/async.c
>> +++ b/kernel/async.c
>> @@ -135,12 +135,12 @@ static void async_run_entry_fn(struct work_struct *work)
>> list_del_init(&entry->domain_list);
>> list_del_init(&entry->global_list);
>>
>> - /* 3) free the entry */
>> - kfree(entry);
>> atomic_dec(&entry_count);
>> -
>> spin_unlock_irqrestore(&async_lock, flags);
>>
>> + /* 3) free the entry */
>> + kfree(entry);
>> +
>> /* 4) wake up any waiters */
>> wake_up(&async_done);
>> }
>> --
>> 2.7.4
>>
>
> Does this result any any measurable performance changes?
>
No performance has been Measured at present, I just want the critical area
to be as short as possible. I think it's good to put it outside.

thanks

> thanks,
>
> greg k-h
>
> .
>