Re: [PATCH V1 1/2] mm/damon/sysfs: avoid call damon_target_has_pid() repeatedly

haoxin
2022-09-16T08:57:39Z

在 2022/9/16 下午4:42, SeongJae Park 写道:
> On Thu, 15 Sep 2022 22:22:36 +0800 Xin Hao <xhao@linux.alibaba.com> wrote:
>
>> In damon_sysfs_destroy_targets(), we call damon_target_has_pid() to
>> check whether the 'ctx' include a valid pid, but there no need to call
>> damon_target_has_pid() to check repeatedly, just need call it once.
> Good eyes, nice finding!
>
>> Signed-off-by: Xin Hao <xhao@linux.alibaba.com>
>> ---
>> mm/damon/sysfs.c | 6 +++++-
>> 1 file changed, 5 insertions(+), 1 deletion(-)
>>
>> diff --git a/mm/damon/sysfs.c b/mm/damon/sysfs.c
>> index 1fa0023f136e..966ea7892ccf 100644
>> --- a/mm/damon/sysfs.c
>> +++ b/mm/damon/sysfs.c
>> @@ -2143,9 +2143,13 @@ static int damon_sysfs_set_attrs(struct damon_ctx *ctx,
>> static void damon_sysfs_destroy_targets(struct damon_ctx *ctx)
>> {
>> struct damon_target *t, *next;
>> + bool has_pid = false;
>> +
>> + if (damon_target_has_pid(ctx))
>> + has_pid = true;
> How about doing more simple and short like below?
>
> bool has_pid = damon_target_has_pid(ctx)
Yes, Do like this, make code look more clean. but this patch has been
merged into,  i send a new one to fix it ?
>
> Other than this,
>
> Reviewed-by: SeongJae Park <sj@kernel.org>
>
>
> Thanks,
> SJ
>
>> damon_for_each_target_safe(t, next, ctx) {
>> - if (damon_target_has_pid(ctx))
>> + if (has_pid)
>> put_pid(t->pid);
>> damon_destroy_target(t);
>> }
>> --
>> 2.31.0