2022-09-15 15:14:36

by haoxin

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

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.

Signed-off-by: Xin Hao <[email protected]>
---
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;

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

2022-09-16 09:02:05

by haoxin

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

在 2022/9/16 下午4:42, SeongJae Park 写道:
> On Thu, 15 Sep 2022 22:22:36 +0800 Xin Hao <[email protected]> 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 <[email protected]>
>> ---
>> 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 <[email protected]>
>
>
> 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

2022-09-16 09:31:08

by SeongJae Park

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

On Thu, 15 Sep 2022 22:22:36 +0800 Xin Hao <[email protected]> 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 <[email protected]>
> ---
> 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)

Other than this,

Reviewed-by: SeongJae Park <[email protected]>


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