2022-09-04 15:42:18

by Kaixu Xia

Subject: [PATCH] mm/damon/sysfs: simplify the judgement whether kdamonds are busy

From: Kaixu Xia <[email protected]>

It is unnecessary to get the number of the running kdamond to judge
whether kdamonds are busy. Here we can use the
damon_sysfs_kdamond_running() helper and return -EBUSY directly
when finding a running kdamond. Meanwhile, merging with the judgement
that a kdamond has current sysfs command callback request to make
the code more clear.

Signed-off-by: Kaixu Xia <[email protected]>
---
mm/damon/sysfs.c | 25 +++++++------------------
1 file changed, 7 insertions(+), 18 deletions(-)

diff --git a/mm/damon/sysfs.c b/mm/damon/sysfs.c
index 7488e27c87c3..fe6c6870cf86 100644
--- a/mm/damon/sysfs.c
+++ b/mm/damon/sysfs.c
@@ -2657,23 +2657,18 @@ static void damon_sysfs_kdamonds_rm_dirs(struct damon_sysfs_kdamonds *kdamonds)
kdamonds->kdamonds_arr = NULL;
}

-static int damon_sysfs_nr_running_ctxs(struct damon_sysfs_kdamond **kdamonds,
+static bool damon_sysfs_kdamonds_busy(struct damon_sysfs_kdamond **kdamonds,
int nr_kdamonds)
{
- int nr_running_ctxs = 0;
int i;

for (i = 0; i < nr_kdamonds; i++) {
- struct damon_ctx *ctx = kdamonds[i]->damon_ctx;
-
- if (!ctx)
- continue;
- mutex_lock(&ctx->kdamond_lock);
- if (ctx->kdamond)
- nr_running_ctxs++;
- mutex_unlock(&ctx->kdamond_lock);
+ if (damon_sysfs_kdamond_running(kdamonds[i]) ||
+ damon_sysfs_cmd_request.kdamond == kdamonds[i])
+ return true;
}
- return nr_running_ctxs;
+
+ return false;
}

static int damon_sysfs_kdamonds_add_dirs(struct damon_sysfs_kdamonds *kdamonds,
@@ -2682,15 +2677,9 @@ static int damon_sysfs_kdamonds_add_dirs(struct damon_sysfs_kdamonds *kdamonds,
struct damon_sysfs_kdamond **kdamonds_arr, *kdamond;
int err, i;

- if (damon_sysfs_nr_running_ctxs(kdamonds->kdamonds_arr, kdamonds->nr))
+ if (damon_sysfs_kdamonds_busy(kdamonds->kdamonds_arr, kdamonds->nr))
return -EBUSY;

- for (i = 0; i < kdamonds->nr; i++) {
- if (damon_sysfs_cmd_request.kdamond ==
- kdamonds->kdamonds_arr[i])
- return -EBUSY;
- }
-
damon_sysfs_kdamonds_rm_dirs(kdamonds);
if (!nr_kdamonds)
return 0;
--
2.27.0

2022-09-05 18:35:40

by SeongJae Park

Subject: Re: [PATCH] mm/damon/sysfs: simplify the judgement whether kdamonds are busy

Hi Kaixu,

On Sun, 4 Sep 2022 22:36:06 +0800 [email protected] wrote:

> From: Kaixu Xia <[email protected]>
>
> It is unnecessary to get the number of the running kdamond to judge
> whether kdamonds are busy. Here we can use the
> damon_sysfs_kdamond_running() helper and return -EBUSY directly
> when finding a running kdamond. Meanwhile, merging with the judgement
> that a kdamond has current sysfs command callback request to make
> the code more clear.
>
> Signed-off-by: Kaixu Xia <[email protected]>

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


Thanks,
SJ

> ---
> mm/damon/sysfs.c | 25 +++++++------------------
> 1 file changed, 7 insertions(+), 18 deletions(-)
>
> diff --git a/mm/damon/sysfs.c b/mm/damon/sysfs.c
> index 7488e27c87c3..fe6c6870cf86 100644
> --- a/mm/damon/sysfs.c
> +++ b/mm/damon/sysfs.c
> @@ -2657,23 +2657,18 @@ static void damon_sysfs_kdamonds_rm_dirs(struct damon_sysfs_kdamonds *kdamonds)
> kdamonds->kdamonds_arr = NULL;
> }
>
> -static int damon_sysfs_nr_running_ctxs(struct damon_sysfs_kdamond **kdamonds,
> +static bool damon_sysfs_kdamonds_busy(struct damon_sysfs_kdamond **kdamonds,
> int nr_kdamonds)
> {
> - int nr_running_ctxs = 0;
> int i;
>
> for (i = 0; i < nr_kdamonds; i++) {
> - struct damon_ctx *ctx = kdamonds[i]->damon_ctx;
> -
> - if (!ctx)
> - continue;
> - mutex_lock(&ctx->kdamond_lock);
> - if (ctx->kdamond)
> - nr_running_ctxs++;
> - mutex_unlock(&ctx->kdamond_lock);
> + if (damon_sysfs_kdamond_running(kdamonds[i]) ||
> + damon_sysfs_cmd_request.kdamond == kdamonds[i])
> + return true;
> }
> - return nr_running_ctxs;
> +
> + return false;
> }
>
> static int damon_sysfs_kdamonds_add_dirs(struct damon_sysfs_kdamonds *kdamonds,
> @@ -2682,15 +2677,9 @@ static int damon_sysfs_kdamonds_add_dirs(struct damon_sysfs_kdamonds *kdamonds,
> struct damon_sysfs_kdamond **kdamonds_arr, *kdamond;
> int err, i;
>
> - if (damon_sysfs_nr_running_ctxs(kdamonds->kdamonds_arr, kdamonds->nr))
> + if (damon_sysfs_kdamonds_busy(kdamonds->kdamonds_arr, kdamonds->nr))
> return -EBUSY;
>
> - for (i = 0; i < kdamonds->nr; i++) {
> - if (damon_sysfs_cmd_request.kdamond ==
> - kdamonds->kdamonds_arr[i])
> - return -EBUSY;
> - }
> -
> damon_sysfs_kdamonds_rm_dirs(kdamonds);
> if (!nr_kdamonds)
> return 0;
> --
> 2.27.0
>
>