2022-11-24 21:32:36

by SeongJae Park

Subject: [RFC PATCH 07/11] mm/damon/sysfs-schemes: connect filter directory and filters directory

Implement 'nr_filters' file under 'filters' directory, which will be
used to populate specific number of 'filter' directory under the
directory, similar to other 'nr_*' files in DAMON sysfs interface.

Signed-off-by: SeongJae Park <[email protected]>
---
mm/damon/sysfs-schemes.c | 67 ++++++++++++++++++++++++++++++++++++++++
1 file changed, 67 insertions(+)

diff --git a/mm/damon/sysfs-schemes.c b/mm/damon/sysfs-schemes.c
index afbfc55a8e84..7f2bab617156 100644
--- a/mm/damon/sysfs-schemes.c
+++ b/mm/damon/sysfs-schemes.c
@@ -269,6 +269,11 @@ struct damon_sysfs_scheme_filter {
char *memcg_path;
};

+static struct damon_sysfs_scheme_filter *damon_sysfs_scheme_filter_alloc(void)
+{
+ return kzalloc(sizeof(struct damon_sysfs_scheme_filter), GFP_KERNEL);
+}
+
/* Should match with enum damos_filter_type */
static const char * const damon_sysfs_scheme_filter_type_strs[] = {
"anon",
@@ -392,6 +397,7 @@ static struct kobj_type damon_sysfs_scheme_filter_ktype = {

struct damon_sysfs_scheme_filters {
struct kobject kobj;
+ struct damon_sysfs_scheme_filter **filters_arr;
int nr;
};

@@ -401,6 +407,57 @@ damon_sysfs_scheme_filters_alloc(void)
return kzalloc(sizeof(struct damon_sysfs_scheme_filters), GFP_KERNEL);
}

+static void damon_sysfs_scheme_filters_rm_dirs(
+ struct damon_sysfs_scheme_filters *filters)
+{
+ struct damon_sysfs_scheme_filter **filters_arr = filters->filters_arr;
+ int i;
+
+ for (i = 0; i < filters->nr; i++)
+ kobject_put(&filters_arr[i]->kobj);
+ filters->nr = 0;
+ kfree(filters_arr);
+ filters->filters_arr = NULL;
+}
+
+static int damon_sysfs_scheme_filters_add_dirs(
+ struct damon_sysfs_scheme_filters *filters, int nr_filters)
+{
+ struct damon_sysfs_scheme_filter **filters_arr, *filter;
+ int err, i;
+
+ damon_sysfs_scheme_filters_rm_dirs(filters);
+ if (!nr_filters)
+ return 0;
+
+ filters_arr = kmalloc_array(nr_filters, sizeof(*filters_arr),
+ GFP_KERNEL | __GFP_NOWARN);
+ if (!filters_arr)
+ return -ENOMEM;
+ filters->filters_arr = filters_arr;
+
+ for (i = 0; i < nr_filters; i++) {
+ filter = damon_sysfs_scheme_filter_alloc();
+ if (!filter) {
+ damon_sysfs_scheme_filters_rm_dirs(filters);
+ return -ENOMEM;
+ }
+
+ err = kobject_init_and_add(&filter->kobj,
+ &damon_sysfs_scheme_filter_ktype,
+ &filters->kobj, "%d", i);
+ if (err) {
+ kobject_put(&filter->kobj);
+ damon_sysfs_scheme_filters_rm_dirs(filters);
+ return err;
+ }
+
+ filters_arr[i] = filter;
+ filters->nr++;
+ }
+ return 0;
+}
+
static ssize_t nr_filters_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
@@ -413,6 +470,7 @@ static ssize_t nr_filters_show(struct kobject *kobj,
static ssize_t nr_filters_store(struct kobject *kobj,
struct kobj_attribute *attr, const char *buf, size_t count)
{
+ struct damon_sysfs_scheme_filters *filters;
int nr, err = kstrtoint(buf, 0, &nr);

if (err)
@@ -420,6 +478,15 @@ static ssize_t nr_filters_store(struct kobject *kobj,
if (nr < 0)
return -EINVAL;

+ filters = container_of(kobj, struct damon_sysfs_scheme_filters, kobj);
+
+ if (!mutex_trylock(&damon_sysfs_lock))
+ return -EBUSY;
+ err = damon_sysfs_scheme_filters_add_dirs(filters, nr);
+ mutex_unlock(&damon_sysfs_lock);
+ if (err)
+ return err;
+
return count;
}

--
2.25.1

2022-11-27 18:35:37

by SeongJae Park

Subject: Re: [RFC PATCH 07/11] mm/damon/sysfs-schemes: connect filter directory and filters directory

On Thu, 24 Nov 2022 21:21:10 +0000 SeongJae Park <[email protected]> wrote:

> Implement 'nr_filters' file under 'filters' directory, which will be
> used to populate specific number of 'filter' directory under the
> directory, similar to other 'nr_*' files in DAMON sysfs interface.
>
> Signed-off-by: SeongJae Park <[email protected]>
> ---
> mm/damon/sysfs-schemes.c | 67 ++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 67 insertions(+)
>
> diff --git a/mm/damon/sysfs-schemes.c b/mm/damon/sysfs-schemes.c
> index afbfc55a8e84..7f2bab617156 100644
> --- a/mm/damon/sysfs-schemes.c
> +++ b/mm/damon/sysfs-schemes.c
[...]
> @@ -401,6 +407,57 @@ damon_sysfs_scheme_filters_alloc(void)
> return kzalloc(sizeof(struct damon_sysfs_scheme_filters), GFP_KERNEL);
> }
>
> +static void damon_sysfs_scheme_filters_rm_dirs(
> + struct damon_sysfs_scheme_filters *filters)
> +{
> + struct damon_sysfs_scheme_filter **filters_arr = filters->filters_arr;
> + int i;
> +
> + for (i = 0; i < filters->nr; i++)
> + kobject_put(&filters_arr[i]->kobj);
> + filters->nr = 0;
> + kfree(filters_arr);
> + filters->filters_arr = NULL;
> +}

This function should also be called from damon_Sysfs_scheme_rm_dirs() but this
patch is missing that. This could result in undeleted filters directory when
writing 0 to 'nr_schemes' file. Next version of this patchset will fix that.


Thanks,
SJ

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