[PATCH 07/12] mm/damon/sysfs: Support DAMOS quotas

[SeongJae Park <sj@xxxxxxxxxx>]

This commit makes DAMON sysfs interface supports the DAMOS quotas
feature.  Specifically, this commit adds 'quotas' directory under each
scheme directory and makes kdamond 'state' file writing respects the
contents in the directory.

As a result, the files hierarchy becomes as below:

    /sys/kernel/mm/damon/admin
    │ kdamonds/nr
    │ │ 0/state,pid
    │ │ │ contexts/nr
    │ │ │ │ 0/operations
    │ │ │ │ │ monitoring_attrs/intervals/sample_us,aggr_us,update_us
    │ │ │ │ │ │ nr_regions/min,max
    │ │ │ │ │ targets/nr
    │ │ │ │ │ │ 0/pid
    │ │ │ │ │ │ │ regions/nr
    │ │ │ │ │ │ │ │ 0/start,end
    │ │ │ │ │ │ │ │ ...
    │ │ │ │ │ │ ...
    │ │ │ │ │ schemes/nr
    │ │ │ │ │ │ 0/action
    │ │ │ │ │ │ │ access_pattern/
    │ │ │ │ │ │ │ │ sz/min,max
    │ │ │ │ │ │ │ │ nr_accesses/min,max
    │ │ │ │ │ │ │ │ age/min,max
    │ │ │ │ │ │ │ quotas/ms,sz,reset_interval_ms    <- NEW DIRECTORY
    │ │ │ │ │ │ ...
    │ │ │ │ ...
    │ │ ...

Signed-off-by: SeongJae Park <sj@xxxxxxxxxx>
---
 mm/damon/sysfs.c | 143 ++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 140 insertions(+), 3 deletions(-)

diff --git a/mm/damon/sysfs.c b/mm/damon/sysfs.c
index 2350a637e662..a14caeb5b6a1 100644
--- a/mm/damon/sysfs.c
+++ b/mm/damon/sysfs.c
@@ -115,6 +115,115 @@ static struct kobj_type damon_sysfs_ul_range_ktype = {
 	.default_groups = damon_sysfs_ul_range_groups,
 };
 
+/*
+ * quotas directory
+ */
+
+struct damon_sysfs_quotas {
+	struct kobject kobj;
+	unsigned long ms;
+	unsigned long sz;
+	unsigned long reset_interval_ms;
+};
+
+static struct damon_sysfs_quotas *damon_sysfs_quotas_alloc(void)
+{
+	return kzalloc(sizeof(struct damon_sysfs_quotas), GFP_KERNEL);
+}
+
+static ssize_t damon_sysfs_quotas_ms_show(struct kobject *kobj,
+		struct kobj_attribute *attr, char *buf)
+{
+	struct damon_sysfs_quotas *quotas = container_of(kobj,
+			struct damon_sysfs_quotas, kobj);
+
+	return sysfs_emit(buf, "%lu\n", quotas->ms);
+}
+
+static ssize_t damon_sysfs_quotas_ms_store(struct kobject *kobj,
+		struct kobj_attribute *attr, const char *buf, size_t count)
+{
+	struct damon_sysfs_quotas *quotas = container_of(kobj,
+			struct damon_sysfs_quotas, kobj);
+	int err = kstrtoul(buf, 0, &quotas->ms);
+
+	if (err)
+		return -EINVAL;
+	return count;
+}
+
+static ssize_t damon_sysfs_quotas_sz_show(struct kobject *kobj,
+		struct kobj_attribute *attr, char *buf)
+{
+	struct damon_sysfs_quotas *quotas = container_of(kobj,
+			struct damon_sysfs_quotas, kobj);
+
+	return sysfs_emit(buf, "%lu\n", quotas->sz);
+}
+
+static ssize_t damon_sysfs_quotas_sz_store(struct kobject *kobj,
+		struct kobj_attribute *attr, const char *buf, size_t count)
+{
+	struct damon_sysfs_quotas *quotas = container_of(kobj,
+			struct damon_sysfs_quotas, kobj);
+	int err = kstrtoul(buf, 0, &quotas->sz);
+
+	if (err)
+		return -EINVAL;
+	return count;
+}
+
+static ssize_t damon_sysfs_quotas_reset_interval_ms_show(struct kobject *kobj,
+		struct kobj_attribute *attr, char *buf)
+{
+	struct damon_sysfs_quotas *quotas = container_of(kobj,
+			struct damon_sysfs_quotas, kobj);
+
+	return sysfs_emit(buf, "%lu\n", quotas->reset_interval_ms);
+}
+
+static ssize_t damon_sysfs_quotas_reset_interval_ms_store(struct kobject *kobj,
+		struct kobj_attribute *attr, const char *buf, size_t count)
+{
+	struct damon_sysfs_quotas *quotas = container_of(kobj,
+			struct damon_sysfs_quotas, kobj);
+	int err = kstrtoul(buf, 0, &quotas->reset_interval_ms);
+
+	if (err)
+		return -EINVAL;
+	return count;
+}
+
+static void damon_sysfs_quotas_release(struct kobject *kobj)
+{
+	kfree(container_of(kobj, struct damon_sysfs_quotas, kobj));
+}
+
+static struct kobj_attribute damon_sysfs_quotas_ms_attr = __ATTR(ms, 0600,
+		damon_sysfs_quotas_ms_show, damon_sysfs_quotas_ms_store);
+
+static struct kobj_attribute damon_sysfs_quotas_sz_attr = __ATTR(sz, 0600,
+		damon_sysfs_quotas_sz_show, damon_sysfs_quotas_sz_store);
+
+static struct kobj_attribute damon_sysfs_quotas_reset_interval_ms_attr =
+		__ATTR(reset_interval_ms, 0600,
+			damon_sysfs_quotas_reset_interval_ms_show,
+			damon_sysfs_quotas_reset_interval_ms_store);
+
+static struct attribute *damon_sysfs_quotas_attrs[] = {
+	&damon_sysfs_quotas_ms_attr.attr,
+	&damon_sysfs_quotas_sz_attr.attr,
+	&damon_sysfs_quotas_reset_interval_ms_attr.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(damon_sysfs_quotas);
+
+static struct kobj_type damon_sysfs_quotas_ktype = {
+	.release = damon_sysfs_quotas_release,
+	.sysfs_ops = &kobj_sysfs_ops,
+	.default_groups = damon_sysfs_quotas_groups,
+};
+
 /*
  * access_pattern directory
  */
@@ -222,6 +331,7 @@ struct damon_sysfs_scheme {
 	struct kobject kobj;
 	enum damos_action action;
 	struct damon_sysfs_access_pattern *access_pattern;
+	struct damon_sysfs_quotas *quotas;
 };
 
 /* This should match with enum damos_action */
@@ -272,6 +382,24 @@ static int damon_sysfs_scheme_set_access_pattern(
 	return err;
 }
 
+static int damon_sysfs_scheme_set_quotas(struct damon_sysfs_scheme *scheme)
+{
+	struct damon_sysfs_quotas *quotas = damon_sysfs_quotas_alloc();
+	int err;
+
+	if (!quotas)
+		return -ENOMEM;
+	err = kobject_init_and_add(&quotas->kobj, &damon_sysfs_quotas_ktype,
+			&scheme->kobj, "quotas");
+	if (err)
+		goto out;
+	return 0;
+
+out:
+	kobject_put(&quotas->kobj);
+	return err;
+}
+
 static int damon_sysfs_scheme_add_dirs(struct damon_sysfs_scheme *scheme)
 {
 	int err;
@@ -279,13 +407,22 @@ static int damon_sysfs_scheme_add_dirs(struct damon_sysfs_scheme *scheme)
 	err = damon_sysfs_scheme_set_access_pattern(scheme);
 	if (err)
 		return err;
+	err = damon_sysfs_scheme_set_quotas(scheme);
+	if (err)
+		goto put_access_pattern_out;
 	return 0;
+
+put_access_pattern_out:
+	kobject_put(&scheme->access_pattern->kobj);
+	scheme->access_pattern = NULL;
+	return err;
 }
 
 static void damon_sysfs_scheme_rm_dirs(struct damon_sysfs_scheme *scheme)
 {
 	damon_sysfs_access_pattern_rm_dirs(scheme->access_pattern);
 	kobject_put(&scheme->access_pattern->kobj);
+	kobject_put(&scheme->quotas->kobj);
 }
 
 static ssize_t damon_sysfs_scheme_action_show(struct kobject *kobj,
@@ -1533,10 +1670,10 @@ static struct damos *damon_sysfs_mk_scheme(
 {
 	struct damon_sysfs_access_pattern *pattern =
 		sysfs_scheme->access_pattern;
+	struct damon_sysfs_quotas *sysfs_quotas = sysfs_scheme->quotas;
 	struct damos_quota quota = {
-		.ms = 0,
-		.sz = 0,
-		.reset_interval = 0,
+		.ms = sysfs_quotas->ms,
+		.sz = sysfs_quotas->sz,
 		.weight_sz = 1000,
 		.weight_nr_accesses = 1000,
 		.weight_age = 1000,
-- 
2.17.1