From: SeongJae Park Subject: mm/damon/sysfs: add a file for listing available monitoring ops DAMON programming interface users can know if specific monitoring ops set is registered or not using 'damon_is_registered_ops()', but there is no such method for the user space. To help the case, this commit adds a new DAMON sysfs file called 'avail_operations' under each context directory for listing available monitoring ops. Reading the file will list each registered monitoring ops on each line. Link: https://lkml.kernel.org/r/20220426203843.45238-3-sj@kernel.org Signed-off-by: SeongJae Park Signed-off-by: Andrew Morton --- mm/damon/sysfs.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) --- a/mm/damon/sysfs.c~mm-damon-sysfs-add-a-file-for-listing-available-monitoring-ops +++ a/mm/damon/sysfs.c @@ -1810,6 +1810,21 @@ static void damon_sysfs_context_rm_dirs( kobject_put(&context->schemes->kobj); } +static ssize_t avail_operations_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + enum damon_ops_id id; + int len = 0; + + for (id = 0; id < NR_DAMON_OPS; id++) { + if (!damon_is_registered_ops(id)) + continue; + len += sysfs_emit_at(buf, len, "%s\n", + damon_sysfs_ops_strs[id]); + } + return len; +} + static ssize_t operations_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf) { @@ -1840,10 +1855,14 @@ static void damon_sysfs_context_release( kfree(container_of(kobj, struct damon_sysfs_context, kobj)); } +static struct kobj_attribute damon_sysfs_context_avail_operations_attr = + __ATTR_RO_MODE(avail_operations, 0400); + static struct kobj_attribute damon_sysfs_context_operations_attr = __ATTR_RW_MODE(operations, 0600); static struct attribute *damon_sysfs_context_attrs[] = { + &damon_sysfs_context_avail_operations_attr.attr, &damon_sysfs_context_operations_attr.attr, NULL, }; _