+ void (*pre_select)(struct sched *s, struct task *t);
+ /**
+ * Convert (filter) the given data.
+ *
+ * Pointer to the converting function of the filter. It should convert as
+ * input data as possible. On errors, the post_select function is supposed
+ * to set t->error to a (negative) error code.
+ */
+ void (*post_select)(struct sched *s, struct task *t);
+ btr_command_handler execute;