linux kernel struct 之 rb_root

linux-4.9.37/include/linux/rbtree.h

红黑树。

struct rb_node {
    unsigned long  __rb_parent_color;       /* 节点颜色，低位为颜色标志位，高位为父节点指针 */
    struct rb_node *rb_right;               /* 右子节点 */
    struct rb_node *rb_left;                /* 左子节点 */
} __attribute__((aligned(sizeof(long))));
    /* The alignment might seem pointless, but allegedly CRIS needs it */

struct rb_root {
    struct rb_node *rb_node;
};

#define rb_parent(r)   ((struct rb_node *)((r)->__rb_parent_color & ~3))