hlist_node hlist_bl_node inode dentry 为什么不一样。

blake326

inode和dentry的hash表节点类型为什么不一样。看起来他们的功能和定义效果都是一样的。

struct inode {
        struct hlist_node        i_hash;
}

struct dentry {
        struct hlist_bl_node d_hash;        /* lookup hash list */
}

blake326

为什么发帖都没人理呢？
好多贴都是十层大海了，伤心了。

T-Bagwell

inode和dentry不一样

"Documentation/filesystems/vfs.txt"

blake326

/*
* Special version of lists, where head of the list has a lock in the lowest
* bit. This is useful for scalable hash tables without increasing memory
* footprint overhead.
*
* For modification operations, the 0 bit of hlist_bl_head->first
* pointer must be set.
*
* With some small modifications, this can easily be adapted to store several
* arbitrary bits (not just a single lock bit), if the need arises to store
* some fast and compact auxiliary data.
*/

没有仔细看，原来hlist_bl 是自带锁的。