epoll 源码实现流程

ep_poll_callback

wait_queue_head

+ lock : spinlock_t+ head : struct list_head

epi

epoll_ctl

poll_table

+ _key : __poll_t+ _qproc : poll_queue_proc

check fd events

ep_ptable_queue_proc

__add_wait_queue

wait_queue_entry

entry : struct list_headfunc : wait_queue_func_t 

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ep_item_poll

driver

socket_wq

+ wait : wait_queue_head_t

events

epitem

tcp_poll

device

1

3

rbn

application

eventpoll

+ wq : wait_queue_head_t+ pool_wait : wait_queue_head_t+ rdllist : list_head+ rbr : rb_root_cached+ ovflist : epitem*+ ws : wakeup_source*+ file : file*

sock_def_wakeup

wakeup

file->f_op->poll

eppoll_entry

base : struct epitem*llink : struct list_head whead : wait_queue_head_t *wait : wait_queue_entry_t 

2

epoll_create

epoll_filefd

+ file : struct file+ fd : int

sock

+ sk_wq : struct socket_wq*

epoll_wait

socket

+ ops : const struct proto_ops *+ file ：struct file*+ wq : struct socket_wq+ sk : struct sock*

task_struct

+ files : struct files_struct *

rbr

ep_insert

ep_pqueue

+ pt : poll_table+ epi : epitem*