: memory accounting and limitation (take 11)

Hello,

I updated patch set of UDP memory accounting and limitation.

The spin lock that I used in previous take was removed from datagram memory accounting functions. As David commented, I used socket lock and backlog processing to keep consistency of memory accounting like TCP. I added socket lock to places where skbuff is freed, since the locking is needed to change sk_forward_alloc only.

Moreover, I revised memory accounting functions. As Herbert commented, I stopped using large inline function and tried to reduce amount of inline functions.

The patch set was tested on net-2.6 tree.

Changelog take 10 -> take 11:
* stopped using spin lock in memory accounting function
* socket lock and backlog processing were used to avoid conflict between receive system call processing and BH
* revised memory accounting functions
* stooped changing sock_queue_rcv_skb() and skb_set_owner_r()
* added __udp_queue_rcv_skb to set proper destructor
* removed udp_set_owner_r()
* removed reclaim in inet_sock_destruct()

Changelog take 9 -> take 10:
* supported using sk_forward_alloc
* introduced several memory accounting functions with spin lock
* changed detagram receive functions to be able to customize destructor
* fixed accounting bugs in previous takes

Changelog take 8 -> take 9:
* introduced mem_schdeule functions for datargram protocols
* removed protocol check function, from patch set
* restructured patch set

Changelog take 7 -> take 8:

* sk_datagram_pages(): avoided using divide instruction
* udp_recvmsg(): fixed referring released truesize in accounting

Best regards,
Hideo Aoki

--
Hitachi Computer Products (America) Inc.