nginx 1.0.2 AIO problem with open_file_cache

[dr-dr xp]

Hello everybody. I recently have had some problem with AIO support and need
some help or advice on it.

With AIO on, everything was OK. But when I enabled open_file_cache, nginx
frequently closed client connection directly without sending back any data.


My platform is linux 2.6.30. CentOS 5.4;

The nginx server that has this issue serves static file at backend. Another
nginx serves as proxy in front of it.
Backend nginx config is like this:
...
aio            on;


directio       512;


output_buffers 1 128k;
...
    location /files {



        internal;


        alias /;
        open_file_cache max=50000 inactive=20s;


        open_file_cache_valid    30s;


        open_file_cache_min_uses 1;


        open_file_cache_errors   on;


With this config, on the frontend proxy server there are error logs like
this:

2011/09/03 17:01:19 [error] 12498#0: *78679759 *upstream prematurely closed
connection while reading response header from upstream*, client:
221.193.212.77, server: , request: "GET .......... HTTP/1.1", upstream:
"http://**/file/871586e763bf4417bf8d475858deee2b/260110/0b47fc7f4d84e4bcb01a6d6d1fcacc94-3581749",
host.....


And I saw in tcpdump output the connection was closed very quickly by
backend nginx:

22:02:22.892327 IP 172.16.113.32.58271 > 172.16.228.63.irdmi: S
1788188296:1788188296(0) win 5840 <mss 1460,sackOK,timestamp 666482608
0,nop,wscale 7>
22:02:22.895683 IP 172.16.228.63.irdmi > 172.16.113.32.58271: S
350810413:350810413(0) ack 1788188297 win 5792 <mss 1460,sackOK,timestamp
1948226601 66<
22:02:22.895695 IP 172.16.113.32.58271 > 172.16.228.63.irdmi: . ack 1 win 46
<nop,nop,timestamp 666482612 1948226601>
22:02:22.895703 IP 172.16.113.32.58271 > 172.16.228.63.irdmi: P 1:181(180)
ack 1 win 46 <nop,nop,timestamp 666482612 1948226601>
22:02:22.897680 IP 172.16.228.63.irdmi > 172.16.113.32.58271: . ack 181 win
54 <nop,nop,timestamp 1948226603 666482612>
22:02:22.898348 IP 172.16.228.63.irdmi > 172.16.113.32.58271: F 1:1(0) ack
181 win 54 <nop,nop,timestamp 1948226603 666482612>
22:02:22.898473 IP 172.16.113.32.58271 > 172.16.228.63.irdmi: F 181:181(0)
ack 2 win 46 <nop,nop,timestamp 666482615 1948226603>
22:02:22.899804 IP 172.16.228.63.irdmi > 172.16.113.32.58271: . ack 182 win
54 <nop,nop,timestamp 1948226605 666482615>


On the backend nginx, strace shows that io_getevents got an error *"-22"
EINVAL*.

  [pid  5275] recvfrom(48, 0x7fffe4400ae7, 1, 2, 0, 0) = -1 EAGAIN (Resource
temporarily unavailable)
  [pid  5275] epoll_wait(6, {{EPOLLIN|EPOLLOUT, {u32=2445415233,
u64=139850875540289}}}, 512, 5672) = 1
  [pid  5275] recvfrom(201, "\1\6\0\1\0\337\1\0Status: 301 Moved Perman"...,
4096, 0, NULL, NULL) = 256
  [pid  5275] close(201)                  = 0
  [pid  5275]
stat("//data1/871586e763bf4417bf8d475858deee2b/g268315/252/995f20f76d0d3871fdb5d71bbc92956c-27769564",
{st_mode=S_IFREG|0600, st_size=122507, ...<
  [pid  5275] io_submit(139850942226432, 1, {{0xf43718, 0, 0, 0, 40}}) = 1


  [pid  5275] epoll_wait(6, {{EPOLLIN, {u32=7173248, u64=7173248}}}, 512,
5671) = 1

  [pid  5275] read(7, "\1\0\0\0\0\0\0\0", 8) = 8
  [pid  5275] *io_getevents(139850942226432, 1, 64, {{0xf43718, 0xf436d8,
-22, 0}}, {0, 0}) = 1*
  [pid  5275] write(24, "172.16.164.30 - - 172.16.228.63:"..., 338) = 338
  [pid  5275] close(48)

And access.log shows that response length is ZERO:

[03/Sep/2011:06:28:48 +0800] "GET
/file/871586e763bf4417bf8d475858deee2b/260284/ed31933859d27e33b8398deaea1d2ade-3969549
HTTP/1.0" 206 0 0.001 "-" "-" "-" Range:bytes=27459105-


After I removed those *open_file_cache* directives, No such error occurred.

And the shorter *inactive* is,  the more often I get such errors.


Anybody has idea about avoiding this or fixing it?



-- 
要了几天饱饭就不记得西北风啥味了
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