Mercurial > hg > nginx-quic
view src/core/ngx_queue.c @ 4010:74a93d3fdd85
Fixing cpu hog with all upstream servers marked "down".
The following configuration causes nginx to hog cpu due to infinite loop
in ngx_http_upstream_get_peer():
upstream backend {
server 127.0.0.1:8080 down;
server 127.0.0.1:8080 down;
}
server {
...
location / {
proxy_pass http://backend;
}
}
Make sure we don't loop infinitely in ngx_http_upstream_get_peer() but stop
after resetting peer weights once.
Return 0 if we are stuck. This is guaranteed to work as peer 0 always exists,
and eventually ngx_http_upstream_get_round_robin_peer() will do the right
thing falling back to backup servers or returning NGX_BUSY.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Thu, 18 Aug 2011 16:52:38 +0000 |
parents | 72db8932f782 |
children | d620f497c50f |
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/* * Copyright (C) Igor Sysoev */ #include <ngx_config.h> #include <ngx_core.h> /* * find the middle queue element if the queue has odd number of elements * or the first element of the queue's second part otherwise */ ngx_queue_t * ngx_queue_middle(ngx_queue_t *queue) { ngx_queue_t *middle, *next; middle = ngx_queue_head(queue); if (middle == ngx_queue_last(queue)) { return middle; } next = ngx_queue_head(queue); for ( ;; ) { middle = ngx_queue_next(middle); next = ngx_queue_next(next); if (next == ngx_queue_last(queue)) { return middle; } next = ngx_queue_next(next); if (next == ngx_queue_last(queue)) { return middle; } } } /* the stable insertion sort */ void ngx_queue_sort(ngx_queue_t *queue, ngx_int_t (*cmp)(const ngx_queue_t *, const ngx_queue_t *)) { ngx_queue_t *q, *prev, *next; q = ngx_queue_head(queue); if (q == ngx_queue_last(queue)) { return; } for (q = ngx_queue_next(q); q != ngx_queue_sentinel(queue); q = next) { prev = ngx_queue_prev(q); next = ngx_queue_next(q); ngx_queue_remove(q); do { if (cmp(prev, q) <= 0) { break; } prev = ngx_queue_prev(prev); } while (prev != ngx_queue_sentinel(queue)); ngx_queue_insert_after(prev, q); } }