# HG changeset patch
# User Maxim Dounin <mdounin@mdounin.ru>
# Date 1316512527 0
# Node ID d8e24515176e73648c2c9fc5d59e2c292597331a
# Parent  a3203c4521c68a4725557de6bd7179d804f67030
Fix of cpu hog in event pipe.

If client closed connection in ngx_event_pipe_write_to_downstream(), buffers
in the "out" chain were lost.  This caused cpu hog if all available buffers
were in the "out" chain.  Fix is to call ngx_chain_update_chains() before
checking return code of output filter to avoid loosing buffers in the "out"
chain.

Note that this situation (all available buffers in the "out" chain) isn't
normal, it should be prevented by busy buffers limit.  Though right now it
may happen with complex protocols like fastcgi.  This should be addressed
separately.

diff --git a/src/event/ngx_event_pipe.c b/src/event/ngx_event_pipe.c
--- a/src/event/ngx_event_pipe.c
+++ b/src/event/ngx_event_pipe.c
@@ -656,13 +656,13 @@ ngx_event_pipe_write_to_downstream(ngx_e
 
         rc = p->output_filter(p->output_ctx, out);
 
+        ngx_chain_update_chains(p->pool, &p->free, &p->busy, &out, p->tag);
+
         if (rc == NGX_ERROR) {
             p->downstream_error = 1;
             return ngx_event_pipe_drain_chains(p);
         }
 
-        ngx_chain_update_chains(p->pool, &p->free, &p->busy, &out, p->tag);
-
         for (cl = p->free; cl; cl = cl->next) {
 
             if (cl->buf->temp_file) {