Workers CPU leak [epoll_wait,epoll_ctl]

[Maxim Dounin]

Hello!

On Sun, Mar 20, 2016 at 04:34:14PM -0400, vizl wrote:

> We found, that we are running 'truncate -s 0' to file before removing them.
> Can it potentially cause the mentioned above  problems ?

Yes, for sure.  This is a modification of a file being served, and 
it's expected to cause the CPU hog in question when using sendfile 
in threads on Linux.  In nginx 1.9.13 nginx will log an alert 
instead, see this commit:

http://hg.nginx.org/nginx/rev/4df3d9fcdee8

-- 
Maxim Dounin
http://nginx.org/