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Date: Thu, 13 Dec 2012 19:08:36 -0500 From: Phil Turmel <philip@...mel.org> To: Eric Wong <normalperson@...t.net> CC: Andreas Voellmy <andreas.voellmy@...e.edu>, viro@...iv.linux.org.uk, linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org Subject: Re: epoll with ONESHOT possibly fails to deliver events On 12/13/2012 04:32 AM, Eric Wong wrote: > Andreas Voellmy <andreas.voellmy@...e.edu> wrote: [trim /] >>> Another thread, distinct from all of the threads serving particular >>> sockets, is perfoming epoll_wait calls. When sockets are returned as >>> being ready from an epoll_wait call, the thread signals to the >>> condition variable for the socket. > > Perhaps there is a bug in the way your epoll_wait thread > uses the condition variable to notify other threads? Have you considered the possibility that data is arriving between epoll_ctl and pthread_cond_wait ? If your monitoring thread returns from epoll_wait within this race window, it will call pthread_cond_signal while the first thread is not yet waiting for it. With the one-shot flag, the next iteration of epoll_wait won't see that socket's new data. Phil -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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