On Thu, Jan 03, 2013 at 08:36:39AM -0600, Staffan Tjernstrom wrote: > This may be completely off-in-newbie land, but I figured I'd throw in what I think I've tracked down. > > It looks as if there was a fairly recent patch to turn locks in > parts of the code into atomic instructions (apologies - I don't have > the patch id to hand atm) in do_get_write_access() amongst others. In fs/jbd2/transaction.c? Can you give me the code snippit and/or function and line number that you're concerned about? > Then in turn the C++ standard library loops around calls to write() > whilst access isn't available, basically blocking on the atomic > (which then in turn doesn't support priority inheritance), causing > the wait loop. Yeah, but do_get_write_access() blocks (usually waiting for the jbd2 kernel thread to complete, but possibly on a memory allocation); we don't return EAGAIN or anything like that. So I don't see how that would cause a wait loop. It's possible we could be returning -ENOMEM; are you looping for all write failures, or just for EAGAIN/EINTR and partial writes? - Ted -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
