* Jason Baron <jbaron@xxxxxxxxxx> wrote: > Hi, > > When we are sharing a wakeup source among multiple epoll > fds, we end up with thundering herd wakeups, since there > is currently no way to add to the wakeup source > exclusively. This series introduces a new EPOLL_ROTATE > flag to allow for round robin exclusive wakeups. > > I believe this patch series addresses the two main > concerns that were raised in prior postings. Namely, that > it affected code (and potentially performance) of the > core kernel wakeup functions, even in cases where it was > not strictly needed, and that it could lead to wakeup > starvation (since we were are no longer waking up all > waiters). It does so by adding an extra layer of > indirection, whereby waiters are attached to a 'psuedo' > epoll fd, which in turn is attached directly to the > wakeup source. > sched/wait: add __wake_up_rotate() > include/linux/wait.h | 1 + > kernel/sched/wait.c | 27 ++++++++++++++++++++++ So the scheduler bits are looking good to me in principle, because they just add a new round-robin-rotating wakeup variant and don't disturb the others. Is there consensus on the epoll ABI changes? With Davide Libenzi inactive eventpoll appears to be without a dedicated maintainer since 2011 or so. Is there anyone who knows the code and its usages in detail and does final ABI decisions on eventpoll - Andrew, Al or Linus? Thanks, Ingo -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
