[PATCH 0/8] simplify ep_poll

[Soheil Hassas Yeganeh]

From: Soheil Hassas Yeganeh <soheil@xxxxxxxxxx>

This patch series is a follow up based on the suggestions and feedback by Linus:
https://lkml.kernel.org/r/CAHk-=wizk=OxUyQPbO8MS41w2Pag1kniUV5WdD5qWL-gq1kjDA@xxxxxxxxxxxxxx

The first patch in the series is a fix for the epoll race in
presence of timeouts, so that it can be cleanly backported to all
affected stable kernels.

The rest of the patch series simplify the ep_poll() implementation.
Some of these simplifications result in minor performance enhancements
as well.  We have kept these changes under self tests and internal
benchmarks for a few days, and there are minor (1-2%) performance
enhancements as a result.

Signed-off-by: Soheil Hassas Yeganeh <soheil@xxxxxxxxxx>

Soheil Hassas Yeganeh (8):
  epoll: check for events when removing a timed out thread from the wait
    queue
  epoll: simplify signal handling
  epoll: pull fatal signal checks into ep_send_events()
  epoll: move eavail next to the list_empty_careful check
  epoll: simplify and optimize busy loop logic
  epoll: pull all code between fetch_events and send_event into the loop
  epoll: replace gotos with a proper loop
  epoll: eliminate unnecessary lock for zero timeout

 fs/eventpoll.c | 159 +++++++++++++++++++++++++------------------------
 1 file changed, 80 insertions(+), 79 deletions(-)

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2.29.1.341.ge80a0c044ae-goog