[0/3] some pipe + wait stuff

Message

Mateusz Guzik March 3, 2025, 11:04 p.m. UTC

As a side effect of looking at the pipe hang I came up with 3 changes to
consider for -next.

The first one is a trivial clean up which I wont mind if it merely gets
folded into someone else's change for pipes.

The second one reduces page alloc/free calls for the backing area (60%
less during a kernel build in my testing). I already posted this, but
the cc list was not proper.

The last one concerns the wait/wakeup mechanism and drops one lock trip
in the common case after waking up. That too was posted some days ago,
but nobody was biting. Perhaps you will be interested (but again, maybe
I got the wrong people from get_maintainer.pl).

Mateusz Guzik (3):
  pipe: drop an always true check in anon_pipe_write()
  pipe: cache 2 pages instead of 1
  wait: avoid spurious calls to prepare_to_wait_event() in
    ___wait_event()

 fs/pipe.c                 | 63 +++++++++++++++++++++++++--------------
 include/linux/pipe_fs_i.h |  2 +-
 include/linux/wait.h      |  3 ++
 3 files changed, 45 insertions(+), 23 deletions(-)