commit 14f5c7b46a41a595fc61db37f55721714729e59e upstream.

PSI defaults to a FIFO-99 thread, reduce this to FIFO-1.

FIFO-99 is the very highest priority available to SCHED_FIFO and
it not a suitable default; it would indicate the psi work is the
most important work on the machine.

Since Real-Time tasks will have pre-allocated memory and locked it in
place, Real-Time tasks do not care about PSI. All it needs is to be
above OTHER.
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: NJohannes Weiner <hannes@cmpxchg.org>
Tested-by: NSuren Baghdasaryan <surenb@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: NJoseph Qi <joseph.qi@linux.alibaba.com>
Acked-by: NCaspar Zhang <caspar@linux.alibaba.com>