mm/munlock: protect the per-CPU pagevec by a local_lock_t

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2109671
Conflicts: A minor fuzz in mm/migrate.c due to missing upstream commit
	   1eba86c0 ("mm: change page type prior to adding page
	   table entry"). Pulling it, however, will require taking in
	   a number of additional patches. So it is not done here.

commit adb11e78
Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date:   Fri, 1 Apr 2022 11:28:33 -0700

    mm/munlock: protect the per-CPU pagevec by a local_lock_t

    The access to mlock_pvec is protected by disabling preemption via
    get_cpu_var() or implicit by having preemption disabled by the caller
    (in mlock_page_drain() case).  This breaks on PREEMPT_RT since
    folio_lruvec_lock_irq() acquires a sleeping lock in this section.

    Create struct mlock_pvec which consits of the local_lock_t and the
    pagevec.  Acquire the local_lock() before accessing the per-CPU pagevec.
    Replace mlock_page_drain() with a _local() version which is invoked on
    the local CPU and acquires the local_lock_t and a _remote() version
    which uses the pagevec from a remote CPU which offline.

    Link: https://lkml.kernel.org/r/YjizWi9IY0mpvIfb@linutronix.de


Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Hugh Dickins <hughd@google.com>
    Cc: Vlastimil Babka <vbabka@suse.cz>
    Cc: Matthew Wilcox <willy@infradead.org>
    Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: Waiman Long <longman@redhat.com>