FROMGIT: maple_tree: add GFP_KERNEL to allocations in mas_expected_entries()

Users complained about OOM errors during fork without triggering
compaction.  This can be fixed by modifying the flags used in
mas_expected_entries() so that the compaction will be triggered in low
memory situations.  Since mas_expected_entries() is only used during
fork, the extra argument does not need to be passed through.

Additionally, the two test_maple_tree test cases and one benchmark test
were altered to use the correct locking type so that allocations would
not trigger sleeping and thus fail.  Testing was completed with lockdep
atomic sleep detection.

The additional locking change requires rwsem support additions to the
tools/ directory through the use of pthreads pthread_rwlock_t.  With
this change test_maple_tree works in userspace, as a module, and
in-kernel.

Users may notice that the system gave up early on attempting to start
new processes instead of attempting to reclaim memory.

Link: https://lore.kernel.org/linux-mm/20231012155233.2272446-1-Liam.Howlett@oracle.com/


Fixes: 54a611b6 ("Maple Tree: add new data structure")
Cc: <stable@vger.kernel.org>
Cc: jason.sim@samsung.com
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
(cherry picked from commit 099d7439
https: //git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-unstable)

Bug: 305860603
Change-Id: I1ea250b37198fb3234136da4737b75c6ee3d9817
Signed-off-by: john.hsu <john.hsu@mediatek.com>