slub: Disable SLUB_CPU_PARTIAL

|BUG: sleeping function called from invalid context at kernel/locking/rtmutex.c:915
|in_atomic(): 1, irqs_disabled(): 0, pid: 87, name: rcuop/7
|1 lock held by rcuop/7/87:
| #0:  (rcu_callback){......}, at: [<ffffffff8112c76a>] rcu_nocb_kthread+0x1ca/0x5d0
|Preemption disabled at:[<ffffffff811eebd9>] put_cpu_partial+0x29/0x220
|
|CPU: 0 PID: 87 Comm: rcuop/7 Tainted: G        W       4.0.0-rt0+ #477
|Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.7.5-20140531_083030-gandalf 04/01/2014
| 000000000007a9fc ffff88013987baf8 ffffffff817441c7 0000000000000007
| 0000000000000000 ffff88013987bb18 ffffffff810eee51 0000000000000000
| ffff88013fc10200 ffff88013987bb48 ffffffff8174a1c4 000000000007a9fc
|Call Trace:
| [<ffffffff817441c7>] dump_stack+0x4f/0x90
| [<ffffffff810eee51>] ___might_sleep+0x121/0x1b0
| [<ffffffff8174a1c4>] rt_spin_lock+0x24/0x60
| [<ffffffff811a689a>] __free_pages_ok+0xaa/0x540
| [<ffffffff811a729d>] __free_pages+0x1d/0x30
| [<ffffffff811eddd5>] __free_slab+0xc5/0x1e0
| [<ffffffff811edf46>] free_delayed+0x56/0x70
| [<ffffffff811eecfd>] put_cpu_partial+0x14d/0x220
| [<ffffffff811efc98>] __slab_free+0x158/0x2c0
| [<ffffffff811f0021>] kmem_cache_free+0x221/0x2d0
| [<ffffffff81204d0c>] file_free_rcu+0x2c/0x40
| [<ffffffff8112c7e3>] rcu_nocb_kthread+0x243/0x5d0
| [<ffffffff810e951c>] kthread+0xfc/0x120
| [<ffffffff8174abc8>] ret_from_fork+0x58/0x90

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

init/Kconfig

@@ -1868,7 +1868,7 @@ config SHUFFLE_PAGE_ALLOCATOR
 
 config SLUB_CPU_PARTIAL
 	default y
-	depends on SLUB && SMP
+	depends on SLUB && SMP && !PREEMPT_RT
 	bool "SLUB per cpu partial cache"
 	help
 	  Per cpu partial caches accelerate objects allocation and freeing