Subject: slub: Enable irqs for __GFP_WAIT
From: Thomas Gleixner <tglx@linutronix.de>
Date: Wed, 09 Jan 2013 12:08:15 +0100
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git
Git-commit: da77ceac3d20f27310a07a7c346a4ee6b40d6c28
Patch-mainline: Queued in subsystem maintainer repository
References: SLE Realtime Extension

SYSTEM_RUNNING might be too late for enabling interrupts. Allocations
with GFP_WAIT can happen before that. So use this as an indicator.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Daniel Wagner <dwagner@suse.de>
---
 mm/slub.c |   10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

--- a/mm/slub.c
+++ b/mm/slub.c
@@ -1627,10 +1627,18 @@ static struct page *allocate_slab(struct
 	void *start, *p, *next;
 	int idx;
 	bool shuffle;
+	bool enableirqs = false;
 
 	flags &= gfp_allowed_mask;
 
 	if (gfpflags_allow_blocking(flags))
+		enableirqs = true;
+
+#ifdef CONFIG_PREEMPT_RT
+	if (system_state > SYSTEM_BOOTING)
+		enableirqs = true;
+#endif
+	if (enableirqs)
 		local_irq_enable();
 
 	flags |= s->allocflags;
@@ -1689,7 +1697,7 @@ static struct page *allocate_slab(struct
 	page->frozen = 1;
 
 out:
-	if (gfpflags_allow_blocking(flags))
+	if (enableirqs)
 		local_irq_disable();
 	if (!page)
 		return NULL;