From: Johannes Weiner <hannes@cmpxchg.org>
Date: Wed, 10 Jun 2015 18:14:54 +0000 (-0700)
Subject: mm: memcontrol: fix false-positive VM_BUG_ON() on -rt
X-Git-Tag: omap-for-v4.3/legacy-v2-signed~241^2~3
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f371763a79d;p=pandora-kernel.git

mm: memcontrol: fix false-positive VM_BUG_ON() on -rt

On -rt, the VM_BUG_ON(!irqs_disabled()) triggers inside the memcg
swapout path because the spin_lock_irq(&mapping->tree_lock) in the
caller doesn't actually disable the hardware interrupts - which is fine,
because on -rt the tophalves run in process context and so we are still
safe from preemption while updating the statistics.

Remove the VM_BUG_ON() but keep the comment of what we rely on.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reported-by: Clark Williams <williams@redhat.com>
Cc: Fernando Lopez-Lezcano <nando@ccrma.Stanford.EDU>
Cc: Steven Rostedt <rostedt@goodmis.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>
---

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