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From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
To: Michael Ellerman <mpe@ellerman.id.au>, Anton Blanchard <anton@ozlabs.org>,
 benh@kernel.crashing.org, paulus@samba.org, acsawdey@linux.vnet.ibm.com
Cc: linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH 3/3] powerpc: Avoid load hit store when using
 find_linux_pte_or_hugepte()
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Date: Tue, 31 May 2016 12:22:22 +0530
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Michael Ellerman <mpe@ellerman.id.au> writes:

> On Tue, 2016-05-31 at 08:59 +0530, Aneesh Kumar K.V wrote:
>> Michael Ellerman <mpe@ellerman.id.au> writes:
>> > On Sun, 2016-05-29 at 22:03 +1000, Anton Blanchard wrote:
>> > > From: Anton Blanchard <anton@samba.org>
>> > > 
>> > > In many cases we disable interrupts right before calling
>> > > find_linux_pte_or_hugepte().
>> > > 
>> > > find_linux_pte_or_hugepte() first checks interrupts are disabled
>> > > before calling __find_linux_pte_or_hugepte():
>> > > 
>> > >         if (!arch_irqs_disabled()) {
>> > >                 pr_info("%s called with irq enabled\n", __func__);
>> > >                 dump_stack();
>> > >         }
>> > 
>> > Should that be a VM_WARN_ON()?
>> > 
>> 
>> VM_WARN_ON() put them inside CONFIG_DEBUG_VM. We should be able to use
>
> Yeah that was my point. Does this still need to be an always-on check, or can
> we hide it behind CONFIG_DEBUG_VM ?

Ok I guess we can move that within a CONFIG_DEBUG_VM #ifdef considering
we will run with DEBUG_VM enabled once in a while to catch wrong usage. I will get
a patch to do that.

-aneesh