From: "Aneesh Kumar K.V" <aneesh.kumar@linux•vnet.ibm.com>
To: Benjamin Herrenschmidt <benh@kernel•crashing.org>,
paulus@samba•org, mpe@ellerman•id.au,
Frederic Barrat <fbarrat@linux•vnet.ibm.com>
Cc: linuxppc-dev@lists•ozlabs.org
Subject: Re: [PATCH 2/3] powerpc/mm: Rename find_linux_pte_or_hugepte
Date: Mon, 29 May 2017 20:02:26 +0530 [thread overview]
Message-ID: <87zidvpwcl.fsf@skywalker.in.ibm.com> (raw)
In-Reply-To: <1494997069.3092.5.camel@kernel.crashing.org>
Benjamin Herrenschmidt <benh@kernel•crashing.org> writes:
> On Wed, 2017-05-17 at 08:57 +0530, Aneesh Kumar K.V wrote:
>> Benjamin Herrenschmidt <benh@kernel•crashing.org> writes:
>>=20
>> > On Tue, 2017-05-16 at 14:56 +0530, Aneesh Kumar K.V wrote:
>> > > +static inline pte_t *find_linux_pte(pgd_t *pgdir, unsigned long ea,
>> > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=
=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 bool *is_th=
p, unsigned *hshift)
>> > > +{
>> > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0VM_WARN((!arch_irqs_disab=
led() && !__hard_irqs_disabled()) ,
>> > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0=C2=A0=C2=A0=C2=A0"%s called with irq enabled\n", __func__);
>> > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0return __find_linux_pte(p=
gdir, ea, is_thp, hshift);
>> > > +}
>> > > +
>> >=20
>> > When is arch_irqs_disabled() not sufficient ?
>>=20
>> We can do lockless page table walk in interrupt handlers where we find
>> MSR_EE =3D 0.=20
>
> Such as ?
>
kvmppc_do_h_enter() when get called in real mode.
For now i have dropped hard_irq_disabled() and switched these usage to
__find_linux_pte with explict comment around them stating they are
called with MSR_EE =3D 0.
-aneesh
next prev parent reply other threads:[~2017-05-29 14:33 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-05-16 9:26 [PATCH 1/3] powerpc: Add __hard_irqs_disabled() Aneesh Kumar K.V
2017-05-16 9:26 ` [PATCH 2/3] powerpc/mm: Rename find_linux_pte_or_hugepte Aneesh Kumar K.V
2017-05-16 11:22 ` Benjamin Herrenschmidt
2017-05-17 3:27 ` Aneesh Kumar K.V
2017-05-17 4:57 ` Benjamin Herrenschmidt
2017-05-17 5:30 ` Madhavan Srinivasan
2017-05-29 14:32 ` Aneesh Kumar K.V [this message]
2017-05-30 3:21 ` Benjamin Herrenschmidt
2017-05-16 9:26 ` [PATCH 3/3] powerpc/mm: Don't send IPI to all cpus on THP updates Aneesh Kumar K.V
2017-05-16 11:22 ` [PATCH 1/3] powerpc: Add __hard_irqs_disabled() Benjamin Herrenschmidt
2017-05-17 11:04 ` Balbir Singh
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