From: Rik van Riel <riel@redhat.com>
To: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>,
benh@kernel.crashing.org, paulus@samba.org
Cc: linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] powerpc/mm: Make sure a local_irq_disable prevent a parallel THP split
Date: Sat, 15 Mar 2014 15:25:30 -0400 [thread overview]
Message-ID: <5324A92A.3040309@redhat.com> (raw)
In-Reply-To: <1394880478-770-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com>
On 03/15/2014 06:47 AM, Aneesh Kumar K.V wrote:
> From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
>
> We have generic code like the one in get_futex_key that assume that
> a local_irq_disable prevents a parallel THP split. Support that by
> adding a dummy smp call function after setting _PAGE_SPLITTING. Code
> paths like get_user_pages_fast still need to check for _PAGE_SPLITTING
> after disabling IRQ which indicate that a parallel THP splitting is
> ongoing. Now if they don't find _PAGE_SPLITTING set, then we can be
> sure that parallel split will now block in pmdp_splitting flush
> until we enables IRQ
>
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: Rik van Riel <riel@redhat.com>
--
All rights reversed
WARNING: multiple messages have this Message-ID (diff)
From: Rik van Riel <riel@redhat.com>
To: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>,
benh@kernel.crashing.org, paulus@samba.org
Cc: linuxppc-dev@lists.ozlabs.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] powerpc/mm: Make sure a local_irq_disable prevent a parallel THP split
Date: Sat, 15 Mar 2014 15:25:30 -0400 [thread overview]
Message-ID: <5324A92A.3040309@redhat.com> (raw)
In-Reply-To: <1394880478-770-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com>
On 03/15/2014 06:47 AM, Aneesh Kumar K.V wrote:
> From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
>
> We have generic code like the one in get_futex_key that assume that
> a local_irq_disable prevents a parallel THP split. Support that by
> adding a dummy smp call function after setting _PAGE_SPLITTING. Code
> paths like get_user_pages_fast still need to check for _PAGE_SPLITTING
> after disabling IRQ which indicate that a parallel THP splitting is
> ongoing. Now if they don't find _PAGE_SPLITTING set, then we can be
> sure that parallel split will now block in pmdp_splitting flush
> until we enables IRQ
>
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: Rik van Riel <riel@redhat.com>
--
All rights reversed
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WARNING: multiple messages have this Message-ID (diff)
From: Rik van Riel <riel@redhat.com>
To: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>,
benh@kernel.crashing.org, paulus@samba.org
Cc: linuxppc-dev@lists.ozlabs.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] powerpc/mm: Make sure a local_irq_disable prevent a parallel THP split
Date: Sat, 15 Mar 2014 15:25:30 -0400 [thread overview]
Message-ID: <5324A92A.3040309@redhat.com> (raw)
In-Reply-To: <1394880478-770-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com>
On 03/15/2014 06:47 AM, Aneesh Kumar K.V wrote:
> From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
>
> We have generic code like the one in get_futex_key that assume that
> a local_irq_disable prevents a parallel THP split. Support that by
> adding a dummy smp call function after setting _PAGE_SPLITTING. Code
> paths like get_user_pages_fast still need to check for _PAGE_SPLITTING
> after disabling IRQ which indicate that a parallel THP splitting is
> ongoing. Now if they don't find _PAGE_SPLITTING set, then we can be
> sure that parallel split will now block in pmdp_splitting flush
> until we enables IRQ
>
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: Rik van Riel <riel@redhat.com>
--
All rights reversed
next prev parent reply other threads:[~2014-03-15 19:25 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-03-15 10:47 [PATCH] powerpc/mm: Make sure a local_irq_disable prevent a parallel THP split Aneesh Kumar K.V
2014-03-15 10:47 ` Aneesh Kumar K.V
2014-03-15 10:47 ` Aneesh Kumar K.V
2014-03-15 19:25 ` Rik van Riel [this message]
2014-03-15 19:25 ` Rik van Riel
2014-03-15 19:25 ` Rik van Riel
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