From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
To: Michael Ellerman <michaele@au1.ibm.com>,
akpm@linux-foundation.org, Rik van Riel <riel@surriel.com>,
Mel Gorman <mgorman@techsingularity.net>,
paulus@ozlabs.org, benh@kernel.crashing.org
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH V2 1/2] mm/autonuma: Let architecture override how the write bit should be stashed in a protnone pte.
Date: Tue, 14 Feb 2017 11:25:48 +0530 [thread overview]
Message-ID: <abd9d231-c380-95b0-0722-8df7be626968@linux.vnet.ibm.com> (raw)
In-Reply-To: <87poilmien.fsf@concordia.ellerman.id.au>
On Tuesday 14 February 2017 11:19 AM, Michael Ellerman wrote:
> "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> writes:
>
>> Autonuma preserves the write permission across numa fault to avoid taking
>> a writefault after a numa fault (Commit: b191f9b106ea " mm: numa: preserve PTE
>> write permissions across a NUMA hinting fault"). Architecture can implement
>> protnone in different ways and some may choose to implement that by clearing Read/
>> Write/Exec bit of pte. Setting the write bit on such pte can result in wrong
>> behaviour. Fix this up by allowing arch to override how to save the write bit
>> on a protnone pte.
> This is pretty obviously a nop on arches that don't implement the new
> hooks, but it'd still be good to get an ack from someone in mm land
> before I merge it.
To get it apply cleanly you may need
http://ozlabs.org/~akpm/mmots/broken-out/mm-autonuma-dont-use-set_pte_at-when-updating-protnone-ptes.patch
http://ozlabs.org/~akpm/mmots/broken-out/mm-autonuma-dont-use-set_pte_at-when-updating-protnone-ptes-fix.patch
They are strictly not needed after the saved write patch. But I didn't
request to drop them, because the patch helps us
to get closer to the goal of no ste_pte_at() call on present ptes.
-aneesh
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next prev parent reply other threads:[~2017-02-14 5:56 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-14 5:31 [PATCH V2 0/2] Numabalancing preserve write fix Aneesh Kumar K.V
2017-02-14 5:31 ` [PATCH V2 1/2] mm/autonuma: Let architecture override how the write bit should be stashed in a protnone pte Aneesh Kumar K.V
2017-02-14 5:49 ` Michael Ellerman
2017-02-14 5:55 ` Aneesh Kumar K.V [this message]
2017-02-14 10:59 ` Michael Ellerman
2017-02-15 0:20 ` Andrew Morton
2017-02-14 5:31 ` [PATCH V2 2/2] powerpc/mm/autonuma: Switch ppc64 to its own implementeation of saved write Aneesh Kumar K.V
2017-02-14 11:04 ` Michael Ellerman
2017-02-14 12:26 ` Aneesh Kumar K.V
2017-02-15 0:45 ` Michael Ellerman
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