* [PATCH] powerpc/mm: numa pte should be handled via slow path in get_user_pages_fast
@ 2014-04-02 16:07 Aneesh Kumar K.V
2014-04-06 23:49 ` Benjamin Herrenschmidt
0 siblings, 1 reply; 3+ messages in thread
From: Aneesh Kumar K.V @ 2014-04-02 16:07 UTC (permalink / raw)
To: benh, paulus; +Cc: linuxppc-dev, Aneesh Kumar K.V
From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
We need to handle numa pte via the slow path
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
arch/powerpc/mm/gup.c | 13 +++++++++++++
1 file changed, 13 insertions(+)
diff --git a/arch/powerpc/mm/gup.c b/arch/powerpc/mm/gup.c
index c5f734e20b0f..d8746684f606 100644
--- a/arch/powerpc/mm/gup.c
+++ b/arch/powerpc/mm/gup.c
@@ -36,6 +36,11 @@ static noinline int gup_pte_range(pmd_t pmd, unsigned long addr,
do {
pte_t pte = ACCESS_ONCE(*ptep);
struct page *page;
+ /*
+ * Similar to the PMD case, NUMA hinting must take slow path
+ */
+ if (pte_numa(pte))
+ return 0;
if ((pte_val(pte) & mask) != result)
return 0;
@@ -75,6 +80,14 @@ static int gup_pmd_range(pud_t pud, unsigned long addr, unsigned long end,
if (pmd_none(pmd) || pmd_trans_splitting(pmd))
return 0;
if (pmd_huge(pmd) || pmd_large(pmd)) {
+ /*
+ * NUMA hinting faults need to be handled in the GUP
+ * slowpath for accounting purposes and so that they
+ * can be serialised against THP migration.
+ */
+ if (pmd_numa(pmd))
+ return 0;
+
if (!gup_hugepte((pte_t *)pmdp, PMD_SIZE, addr, next,
write, pages, nr))
return 0;
--
1.8.3.2
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] powerpc/mm: numa pte should be handled via slow path in get_user_pages_fast
2014-04-02 16:07 [PATCH] powerpc/mm: numa pte should be handled via slow path in get_user_pages_fast Aneesh Kumar K.V
@ 2014-04-06 23:49 ` Benjamin Herrenschmidt
2014-04-07 7:38 ` Aneesh Kumar K.V
0 siblings, 1 reply; 3+ messages in thread
From: Benjamin Herrenschmidt @ 2014-04-06 23:49 UTC (permalink / raw)
To: Aneesh Kumar K.V; +Cc: linuxppc-dev, paulus
On Wed, 2014-04-02 at 21:37 +0530, Aneesh Kumar K.V wrote:
> From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
>
> We need to handle numa pte via the slow path
Is this -stable material ? If yes how far back ?
Cheers,
Ben.
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
> ---
> arch/powerpc/mm/gup.c | 13 +++++++++++++
> 1 file changed, 13 insertions(+)
>
> diff --git a/arch/powerpc/mm/gup.c b/arch/powerpc/mm/gup.c
> index c5f734e20b0f..d8746684f606 100644
> --- a/arch/powerpc/mm/gup.c
> +++ b/arch/powerpc/mm/gup.c
> @@ -36,6 +36,11 @@ static noinline int gup_pte_range(pmd_t pmd, unsigned long addr,
> do {
> pte_t pte = ACCESS_ONCE(*ptep);
> struct page *page;
> + /*
> + * Similar to the PMD case, NUMA hinting must take slow path
> + */
> + if (pte_numa(pte))
> + return 0;
>
> if ((pte_val(pte) & mask) != result)
> return 0;
> @@ -75,6 +80,14 @@ static int gup_pmd_range(pud_t pud, unsigned long addr, unsigned long end,
> if (pmd_none(pmd) || pmd_trans_splitting(pmd))
> return 0;
> if (pmd_huge(pmd) || pmd_large(pmd)) {
> + /*
> + * NUMA hinting faults need to be handled in the GUP
> + * slowpath for accounting purposes and so that they
> + * can be serialised against THP migration.
> + */
> + if (pmd_numa(pmd))
> + return 0;
> +
> if (!gup_hugepte((pte_t *)pmdp, PMD_SIZE, addr, next,
> write, pages, nr))
> return 0;
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] powerpc/mm: numa pte should be handled via slow path in get_user_pages_fast
2014-04-06 23:49 ` Benjamin Herrenschmidt
@ 2014-04-07 7:38 ` Aneesh Kumar K.V
0 siblings, 0 replies; 3+ messages in thread
From: Aneesh Kumar K.V @ 2014-04-07 7:38 UTC (permalink / raw)
To: Benjamin Herrenschmidt; +Cc: linuxppc-dev, paulus
Benjamin Herrenschmidt <benh@kernel.crashing.org> writes:
> On Wed, 2014-04-02 at 21:37 +0530, Aneesh Kumar K.V wrote:
>> From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
>>
>> We need to handle numa pte via the slow path
>
> Is this -stable material ? If yes how far back ?
I am not sure we really need to backport this. We got numa faulting bits
in 3.14. Currently there are two out-standing patches. One is this and
the other. http://mid.gmane.org/1390292129-15871-1-git-send-email-pingfank@linux.vnet.ibm.com
powernv: kvm: make _PAGE_NUMA take effect
I would not consider them critical enough to impact the general user of
3.14 kernel.
-aneesh
>
> Cheers,
> Ben.
>
>> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
>> ---
>> arch/powerpc/mm/gup.c | 13 +++++++++++++
>> 1 file changed, 13 insertions(+)
>>
>> diff --git a/arch/powerpc/mm/gup.c b/arch/powerpc/mm/gup.c
>> index c5f734e20b0f..d8746684f606 100644
>> --- a/arch/powerpc/mm/gup.c
>> +++ b/arch/powerpc/mm/gup.c
>> @@ -36,6 +36,11 @@ static noinline int gup_pte_range(pmd_t pmd, unsigned long addr,
>> do {
>> pte_t pte = ACCESS_ONCE(*ptep);
>> struct page *page;
>> + /*
>> + * Similar to the PMD case, NUMA hinting must take slow path
>> + */
>> + if (pte_numa(pte))
>> + return 0;
>>
>> if ((pte_val(pte) & mask) != result)
>> return 0;
>> @@ -75,6 +80,14 @@ static int gup_pmd_range(pud_t pud, unsigned long addr, unsigned long end,
>> if (pmd_none(pmd) || pmd_trans_splitting(pmd))
>> return 0;
>> if (pmd_huge(pmd) || pmd_large(pmd)) {
>> + /*
>> + * NUMA hinting faults need to be handled in the GUP
>> + * slowpath for accounting purposes and so that they
>> + * can be serialised against THP migration.
>> + */
>> + if (pmd_numa(pmd))
>> + return 0;
>> +
>> if (!gup_hugepte((pte_t *)pmdp, PMD_SIZE, addr, next,
>> write, pages, nr))
>> return 0;
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2014-04-07 7:38 UTC | newest]
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2014-04-02 16:07 [PATCH] powerpc/mm: numa pte should be handled via slow path in get_user_pages_fast Aneesh Kumar K.V
2014-04-06 23:49 ` Benjamin Herrenschmidt
2014-04-07 7:38 ` Aneesh Kumar K.V
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