* [PATCH 0/3] optimize for powerpc _PAGE_NUMA
@ 2013-12-04 6:59 Liu Ping Fan
2013-12-04 6:59 ` [PATCH 1/3] powerpc: mm: make _PAGE_NUMA take effect Liu Ping Fan
` (2 more replies)
0 siblings, 3 replies; 13+ messages in thread
From: Liu Ping Fan @ 2013-12-04 6:59 UTC (permalink / raw)
To: linuxppc-dev; +Cc: Paul Mackerras, Aneesh Kumar K.V
I saw Aneesh had implemented Numa faults on ppc64. Most of them have been reviewed-by.
So I just diff mine and his to form some trivial modification.
Based on Aneesh's series "[PATCH -V2 0/5] powerpc: mm: Numa faults support for ppc64"
Liu Ping Fan (3):
powerpc: mm: make _PAGE_NUMA take effect
mm: export numa_migrate_prep()
powerpc: mm: optimize for the correctly placed page
arch/powerpc/mm/hash_utils_64.c | 32 ++++++++++++++++++++++++++++++++
include/linux/mm.h | 2 ++
2 files changed, 34 insertions(+)
--
1.8.1.4
^ permalink raw reply [flat|nested] 13+ messages in thread
* [PATCH 1/3] powerpc: mm: make _PAGE_NUMA take effect
2013-12-04 6:59 [PATCH 0/3] optimize for powerpc _PAGE_NUMA Liu Ping Fan
@ 2013-12-04 6:59 ` Liu Ping Fan
2013-12-05 10:53 ` Aneesh Kumar K.V
2013-12-04 6:59 ` [PATCH 2/3] mm: export numa_migrate_prep() Liu Ping Fan
2013-12-04 6:59 ` [PATCH 3/3] powerpc: mm: optimize for the correctly placed page Liu Ping Fan
2 siblings, 1 reply; 13+ messages in thread
From: Liu Ping Fan @ 2013-12-04 6:59 UTC (permalink / raw)
To: linuxppc-dev; +Cc: Paul Mackerras, Aneesh Kumar K.V
To enable the do_numa_page(), we should not fix _PAGE_NUMA in
hash_page(), so bail out for the case of pte_numa().
Signed-off-by: Liu Ping Fan <pingfank@linux.vnet.ibm.com>
---
arch/powerpc/mm/hash_utils_64.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
index fb176e9..9bf1195 100644
--- a/arch/powerpc/mm/hash_utils_64.c
+++ b/arch/powerpc/mm/hash_utils_64.c
@@ -1033,7 +1033,7 @@ int hash_page(unsigned long ea, unsigned long access, unsigned long trap)
/* Get PTE and page size from page tables */
ptep = find_linux_pte_or_hugepte(pgdir, ea, &hugeshift);
- if (ptep == NULL || !pte_present(*ptep)) {
+ if (ptep == NULL || !pte_present(*ptep) || pte_numa(*ptep)) {
DBG_LOW(" no PTE !\n");
rc = 1;
goto bail;
--
1.8.1.4
^ permalink raw reply related [flat|nested] 13+ messages in thread
* [PATCH 2/3] mm: export numa_migrate_prep()
2013-12-04 6:59 [PATCH 0/3] optimize for powerpc _PAGE_NUMA Liu Ping Fan
2013-12-04 6:59 ` [PATCH 1/3] powerpc: mm: make _PAGE_NUMA take effect Liu Ping Fan
@ 2013-12-04 6:59 ` Liu Ping Fan
2013-12-04 6:59 ` [PATCH 3/3] powerpc: mm: optimize for the correctly placed page Liu Ping Fan
2 siblings, 0 replies; 13+ messages in thread
From: Liu Ping Fan @ 2013-12-04 6:59 UTC (permalink / raw)
To: linuxppc-dev; +Cc: Paul Mackerras, Aneesh Kumar K.V
powerpc will use it in fast path.
Signed-off-by: Liu Ping Fan <pingfank@linux.vnet.ibm.com>
---
include/linux/mm.h | 2 ++
1 file changed, 2 insertions(+)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 5ab0e22..420fb77 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1092,6 +1092,8 @@ extern unsigned long change_protection(struct vm_area_struct *vma, unsigned long
extern int mprotect_fixup(struct vm_area_struct *vma,
struct vm_area_struct **pprev, unsigned long start,
unsigned long end, unsigned long newflags);
+extern int numa_migrate_prep(struct page *page, struct vm_area_struct *vma,
+ unsigned long addr, int page_nid);
/*
* doesn't attempt to fault and will return short.
--
1.8.1.4
^ permalink raw reply related [flat|nested] 13+ messages in thread
* [PATCH 3/3] powerpc: mm: optimize for the correctly placed page
2013-12-04 6:59 [PATCH 0/3] optimize for powerpc _PAGE_NUMA Liu Ping Fan
2013-12-04 6:59 ` [PATCH 1/3] powerpc: mm: make _PAGE_NUMA take effect Liu Ping Fan
2013-12-04 6:59 ` [PATCH 2/3] mm: export numa_migrate_prep() Liu Ping Fan
@ 2013-12-04 6:59 ` Liu Ping Fan
2013-12-05 10:58 ` Aneesh Kumar K.V
2 siblings, 1 reply; 13+ messages in thread
From: Liu Ping Fan @ 2013-12-04 6:59 UTC (permalink / raw)
To: linuxppc-dev; +Cc: Paul Mackerras, Aneesh Kumar K.V
The period check of _PAGE_NUMA can probably trigger the check on
the correctly placed page. For this case, we can just insert hpte and
do fast exception return.
Signed-off-by: Liu Ping Fan <pingfank@linux.vnet.ibm.com>
---
arch/powerpc/mm/hash_utils_64.c | 34 +++++++++++++++++++++++++++++++++-
1 file changed, 33 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
index 9bf1195..735678c 100644
--- a/arch/powerpc/mm/hash_utils_64.c
+++ b/arch/powerpc/mm/hash_utils_64.c
@@ -965,6 +965,10 @@ int hash_page(unsigned long ea, unsigned long access, unsigned long trap)
const struct cpumask *tmp;
int rc, user_region = 0, local = 0;
int psize, ssize;
+ pte_t old, new;
+ struct vm_area_struct *vma;
+ int page_nid, target_nid;
+ struct page *test_page;
DBG_LOW("hash_page(ea=%016lx, access=%lx, trap=%lx\n",
ea, access, trap);
@@ -1033,12 +1037,40 @@ int hash_page(unsigned long ea, unsigned long access, unsigned long trap)
/* Get PTE and page size from page tables */
ptep = find_linux_pte_or_hugepte(pgdir, ea, &hugeshift);
- if (ptep == NULL || !pte_present(*ptep) || pte_numa(*ptep)) {
+ if (ptep == NULL || !pte_present(*ptep)) {
DBG_LOW(" no PTE !\n");
rc = 1;
goto bail;
}
+ old = pte_val(*ptep);
+ if (pte_numa(old)) {
+ /* If fail to lock, let do_page_fault() to handle it */
+ if (down_read_trylock(&mm->mmap_sem)) {
+ vma = find_vma(mm, ea);
+ up_read(&mm->mmap_sem);
+ test_page = pte_page(old);
+ page_nid = page_to_nid(test_page);
+ target_nid = numa_migrate_prep(test_page, vma, ea,
+ page_nid);
+ if (target_nid < 0) {
+ new = pte_mknonnuma(old);
+ /* If ptep is modified under us,
+ * just retry the access
+ */
+ if (unlikely(cmpxchg(ptep, old, new) != old)) {
+ put_page(test_page);
+ return 0;
+ }
+ put_page(test_page);
+ }
+ } else {
+ put_page(test_page);
+ rc = 1;
+ goto bail;
+ }
+ }
+
/* Add _PAGE_PRESENT to the required access perm */
access |= _PAGE_PRESENT;
--
1.8.1.4
^ permalink raw reply related [flat|nested] 13+ messages in thread
* Re: [PATCH 1/3] powerpc: mm: make _PAGE_NUMA take effect
2013-12-04 6:59 ` [PATCH 1/3] powerpc: mm: make _PAGE_NUMA take effect Liu Ping Fan
@ 2013-12-05 10:53 ` Aneesh Kumar K.V
2013-12-09 0:31 ` Benjamin Herrenschmidt
2013-12-11 8:50 ` Liu ping fan
0 siblings, 2 replies; 13+ messages in thread
From: Aneesh Kumar K.V @ 2013-12-05 10:53 UTC (permalink / raw)
To: Liu Ping Fan, linuxppc-dev; +Cc: Paul Mackerras
Liu Ping Fan <kernelfans@gmail.com> writes:
> To enable the do_numa_page(), we should not fix _PAGE_NUMA in
> hash_page(), so bail out for the case of pte_numa().
>
> Signed-off-by: Liu Ping Fan <pingfank@linux.vnet.ibm.com>
> ---
> arch/powerpc/mm/hash_utils_64.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
> index fb176e9..9bf1195 100644
> --- a/arch/powerpc/mm/hash_utils_64.c
> +++ b/arch/powerpc/mm/hash_utils_64.c
> @@ -1033,7 +1033,7 @@ int hash_page(unsigned long ea, unsigned long access, unsigned long trap)
>
> /* Get PTE and page size from page tables */
> ptep = find_linux_pte_or_hugepte(pgdir, ea, &hugeshift);
> - if (ptep == NULL || !pte_present(*ptep)) {
> + if (ptep == NULL || !pte_present(*ptep) || pte_numa(*ptep)) {
> DBG_LOW(" no PTE !\n");
> rc = 1;
> goto bail;
why ? , All the hash routines do check for _PAGE_PRESENT via access
variable.
-aneesh
^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [PATCH 3/3] powerpc: mm: optimize for the correctly placed page
2013-12-04 6:59 ` [PATCH 3/3] powerpc: mm: optimize for the correctly placed page Liu Ping Fan
@ 2013-12-05 10:58 ` Aneesh Kumar K.V
2013-12-05 13:27 ` Liu ping fan
0 siblings, 1 reply; 13+ messages in thread
From: Aneesh Kumar K.V @ 2013-12-05 10:58 UTC (permalink / raw)
To: Liu Ping Fan, linuxppc-dev; +Cc: Paul Mackerras
Liu Ping Fan <kernelfans@gmail.com> writes:
> The period check of _PAGE_NUMA can probably trigger the check on
> the correctly placed page. For this case, we can just insert hpte and
> do fast exception return.
I still don't understand why we need to handle numa faults in hash
page ? Are you trying to optimize the code path ? If so can you explain
the benefits ? Some numbers showing it is helping ?
>
> Signed-off-by: Liu Ping Fan <pingfank@linux.vnet.ibm.com>
> ---
> arch/powerpc/mm/hash_utils_64.c | 34 +++++++++++++++++++++++++++++++++-
> 1 file changed, 33 insertions(+), 1 deletion(-)
>
> diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
> index 9bf1195..735678c 100644
> --- a/arch/powerpc/mm/hash_utils_64.c
> +++ b/arch/powerpc/mm/hash_utils_64.c
> @@ -965,6 +965,10 @@ int hash_page(unsigned long ea, unsigned long access, unsigned long trap)
> const struct cpumask *tmp;
> int rc, user_region = 0, local = 0;
> int psize, ssize;
> + pte_t old, new;
> + struct vm_area_struct *vma;
> + int page_nid, target_nid;
> + struct page *test_page;
>
> DBG_LOW("hash_page(ea=%016lx, access=%lx, trap=%lx\n",
> ea, access, trap);
> @@ -1033,12 +1037,40 @@ int hash_page(unsigned long ea, unsigned long access, unsigned long trap)
>
> /* Get PTE and page size from page tables */
> ptep = find_linux_pte_or_hugepte(pgdir, ea, &hugeshift);
> - if (ptep == NULL || !pte_present(*ptep) || pte_numa(*ptep)) {
> + if (ptep == NULL || !pte_present(*ptep)) {
> DBG_LOW(" no PTE !\n");
> rc = 1;
> goto bail;
> }
>
> + old = pte_val(*ptep);
> + if (pte_numa(old)) {
> + /* If fail to lock, let do_page_fault() to handle it */
> + if (down_read_trylock(&mm->mmap_sem)) {
hmm is that something we want to do in hash_page ?
> + vma = find_vma(mm, ea);
> + up_read(&mm->mmap_sem);
> + test_page = pte_page(old);
> + page_nid = page_to_nid(test_page);
> + target_nid = numa_migrate_prep(test_page, vma, ea,
> + page_nid);
> + if (target_nid < 0) {
> + new = pte_mknonnuma(old);
> + /* If ptep is modified under us,
> + * just retry the access
> + */
> + if (unlikely(cmpxchg(ptep, old, new) != old)) {
> + put_page(test_page);
> + return 0;
> + }
> + put_page(test_page);
> + }
> + } else {
> + put_page(test_page);
> + rc = 1;
> + goto bail;
> + }
> + }
> +
> /* Add _PAGE_PRESENT to the required access perm */
> access |= _PAGE_PRESENT;
>
-aneesh
^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [PATCH 3/3] powerpc: mm: optimize for the correctly placed page
2013-12-05 10:58 ` Aneesh Kumar K.V
@ 2013-12-05 13:27 ` Liu ping fan
0 siblings, 0 replies; 13+ messages in thread
From: Liu ping fan @ 2013-12-05 13:27 UTC (permalink / raw)
To: Aneesh Kumar K.V; +Cc: linuxppc-dev, Paul Mackerras
On Thu, Dec 5, 2013 at 6:58 PM, Aneesh Kumar K.V
<aneesh.kumar@linux.vnet.ibm.com> wrote:
> Liu Ping Fan <kernelfans@gmail.com> writes:
>
>> The period check of _PAGE_NUMA can probably trigger the check on
>> the correctly placed page. For this case, we can just insert hpte and
>> do fast exception return.
>
> I still don't understand why we need to handle numa faults in hash
> page ? Are you trying to optimize the code path ? If so can you explain
> the benefits ? Some numbers showing it is helping ?
>
When return from hash_page(), we will take fast_exc_return_irq, while
from do_page_fault(), we take ret_from_except.
As the "fast" implies that there are more complicated logic to sync
the interrupt states in ret_from_except, which cost much.
Do you think so?
>>
>> Signed-off-by: Liu Ping Fan <pingfank@linux.vnet.ibm.com>
>> ---
>> arch/powerpc/mm/hash_utils_64.c | 34 +++++++++++++++++++++++++++++++++-
>> 1 file changed, 33 insertions(+), 1 deletion(-)
>>
>> diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
>> index 9bf1195..735678c 100644
>> --- a/arch/powerpc/mm/hash_utils_64.c
>> +++ b/arch/powerpc/mm/hash_utils_64.c
>> @@ -965,6 +965,10 @@ int hash_page(unsigned long ea, unsigned long access, unsigned long trap)
>> const struct cpumask *tmp;
>> int rc, user_region = 0, local = 0;
>> int psize, ssize;
>> + pte_t old, new;
>> + struct vm_area_struct *vma;
>> + int page_nid, target_nid;
>> + struct page *test_page;
>>
>> DBG_LOW("hash_page(ea=%016lx, access=%lx, trap=%lx\n",
>> ea, access, trap);
>> @@ -1033,12 +1037,40 @@ int hash_page(unsigned long ea, unsigned long access, unsigned long trap)
>>
>> /* Get PTE and page size from page tables */
>> ptep = find_linux_pte_or_hugepte(pgdir, ea, &hugeshift);
>> - if (ptep == NULL || !pte_present(*ptep) || pte_numa(*ptep)) {
>> + if (ptep == NULL || !pte_present(*ptep)) {
>> DBG_LOW(" no PTE !\n");
>> rc = 1;
>> goto bail;
>> }
>>
>> + old = pte_val(*ptep);
>> + if (pte_numa(old)) {
>> + /* If fail to lock, let do_page_fault() to handle it */
>> + if (down_read_trylock(&mm->mmap_sem)) {
>
> hmm is that something we want to do in hash_page ?
>
Yes, the function has no relation with hash. But I think it depends on
whether it is worth to optimize or not.
Thanks and regards,
Pingfan
>> + vma = find_vma(mm, ea);
>> + up_read(&mm->mmap_sem);
>> + test_page = pte_page(old);
>> + page_nid = page_to_nid(test_page);
>> + target_nid = numa_migrate_prep(test_page, vma, ea,
>> + page_nid);
>> + if (target_nid < 0) {
>> + new = pte_mknonnuma(old);
>> + /* If ptep is modified under us,
>> + * just retry the access
>> + */
>> + if (unlikely(cmpxchg(ptep, old, new) != old)) {
>> + put_page(test_page);
>> + return 0;
>> + }
>> + put_page(test_page);
>> + }
>> + } else {
>> + put_page(test_page);
>> + rc = 1;
>> + goto bail;
>> + }
>> + }
>> +
>> /* Add _PAGE_PRESENT to the required access perm */
>> access |= _PAGE_PRESENT;
>>
>
> -aneesh
>
^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [PATCH 1/3] powerpc: mm: make _PAGE_NUMA take effect
2013-12-05 10:53 ` Aneesh Kumar K.V
@ 2013-12-09 0:31 ` Benjamin Herrenschmidt
2013-12-09 6:17 ` Liu ping fan
2013-12-11 8:50 ` Liu ping fan
1 sibling, 1 reply; 13+ messages in thread
From: Benjamin Herrenschmidt @ 2013-12-09 0:31 UTC (permalink / raw)
To: Aneesh Kumar K.V; +Cc: Paul Mackerras, linuxppc-dev, Liu Ping Fan
On Thu, 2013-12-05 at 16:23 +0530, Aneesh Kumar K.V wrote:
> Liu Ping Fan <kernelfans@gmail.com> writes:
>
> > To enable the do_numa_page(), we should not fix _PAGE_NUMA in
> > hash_page(), so bail out for the case of pte_numa().
For some reason I don't have 2/3 and 3/3 in my mbox (though I do have
them on patchwork) so I'll reply to this one.
Overall, your statement that this is a faster path needs to be backed up
with numbers.
The code is complicated enough as it-is, such additional mess in the low
level hashing code requires a good justification, and also a
demonstration that it doesn't add overhead to the normal hash path.
Cheers,
Ben.
^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [PATCH 1/3] powerpc: mm: make _PAGE_NUMA take effect
2013-12-09 0:31 ` Benjamin Herrenschmidt
@ 2013-12-09 6:17 ` Liu ping fan
2013-12-09 6:19 ` Benjamin Herrenschmidt
0 siblings, 1 reply; 13+ messages in thread
From: Liu ping fan @ 2013-12-09 6:17 UTC (permalink / raw)
To: Benjamin Herrenschmidt; +Cc: Paul Mackerras, linuxppc-dev, Aneesh Kumar K.V
On Mon, Dec 9, 2013 at 8:31 AM, Benjamin Herrenschmidt
<benh@kernel.crashing.org> wrote:
> On Thu, 2013-12-05 at 16:23 +0530, Aneesh Kumar K.V wrote:
>> Liu Ping Fan <kernelfans@gmail.com> writes:
>>
>> > To enable the do_numa_page(), we should not fix _PAGE_NUMA in
>> > hash_page(), so bail out for the case of pte_numa().
>
> For some reason I don't have 2/3 and 3/3 in my mbox (though I do have
> them on patchwork) so I'll reply to this one.
>
> Overall, your statement that this is a faster path needs to be backed up
> with numbers.
>
> The code is complicated enough as it-is, such additional mess in the low
> level hashing code requires a good justification, and also a
> demonstration that it doesn't add overhead to the normal hash path.
>
For the test, is it ok to have an user application to copy page where
all page are PG_mlocked?
Thanks and regards,
Pingfan
^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [PATCH 1/3] powerpc: mm: make _PAGE_NUMA take effect
2013-12-09 6:17 ` Liu ping fan
@ 2013-12-09 6:19 ` Benjamin Herrenschmidt
0 siblings, 0 replies; 13+ messages in thread
From: Benjamin Herrenschmidt @ 2013-12-09 6:19 UTC (permalink / raw)
To: Liu ping fan; +Cc: Paul Mackerras, linuxppc-dev, Aneesh Kumar K.V
On Mon, 2013-12-09 at 14:17 +0800, Liu ping fan wrote:
> On Mon, Dec 9, 2013 at 8:31 AM, Benjamin Herrenschmidt
> <benh@kernel.crashing.org> wrote:
> > On Thu, 2013-12-05 at 16:23 +0530, Aneesh Kumar K.V wrote:
> >> Liu Ping Fan <kernelfans@gmail.com> writes:
> >>
> >> > To enable the do_numa_page(), we should not fix _PAGE_NUMA in
> >> > hash_page(), so bail out for the case of pte_numa().
> >
> > For some reason I don't have 2/3 and 3/3 in my mbox (though I do have
> > them on patchwork) so I'll reply to this one.
> >
> > Overall, your statement that this is a faster path needs to be backed up
> > with numbers.
> >
> > The code is complicated enough as it-is, such additional mess in the low
> > level hashing code requires a good justification, and also a
> > demonstration that it doesn't add overhead to the normal hash path.
> >
> For the test, is it ok to have an user application to copy page where
> all page are PG_mlocked?
If that specific scenario is relevant in practice, then yes, though also
demonstrate the lack of regression with some more normal path such as a
kernel compile.
Cheers,
Ben.
^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [PATCH 1/3] powerpc: mm: make _PAGE_NUMA take effect
2013-12-05 10:53 ` Aneesh Kumar K.V
2013-12-09 0:31 ` Benjamin Herrenschmidt
@ 2013-12-11 8:50 ` Liu ping fan
2013-12-11 9:50 ` Benjamin Herrenschmidt
1 sibling, 1 reply; 13+ messages in thread
From: Liu ping fan @ 2013-12-11 8:50 UTC (permalink / raw)
To: Aneesh Kumar K.V; +Cc: Paul Mackerras, linuxppc-dev
On Thu, Dec 5, 2013 at 6:53 PM, Aneesh Kumar K.V
<aneesh.kumar@linux.vnet.ibm.com> wrote:
> Liu Ping Fan <kernelfans@gmail.com> writes:
>
>> To enable the do_numa_page(), we should not fix _PAGE_NUMA in
>> hash_page(), so bail out for the case of pte_numa().
>>
>> Signed-off-by: Liu Ping Fan <pingfank@linux.vnet.ibm.com>
>> ---
>> arch/powerpc/mm/hash_utils_64.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
>> index fb176e9..9bf1195 100644
>> --- a/arch/powerpc/mm/hash_utils_64.c
>> +++ b/arch/powerpc/mm/hash_utils_64.c
>> @@ -1033,7 +1033,7 @@ int hash_page(unsigned long ea, unsigned long access, unsigned long trap)
>>
>> /* Get PTE and page size from page tables */
>> ptep = find_linux_pte_or_hugepte(pgdir, ea, &hugeshift);
>> - if (ptep == NULL || !pte_present(*ptep)) {
>> + if (ptep == NULL || !pte_present(*ptep) || pte_numa(*ptep)) {
>> DBG_LOW(" no PTE !\n");
>> rc = 1;
>> goto bail;
>
> why ? , All the hash routines do check for _PAGE_PRESENT via access
> variable.
>
Going through __hash_page_4K(4k on 4k HW), I do not find such check.
Am I wrong? Or I will send out a patch to fix that.
Thanks and regards,
Pingfan
> -aneesh
>
^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [PATCH 1/3] powerpc: mm: make _PAGE_NUMA take effect
2013-12-11 8:50 ` Liu ping fan
@ 2013-12-11 9:50 ` Benjamin Herrenschmidt
2013-12-12 2:19 ` Liu ping fan
0 siblings, 1 reply; 13+ messages in thread
From: Benjamin Herrenschmidt @ 2013-12-11 9:50 UTC (permalink / raw)
To: Liu ping fan; +Cc: linuxppc-dev, Paul Mackerras, Aneesh Kumar K.V
On Wed, 2013-12-11 at 16:50 +0800, Liu ping fan wrote:
> > why ? , All the hash routines do check for _PAGE_PRESENT via access
> > variable.
> >
> Going through __hash_page_4K(4k on 4k HW), I do not find such check.
> Am I wrong? Or I will send out a patch to fix that.
We pass a bitmask of flags to check which are tested by doing an "andc"
of the PTE on that mask and checking if anything is left...
Ben.
^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [PATCH 1/3] powerpc: mm: make _PAGE_NUMA take effect
2013-12-11 9:50 ` Benjamin Herrenschmidt
@ 2013-12-12 2:19 ` Liu ping fan
0 siblings, 0 replies; 13+ messages in thread
From: Liu ping fan @ 2013-12-12 2:19 UTC (permalink / raw)
To: Benjamin Herrenschmidt; +Cc: linuxppc-dev, Paul Mackerras, Aneesh Kumar K.V
On Wed, Dec 11, 2013 at 5:50 PM, Benjamin Herrenschmidt
<benh@kernel.crashing.org> wrote:
> On Wed, 2013-12-11 at 16:50 +0800, Liu ping fan wrote:
>> > why ? , All the hash routines do check for _PAGE_PRESENT via access
>> > variable.
>> >
>> Going through __hash_page_4K(4k on 4k HW), I do not find such check.
>> Am I wrong? Or I will send out a patch to fix that.
>
> We pass a bitmask of flags to check which are tested by doing an "andc"
> of the PTE on that mask and checking if anything is left...
>
Oh, see it, thank you very much
Regards,
Pingfan
^ permalink raw reply [flat|nested] 13+ messages in thread
end of thread, other threads:[~2013-12-12 2:19 UTC | newest]
Thread overview: 13+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2013-12-04 6:59 [PATCH 0/3] optimize for powerpc _PAGE_NUMA Liu Ping Fan
2013-12-04 6:59 ` [PATCH 1/3] powerpc: mm: make _PAGE_NUMA take effect Liu Ping Fan
2013-12-05 10:53 ` Aneesh Kumar K.V
2013-12-09 0:31 ` Benjamin Herrenschmidt
2013-12-09 6:17 ` Liu ping fan
2013-12-09 6:19 ` Benjamin Herrenschmidt
2013-12-11 8:50 ` Liu ping fan
2013-12-11 9:50 ` Benjamin Herrenschmidt
2013-12-12 2:19 ` Liu ping fan
2013-12-04 6:59 ` [PATCH 2/3] mm: export numa_migrate_prep() Liu Ping Fan
2013-12-04 6:59 ` [PATCH 3/3] powerpc: mm: optimize for the correctly placed page Liu Ping Fan
2013-12-05 10:58 ` Aneesh Kumar K.V
2013-12-05 13:27 ` Liu ping fan
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