* [PATCH -next] riscv: TRANSPARENT_HUGEPAGE: depends on MMU
@ 2021-05-25 0:13 Randy Dunlap
2021-05-25 10:33 ` Mike Rapoport
0 siblings, 1 reply; 4+ messages in thread
From: Randy Dunlap @ 2021-05-25 0:13 UTC (permalink / raw)
To: linux-mm
Cc: Randy Dunlap, Paul Walmsley, Palmer Dabbelt, Albert Ou,
linux-riscv, Andrew Morton, Nanyong Sun
Fix a Kconfig warning and many build errors:
WARNING: unmet direct dependencies detected for COMPACTION
Depends on [n]: MMU [=n]
Selected by [y]:
- TRANSPARENT_HUGEPAGE [=y] && HAVE_ARCH_TRANSPARENT_HUGEPAGE [=y]
and the subseqent thousands of build errors and warnings.
Fixes: e88b333142e4 ("riscv: mm: add THP support on 64-bit")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: linux-riscv@lists.infradead.org
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Nanyong Sun <sunnanyong@huawei.com>
---
I really think that mm/Kconfig should have "depends on MMU" for
TRANSPARENT_HUGEPAGE, but commit 15626062f4a9 from 2012
("thp, x86: introduce HAVE_ARCH_TRANSPARENT_HUGEPAGE") thought
differently. I.e., mm/Kconfig should be protecting all arches
against this Kconfig problem.
arch/riscv/Kconfig | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- linux-next-20210524.orig/arch/riscv/Kconfig
+++ linux-next-20210524/arch/riscv/Kconfig
@@ -106,7 +106,7 @@ config RISCV
select SYSCTL_EXCEPTION_TRACE
select THREAD_INFO_IN_TASK
select UACCESS_MEMCPY if !MMU
- select HAVE_ARCH_TRANSPARENT_HUGEPAGE if 64BIT
+ select HAVE_ARCH_TRANSPARENT_HUGEPAGE if 64BIT && MMU
config ARCH_MMAP_RND_BITS_MIN
default 18 if 64BIT
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH -next] riscv: TRANSPARENT_HUGEPAGE: depends on MMU
2021-05-25 0:13 [PATCH -next] riscv: TRANSPARENT_HUGEPAGE: depends on MMU Randy Dunlap
@ 2021-05-25 10:33 ` Mike Rapoport
2021-05-25 15:40 ` Randy Dunlap
0 siblings, 1 reply; 4+ messages in thread
From: Mike Rapoport @ 2021-05-25 10:33 UTC (permalink / raw)
To: Randy Dunlap
Cc: linux-mm, Paul Walmsley, Palmer Dabbelt, Albert Ou, linux-riscv,
Andrew Morton, Nanyong Sun
On Mon, May 24, 2021 at 05:13:02PM -0700, Randy Dunlap wrote:
> Fix a Kconfig warning and many build errors:
>
> WARNING: unmet direct dependencies detected for COMPACTION
> Depends on [n]: MMU [=n]
> Selected by [y]:
> - TRANSPARENT_HUGEPAGE [=y] && HAVE_ARCH_TRANSPARENT_HUGEPAGE [=y]
>
> and the subseqent thousands of build errors and warnings.
>
> Fixes: e88b333142e4 ("riscv: mm: add THP support on 64-bit")
> Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
> Cc: Paul Walmsley <paul.walmsley@sifive.com>
> Cc: Palmer Dabbelt <palmer@dabbelt.com>
> Cc: Albert Ou <aou@eecs.berkeley.edu>
> Cc: linux-riscv@lists.infradead.org
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Nanyong Sun <sunnanyong@huawei.com>
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
> ---
> I really think that mm/Kconfig should have "depends on MMU" for
> TRANSPARENT_HUGEPAGE, but commit 15626062f4a9 from 2012
> ("thp, x86: introduce HAVE_ARCH_TRANSPARENT_HUGEPAGE") thought
> differently. I.e., mm/Kconfig should be protecting all arches
> against this Kconfig problem.
We could
diff --git a/mm/Kconfig b/mm/Kconfig
index 02d44e3420f5..85bc8bf32e7b 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -403,7 +403,7 @@ config NOMMU_INITIAL_TRIM_EXCESS
config TRANSPARENT_HUGEPAGE
bool "Transparent Hugepage Support"
- depends on HAVE_ARCH_TRANSPARENT_HUGEPAGE
+ depends on MMU && HAVE_ARCH_TRANSPARENT_HUGEPAGE
select COMPACTION
select XARRAY_MULTI
help
but in a sense HAVE_ARCH_TRANSPARENT_HUGEPAGE should imply that MMU is
selected :)
> arch/riscv/Kconfig | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> --- linux-next-20210524.orig/arch/riscv/Kconfig
> +++ linux-next-20210524/arch/riscv/Kconfig
> @@ -106,7 +106,7 @@ config RISCV
> select SYSCTL_EXCEPTION_TRACE
> select THREAD_INFO_IN_TASK
> select UACCESS_MEMCPY if !MMU
> - select HAVE_ARCH_TRANSPARENT_HUGEPAGE if 64BIT
> + select HAVE_ARCH_TRANSPARENT_HUGEPAGE if 64BIT && MMU
>
> config ARCH_MMAP_RND_BITS_MIN
> default 18 if 64BIT
>
--
Sincerely yours,
Mike.
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH -next] riscv: TRANSPARENT_HUGEPAGE: depends on MMU
2021-05-25 10:33 ` Mike Rapoport
@ 2021-05-25 15:40 ` Randy Dunlap
2021-05-29 23:08 ` Palmer Dabbelt
0 siblings, 1 reply; 4+ messages in thread
From: Randy Dunlap @ 2021-05-25 15:40 UTC (permalink / raw)
To: Mike Rapoport
Cc: linux-mm, Paul Walmsley, Palmer Dabbelt, Albert Ou, linux-riscv,
Andrew Morton, Nanyong Sun
On 5/25/21 3:33 AM, Mike Rapoport wrote:
> On Mon, May 24, 2021 at 05:13:02PM -0700, Randy Dunlap wrote:
>> Fix a Kconfig warning and many build errors:
>>
>> WARNING: unmet direct dependencies detected for COMPACTION
>> Depends on [n]: MMU [=n]
>> Selected by [y]:
>> - TRANSPARENT_HUGEPAGE [=y] && HAVE_ARCH_TRANSPARENT_HUGEPAGE [=y]
>>
>> and the subseqent thousands of build errors and warnings.
>>
>> Fixes: e88b333142e4 ("riscv: mm: add THP support on 64-bit")
>> Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
>> Cc: Paul Walmsley <paul.walmsley@sifive.com>
>> Cc: Palmer Dabbelt <palmer@dabbelt.com>
>> Cc: Albert Ou <aou@eecs.berkeley.edu>
>> Cc: linux-riscv@lists.infradead.org
>> Cc: Andrew Morton <akpm@linux-foundation.org>
>> Cc: Nanyong Sun <sunnanyong@huawei.com>
>
> Acked-by: Mike Rapoport <rppt@linux.ibm.com>
>
>> ---
>> I really think that mm/Kconfig should have "depends on MMU" for
>> TRANSPARENT_HUGEPAGE, but commit 15626062f4a9 from 2012
>> ("thp, x86: introduce HAVE_ARCH_TRANSPARENT_HUGEPAGE") thought
>> differently. I.e., mm/Kconfig should be protecting all arches
>> against this Kconfig problem.
>
> We could
>
> diff --git a/mm/Kconfig b/mm/Kconfig
> index 02d44e3420f5..85bc8bf32e7b 100644
> --- a/mm/Kconfig
> +++ b/mm/Kconfig
> @@ -403,7 +403,7 @@ config NOMMU_INITIAL_TRIM_EXCESS
>
> config TRANSPARENT_HUGEPAGE
> bool "Transparent Hugepage Support"
> - depends on HAVE_ARCH_TRANSPARENT_HUGEPAGE
> + depends on MMU && HAVE_ARCH_TRANSPARENT_HUGEPAGE
> select COMPACTION
> select XARRAY_MULTI
> help
>
> but in a sense HAVE_ARCH_TRANSPARENT_HUGEPAGE should imply that MMU is
> selected :)
Yes, I had this patch before the one that I sent but decided against it
based on history.
>> arch/riscv/Kconfig | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> --- linux-next-20210524.orig/arch/riscv/Kconfig
>> +++ linux-next-20210524/arch/riscv/Kconfig
>> @@ -106,7 +106,7 @@ config RISCV
>> select SYSCTL_EXCEPTION_TRACE
>> select THREAD_INFO_IN_TASK
>> select UACCESS_MEMCPY if !MMU
>> - select HAVE_ARCH_TRANSPARENT_HUGEPAGE if 64BIT
>> + select HAVE_ARCH_TRANSPARENT_HUGEPAGE if 64BIT && MMU
>>
>> config ARCH_MMAP_RND_BITS_MIN
>> default 18 if 64BIT
>>
>
thanks.
--
~Randy
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH -next] riscv: TRANSPARENT_HUGEPAGE: depends on MMU
2021-05-25 15:40 ` Randy Dunlap
@ 2021-05-29 23:08 ` Palmer Dabbelt
0 siblings, 0 replies; 4+ messages in thread
From: Palmer Dabbelt @ 2021-05-29 23:08 UTC (permalink / raw)
To: rdunlap, rppt; +Cc: linux-mm, Paul Walmsley, aou, linux-riscv, akpm, sunnanyong
On Tue, 25 May 2021 08:40:10 PDT (-0700), rdunlap@infradead.org wrote:
> On 5/25/21 3:33 AM, Mike Rapoport wrote:
>> On Mon, May 24, 2021 at 05:13:02PM -0700, Randy Dunlap wrote:
>>> Fix a Kconfig warning and many build errors:
>>>
>>> WARNING: unmet direct dependencies detected for COMPACTION
>>> Depends on [n]: MMU [=n]
>>> Selected by [y]:
>>> - TRANSPARENT_HUGEPAGE [=y] && HAVE_ARCH_TRANSPARENT_HUGEPAGE [=y]
>>>
>>> and the subseqent thousands of build errors and warnings.
>>>
>>> Fixes: e88b333142e4 ("riscv: mm: add THP support on 64-bit")
>>> Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
>>> Cc: Paul Walmsley <paul.walmsley@sifive.com>
>>> Cc: Palmer Dabbelt <palmer@dabbelt.com>
>>> Cc: Albert Ou <aou@eecs.berkeley.edu>
>>> Cc: linux-riscv@lists.infradead.org
>>> Cc: Andrew Morton <akpm@linux-foundation.org>
>>> Cc: Nanyong Sun <sunnanyong@huawei.com>
>>
>> Acked-by: Mike Rapoport <rppt@linux.ibm.com>
>>
>>> ---
>>> I really think that mm/Kconfig should have "depends on MMU" for
>>> TRANSPARENT_HUGEPAGE, but commit 15626062f4a9 from 2012
>>> ("thp, x86: introduce HAVE_ARCH_TRANSPARENT_HUGEPAGE") thought
>>> differently. I.e., mm/Kconfig should be protecting all arches
>>> against this Kconfig problem.
>>
>> We could
>>
>> diff --git a/mm/Kconfig b/mm/Kconfig
>> index 02d44e3420f5..85bc8bf32e7b 100644
>> --- a/mm/Kconfig
>> +++ b/mm/Kconfig
>> @@ -403,7 +403,7 @@ config NOMMU_INITIAL_TRIM_EXCESS
>>
>> config TRANSPARENT_HUGEPAGE
>> bool "Transparent Hugepage Support"
>> - depends on HAVE_ARCH_TRANSPARENT_HUGEPAGE
>> + depends on MMU && HAVE_ARCH_TRANSPARENT_HUGEPAGE
>> select COMPACTION
>> select XARRAY_MULTI
>> help
>>
>> but in a sense HAVE_ARCH_TRANSPARENT_HUGEPAGE should imply that MMU is
>> selected :)
>
> Yes, I had this patch before the one that I sent but decided against it
> based on history.
IMO 15626062f4a9 ("thp, x86: introduce HAVE_ARCH_TRANSPARENT_HUGEPAGE")
is really saying "the arches that have transparent huge pages are MMU=y,
so we don't need the extra check". That seems reasonable as of when the
code landed, and while arm has MMU=n and THP it already depends on MMU
(via ARM_LPAE, which seems kind of natural there).
The generic version seems fine to me, but I'm going to take this one now
so we can avoid the build issues.
>>> arch/riscv/Kconfig | 2 +-
>>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> --- linux-next-20210524.orig/arch/riscv/Kconfig
>>> +++ linux-next-20210524/arch/riscv/Kconfig
>>> @@ -106,7 +106,7 @@ config RISCV
>>> select SYSCTL_EXCEPTION_TRACE
>>> select THREAD_INFO_IN_TASK
>>> select UACCESS_MEMCPY if !MMU
>>> - select HAVE_ARCH_TRANSPARENT_HUGEPAGE if 64BIT
>>> + select HAVE_ARCH_TRANSPARENT_HUGEPAGE if 64BIT && MMU
>>>
>>> config ARCH_MMAP_RND_BITS_MIN
>>> default 18 if 64BIT
>>>
>>
>
> thanks.
^ permalink raw reply [flat|nested] 4+ messages in thread
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