enable PT_RECLAIM on more 64-bit architectures

[PATCH v4 7/8] mm: convert __HAVE_ARCH_TLB_REMOVE_TABLE to CONFIG_HAVE_ARCH_TLB_REMOVE_TABLE config

Posted by Qi Zheng 1 week, 5 days ago

From: Qi Zheng <zhengqi.arch@bytedance.com>

For architectures that define __HAVE_ARCH_TLB_REMOVE_TABLE, the page
tables at the pmd/pud level are generally not of struct ptdesc type, and
do not have pt_rcu_head member, thus these architectures cannot support
PT_RECLAIM.

In preparation for enabling PT_RECLAIM on more architectures, convert
__HAVE_ARCH_TLB_REMOVE_TABLE to CONFIG_HAVE_ARCH_TLB_REMOVE_TABLE config,
so that we can make conditional judgments in Kconfig.

Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
---
 arch/powerpc/Kconfig            | 1 +
 arch/powerpc/include/asm/tlb.h  | 1 -
 arch/sparc/Kconfig              | 1 +
 arch/sparc/include/asm/tlb_64.h | 1 -
 include/asm-generic/tlb.h       | 2 +-
 mm/Kconfig                      | 3 +++
 6 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 9537a61ebae02..b47aa8fd62742 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -304,6 +304,7 @@ config PPC
 	select LOCK_MM_AND_FIND_VMA
 	select MMU_GATHER_PAGE_SIZE
 	select MMU_GATHER_RCU_TABLE_FREE
+	select HAVE_ARCH_TLB_REMOVE_TABLE
 	select MMU_GATHER_MERGE_VMAS
 	select MMU_LAZY_TLB_SHOOTDOWN		if PPC_BOOK3S_64
 	select MODULES_USE_ELF_RELA
diff --git a/arch/powerpc/include/asm/tlb.h b/arch/powerpc/include/asm/tlb.h
index 2058e8d3e0138..1ca7d4c4b90db 100644
--- a/arch/powerpc/include/asm/tlb.h
+++ b/arch/powerpc/include/asm/tlb.h
@@ -37,7 +37,6 @@ extern void tlb_flush(struct mmu_gather *tlb);
  */
 #define tlb_needs_table_invalidate()	radix_enabled()
 
-#define __HAVE_ARCH_TLB_REMOVE_TABLE
 /* Get the generic bits... */
 #include <asm-generic/tlb.h>
 
diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig
index a630d373e6453..25fa2908d6152 100644
--- a/arch/sparc/Kconfig
+++ b/arch/sparc/Kconfig
@@ -74,6 +74,7 @@ config SPARC64
 	select HAVE_KRETPROBES
 	select HAVE_KPROBES
 	select MMU_GATHER_RCU_TABLE_FREE if SMP
+	select HAVE_ARCH_TLB_REMOVE_TABLE if SMP
 	select MMU_GATHER_MERGE_VMAS
 	select MMU_GATHER_NO_FLUSH_CACHE
 	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
diff --git a/arch/sparc/include/asm/tlb_64.h b/arch/sparc/include/asm/tlb_64.h
index 1a6e694418e39..3037187482db7 100644
--- a/arch/sparc/include/asm/tlb_64.h
+++ b/arch/sparc/include/asm/tlb_64.h
@@ -33,7 +33,6 @@ void flush_tlb_pending(void);
 #define tlb_needs_table_invalidate()	(false)
 #endif
 
-#define __HAVE_ARCH_TLB_REMOVE_TABLE
 #include <asm-generic/tlb.h>
 
 #endif /* _SPARC64_TLB_H */
diff --git a/include/asm-generic/tlb.h b/include/asm-generic/tlb.h
index 4d679d2a206b4..3427b8036ba33 100644
--- a/include/asm-generic/tlb.h
+++ b/include/asm-generic/tlb.h
@@ -213,7 +213,7 @@ struct mmu_table_batch {
 #define MAX_TABLE_BATCH		\
 	((PAGE_SIZE - sizeof(struct mmu_table_batch)) / sizeof(void *))
 
-#ifndef __HAVE_ARCH_TLB_REMOVE_TABLE
+#ifndef CONFIG_HAVE_ARCH_TLB_REMOVE_TABLE
 static inline void __tlb_remove_table(void *table)
 {
 	struct ptdesc *ptdesc = (struct ptdesc *)table;
diff --git a/mm/Kconfig b/mm/Kconfig
index a992f2203eb91..456e9eaedca39 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -1451,6 +1451,9 @@ config ARCH_HAS_USER_SHADOW_STACK
 	  The architecture has hardware support for userspace shadow call
           stacks (eg, x86 CET, arm64 GCS or RISC-V Zicfiss).
 
+config HAVE_ARCH_TLB_REMOVE_TABLE
+	def_bool n
+
 config ARCH_SUPPORTS_PT_RECLAIM
 	def_bool n
 
-- 
2.20.1

Re: [PATCH v4 7/8] mm: convert __HAVE_ARCH_TLB_REMOVE_TABLE to CONFIG_HAVE_ARCH_TLB_REMOVE_TABLE config

Posted by David Hildenbrand (Arm) 2 days, 21 hours ago

On 1/27/26 13:13, Qi Zheng wrote:
> From: Qi Zheng <zhengqi.arch@bytedance.com>
> 
> For architectures that define __HAVE_ARCH_TLB_REMOVE_TABLE, the page
> tables at the pmd/pud level are generally not of struct ptdesc type, and
> do not have pt_rcu_head member, thus these architectures cannot support
> PT_RECLAIM.
> 
> In preparation for enabling PT_RECLAIM on more architectures, convert
> __HAVE_ARCH_TLB_REMOVE_TABLE to CONFIG_HAVE_ARCH_TLB_REMOVE_TABLE config,
> so that we can make conditional judgments in Kconfig.
> 
> Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
> ---
>   arch/powerpc/Kconfig            | 1 +
>   arch/powerpc/include/asm/tlb.h  | 1 -
>   arch/sparc/Kconfig              | 1 +
>   arch/sparc/include/asm/tlb_64.h | 1 -
>   include/asm-generic/tlb.h       | 2 +-
>   mm/Kconfig                      | 3 +++
>   6 files changed, 6 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
> index 9537a61ebae02..b47aa8fd62742 100644
> --- a/arch/powerpc/Kconfig
> +++ b/arch/powerpc/Kconfig
> @@ -304,6 +304,7 @@ config PPC
>   	select LOCK_MM_AND_FIND_VMA
>   	select MMU_GATHER_PAGE_SIZE
>   	select MMU_GATHER_RCU_TABLE_FREE
> +	select HAVE_ARCH_TLB_REMOVE_TABLE
>   	select MMU_GATHER_MERGE_VMAS
>   	select MMU_LAZY_TLB_SHOOTDOWN		if PPC_BOOK3S_64
>   	select MODULES_USE_ELF_RELA
> diff --git a/arch/powerpc/include/asm/tlb.h b/arch/powerpc/include/asm/tlb.h
> index 2058e8d3e0138..1ca7d4c4b90db 100644
> --- a/arch/powerpc/include/asm/tlb.h
> +++ b/arch/powerpc/include/asm/tlb.h
> @@ -37,7 +37,6 @@ extern void tlb_flush(struct mmu_gather *tlb);
>    */
>   #define tlb_needs_table_invalidate()	radix_enabled()
>   
> -#define __HAVE_ARCH_TLB_REMOVE_TABLE
>   /* Get the generic bits... */
>   #include <asm-generic/tlb.h>
>   
> diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig
> index a630d373e6453..25fa2908d6152 100644
> --- a/arch/sparc/Kconfig
> +++ b/arch/sparc/Kconfig
> @@ -74,6 +74,7 @@ config SPARC64
>   	select HAVE_KRETPROBES
>   	select HAVE_KPROBES
>   	select MMU_GATHER_RCU_TABLE_FREE if SMP
> +	select HAVE_ARCH_TLB_REMOVE_TABLE if SMP

Why the SMP? At least in tlb_64.h, it was not protected by SMP IIUC.

Apart from that LGTM.

-- 
Cheers,

David

Re: [PATCH v4 7/8] mm: convert __HAVE_ARCH_TLB_REMOVE_TABLE to CONFIG_HAVE_ARCH_TLB_REMOVE_TABLE config

Posted by Qi Zheng 2 days, 20 hours ago


On 2/6/26 7:06 PM, David Hildenbrand (Arm) wrote:
> On 1/27/26 13:13, Qi Zheng wrote:
>> From: Qi Zheng <zhengqi.arch@bytedance.com>
>>
>> For architectures that define __HAVE_ARCH_TLB_REMOVE_TABLE, the page
>> tables at the pmd/pud level are generally not of struct ptdesc type, and
>> do not have pt_rcu_head member, thus these architectures cannot support
>> PT_RECLAIM.
>>
>> In preparation for enabling PT_RECLAIM on more architectures, convert
>> __HAVE_ARCH_TLB_REMOVE_TABLE to CONFIG_HAVE_ARCH_TLB_REMOVE_TABLE config,
>> so that we can make conditional judgments in Kconfig.
>>
>> Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
>> ---
>>   arch/powerpc/Kconfig            | 1 +
>>   arch/powerpc/include/asm/tlb.h  | 1 -
>>   arch/sparc/Kconfig              | 1 +
>>   arch/sparc/include/asm/tlb_64.h | 1 -
>>   include/asm-generic/tlb.h       | 2 +-
>>   mm/Kconfig                      | 3 +++
>>   6 files changed, 6 insertions(+), 3 deletions(-)
>>
>> diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
>> index 9537a61ebae02..b47aa8fd62742 100644
>> --- a/arch/powerpc/Kconfig
>> +++ b/arch/powerpc/Kconfig
>> @@ -304,6 +304,7 @@ config PPC
>>       select LOCK_MM_AND_FIND_VMA
>>       select MMU_GATHER_PAGE_SIZE
>>       select MMU_GATHER_RCU_TABLE_FREE
>> +    select HAVE_ARCH_TLB_REMOVE_TABLE
>>       select MMU_GATHER_MERGE_VMAS
>>       select MMU_LAZY_TLB_SHOOTDOWN        if PPC_BOOK3S_64
>>       select MODULES_USE_ELF_RELA
>> diff --git a/arch/powerpc/include/asm/tlb.h b/arch/powerpc/include/ 
>> asm/tlb.h
>> index 2058e8d3e0138..1ca7d4c4b90db 100644
>> --- a/arch/powerpc/include/asm/tlb.h
>> +++ b/arch/powerpc/include/asm/tlb.h
>> @@ -37,7 +37,6 @@ extern void tlb_flush(struct mmu_gather *tlb);
>>    */
>>   #define tlb_needs_table_invalidate()    radix_enabled()
>> -#define __HAVE_ARCH_TLB_REMOVE_TABLE
>>   /* Get the generic bits... */
>>   #include <asm-generic/tlb.h>
>> diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig
>> index a630d373e6453..25fa2908d6152 100644
>> --- a/arch/sparc/Kconfig
>> +++ b/arch/sparc/Kconfig
>> @@ -74,6 +74,7 @@ config SPARC64
>>       select HAVE_KRETPROBES
>>       select HAVE_KPROBES
>>       select MMU_GATHER_RCU_TABLE_FREE if SMP
>> +    select HAVE_ARCH_TLB_REMOVE_TABLE if SMP
> 
> Why the SMP? At least in tlb_64.h, it was not protected by SMP IIUC.

Ah, It's just simply aligned with the MMU_GATHER_RCU_TABLE_FREE above.

> 
> Apart from that LGTM.

Thanks!

>

Re: [PATCH v4 7/8] mm: convert __HAVE_ARCH_TLB_REMOVE_TABLE to CONFIG_HAVE_ARCH_TLB_REMOVE_TABLE config

Posted by David Hildenbrand (Arm) 2 days, 20 hours ago

On 2/6/26 12:13, Qi Zheng wrote:
> 
> 
> On 2/6/26 7:06 PM, David Hildenbrand (Arm) wrote:
>> On 1/27/26 13:13, Qi Zheng wrote:
>>> From: Qi Zheng <zhengqi.arch@bytedance.com>
>>>
>>> For architectures that define __HAVE_ARCH_TLB_REMOVE_TABLE, the page
>>> tables at the pmd/pud level are generally not of struct ptdesc type, and
>>> do not have pt_rcu_head member, thus these architectures cannot support
>>> PT_RECLAIM.
>>>
>>> In preparation for enabling PT_RECLAIM on more architectures, convert
>>> __HAVE_ARCH_TLB_REMOVE_TABLE to CONFIG_HAVE_ARCH_TLB_REMOVE_TABLE 
>>> config,
>>> so that we can make conditional judgments in Kconfig.
>>>
>>> Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
>>> ---
>>>   arch/powerpc/Kconfig            | 1 +
>>>   arch/powerpc/include/asm/tlb.h  | 1 -
>>>   arch/sparc/Kconfig              | 1 +
>>>   arch/sparc/include/asm/tlb_64.h | 1 -
>>>   include/asm-generic/tlb.h       | 2 +-
>>>   mm/Kconfig                      | 3 +++
>>>   6 files changed, 6 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
>>> index 9537a61ebae02..b47aa8fd62742 100644
>>> --- a/arch/powerpc/Kconfig
>>> +++ b/arch/powerpc/Kconfig
>>> @@ -304,6 +304,7 @@ config PPC
>>>       select LOCK_MM_AND_FIND_VMA
>>>       select MMU_GATHER_PAGE_SIZE
>>>       select MMU_GATHER_RCU_TABLE_FREE
>>> +    select HAVE_ARCH_TLB_REMOVE_TABLE
>>>       select MMU_GATHER_MERGE_VMAS
>>>       select MMU_LAZY_TLB_SHOOTDOWN        if PPC_BOOK3S_64
>>>       select MODULES_USE_ELF_RELA
>>> diff --git a/arch/powerpc/include/asm/tlb.h b/arch/powerpc/include/ 
>>> asm/tlb.h
>>> index 2058e8d3e0138..1ca7d4c4b90db 100644
>>> --- a/arch/powerpc/include/asm/tlb.h
>>> +++ b/arch/powerpc/include/asm/tlb.h
>>> @@ -37,7 +37,6 @@ extern void tlb_flush(struct mmu_gather *tlb);
>>>    */
>>>   #define tlb_needs_table_invalidate()    radix_enabled()
>>> -#define __HAVE_ARCH_TLB_REMOVE_TABLE
>>>   /* Get the generic bits... */
>>>   #include <asm-generic/tlb.h>
>>> diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig
>>> index a630d373e6453..25fa2908d6152 100644
>>> --- a/arch/sparc/Kconfig
>>> +++ b/arch/sparc/Kconfig
>>> @@ -74,6 +74,7 @@ config SPARC64
>>>       select HAVE_KRETPROBES
>>>       select HAVE_KPROBES
>>>       select MMU_GATHER_RCU_TABLE_FREE if SMP
>>> +    select HAVE_ARCH_TLB_REMOVE_TABLE if SMP
>>
>> Why the SMP? At least in tlb_64.h, it was not protected by SMP IIUC.
> 
> Ah, It's just simply aligned with the MMU_GATHER_RCU_TABLE_FREE above.

But does that work as expected for !SMP?

-- 
Cheers,

David

Re: [PATCH v4 7/8] mm: convert __HAVE_ARCH_TLB_REMOVE_TABLE to CONFIG_HAVE_ARCH_TLB_REMOVE_TABLE config

Posted by Qi Zheng 2 days, 20 hours ago


On 2/6/26 7:45 PM, David Hildenbrand (Arm) wrote:
> On 2/6/26 12:13, Qi Zheng wrote:
>>
>>
>> On 2/6/26 7:06 PM, David Hildenbrand (Arm) wrote:
>>> On 1/27/26 13:13, Qi Zheng wrote:
>>>> From: Qi Zheng <zhengqi.arch@bytedance.com>
>>>>
>>>> For architectures that define __HAVE_ARCH_TLB_REMOVE_TABLE, the page
>>>> tables at the pmd/pud level are generally not of struct ptdesc type, 
>>>> and
>>>> do not have pt_rcu_head member, thus these architectures cannot support
>>>> PT_RECLAIM.
>>>>
>>>> In preparation for enabling PT_RECLAIM on more architectures, convert
>>>> __HAVE_ARCH_TLB_REMOVE_TABLE to CONFIG_HAVE_ARCH_TLB_REMOVE_TABLE 
>>>> config,
>>>> so that we can make conditional judgments in Kconfig.
>>>>
>>>> Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
>>>> ---
>>>>   arch/powerpc/Kconfig            | 1 +
>>>>   arch/powerpc/include/asm/tlb.h  | 1 -
>>>>   arch/sparc/Kconfig              | 1 +
>>>>   arch/sparc/include/asm/tlb_64.h | 1 -
>>>>   include/asm-generic/tlb.h       | 2 +-
>>>>   mm/Kconfig                      | 3 +++
>>>>   6 files changed, 6 insertions(+), 3 deletions(-)
>>>>
>>>> diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
>>>> index 9537a61ebae02..b47aa8fd62742 100644
>>>> --- a/arch/powerpc/Kconfig
>>>> +++ b/arch/powerpc/Kconfig
>>>> @@ -304,6 +304,7 @@ config PPC
>>>>       select LOCK_MM_AND_FIND_VMA
>>>>       select MMU_GATHER_PAGE_SIZE
>>>>       select MMU_GATHER_RCU_TABLE_FREE
>>>> +    select HAVE_ARCH_TLB_REMOVE_TABLE
>>>>       select MMU_GATHER_MERGE_VMAS
>>>>       select MMU_LAZY_TLB_SHOOTDOWN        if PPC_BOOK3S_64
>>>>       select MODULES_USE_ELF_RELA
>>>> diff --git a/arch/powerpc/include/asm/tlb.h b/arch/powerpc/include/ 
>>>> asm/tlb.h
>>>> index 2058e8d3e0138..1ca7d4c4b90db 100644
>>>> --- a/arch/powerpc/include/asm/tlb.h
>>>> +++ b/arch/powerpc/include/asm/tlb.h
>>>> @@ -37,7 +37,6 @@ extern void tlb_flush(struct mmu_gather *tlb);
>>>>    */
>>>>   #define tlb_needs_table_invalidate()    radix_enabled()
>>>> -#define __HAVE_ARCH_TLB_REMOVE_TABLE
>>>>   /* Get the generic bits... */
>>>>   #include <asm-generic/tlb.h>
>>>> diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig
>>>> index a630d373e6453..25fa2908d6152 100644
>>>> --- a/arch/sparc/Kconfig
>>>> +++ b/arch/sparc/Kconfig
>>>> @@ -74,6 +74,7 @@ config SPARC64
>>>>       select HAVE_KRETPROBES
>>>>       select HAVE_KPROBES
>>>>       select MMU_GATHER_RCU_TABLE_FREE if SMP
>>>> +    select HAVE_ARCH_TLB_REMOVE_TABLE if SMP
>>>
>>> Why the SMP? At least in tlb_64.h, it was not protected by SMP IIUC.
>>
>> Ah, It's just simply aligned with the MMU_GATHER_RCU_TABLE_FREE above.
> 
> But does that work as expected for !SMP?

In the case of !SMP, tlb_remove_table() will not be called:

static inline void pgtable_free_tlb(struct mmu_gather *tlb, void *table, 
bool is_page)
{
	pgtable_free(table, is_page);
}


so I think it's okay to only select it in case of SMP.

>

Re: [PATCH v4 7/8] mm: convert __HAVE_ARCH_TLB_REMOVE_TABLE to CONFIG_HAVE_ARCH_TLB_REMOVE_TABLE config

Posted by David Hildenbrand (Arm) 2 days, 19 hours ago

On 2/6/26 12:58, Qi Zheng wrote:
> 
> 
> On 2/6/26 7:45 PM, David Hildenbrand (Arm) wrote:
>> On 2/6/26 12:13, Qi Zheng wrote:
>>>
>>>
>>>
>>> Ah, It's just simply aligned with the MMU_GATHER_RCU_TABLE_FREE above.
>>
>> But does that work as expected for !SMP?
> 
> In the case of !SMP, tlb_remove_table() will not be called:
> 
> static inline void pgtable_free_tlb(struct mmu_gather *tlb, void *table, 
> bool is_page)
> {
>      pgtable_free(table, is_page);
> }

Ah, okay. Confusing stuff. Would have been nice to document/mention that 
in the patch description.

So if it compiles, all good

Acked-by: David Hildenbrand (Arm) <david@kernel.org>

-- 
Cheers,

David

Re: [PATCH v4 7/8] mm: convert __HAVE_ARCH_TLB_REMOVE_TABLE to CONFIG_HAVE_ARCH_TLB_REMOVE_TABLE config

Posted by Andreas Larsson 2 days, 18 hours ago

On 2026-02-06 13:59, David Hildenbrand (Arm) wrote:
> On 2/6/26 12:58, Qi Zheng wrote:
>>
>>
>> On 2/6/26 7:45 PM, David Hildenbrand (Arm) wrote:
>>> On 2/6/26 12:13, Qi Zheng wrote:
>>>>
>>>>
>>>>
>>>> Ah, It's just simply aligned with the MMU_GATHER_RCU_TABLE_FREE above.
>>>
>>> But does that work as expected for !SMP?
>>
>> In the case of !SMP, tlb_remove_table() will not be called:
>>
>> static inline void pgtable_free_tlb(struct mmu_gather *tlb, void *table, bool is_page)
>> {
>>      pgtable_free(table, is_page);
>> }
> 
> Ah, okay. Confusing stuff. Would have been nice to document/mention that in the patch description.
> 
> So if it compiles, all good
> 
> Acked-by: David Hildenbrand (Arm) <david@kernel.org>
> 

It looks a bit weird, but it is actually more logically correct than
before the patch. Before this in the !SMP sparc64 case
__HAVE_ARCH_TLB_REMOVE_TABLE was defined even with no actual
__tlb_remove_table() present. But it did not matter in practice.
But I agree that a mention would not hurt.

Tested both with SMP and !SMP

Tested-by: Andreas Larsson <andreas@gaisler.com> #sparc
Acked-by: Andreas Larsson <andreas@gaisler.com> #sparc

Cheers,
Andreas