linux-kernel - Re: [PATCH v4 7/8] mm: convert __HAVE_ARCH_TLB_REMOVE_TABLE to CONFIG_HAVE_ARCH_TLB_REMOVE

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Message-ID: <a404e9ec-35ff-44b1-b321-9cc4fbf72060@kernel.org>
Date: Fri, 6 Feb 2026 12:06:29 +0100
From: "David Hildenbrand (Arm)" <david@...nel.org>
To: Qi Zheng <qi.zheng@...ux.dev>, andreas@...sler.com,
 richard.weiyang@...il.com, will@...nel.org, peterz@...radead.org,
 aneesh.kumar@...nel.org, npiggin@...il.com, dev.jain@....com,
 ioworker0@...il.com, linmag7@...il.com, akpm@...ux-foundation.org
Cc: linux-arch@...r.kernel.org, linux-kernel@...r.kernel.org,
 linux-mm@...ck.org, linux-alpha@...r.kernel.org, loongarch@...ts.linux.dev,
 linux-mips@...r.kernel.org, linux-parisc@...r.kernel.org,
 linux-um@...ts.infradead.org, sparclinux@...r.kernel.org,
 Qi Zheng <zhengqi.arch@...edance.com>
Subject: Re: [PATCH v4 7/8] mm: convert __HAVE_ARCH_TLB_REMOVE_TABLE to
 CONFIG_HAVE_ARCH_TLB_REMOVE_TABLE config

On 1/27/26 13:13, Qi Zheng wrote:
> From: Qi Zheng <zhengqi.arch@...edance.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@...edance.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