linux-kernel - [RFC PATCH] mm: Enable CONFIG_PT

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Message-Id: <20251103063718.90743-1-dev.jain@arm.com>
Date: Mon,  3 Nov 2025 12:07:18 +0530
From: Dev Jain <dev.jain@....com>
To: tglx@...utronix.de,
	mingo@...hat.com,
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	Dev Jain <dev.jain@....com>
Subject: [RFC PATCH] mm: Enable CONFIG_PT_RECLAIM on all architectures

The implementation of CONFIG_PT_RECLAIM is completely contained in generic
mm code. It depends on the RCU callback which will reclaim the pagetables -
there is nothing arch-specific about that. So, enable this config for
all architectures.

Signed-off-by: Dev Jain <dev.jain@....com>
---
 arch/x86/Kconfig | 1 -
 mm/Kconfig       | 5 +----
 mm/pt_reclaim.c  | 2 +-
 3 files changed, 2 insertions(+), 6 deletions(-)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index fa3b616af03a..5681308a5650 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -327,7 +327,6 @@ config X86
 	select FUNCTION_ALIGNMENT_4B
 	imply IMA_SECURE_AND_OR_TRUSTED_BOOT    if EFI
 	select HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
-	select ARCH_SUPPORTS_PT_RECLAIM		if X86_64
 	select ARCH_SUPPORTS_SCHED_SMT		if SMP
 	select SCHED_SMT			if SMP
 	select ARCH_SUPPORTS_SCHED_CLUSTER	if SMP
diff --git a/mm/Kconfig b/mm/Kconfig
index 0e26f4fc8717..903c37d02555 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -1355,13 +1355,10 @@ 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 ARCH_SUPPORTS_PT_RECLAIM
-	def_bool n
-
 config PT_RECLAIM
 	bool "reclaim empty user page table pages"
 	default y
-	depends on ARCH_SUPPORTS_PT_RECLAIM && MMU && SMP
+	depends on MMU && SMP
 	select MMU_GATHER_RCU_TABLE_FREE
 	help
 	  Try to reclaim empty user page table pages in paths other than munmap
diff --git a/mm/pt_reclaim.c b/mm/pt_reclaim.c
index 7e9455a18aae..049e17f08c6a 100644
--- a/mm/pt_reclaim.c
+++ b/mm/pt_reclaim.c
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0
 #include <linux/hugetlb.h>
-#include <asm-generic/tlb.h>
+#include <asm/tlb.h>
 #include <asm/pgalloc.h>
 
 #include "internal.h"
-- 
2.30.2