[PATCH v2 06/12] mm: enable MMU_GATHER_RCU_TABLE_FREE for sparc64
From: "Lorenzo Stoakes (ARM)" <ljs@kernel.org>
Date: 2026-09-08 12:35:07
Also in:
linux-alpha, linux-m68k, linux-mips, linux-mm, linux-riscv, linux-s390, linux-sh, linux-um, linuxppc-dev, lkml, loongarch, sparclinux
Subsystem:
sparc + ultrasparc (sparc/sparc64), the rest · Maintainers:
"David S. Miller", Andreas Larsson, Linus Torvalds
Commit 4a0100f7546f ("sparc64: use RCU page table freeing") enabled
CONFIG_MMU_GATHER_RCU_TABLE_FREE for SMP sparc64 architectures, expressly
for GUP-fast page table walkers.
Naturally, UP systems do not have to worry about concurrent GUP fast
operations.
However, CONFIG_PREEMPT_RCU is also available even on a UP system, so a
future pure-RCU page table walker requires MMU_GATHER_RCU_TABLE_FREE to be
enabled on UP, even if concurrent GUP fast is not possible there.
To enable future pure-RCU page table walkers, enable
MMU_GATHER_RCU_TABLE_FREE unconditionally.
With this change, it is no longer necessary to have !CONFIG_SMP
pgtable_free_tlb(), so also remove this now dead code.
This forms part of an overall effort to switch every architecture to this
mode.
Signed-off-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
---
arch/sparc/Kconfig | 4 ++--
arch/sparc/include/asm/pgalloc_64.h | 8 --------
2 files changed, 2 insertions(+), 10 deletions(-)
diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig
index ab77d3f2536e..8d42ebc6d302 100644
--- a/arch/sparc/Kconfig
+++ b/arch/sparc/Kconfig@@ -75,8 +75,8 @@ config SPARC64 select HAVE_FUNCTION_GRAPH_TRACER 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_RCU_TABLE_FREE + select HAVE_ARCH_TLB_REMOVE_TABLE select MMU_GATHER_MERGE_VMAS select MMU_GATHER_NO_FLUSH_CACHE select HAVE_ARCH_TRANSPARENT_HUGEPAGE
diff --git a/arch/sparc/include/asm/pgalloc_64.h b/arch/sparc/include/asm/pgalloc_64.h
index caa7632be4c2..b5055d259b74 100644
--- a/arch/sparc/include/asm/pgalloc_64.h
+++ b/arch/sparc/include/asm/pgalloc_64.h@@ -74,8 +74,6 @@ void pte_free_defer(struct mm_struct *mm, pgtable_t pgtable); void pgtable_free(void *table, bool is_page); -#ifdef CONFIG_SMP - struct mmu_gather; void tlb_remove_table(struct mmu_gather *, void *);
@@ -96,12 +94,6 @@ static inline void __tlb_remove_table(void *_table) is_page = true; pgtable_free(table, is_page); } -#else /* CONFIG_SMP */ -static inline void pgtable_free_tlb(struct mmu_gather *tlb, void *table, bool is_page) -{ - pgtable_free(table, is_page); -} -#endif /* !CONFIG_SMP */ static inline void __pte_free_tlb(struct mmu_gather *tlb, pte_t *pte, unsigned long address)
--
2.55.0