+ loongarch-mm-enable-mmu_gather_rcu_table_free.patch added to mm-new branch

+ loongarch-mm-enable-mmu_gather_rcu_table_free.patch added to mm-new branch

[Andrew Morton]

The patch titled
     Subject: LoongArch: mm: enable MMU_GATHER_RCU_TABLE_FREE
has been added to the -mm mm-new branch.  Its filename is
     loongarch-mm-enable-mmu_gather_rcu_table_free.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/loongarch-mm-enable-mmu_gather_rcu_table_free.patch

This patch will later appear in the mm-new branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Note, mm-new is a provisional staging ground for work-in-progress
patches, and acceptance into mm-new is a notification for others take
notice and to finish up reviews.  Please do not hesitate to respond to
review feedback and post updated versions to replace or incrementally
fixup patches in mm-new.

The mm-new branch of mm.git is not included in linux-next

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------------------------------------------------------
From: Qi Zheng <zhengqi.arch@bytedance.com>
Subject: LoongArch: mm: enable MMU_GATHER_RCU_TABLE_FREE
Date: Wed, 17 Dec 2025 17:45:44 +0800

On a 64-bit system, madvise(MADV_DONTNEED) may cause a large number of
empty PTE page table pages (such as 100GB+).  To resolve this problem,
first enable MMU_GATHER_RCU_TABLE_FREE to prepare for enabling the
PT_RECLAIM feature, which resolves this problem.

Link: https://lkml.kernel.org/r/dae0a0b490e912273a62a49be9d92f470fbcaf04.1765963770.git.zhengqi.arch@bytedance.com
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: WANG Xuerui <kernel@xen0n.name>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@kernel.org>
Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Cc: David Hildenbrand (Red Hat) <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Lance Yang <ioworker0@gmail.com>
Cc: Magnus Lindholm <linmag7@gmail.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Richard Henderson <richard.henderson@linaro.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 arch/loongarch/Kconfig               |    1 +
 arch/loongarch/include/asm/pgalloc.h |    7 +++----
 2 files changed, 4 insertions(+), 4 deletions(-)

--- a/arch/loongarch/include/asm/pgalloc.h~loongarch-mm-enable-mmu_gather_rcu_table_free
+++ a/arch/loongarch/include/asm/pgalloc.h
@@ -55,8 +55,7 @@ static inline pte_t *pte_alloc_one_kerne
 	return pte;
 }
 
-#define __pte_free_tlb(tlb, pte, address)	\
-	tlb_remove_ptdesc((tlb), page_ptdesc(pte))
+#define __pte_free_tlb(tlb, pte, address)	tlb_remove_ptdesc((tlb), page_ptdesc(pte))
 
 #ifndef __PAGETABLE_PMD_FOLDED
 
@@ -79,7 +78,7 @@ static inline pmd_t *pmd_alloc_one(struc
 	return pmd;
 }
 
-#define __pmd_free_tlb(tlb, x, addr)	pmd_free((tlb)->mm, x)
+#define __pmd_free_tlb(tlb, x, addr)	tlb_remove_ptdesc((tlb), virt_to_ptdesc(x))
 
 #endif
 
@@ -99,7 +98,7 @@ static inline pud_t *pud_alloc_one(struc
 	return pud;
 }
 
-#define __pud_free_tlb(tlb, x, addr)	pud_free((tlb)->mm, x)
+#define __pud_free_tlb(tlb, x, addr)	tlb_remove_ptdesc((tlb), virt_to_ptdesc(x))
 
 #endif /* __PAGETABLE_PUD_FOLDED */
 
--- a/arch/loongarch/Kconfig~loongarch-mm-enable-mmu_gather_rcu_table_free
+++ a/arch/loongarch/Kconfig
@@ -187,6 +187,7 @@ config LOONGARCH
 	select IRQ_LOONGARCH_CPU
 	select LOCK_MM_AND_FIND_VMA
 	select MMU_GATHER_MERGE_VMAS if MMU
+	select MMU_GATHER_RCU_TABLE_FREE
 	select MODULES_USE_ELF_RELA if MODULES
 	select NEED_PER_CPU_EMBED_FIRST_CHUNK
 	select NEED_PER_CPU_PAGE_FIRST_CHUNK
_

Patches currently in -mm which might be from zhengqi.arch@bytedance.com are

mm-change-mm-pt_reclaimc-to-use-asm-tlbh-instead-of-asm-generic-tlbh.patch
alpha-mm-enable-mmu_gather_rcu_table_free.patch
loongarch-mm-enable-mmu_gather_rcu_table_free.patch
mips-mm-enable-mmu_gather_rcu_table_free.patch
parisc-mm-enable-mmu_gather_rcu_table_free.patch
um-mm-enable-mmu_gather_rcu_table_free.patch
mm-make-pt_reclaim-depends-on-mmu_gather_rcu_table_free.patch