From: sashiko-bot@kernel.org
To: "Lorenzo Stoakes (ARM)" <ljs@kernel.org>
Cc: "Alexander Gordeev" <agordeev@linux.ibm.com>,
linux-s390@vger.kernel.org,
"Christian Borntraeger" <borntraeger@linux.ibm.com>,
"Vasily Gorbik" <gor@linux.ibm.com>,
"Heiko Carstens" <hca@linux.ibm.com>
Subject: Re: [PATCH 03/12] mm: enable MMU_GATHER_RCU_TABLE_FREE for MMU riscv
Date: Tue, 01 Sep 2026 11:14:39 +0000 [thread overview]
Message-ID: <20260901111439.D6B9C1F000E9@smtp.kernel.org> (raw)
In-Reply-To: <20260901-rcu-pagetable-freeing-v1-3-5456a81c8212@kernel.org>
> Currently riscv gates MMU_GATHER_RCU_TABLE_FREE on CONFIG_SMP and
> CONFIG_MMU.
>
> Commit 69be3fb111e7 ("riscv: enable MMU_GATHER_RCU_TABLE_FREE for SMP &&
> MMU") enabled CONFIG_MMU_GATHER_RCU_TABLE_FREE for CONFIG_SMP, CONFIG_MMU
> riscv builds.
>
> This is expressly for the safety of GUP-fast walkers (CONFIG_HAVE_GUP_FAST
> is enabled if CONFIG_MMU is enabled).
>
> Naturally a single core system does not encounter issues with software page
> table walkers being correctly synchronised across cores, as there is only a
> single core.
>
> However, CONFIG_PREEMPT_RCU is still available on a riscv UP system, so for
> a future RCU-only page table walker, this guarantee is required to prevent
> concurrent page table teardown.
>
> All page table freeing is already done via tlb_remove_ptdesc() so the
> conditions of CONFIG_MMU_GATHER_RCU_TABLE_FREE are already met.
>
> This forms part of an overall effort to switch every architecture to this
> mode.
>
> Signed-off-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Sashiko has reviewed this patch and found no issues. It looks great!
--
Sashiko AI review · https://sashiko.dev/#/patchset/20260901-rcu-pagetable-freeing-v1-0-5456a81c8212@kernel.org?part=3
next prev parent reply other threads:[~2026-09-01 11:14 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-01 11:01 [PATCH 00/12] mm: make userland page table freeing RCU-safe Lorenzo Stoakes (ARM)
2026-09-01 11:01 ` [PATCH 01/12] mm/huge_memory: zap deposited page tables after an RCU grace period Lorenzo Stoakes (ARM)
2026-09-01 11:18 ` sashiko-bot
2026-09-01 13:19 ` Kiryl Shutsemau
2026-09-01 14:12 ` Lorenzo Stoakes (ARM)
2026-09-01 14:24 ` Jason Gunthorpe
2026-09-01 14:41 ` Lorenzo Stoakes (ARM)
2026-09-01 15:28 ` Kiryl Shutsemau
2026-09-01 15:45 ` Lorenzo Stoakes (ARM)
2026-09-01 17:11 ` Kiryl Shutsemau
2026-09-01 17:14 ` Lorenzo Stoakes (ARM)
2026-09-01 15:54 ` Liam R. Howlett
2026-09-01 16:06 ` Jason Gunthorpe
2026-09-01 17:13 ` Kiryl Shutsemau
2026-09-01 17:47 ` Liam R. Howlett
2026-09-01 11:01 ` [PATCH 02/12] mm: enable MMU_GATHER_RCU_TABLE_FREE for most 2-level architectures Lorenzo Stoakes (ARM)
2026-09-01 11:22 ` sashiko-bot
2026-09-01 11:01 ` [PATCH 03/12] mm: enable MMU_GATHER_RCU_TABLE_FREE for MMU riscv Lorenzo Stoakes (ARM)
2026-09-01 11:14 ` sashiko-bot [this message]
2026-09-01 11:01 ` [PATCH 04/12] mm: enable MMU_GATHER_RCU_TABLE_FREE for MMU arm Lorenzo Stoakes (ARM)
2026-09-01 11:18 ` sashiko-bot
2026-09-01 11:01 ` [PATCH 05/12] mm: enable MMU_GATHER_RCU_TABLE_FREE for arc, microblaze, xtensa Lorenzo Stoakes (ARM)
2026-09-01 11:28 ` sashiko-bot
2026-09-01 11:01 ` [PATCH 06/12] mm: enable MMU_GATHER_RCU_TABLE_FREE for sparc64 Lorenzo Stoakes (ARM)
2026-09-01 11:23 ` sashiko-bot
2026-09-01 11:01 ` [PATCH 07/12] mm: enable MMU_GATHER_RCU_TABLE_FREE for m68k-coldfire Lorenzo Stoakes (ARM)
2026-09-01 11:23 ` sashiko-bot
2026-09-01 11:01 ` [PATCH 08/12] mm: enable MMU_GATHER_RCU_TABLE_FREE for sh-X2 Lorenzo Stoakes (ARM)
2026-09-01 11:30 ` sashiko-bot
2026-09-01 11:01 ` [PATCH 09/12] mm: enable MMU_GATHER_RCU_TABLE_FREE for m68k-motorola Lorenzo Stoakes (ARM)
2026-09-01 11:30 ` sashiko-bot
2026-09-01 11:01 ` [PATCH 10/12] mm: enable MMU_GATHER_RCU_TABLE_FREE for sparc32 Lorenzo Stoakes (ARM)
2026-09-01 11:37 ` sashiko-bot
2026-09-01 11:01 ` [PATCH 11/12] mm: make userland page table freeing RCU-safe Lorenzo Stoakes (ARM)
2026-09-01 11:52 ` sashiko-bot
2026-09-01 13:33 ` Kiryl Shutsemau
2026-09-01 14:03 ` Lorenzo Stoakes (ARM)
2026-09-01 11:01 ` [PATCH 12/12] mm: change the contract for free_pgtables(), update docs Lorenzo Stoakes (ARM)
2026-09-01 11:37 ` sashiko-bot
2026-09-01 13:57 ` Kiryl Shutsemau
2026-09-01 14:31 ` Lorenzo Stoakes (ARM)
2026-09-01 17:15 ` Kiryl Shutsemau
2026-09-01 17:25 ` Lorenzo Stoakes (ARM)
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