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charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org On Tue, Sep 22, 2026 at 04:35:42PM +0100, Lorenzo Stoakes (ARM) wrote: >Now every architecture has been converted to support >CONFIG_MMU_GATHER_RCU_TABLE_FREE, this configuration option no longer makes >any sense to keep around. > >Therefore remove it, and remove all the dead code that existed for >!CONFIG_MMU_GATHER_RCU_TABLE_FREE architectures previously. > >Additionally, CONFIG_MMU_GATHER_TABLE_FREE is no longer necessary, as all >architectures instead use CONFIG_HAVE_ARCH_TLB_REMOVE_TABLE when a custom >__tlb_remove_table() is required, so remove this too. > >A number of architectures only enabled CONFIG_MMU_GATHER_RCU_TABLE_FREE if >CONFIG_MMU was set, however the mmu_gather logic only actually does >something meaningful if CONFIG_MMU is set (mmu_gather.c is only compiled in >this case, for instance). > >As a result, there's no need to gate any of this logic on CONFIG_MMU >explicitly. > >CONFIG_PT_RECLAIM however does have a strict dependency on CONFIG_MMU, so >make this dependency explicit. > >Additionally, correct comments to remove references to non-RCU page table >gathering and make it clear that this is not 'semi-RCU', nor has it been >since commit 1fb3d8c20bfa ("mm/mmu_gather: replace IPI with >synchronize_rcu() when batch allocation fails"). > >With this change in place the kernel policy is now that userspace page >tables are freed after an RCU grace period, and thus it is now safe to >unconditionally perform page table walks under RCU, safe in the knowledge >that page tables will not be freed underneath the walker. > >This is all that is guaranteed, however, so naturally it is still incumbent >upon page table walkers to ensure that the page table entries are as >expected. > >Acked-by: Kiryl Shutsemau (Meta) >Signed-off-by: Lorenzo Stoakes (ARM) >--- with David's feedback folded in, LGTM! Reviewed-by: Lance Yang _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv