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Message-ID: <mhng-6dc92fd9-0fe6-4a0d-974f-4f4468f143e4@palmer-ri-x1c9>
Date: Tue, 14 Feb 2023 19:19:16 -0800 (PST)
From: Palmer Dabbelt <palmer@...belt.com>
To: mike.kravetz@...cle.com
CC: linux-mm@...ck.org, linux-kernel@...r.kernel.org,
linuxppc-dev@...ts.ozlabs.org, linux-riscv@...ts.infradead.org,
linux-s390@...r.kernel.org, netdev@...r.kernel.org,
Christoph Hellwig <hch@...radead.org>, david@...hat.com,
mhocko@...e.com, peterx@...hat.com, nadav.amit@...il.com,
willy@...radead.org, vbabka@...e.cz, riel@...riel.com,
Will Deacon <will@...nel.org>, mpe@...erman.id.au,
borntraeger@...ux.ibm.com, dave.hansen@...ux.intel.com,
brauner@...nel.org, edumazet@...gle.com, akpm@...ux-foundation.org,
mike.kravetz@...cle.com
Subject: Re: [PATCH] mm: remove zap_page_range and create zap_vma_pages
On Tue, 03 Jan 2023 16:27:32 PST (-0800), mike.kravetz@...cle.com wrote:
> zap_page_range was originally designed to unmap pages within an address
> range that could span multiple vmas. While working on [1], it was
> discovered that all callers of zap_page_range pass a range entirely within
> a single vma. In addition, the mmu notification call within zap_page
> range does not correctly handle ranges that span multiple vmas. When
> crossing a vma boundary, a new mmu_notifier_range_init/end call pair
> with the new vma should be made.
>
> Instead of fixing zap_page_range, do the following:
> - Create a new routine zap_vma_pages() that will remove all pages within
> the passed vma. Most users of zap_page_range pass the entire vma and
> can use this new routine.
> - For callers of zap_page_range not passing the entire vma, instead call
> zap_page_range_single().
> - Remove zap_page_range.
>
> [1] https://lore.kernel.org/linux-mm/20221114235507.294320-2-mike.kravetz@oracle.com/
> Suggested-by: Peter Xu <peterx@...hat.com>
> Signed-off-by: Mike Kravetz <mike.kravetz@...cle.com>
[...]
> diff --git a/arch/riscv/kernel/vdso.c b/arch/riscv/kernel/vdso.c
> index e410275918ac..5c30212d8d1c 100644
> --- a/arch/riscv/kernel/vdso.c
> +++ b/arch/riscv/kernel/vdso.c
> @@ -124,13 +124,11 @@ int vdso_join_timens(struct task_struct *task, struct time_namespace *ns)
> mmap_read_lock(mm);
>
> for_each_vma(vmi, vma) {
> - unsigned long size = vma->vm_end - vma->vm_start;
> -
> if (vma_is_special_mapping(vma, vdso_info.dm))
> - zap_page_range(vma, vma->vm_start, size);
> + zap_vma_pages(vma);
> #ifdef CONFIG_COMPAT
> if (vma_is_special_mapping(vma, compat_vdso_info.dm))
> - zap_page_range(vma, vma->vm_start, size);
> + zap_vma_pages(vma);
> #endif
> }
Acked-by: Palmer Dabbelt <palmer@...osinc.com> # RISC-V
Thanks!
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