From: Barry Song <baohua@kernel.org>
To: Dev Jain <dev.jain@arm.com>
Cc: linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org,
catalin.marinas@arm.com, will@kernel.org,
akpm@linux-foundation.org, urezki@gmail.com,
linux-kernel@vger.kernel.org, anshuman.khandual@arm.com,
ryan.roberts@arm.com, ajd@linux.ibm.com, rppt@kernel.org,
david@kernel.org, Xueyuan.chen21@gmail.com
Subject: Re: [RFC PATCH 7/8] mm/vmalloc: Coalesce same page_shift mappings in vmap to avoid pgtable zigzag
Date: Thu, 9 Apr 2026 05:58:28 +0800 [thread overview]
Message-ID: <CAGsJ_4zn9KcA-KXTp3-F6uCe-AEiqrawdwFffBvxTJbDVwgyvQ@mail.gmail.com> (raw)
In-Reply-To: <90cfbbb4-9f75-4c67-a1c5-34780b2f7108@arm.com>
On Wed, Apr 8, 2026 at 7:36 PM Dev Jain <dev.jain@arm.com> wrote:
>
>
>
> On 08/04/26 8:21 am, Barry Song (Xiaomi) wrote:
> > For vmap(), detect pages with the same page_shift and map them in
> > batches, avoiding the pgtable zigzag caused by per-page mapping.
> >
> > Signed-off-by: Barry Song (Xiaomi) <baohua@kernel.org>
> > ---
>
> In patch 4, you eliminate the pagetable rewalk, and in patch 5,
> you re-introduce it, then in this patch you eliminate it again.
> So please just squash this into #5.
>
Sure. I guess I revealed some of the development process in this
patchset. The patch was initially written with page table rewalks
for simplicity and then iteratively improved. I agree that nobody
really cares how it was originally written :-)
Best Regards
Barry
next prev parent reply other threads:[~2026-04-08 21:58 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-08 2:51 [RFC PATCH 0/8] mm/vmalloc: Speed up ioremap, vmalloc and vmap with contiguous memory Barry Song (Xiaomi)
2026-04-08 2:51 ` [RFC PATCH 1/8] arm64/hugetlb: Extend batching of multiple CONT_PTE in a single PTE setup Barry Song (Xiaomi)
2026-04-08 10:32 ` Dev Jain
2026-04-08 11:00 ` Barry Song
2026-04-08 2:51 ` [RFC PATCH 2/8] arm64/vmalloc: Allow arch_vmap_pte_range_map_size to batch multiple CONT_PTE Barry Song (Xiaomi)
2026-04-08 2:51 ` [RFC PATCH 3/8] mm/vmalloc: Extend vmap_small_pages_range_noflush() to support larger page_shift sizes Barry Song (Xiaomi)
2026-04-08 11:08 ` Dev Jain
2026-04-08 21:29 ` Barry Song
2026-04-08 2:51 ` [RFC PATCH 4/8] mm/vmalloc: Eliminate page table zigzag for huge vmalloc mappings Barry Song (Xiaomi)
2026-04-08 2:51 ` [RFC PATCH 5/8] mm/vmalloc: map contiguous pages in batches for vmap() if possible Barry Song (Xiaomi)
2026-04-08 4:19 ` Dev Jain
2026-04-08 5:12 ` Barry Song
2026-04-08 11:22 ` Dev Jain
2026-04-08 14:03 ` Dev Jain
2026-04-08 21:54 ` Barry Song
2026-04-08 2:51 ` [RFC PATCH 6/8] mm/vmalloc: align vm_area so vmap() can batch mappings Barry Song (Xiaomi)
2026-04-08 2:51 ` [RFC PATCH 7/8] mm/vmalloc: Coalesce same page_shift mappings in vmap to avoid pgtable zigzag Barry Song (Xiaomi)
2026-04-08 11:36 ` Dev Jain
2026-04-08 21:58 ` Barry Song [this message]
2026-04-08 2:51 ` [RFC PATCH 8/8] mm/vmalloc: Stop scanning for compound pages after encountering small pages in vmap Barry Song (Xiaomi)
2026-04-08 9:14 ` [RFC PATCH 0/8] mm/vmalloc: Speed up ioremap, vmalloc and vmap with contiguous memory Dev Jain
2026-04-08 10:51 ` Barry Song
2026-04-08 10:55 ` Dev Jain
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