From: Matthew Wilcox <willy@infradead.org>
To: Dev Jain <dev.jain@arm.com>
Cc: akpm@linux-foundation.org, david@kernel.org,
lorenzo.stoakes@oracle.com, Liam.Howlett@oracle.com,
vbabka@suse.cz, rppt@kernel.org, surenb@google.com,
mhocko@suse.com, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, ryan.roberts@arm.com,
anshuman.khandual@arm.com, kirill@shutemov.name
Subject: Re: [PATCH] mm: map maximum pages possible in finish_fault
Date: Fri, 6 Feb 2026 15:22:02 +0000 [thread overview]
Message-ID: <aYYHGisOQFQINXwR@casper.infradead.org> (raw)
In-Reply-To: <20260206135648.38164-1-dev.jain@arm.com>
On Fri, Feb 06, 2026 at 07:26:48PM +0530, Dev Jain wrote:
> We test the patch with the following userspace program. A shmem VMA of
> 2M is created, and faulted in, with sysfs setting
> hugepages-2048k/shmem_enabled = always, so that the pagecache is populated
> with a 2M folio. Then, a 64K VMA is created, and we fault on each page.
> Then, we do MADV_DONTNEED to zap the pagetable, so that we can fault again
> in the next iteration. We measure the accumulated time taken during
> faulting the VMA.
>
> On arm64,
>
> without patch:
> Total time taken by inner loop: 4701721766 ns
>
> with patch:
> Total time taken by inner loop: 516043507 ns
>
> giving a 9x improvement.
It's nice that you can construct a test-case that shows improvement, but
is there any real workload that benefits from this?
next prev parent reply other threads:[~2026-02-06 15:22 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-02-06 13:56 Dev Jain
2026-02-06 15:22 ` Matthew Wilcox [this message]
2026-02-10 13:28 ` Dev Jain
2026-02-10 13:39 ` Lorenzo Stoakes
2026-02-10 13:54 ` Dev Jain
2026-02-10 16:27 ` Matthew Wilcox
2026-02-06 19:27 ` [syzbot ci] " syzbot ci
2026-02-07 18:08 ` [PATCH] " Usama Arif
2026-02-10 13:29 ` Dev Jain
2026-02-11 11:33 ` David Hildenbrand (Arm)
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