From: Jason Gunthorpe <jgg@ziepe.ca>
To: Yu Zhao <yuzhao@google.com>
Cc: lsf-pc@lists.linux-foundation.org, Linux-MM <linux-mm@kvack.org>,
Yang Shi <shy828301@gmail.com>,
Matthew Wilcox <willy@infradead.org>,
"Yin, Fengwei" <fengwei.yin@intel.com>,
Hugh Dickins <hughd@google.com>,
"Kirill A . Shutemov" <kirill@shutemov.name>
Subject: Re: [LSF/MM/BPF TOPIC] Flexible orders for anonymous folios
Date: Fri, 24 Feb 2023 16:34:10 -0400 [thread overview]
Message-ID: <Y/kfQqJMSJkwO1Ku@ziepe.ca> (raw)
In-Reply-To: <CAOUHufYEj+pYK7tO4JGJx80xYsFdgGcHzMjqr5tJnYuuf7YG7w@mail.gmail.com>
On Wed, Feb 22, 2023 at 04:55:20PM -0700, Yu Zhao wrote:
> Currently anonymous folios only support two orders: 0 and the PMD
> order. Flexible orders for anonymous folios can resist both internal
> or external fragmentations when the PMD order is too underutilized or
> costly to allocate. Flexible orders can also leverage the TLB
> coalescing feature, .e.g., order 3 for AMD and order 4 for ARM CPUs.
I'm interested in this too - we've started to look at using 64K as a
base page size on ARM systems and having an order 3 folio would be the
usual 2M "THP" size with the coalescing feature. Keeping THP is a
desirable thing.
We also have some IOMMU HW that can do flexible orders, so even if the
CPU TLB cannot store odd folio sizes the IOMMU TLB can, which can be
interesting for KVM & VFIO.
Thanks,
Jason
next prev parent reply other threads:[~2023-02-24 20:34 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-22 23:55 Yu Zhao
2023-02-23 0:16 ` Suren Baghdasaryan
2023-02-23 4:01 ` Matthew Wilcox
2023-02-23 4:45 ` Yin, Fengwei
2023-02-23 18:07 ` Yang Shi
2023-03-01 10:35 ` Ryan Roberts
2023-03-06 20:57 ` Zi Yan
2023-02-24 20:34 ` Jason Gunthorpe [this message]
2023-02-26 1:30 ` Hillf Danton
2023-02-26 2:34 ` Matthew Wilcox
2023-02-26 4:12 ` Hillf Danton
2023-02-27 0:58 ` Hillf Danton
2023-03-01 23:29 ` Chris Li
2023-03-02 4:05 ` Yu Zhao
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