From: Joao Martins <joao.m.martins@oracle.com>
To: Muchun Song <songmuchun@bytedance.com>
Cc: Linux Memory Management List <linux-mm@kvack.org>,
Dan Williams <dan.j.williams@intel.com>,
Vishal Verma <vishal.l.verma@intel.com>,
Matthew Wilcox <willy@infradead.org>,
Jason Gunthorpe <jgg@ziepe.ca>, Jane Chu <jane.chu@oracle.com>,
Mike Kravetz <mike.kravetz@oracle.com>,
Andrew Morton <akpm@linux-foundation.org>,
Jonathan Corbet <corbet@lwn.net>, Christoph Hellwig <hch@lst.de>,
nvdimm@lists.linux.dev,
Linux Doc Mailing List <linux-doc@vger.kernel.org>
Subject: Re: [PATCH v6 5/5] mm/page_alloc: reuse tail struct pages for compound devmaps
Date: Thu, 24 Feb 2022 16:49:02 +0000 [thread overview]
Message-ID: <4ac9b3cd-0158-19e5-2667-b6758cc8badd@oracle.com> (raw)
In-Reply-To: <CAMZfGtVCXDeF=3=0n83Bx_20MHOqWsRoJAtZeE53WMr3FA+j7w@mail.gmail.com>
On 2/24/22 15:41, Muchun Song wrote:
> On Thu, Feb 24, 2022 at 3:48 AM Joao Martins <joao.m.martins@oracle.com> wrote:
>>
>> Currently memmap_init_zone_device() ends up initializing 32768 pages
>> when it only needs to initialize 128 given tail page reuse. That
>> number is worse with 1GB compound pages, 262144 instead of 128. Update
>> memmap_init_zone_device() to skip redundant initialization, detailed
>> below.
>>
>> When a pgmap @vmemmap_shift is set, all pages are mapped at a given
>> huge page alignment and use compound pages to describe them as opposed
>> to a struct per 4K.
>>
>> With @vmemmap_shift > 0 and when struct pages are stored in ram
>> (!altmap) most tail pages are reused. Consequently, the amount of
>> unique struct pages is a lot smaller that the total amount of struct
>
> s/that/than/g
Fixed as well.
prev parent reply other threads:[~2022-02-24 16:49 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-23 19:48 [PATCH v6 0/5] sparse-vmemmap: memory savings for compound devmaps (device-dax) Joao Martins
2022-02-23 19:48 ` [PATCH v6 1/5] mm/sparse-vmemmap: add a pgmap argument to section activation Joao Martins
2022-02-24 3:02 ` Muchun Song
2022-02-24 10:38 ` Joao Martins
2022-02-23 19:48 ` [PATCH v6 2/5] mm/sparse-vmemmap: refactor core of vmemmap_populate_basepages() to helper Joao Martins
2022-02-24 3:10 ` Muchun Song
2022-02-24 10:39 ` Joao Martins
2022-02-23 19:48 ` [PATCH v6 3/5] mm/hugetlb_vmemmap: move comment block to Documentation/vm Joao Martins
2022-02-23 19:48 ` [PATCH v6 4/5] mm/sparse-vmemmap: improve memory savings for compound devmaps Joao Martins
2022-02-24 5:54 ` Muchun Song
2022-02-24 11:46 ` Joao Martins
2022-02-24 15:34 ` Muchun Song
2022-02-23 19:48 ` [PATCH v6 5/5] mm/page_alloc: reuse tail struct pages " Joao Martins
2022-02-24 5:57 ` Muchun Song
2022-02-24 11:47 ` Joao Martins
2022-02-24 15:41 ` Muchun Song
2022-02-24 16:49 ` Joao Martins [this message]
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