From: Anshuman Khandual <anshuman.khandual@arm.com>
To: Muchun Song <songmuchun@bytedance.com>,
will@kernel.org, akpm@linux-foundation.org, david@redhat.com,
bodeddub@amazon.com, osalvador@suse.de, mike.kravetz@oracle.com,
rientjes@google.com, mark.rutland@arm.com,
catalin.marinas@arm.com, james.morse@arm.com, 21cnbao@gmail.com
Cc: linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
duanxiongchun@bytedance.com, fam.zheng@bytedance.com,
smuchun@gmail.com
Subject: Re: [PATCH v4 2/2] arm64: mm: hugetlb: Enable HUGETLB_PAGE_FREE_VMEMMAP for arm64
Date: Mon, 4 Apr 2022 14:56:17 +0530 [thread overview]
Message-ID: <dd980687-a1ef-f4b5-bb29-da14f89c087e@arm.com> (raw)
In-Reply-To: <20220331065640.5777-2-songmuchun@bytedance.com>
Hello Muchun,
On 3/31/22 12:26, Muchun Song wrote:
> The feature of minimizing overhead of struct page associated with each
> HugeTLB page aims to free its vmemmap pages (used as struct page) to
> save memory, where is ~14GB/16GB per 1TB HugeTLB pages (2MB/1GB type).
Enabling this feature saves us around 1.4/1.6 % memory but looking from
other way around, unavailability of vmemmap backing pages (~1.4GB) when
freeing up a corresponding HugeTLB page, could prevent ~1TB memory from
being used as normal page form (requiring their own struct pages), thus
forcing the HugeTLB page to remain as such ? Is not this problematic ?
These additional 1TB memory in normal pages, from a HugeTLB dissolution
could have eased the system's memory pressure without this feature being
enabled.
- Anshuman
next prev parent reply other threads:[~2022-04-04 9:26 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-31 6:56 [PATCH v4 1/2] mm: hugetlb_vmemmap: introduce ARCH_WANT_HUGETLB_PAGE_FREE_VMEMMAP Muchun Song
2022-03-31 6:56 ` [PATCH v4 2/2] arm64: mm: hugetlb: Enable HUGETLB_PAGE_FREE_VMEMMAP for arm64 Muchun Song
2022-03-31 22:31 ` Barry Song
2022-04-04 9:26 ` Anshuman Khandual [this message]
2022-04-04 12:01 ` Muchun Song
2022-04-05 3:34 ` Anshuman Khandual
2022-04-05 3:49 ` Muchun Song
2022-04-05 4:45 ` Anshuman Khandual
2022-04-05 8:38 ` Muchun Song
2022-04-11 9:17 ` Anshuman Khandual
2022-04-11 10:40 ` Muchun Song
2022-04-11 10:12 ` Anshuman Khandual
2022-04-11 11:55 ` Muchun Song
2022-04-13 10:33 ` Anshuman Khandual
2022-04-13 14:59 ` Muchun Song
2022-03-31 8:42 ` [PATCH v4 1/2] mm: hugetlb_vmemmap: introduce ARCH_WANT_HUGETLB_PAGE_FREE_VMEMMAP David Hildenbrand
2022-03-31 8:48 ` Muchun Song
2022-03-31 8:50 ` David Hildenbrand
2022-03-31 8:53 ` Muchun Song
2022-03-31 22:19 ` Barry Song
2022-04-04 9:05 ` Anshuman Khandual
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