From: Mike Kravetz <mike.kravetz@oracle.com>
To: Muchun Song <songmuchun@bytedance.com>,
corbet@lwn.net, tglx@linutronix.de, mingo@redhat.com,
bp@alien8.de, x86@kernel.org, hpa@zytor.com,
dave.hansen@linux.intel.com, luto@kernel.org,
peterz@infradead.org, viro@zeniv.linux.org.uk,
akpm@linux-foundation.org, paulmck@kernel.org,
pawan.kumar.gupta@linux.intel.com, rdunlap@infradead.org,
oneukum@suse.com, anshuman.khandual@arm.com, jroedel@suse.de,
almasrymina@google.com, rientjes@google.com, willy@infradead.org,
osalvador@suse.de, mhocko@suse.com, song.bao.hua@hisilicon.com,
david@redhat.com, naoya.horiguchi@nec.com,
joao.m.martins@oracle.com
Cc: duanxiongchun@bytedance.com, fam.zheng@bytedance.com,
linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-mm@kvack.org, linux-fsdevel@vger.kernel.org,
Chen Huang <chenhuang5@huawei.com>,
Bodeddula Balasubramaniam <bodeddub@amazon.com>
Subject: Re: [PATCH v20 4/9] mm: hugetlb: free the vmemmap pages associated with each HugeTLB page
Date: Fri, 16 Apr 2021 14:10:39 -0700 [thread overview]
Message-ID: <602af5f8-f103-438e-d88e-2819404b9dab@oracle.com> (raw)
In-Reply-To: <20210415084005.25049-5-songmuchun@bytedance.com>
On 4/15/21 1:40 AM, Muchun Song wrote:
> Every HugeTLB has more than one struct page structure. We __know__ that
> we only use the first 4 (__NR_USED_SUBPAGE) struct page structures
> to store metadata associated with each HugeTLB.
>
> There are a lot of struct page structures associated with each HugeTLB
> page. For tail pages, the value of compound_head is the same. So we can
> reuse first page of tail page structures. We map the virtual addresses
> of the remaining pages of tail page structures to the first tail page
> struct, and then free these page frames. Therefore, we need to reserve
> two pages as vmemmap areas.
>
> When we allocate a HugeTLB page from the buddy, we can free some vmemmap
> pages associated with each HugeTLB page. It is more appropriate to do it
> in the prep_new_huge_page().
>
> The free_vmemmap_pages_per_hpage(), which indicates how many vmemmap
> pages associated with a HugeTLB page can be freed, returns zero for
> now, which means the feature is disabled. We will enable it once all
> the infrastructure is there.
>
> Signed-off-by: Muchun Song <songmuchun@bytedance.com>
> Reviewed-by: Oscar Salvador <osalvador@suse.de>
> Tested-by: Chen Huang <chenhuang5@huawei.com>
> Tested-by: Bodeddula Balasubramaniam <bodeddub@amazon.com>
> Acked-by: Michal Hocko <mhocko@suse.com>
There may need to be some trivial rebasing due to Oscar's changes
when they go in.
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
--
Mike Kravetz
next prev parent reply other threads:[~2021-04-16 21:11 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-15 8:39 [PATCH v20 0/9] Free some vmemmap pages of HugeTLB page Muchun Song
2021-04-15 8:39 ` [PATCH v20 1/9] mm: memory_hotplug: factor out bootmem core functions to bootmem_info.c Muchun Song
2021-04-15 8:39 ` [PATCH v20 2/9] mm: hugetlb: introduce a new config HUGETLB_PAGE_FREE_VMEMMAP Muchun Song
2021-04-15 8:39 ` [PATCH v20 3/9] mm: hugetlb: gather discrete indexes of tail page Muchun Song
2021-04-16 18:54 ` Mike Kravetz
2021-04-15 8:40 ` [PATCH v20 4/9] mm: hugetlb: free the vmemmap pages associated with each HugeTLB page Muchun Song
2021-04-16 21:10 ` Mike Kravetz [this message]
2021-04-17 2:55 ` [External] " Muchun Song
2021-04-15 8:40 ` [PATCH v20 5/9] mm: hugetlb: defer freeing of HugeTLB pages Muchun Song
2021-04-16 23:55 ` Mike Kravetz
2021-04-17 4:13 ` [External] " Muchun Song
2021-04-15 8:40 ` [PATCH v20 6/9] mm: hugetlb: alloc the vmemmap pages associated with each HugeTLB page Muchun Song
2021-04-19 23:19 ` Mike Kravetz
2021-04-20 8:46 ` [External] " Muchun Song
2021-04-20 17:48 ` Mike Kravetz
2021-04-21 3:42 ` Muchun Song
2021-04-15 8:40 ` [PATCH v20 7/9] mm: hugetlb: add a kernel parameter hugetlb_free_vmemmap Muchun Song
2021-04-19 23:41 ` Mike Kravetz
2021-04-15 8:40 ` [PATCH v20 8/9] mm: memory_hotplug: disable memmap_on_memory when hugetlb_free_vmemmap enabled Muchun Song
2021-04-20 10:35 ` Oscar Salvador
2021-04-21 3:41 ` [External] " Muchun Song
2021-04-21 7:33 ` Oscar Salvador
2021-04-21 9:06 ` Muchun Song
2021-04-15 8:40 ` [PATCH v20 9/9] mm: hugetlb: introduce nr_free_vmemmap_pages in the struct hstate Muchun Song
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