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From: Muchun Song <songmuchun@bytedance.com>
To: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Jonathan Corbet <corbet@lwn.net>,
	Thomas Gleixner <tglx@linutronix.de>,
	mingo@redhat.com, bp@alien8.de,  x86@kernel.org, hpa@zytor.com,
	dave.hansen@linux.intel.com, luto@kernel.org,
	 Peter Zijlstra <peterz@infradead.org>,
	viro@zeniv.linux.org.uk,
	 Andrew Morton <akpm@linux-foundation.org>,
	paulmck@kernel.org, mchehab+huawei@kernel.org,
	 pawan.kumar.gupta@linux.intel.com,
	Randy Dunlap <rdunlap@infradead.org>,
	oneukum@suse.com,  anshuman.khandual@arm.com, jroedel@suse.de,
	 Mina Almasry <almasrymina@google.com>,
	David Rientjes <rientjes@google.com>,
	linux-doc@vger.kernel.org,  LKML <linux-kernel@vger.kernel.org>,
	 Linux Memory Management List <linux-mm@kvack.org>,
	linux-fsdevel@vger.kernel.org
Subject: Re: [External] Re: [RFC PATCH 03/24] mm/hugetlb: Introduce a new config HUGETLB_PAGE_FREE_VMEMMAP
Date: Wed, 30 Sep 2020 10:56:42 +0800	[thread overview]
Message-ID: <CAMZfGtWZ739Qd+9WZYtBTbQLjEqJa2BRa=5NBP9QMJQjsJS0mg@mail.gmail.com> (raw)
In-Reply-To: <07e7d497-e800-be28-dfea-047579c3b27d@oracle.com>

On Wed, Sep 30, 2020 at 7:41 AM Mike Kravetz <mike.kravetz@oracle.com> wrote:
>
> On 9/15/20 5:59 AM, Muchun Song wrote:
> > The purpose of introducing HUGETLB_PAGE_FREE_VMEMMAP is to configure
> > whether to enable the feature of freeing unused vmemmap associated
> > with HugeTLB pages.
> >
> > Signed-off-by: Muchun Song <songmuchun@bytedance.com>
> > ---
> >  fs/Kconfig | 15 +++++++++++++++
> >  1 file changed, 15 insertions(+)
> >
> > diff --git a/fs/Kconfig b/fs/Kconfig
> > index 976e8b9033c4..61e9c08096ca 100644
> > --- a/fs/Kconfig
> > +++ b/fs/Kconfig
> > @@ -245,6 +245,21 @@ config HUGETLBFS
> >  config HUGETLB_PAGE
> >       def_bool HUGETLBFS
> >
> > +config HUGETLB_PAGE_FREE_VMEMMAP
> > +     bool "Free unused vmemmap associated with HugeTLB pages"
> > +     default n
> > +     depends on HUGETLB_PAGE
> > +     depends on SPARSEMEM_VMEMMAP
> > +     depends on HAVE_BOOTMEM_INFO_NODE
> > +     help
> > +       There are many struct page structure associated with each HugeTLB
> > +       page. But we only use a few struct page structure. In this case,
> > +       it waste some memory. It is better to free the unused struct page
> > +       structures to buddy system which can save some memory. For
> > +       architectures that support it, say Y here.
> > +
> > +       If unsure, say N.
> > +
>
> I could be wrong, but I believe the convention is introduce the config
> option at the same time code which depends on the option is introduced.
> Therefore, it might be better to combine with the next patch.

Yeah, great. Will do that. Thanks.

>
> Also, it looks like most of your development was done on x86.  Should
> this option be limited to x86 only for now?

Now only the x86 has the HAVE_BOOTMEM_INFO_NODE option. So
maybe this is enough :)

> --
> Mike Kravetz



-- 
Yours,
Muchun


  reply	other threads:[~2020-09-30  2:57 UTC|newest]

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-15 12:59 [RFC PATCH 00/24] mm/hugetlb: Free some vmemmap pages of hugetlb page Muchun Song
2020-09-15 12:59 ` [RFC PATCH 01/24] mm/memory_hotplug: Move bootmem info registration API to bootmem_info.c Muchun Song
2020-09-29 22:46   ` Mike Kravetz
2020-09-15 12:59 ` [RFC PATCH 02/24] mm/memory_hotplug: Move {get,put}_page_bootmem() " Muchun Song
2020-09-29 23:30   ` Mike Kravetz
2020-09-15 12:59 ` [RFC PATCH 03/24] mm/hugetlb: Introduce a new config HUGETLB_PAGE_FREE_VMEMMAP Muchun Song
2020-09-16  2:13   ` Randy Dunlap
2020-09-29 23:41   ` Mike Kravetz
2020-09-30  2:56     ` Muchun Song [this message]
2020-09-15 12:59 ` [RFC PATCH 04/24] mm/hugetlb: Register bootmem info when CONFIG_HUGETLB_PAGE_FREE_VMEMMAP Muchun Song
2020-09-15 12:59 ` [RFC PATCH 05/24] mm/hugetlb: Introduce nr_free_vmemmap_pages in the struct hstate Muchun Song
2020-09-30 22:41   ` Mike Kravetz
2020-10-01  2:57     ` [External] " Muchun Song
2020-09-15 12:59 ` [RFC PATCH 06/24] mm/hugetlb: Introduce pgtable allocation/freeing helpers Muchun Song
2020-09-15 12:59 ` [RFC PATCH 07/24] mm/hugetlb: Add freeing unused vmemmap pages support for x86 Muchun Song
2020-09-15 12:59 ` [RFC PATCH 08/24] mm/bootmem_info: Introduce {free,prepare}_vmemmap_page() Muchun Song
2020-09-15 12:59 ` [RFC PATCH 09/24] x86/mm: Introduce VMEMMAP_SIZE/VMEMMAP_END macro Muchun Song
2020-09-15 12:59 ` [RFC PATCH 10/24] mm/hugetlb: Free the vmemmap pages associated with each hugetlb page Muchun Song
2020-09-15 12:59 ` [RFC PATCH 11/24] mm/hugetlb: Add vmemmap_pmd_huge macro for x86 Muchun Song
2020-09-15 12:59 ` [RFC PATCH 12/24] mm/hugetlb: Defer freeing of hugetlb pages Muchun Song
2020-09-15 12:59 ` [RFC PATCH 13/24] mm/hugetlb: Allocate the vmemmap pages associated with each hugetlb page Muchun Song
2020-09-15 12:59 ` [RFC PATCH 14/24] mm/hugetlb: Introduce remap_huge_page_pmd_vmemmap helper Muchun Song
2020-09-15 12:59 ` [RFC PATCH 15/24] mm/hugetlb: Use PG_slab to indicate split pmd Muchun Song
2020-09-15 12:59 ` [RFC PATCH 16/24] mm/hugetlb: Support freeing vmemmap pages of gigantic page Muchun Song
2020-09-15 12:59 ` [RFC PATCH 17/24] mm/hugetlb: Add a BUILD_BUG_ON to check if struct page size is a power of two Muchun Song
2020-09-15 12:59 ` [RFC PATCH 18/24] mm/hugetlb: Clear PageHWPoison on the non-error memory page Muchun Song
2020-09-15 12:59 ` [RFC PATCH 19/24] mm/hugetlb: Flush work when dissolving hugetlb page Muchun Song
2020-09-15 12:59 ` [RFC PATCH 20/24] mm/hugetlb: Add a kernel parameter hugetlb_free_vmemmap Muchun Song
2020-09-16  2:10   ` Randy Dunlap
2020-09-16  2:50     ` [External] " Muchun Song
2020-09-15 12:59 ` [RFC PATCH 21/24] mm/hugetlb: Merge pte to huge pmd only for gigantic page Muchun Song
2020-09-20  9:59   ` Muchun Song
2020-09-15 12:59 ` [RFC PATCH 22/24] mm/hugetlb: Implement vmemmap_pmd_mkhuge macro Muchun Song
2020-09-15 12:59 ` [RFC PATCH 23/24] mm/hugetlb: Gather discrete indexes of tail page Muchun Song
2020-09-15 12:59 ` [RFC PATCH 24/24] mm/hugetlb: Add BUILD_BUG_ON to catch invalid usage of tail struct page Muchun Song
2020-09-15 14:32 ` [RFC PATCH 00/24] mm/hugetlb: Free some vmemmap pages of hugetlb page Matthew Wilcox
2020-09-15 14:53   ` Dave Hansen
2020-09-15 15:28   ` [External] " Muchun Song
2020-09-15 15:42     ` Matthew Wilcox
2020-09-15 17:32       ` Muchun Song
2020-09-15 17:39         ` Matthew Wilcox
2020-09-15 18:03           ` Muchun Song
2020-09-15 18:15             ` Matthew Wilcox
2020-09-16  2:45               ` Muchun Song
2020-09-29 21:58 ` Mike Kravetz
2020-09-30  3:13   ` Matthew Wilcox
2020-10-07 21:12   ` Mike Kravetz
2020-10-09  4:13     ` [External] " Muchun Song

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