From: Jia He <hejianet@gmail.com>
To: Michal Hocko <mhocko@kernel.org>
Cc: Russell King <linux@armlinux.org.uk>,
Andrew Morton <akpm@linux-foundation.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Mel Gorman <mgorman@suse.de>, Will Deacon <will.deacon@arm.com>,
Mark Rutland <mark.rutland@arm.com>,
"H. Peter Anvin" <hpa@zytor.com>,
Pavel Tatashin <pasha.tatashin@oracle.com>,
Daniel Jordan <daniel.m.jordan@oracle.com>,
AKASHI Takahiro <takahiro.akashi@linaro.org>,
Gioh Kim <gi-oh.kim@profitbricks.com>,
Steven Sistare <steven.sistare@oracle.com>,
Daniel Vacek <neelx@redhat.com>,
Eugeniu Rosca <erosca@de.adit-jv.com>,
Vlastimil Babka <vbabka@suse.cz>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
James Morse <james.morse@arm.com>,
Ard Biesheuvel <ard.biesheuvel@linaro.org>,
Steve Capper <steve.capper@arm.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Kate Stewart <kstewart@linuxfoundation.org>,
Philippe Ombredanne <pombredanne@nexb.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Kemi Wang <kemi.wang@intel.com>, Petr Tesarik <ptesarik@suse.com>,
YASUAKI ISHIMATSU <yasu.isimatu@gmail.com>,
Andrey Ryabinin <aryabinin@virtuozzo.com>,
Nikolay Borisov <nborisov@suse.com>,
richard.weiyang@gmail.com
Subject: Re: [PATCH v9 0/6] optimize memblock_next_valid_pfn and early_pfn_valid on arm and arm64
Date: Tue, 3 Jul 2018 10:11:11 +0800 [thread overview]
Message-ID: <779be6bf-db64-9175-f4c0-2baa0ea6defd@gmail.com> (raw)
In-Reply-To: <20180702114037.GJ19043@dhcp22.suse.cz>
On 7/2/2018 7:40 PM, Michal Hocko Wrote:
> On Fri 29-06-18 10:29:17, Jia He wrote:
>> Commit b92df1de5d28 ("mm: page_alloc: skip over regions of invalid pfns
>> where possible") tried to optimize the loop in memmap_init_zone(). But
>> there is still some room for improvement.
>
> It would be great to shortly describe those optimization from high level
> POV.
>
>>
>> Patch 1 introduce new config to make codes more generic
>> Patch 2 remain the memblock_next_valid_pfn on arm and arm64
>> Patch 3 optimizes the memblock_next_valid_pfn()
>> Patch 4~6 optimizes the early_pfn_valid()
>>
>> As for the performance improvement, after this set, I can see the time
>> overhead of memmap_init() is reduced from 27956us to 13537us in my
>> armv8a server(QDF2400 with 96G memory, pagesize 64k).
>
> So this is 13ms saving when booting 96G machine. Is this really worth
> the additional code? Are there any other benefits?
Sorry, Michal
I missed one thing.
This 13ms optimization is merely the result of my patch 3~6
Patch 1 is originated by Paul Burton in commit b92df1de5d289.
In its description,
===
James said "I have tested this patch on a virtual model of a Samurai CPU
with a sparse memory map. The kernel boot time drops from 109 to
62 seconds. "
===
--
Cheers,
Jia
> [...]
>> arch/arm/Kconfig | 4 +++
>> arch/arm/mm/init.c | 1 +
>> arch/arm64/Kconfig | 4 +++
>> arch/arm64/mm/init.c | 1 +
>> include/linux/early_pfn.h | 79 +++++++++++++++++++++++++++++++++++++++++++++++
>> include/linux/memblock.h | 2 ++
>> include/linux/mmzone.h | 18 ++++++++++-
>> mm/Kconfig | 3 ++
>> mm/memblock.c | 9 ++++++
>> mm/page_alloc.c | 5 ++-
>> 10 files changed, 124 insertions(+), 2 deletions(-)
>> create mode 100644 include/linux/early_pfn.h
>
next prev parent reply other threads:[~2018-07-03 2:11 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-29 2:29 [PATCH v9 0/6] optimize memblock_next_valid_pfn and early_pfn_valid on arm and arm64 Jia He
2018-06-29 2:29 ` [PATCH v9 1/6] arm: arm64: introduce CONFIG_HAVE_MEMBLOCK_PFN_VALID Jia He
2018-06-29 18:08 ` Pavel Tatashin
2018-06-29 2:29 ` [PATCH v9 2/6] mm: page_alloc: remain memblock_next_valid_pfn() on arm/arm64 Jia He
2018-06-29 17:07 ` Pavel Tatashin
2018-07-06 1:38 ` Jia He
2018-06-29 18:13 ` Pavel Tatashin
2018-07-02 11:38 ` Michal Hocko
2018-07-03 1:55 ` Jia He
2018-07-03 3:03 ` Pavel Tatashin
2018-06-29 2:29 ` [PATCH v9 3/6] arm: arm64: page_alloc: reduce unnecessary binary search in memblock_next_valid_pfn() Jia He
2018-06-29 2:29 ` [PATCH v9 4/6] mm/memblock: introduce memblock_search_pfn_regions() Jia He
2018-06-29 2:29 ` [PATCH v9 5/6] arm: arm64: introduce pfn_valid_region() Jia He
2018-06-29 2:29 ` [PATCH v9 6/6] mm: page_alloc: reduce unnecessary binary search in early_pfn_valid() Jia He
2018-07-02 11:40 ` [PATCH v9 0/6] optimize memblock_next_valid_pfn and early_pfn_valid on arm and arm64 Michal Hocko
2018-07-02 12:06 ` Pavel Tatashin
2018-07-03 2:00 ` Jia He
2018-07-03 2:11 ` Jia He [this message]
2018-07-03 7:28 ` Michal Hocko
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