From: "孙世龙 sunshilong" <sunshilong369@gmail.com>
To: David Hildenbrand <david@redhat.com>
Cc: linux-mm@kvack.org
Subject: Re: Are there still some methods that could be used by the Linux kernel to reduce memory fragmentation while both CONFIG-MIGRATION and CONFIG-COMPACTION are disabled?
Date: Wed, 24 Jun 2020 19:16:49 +0800 [thread overview]
Message-ID: <CAAvDm6ar+XTMx58cP4twg_TXSOtZQrqC4kGTs+Cp-diQUFjgYw@mail.gmail.com> (raw)
In-Reply-To: <73b5db17-805a-4f1a-60f7-26695c0422e8@redhat.com>
Thank you for your attention to this matter.
>> Are there still some methods that could be used by the Linux kernel
>> to reduce memory fragmentation while both CONFIG-MIGRATION
>> and CONFIG-COMPACTION are disabled?
>
>
>We do have mobility grouping on pageblock order.
>Also, I think you can use ZONE_MOVABLE without migration and compaction,
>to at least locally limit unmovable fragmentation.
It's a good news.
Could you please explain that in more detail for me or suggest some documents
for me to go through.
As per the post(http://lkml.iu.edu/hypermail/linux/kernel/1703.1/06782.html),
I think it's something like ZONE_NORMAL. And I find that
"ZONE_MOVEABLE" is available on Linux-v4.9.
>>
>> Are there some system settings that could make for this goal?
>
>Why don't you want page compaction/migration?
Because I am using a real-time system(and I have to apply a patch
to Linux kernel), I have no choice other than disabling these
aforementioned options.
Is there some potential problems that I should be aware of if I enable
"ZONE_MOVABLE" on real-time system?
Best Regards.
David Hildenbrand <david@redhat.com> 于2020年6月24日周三 下午5:53写道:
>
> On 23.06.20 17:52, 孙世龙 sunshilong wrote:
> > Are there still some methods that could be used by the Linux kernel
> > to reduce memory fragmentation while both CONFIG-MIGRATION
> > and CONFIG-COMPACTION are disabled?
>
> We do have mobility grouping on pageblock order.
>
> Also, I think you can use ZONE_MOVABLE without migration and compaction,
> to at least locally limit unmovable fragmentation.
>
> >
> > Are there some system settings that could make for this goal?
>
> Why don't you want page compaction/migration?
>
> --
> Thanks,
>
> David / dhildenb
>
next prev parent reply other threads:[~2020-06-24 11:17 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-23 15:52 Are there still some methods that could be used by the Linux kernel to reduce memory fragmentation while both CONFIG-MIGRATION and CONFIG-COMPACTION are disabled? 孙世龙 sunshilong
2020-06-24 9:53 ` David Hildenbrand
2020-06-24 11:16 ` 孙世龙 sunshilong [this message]
2020-06-24 17:22 ` David Rientjes
2020-06-25 3:22 ` 孙世龙 sunshilong
2020-06-28 3:27 ` David Rientjes
2020-06-28 5:15 ` 孙世龙 sunshilong
2020-06-28 20:39 ` David Rientjes
-- strict thread matches above, loose matches on Subject: below --
2020-06-23 15:39 孙世龙 sunshilong
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