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From: "孙世龙 sunshilong" <sunshilong369@gmail.com>
To: Kernelnewbies@kernelnewbies.org,
	"Valdis Klētnieks" <valdis.kletnieks@vt.edu>,
	mulyadi.santosa@gmail.com
Subject: Re: Is there some method or software that could purposely generate a lot of physical memory fragmentations on linux?
Date: Fri, 3 Jul 2020 13:20:50 +0800	[thread overview]
Message-ID: <CAAvDm6YCaSynENCZUgomQTJqM=N=HDnEOrXk7cxgytKmVnG8pw@mail.gmail.com> (raw)
In-Reply-To: <CAAvDm6aumLxZdYPZxzhA+4a1LGuJS8+ui1cruE2eGwBxic11Hw@mail.gmail.com>


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Hi, Valdis Klētnieks, Mulyadi Santosa

Thanks to both of you.
>> Just pseudo idea, if this is in user space, try to:  allocate many blocks
>> of memory using malloc, each having different size, keep the returned
>> pointer, then randomly free() some of them, then malloc() again with
>> different size

>That will cause userspace malloc() to have fragmentation, but as far
>as the kernel is concerned it's all just 4K pages of user memory.
>Causing physical memory fragmentation will require abusing the kernel
>memory allocators such as kmalloc() and vmalloc() and friends.

I fully understand what you mean by "cause userspace malloc() to have
fragmentation".
I am sorry, maybe I mislead you. I just want there are no available free
high order blocks(i.e
32KB,64KB, 128KB and etc) on the platform.
How can I more efficiently and automatically achieve this goal?

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      parent reply	other threads:[~2020-07-03  5:21 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-30  6:51 Is there some method or software that could purposely generate a lot of physical memory fragmentations on linux? 孙世龙 sunshilong
2020-07-02  8:29 ` Mulyadi Santosa
2020-07-03  4:58   ` Valdis Klētnieks
2020-07-03  5:20 ` 孙世龙 sunshilong [this message]

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