From: Shentino <shentino@gmail.com>
To: Cong Wang <xiyou.wangcong@gmail.com>
Cc: linux-mm@kvack.org, stable@vger.kernel.org
Subject: Re: Consider for longterm kernels: mm: avoid swapping out with swappiness==0
Date: Mon, 10 Sep 2012 10:40:28 -0700 [thread overview]
Message-ID: <CAGDaZ_peCVb_8JOVByHH5iUF6upVPVaYw3XR=+fFGkF=k6wGXQ@mail.gmail.com> (raw)
In-Reply-To: <CAGDaZ_rBMadBmpPTpoV1vvkfmdf-sRt-9q_o_9jyFuiSJ3ve5w@mail.gmail.com>
On Mon, Sep 10, 2012 at 10:07 AM, Shentino <shentino@gmail.com> wrote:
> On Mon, Sep 10, 2012 at 6:36 AM, Cong Wang <xiyou.wangcong@gmail.com> wrote:
>> On Sun, 09 Sep 2012 at 18:03 GMT, Shentino <shentino@gmail.com> wrote:
>>>
>>> Just curious, but what theoretically would happen if someone were to
>>> want to set swappiness to 200 or something?
>>>
>>> Should it be sorta like vfs_cache_pressure?
>>>
>>
>>
>> How could it be set to 200? As 0~100 is valid:
>>
>> {
>> .procname = "swappiness",
>> .data = &vm_swappiness,
>> .maxlen = sizeof(vm_swappiness),
>> .mode = 0644,
>> .proc_handler = proc_dointvec_minmax,
>> .extra1 = &zero,
>> .extra2 = &one_hundred,
>> },
>
> My comment/question was more abstract and focusing on the comparison
> to vfs_cache_pressure.
Just to be clear about what I meant.
Both swapping and reclaiming from dentry/inode caches both share the
common factor of being alternatives to reclaiming from page cache when
memory is tight.
So I was wondering how similiar in effect these two knobs should be.
One possible use case off the top of my head is a file server that
banks heavily on page cache and spends most of its runtime sending
file data over the network. It might be overkill but swappiness > 100
might actually be beneficial here. I have no numbers to back it up
though as it's a rough idea.
Sorry if I'm butting in on the subject but I was curious about the idea.
Also still learning how to pos tin general on the kernel lists, so
apologies if I've been rude or anything.
>
> :P
>>
>> --
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next prev parent reply other threads:[~2012-09-10 17:41 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <5038E7AA.5030107@gmail.com>
2012-09-09 16:57 ` Ben Hutchings
2012-09-09 17:15 ` Rik van Riel
2012-09-09 18:03 ` Shentino
2012-09-10 13:36 ` Cong Wang
2012-09-10 17:07 ` Shentino
2012-09-10 17:40 ` Shentino [this message]
2012-09-09 18:27 ` Ben Hutchings
2012-09-09 20:34 ` Willy Tarreau
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