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From: Denis Magda <dmagda@apache.org>
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Subject: Re: Page Memory behavior with default memory policy
Date: Mon, 17 Apr 2017 18:00:17 -0700
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archived-at: Tue, 18 Apr 2017 01:00:21 -0000

Dmitriy,

All the nodes will request its own continuous memory region that takes =
70-80% of all RAM from an underlying operation system. However, the =
operating system will not outfit the nodes with physical pages mapped to =
RAM immediately allowing every node's process to start successfully. The =
nodes will communicate to RAM via a virtual memory which in its turn =
will give an access to physical pages whenever is needed applying low =
level eviction and swapping techniques.

Alex G., please confirm that we=E2=80=99re applying on this low level =
guarantees in our page memory impl.

=E2=80=94
Denis

> On Apr 17, 2017, at 5:50 PM, Dmitriy Setrakyan <dsetrakyan@apache.org> =
wrote:
>=20
> On Mon, Apr 17, 2017 at 5:46 PM, Denis Magda <dmagda@apache.org> =
wrote:
>=20
>> Guys,
>>=20
>> If a memory region is not expandable can we calculate the size of the
>> default one automatically rather than setting it to predefined value =
like 1
>> GB, 512 MB, etc. ?
>>=20
>> For instance, when a node is being started it finds out how much RAM =
is
>> available and requests 70-80% of it for the default memory region =
usage.
>> This should help us avoid this usability issue caused by the fact =
that we
>> hard code the size.
>>=20
>=20
> Denis, what happens if user plans to start multiple nodes on the same =
box?