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From Dmitry Pavlov <dpavlov....@gmail.com>
Subject Re: Quick questions on segments and page map buckets
Date Fri, 22 Jun 2018 12:18:16 GMT
Hi Ed,

Which Sergey do you mean? I know a number of contributors.

Sincerely,


вт, 19 июн. 2018 г. в 22:15, Eduard Shangareev <eduard.shangareev@gmail.com
>:

> Hi,
>
> 1. It looks weird, yeah. Need to ask Sergey, who has changed it last time.
>
> 2. Because we could reuse memory. For example, after cache destroy or
> something like that.
>
> On Tue, Jun 19, 2018 at 9:58 PM, John Wilson <sami.hailu.15@gmail.com>
> wrote:
>
> > Hi,
> >
> > Two quick questions:
> >
> >
> >    1. The design documentation here,
> >    https://cwiki.apache.org/confluence/display/IGNITE/
> > Ignite+Durable+Memory+-+under+the+hood,
> >    states that the default segment count is equal to the number of
> logical
> >    cores available in the underlying machine. However, the segments array
> > in
> >    PageMemory indicates that the maximum number of segments is: 1 <<
> > SEG_BITS.
> >    Since SEG_BITS = 4, the max # segments is 16. Did I miss something
> here?
> >    2. Reading the code in PageMemoryNoStoreImp, it looks like pages are
> >    allocated segment sequentially in a bump-the-pointer strategy where
> the
> >    first 8 bytes of a segment hold a pointer to the index of the last
> >    allocated page. If this is true, then I don't understand the point of
> >    having a page map buckets. Why not use a simple arithmetic index *
> > pageSize
> >    to get the offset of a page?
> >
> > Thanks.
> > John
> >
>

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