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Date: Mon, 14 Sep 2015 16:12:22 +0200
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Subject: Re: [PATCH 0/3] allow zram to use zbud as underlying allocator
From: Vitaly Wool <vitalywool@gmail.com>
To: Vlastimil Babka <vbabka@suse.cz>
Cc: minchan@kernel.org, sergey.senozhatsky@gmail.com, ddstreet@ieee.org,
        LKML <linux-kernel@vger.kernel.org>, linux-mm@kvack.org
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On Mon, Sep 14, 2015 at 4:01 PM, Vlastimil Babka <vbabka@suse.cz> wrote:
>
> On 09/14/2015 03:49 PM, Vitaly Wool wrote:
>>
>> While using ZRAM on a small RAM footprint devices, together with
>> KSM,
>> I ran into several occasions when moving pages from compressed swap back
>> into the "normal" part of RAM caused significant latencies in system
>
>
> I'm sure Minchan will want to hear the details of that :)
>
>> operation. By using zbud I lose in compression ratio but gain in
>> determinism, lower latencies and lower fragmentation, so in the coming
>
>
> I doubt the "lower fragmentation" part given what I've read about the design of zbud and zsmalloc?

As it turns out, I see more cases of compaction kicking in and
significantly more compact_stalls with zsmalloc.

~vitaly