linux-kernel - Re: [PATCH 2/2] zram: idle memory tracking

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Message-ID: <20180327004911.GA467@jagdpanzerIV>
Date:   Tue, 27 Mar 2018 09:49:11 +0900
From:   Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>
To:     Minchan Kim <minchan@...nel.org>
Cc:     Andrew Morton <akpm@...ux-foundation.org>,
        Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 2/2] zram: idle memory tracking

On (03/26/18 15:49), Minchan Kim wrote:
> zRam as swap is useful for small memory device. However, swap means
> those pages on zram are mostly cold pages due to VM's LRU algorithm.
> Especially, once init data for application are touched for launching,
> they tend to be not accessed any more and finally swapped out.
> zRAM can store such cold pages as compressed form but it's pointless
> to keep in memory. Better idea is app developers free them directly
> rather than remaining them on heap.
> 
> This patch tell us last accesss time of each block of zram via
> "cat /sys/kernel/debug/zram/zram0/access_time".
> 
> The output is as follows,
> 
> 276 1250
> 277 1800
> ..  ..
> ..  ..

So can we just use CONFIG_IDLE_PAGE_TRACKING + CONFIG_PAGE_OWNER?

	-ss