From: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
To: Minchan Kim <minchan@kernel.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 2/2] zram: idle memory tracking
Date: Tue, 27 Mar 2018 10:13:27 +0900 [thread overview]
Message-ID: <20180327011327.GE467@jagdpanzerIV> (raw)
In-Reply-To: <20180327010347.GA41148@rodete-desktop-imager.corp.google.com>
On (03/27/18 10:03), Minchan Kim wrote:
> On Tue, Mar 27, 2018 at 09:49:11AM +0900, Sergey Senozhatsky wrote:
> > 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?
>
> The goal is not mapped memory tracking but one swapped out.
> Can we do it by above two combination?
Ah, you are right. page_idle tracks only pages which are on LRU lists.
> Furthermore, I am planning to provide incompressible pages as well
> as access time so I will change interface at v2.
OK.
-ss
next prev parent reply other threads:[~2018-03-27 1:13 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-26 6:49 [PATCH 1/2] zram: correct flag name of ZRAM_ACCESS Minchan Kim
2018-03-26 6:49 ` [PATCH 2/2] zram: idle memory tracking Minchan Kim
2018-03-26 8:15 ` Greg KH
2018-03-26 9:57 ` Minchan Kim
2018-03-27 0:49 ` Sergey Senozhatsky
2018-03-27 1:03 ` Minchan Kim
2018-03-27 1:13 ` Sergey Senozhatsky [this message]
2018-03-27 1:47 ` Sergey Senozhatsky
2018-03-27 2:05 ` Minchan Kim
2018-03-27 2:21 ` Sergey Senozhatsky
2018-03-27 2:26 ` Minchan Kim
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