From: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
To: Minchan Kim <minchan@kernel.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v6 11/12] zsmalloc: page migration support
Date: Thu, 26 May 2016 09:59:26 +0900 [thread overview]
Message-ID: <20160526005926.GA532@swordfish> (raw)
In-Reply-To: <20160526003241.GA9661@bbox>
Hello Minchan,
On (05/26/16 09:32), Minchan Kim wrote:
[..]
> Unfortunately, I don't have now. However, I don't feel we need a data for
> that because *unbounded work* within VM interaction context is bad. ;-)
fair enough, even though the shrinker doesn't put any constraints here.
> > hm, probably it makes sense to change it. but if the change will
> > replace "1 full pool scan" to "2 scans of 1/2 of pool's classes",
> > then I'm less sure.
>
> Other shrinker is on same page. They have *cache* which is helpful for
> performance but if it's not hot, it can lose performance if memory
> pressure is severe. For the balance, comprimise approach is shrinker.
>
> We can see fragement space in zspage as wasted memory which is bad
> on the other hand we can see it as cache to store upcoming compressed
> page. So, too much freeing can hurt the performance so, let's obey
> VM's rule. If memory pressure goes severe, they want to reclaim more
> pages with proportional of memory pressure.
I agree that the unused memory has a dual nature here. we don't really
do the "compact too much" thing, in a sense that we very rarely compact
classes to be ZS_FULL. ~2-3% of the cases (if I recall the testing
results correctly). but reducing the class ->lock pressure is a nice
thing on its own. so yeah, let's do it!
btw, I've uploaded zram-fio test script to
https://github.com/sergey-senozhatsky/zram-perf-test
it's very minimalistic and half baked, but can be used
to some degree. open to patches, improvements, etc.
-ss
next prev parent reply other threads:[~2016-05-26 0:59 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-20 14:23 [PATCH v6 00/12] Support non-lru page migration Minchan Kim
2016-05-20 14:23 ` [PATCH v6 01/12] mm: use put_page to free page instead of putback_lru_page Minchan Kim
2016-05-20 14:23 ` [PATCH v6 02/12] mm: migrate: support non-lru movable page migration Minchan Kim
2016-05-27 14:26 ` Vlastimil Babka
2016-05-30 1:33 ` Minchan Kim
2016-05-30 9:01 ` Vlastimil Babka
2016-05-30 1:39 ` PATCH v6v2 " Minchan Kim
2016-05-30 9:36 ` Vlastimil Babka
2016-05-30 16:25 ` Minchan Kim
2016-05-31 7:51 ` Vlastimil Babka
2016-05-31 0:01 ` [PATCH v6v3 " Minchan Kim
2016-05-31 7:52 ` Vlastimil Babka
2016-05-31 23:05 ` Minchan Kim
2016-06-13 9:38 ` Anshuman Khandual
2016-06-15 2:32 ` Minchan Kim
2016-06-15 6:45 ` Anshuman Khandual
2016-06-16 0:26 ` Minchan Kim
2016-06-16 3:42 ` Anshuman Khandual
2016-06-16 5:37 ` Minchan Kim
2016-06-27 5:51 ` Anshuman Khandual
2016-06-28 6:39 ` Minchan Kim
2016-06-30 5:56 ` Anshuman Khandual
2016-06-30 6:18 ` Minchan Kim
2016-05-20 14:23 ` [PATCH v6 03/12] mm: balloon: use general non-lru movable page feature Minchan Kim
2016-05-30 12:16 ` Vlastimil Babka
2016-05-20 14:23 ` [PATCH v6 04/12] zsmalloc: keep max_object in size_class Minchan Kim
2016-05-20 14:23 ` [PATCH v6 05/12] zsmalloc: use bit_spin_lock Minchan Kim
2016-05-20 14:23 ` [PATCH v6 06/12] zsmalloc: use accessor Minchan Kim
2016-05-20 14:23 ` [PATCH v6 07/12] zsmalloc: factor page chain functionality out Minchan Kim
2016-05-20 14:23 ` [PATCH v6 08/12] zsmalloc: introduce zspage structure Minchan Kim
2016-05-20 14:23 ` [PATCH v6 09/12] zsmalloc: separate free_zspage from putback_zspage Minchan Kim
2016-05-20 14:23 ` [PATCH v6 10/12] zsmalloc: use freeobj for index Minchan Kim
2016-05-20 14:23 ` [PATCH v6 11/12] zsmalloc: page migration support Minchan Kim
2016-05-24 5:28 ` Sergey Senozhatsky
2016-05-24 6:28 ` Minchan Kim
2016-05-24 8:05 ` Sergey Senozhatsky
2016-05-24 8:17 ` Minchan Kim
2016-05-25 5:14 ` Minchan Kim
2016-05-25 15:23 ` Sergey Senozhatsky
2016-05-26 0:32 ` Minchan Kim
2016-05-26 0:59 ` Sergey Senozhatsky [this message]
2016-05-26 4:37 ` Minchan Kim
2016-05-26 21:50 ` [PATCH v6r2 " Minchan Kim
2016-05-20 14:23 ` [PATCH v6 12/12] zram: use __GFP_MOVABLE for memory allocation Minchan Kim
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