From: Minchan Kim <minchan@kernel.org>
To: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCHv2 1/4] zsmalloc: rework zspage chain size selection
Date: Fri, 13 Jan 2023 09:32:21 -0800 [thread overview]
Message-ID: <Y8GVpW0FkRh028hU@google.com> (raw)
In-Reply-To: <20230109033838.2779902-2-senozhatsky@chromium.org>
On Mon, Jan 09, 2023 at 12:38:35PM +0900, Sergey Senozhatsky wrote:
> Computers are bad at division. We currently decide the best
> zspage chain size (max number of physical pages per-zspage)
> by looking at a `used percentage` value. This is not enough
> as we lose precision during usage percentage calculations
> For example, let's look at size class 208:
>
> pages per zspage wasted bytes used%
> 1 144 96
> 2 80 99
> 3 16 99
> 4 160 99
>
> Current algorithm will select 2 page per zspage configuration,
> as it's the first one to reach 99%. However, 3 pages per zspage
> waste less memory.
>
> Change algorithm and select zspage configuration that has
> lowest wasted value.
>
> Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Acked-by: Minchan Kim <minchan@kernel.org>
next prev parent reply other threads:[~2023-01-13 17:32 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-09 3:38 [PATCHv2 0/4] zsmalloc: make zspage chain size configurable Sergey Senozhatsky
2023-01-09 3:38 ` [PATCHv2 1/4] zsmalloc: rework zspage chain size selection Sergey Senozhatsky
2023-01-13 17:32 ` Minchan Kim [this message]
2023-01-09 3:38 ` [PATCHv2 2/4] zsmalloc: skip chain size calculation for pow_of_2 classes Sergey Senozhatsky
2023-01-13 17:32 ` Minchan Kim
2023-01-09 3:38 ` [PATCHv2 3/4] zsmalloc: make zspage chain size configurable Sergey Senozhatsky
2023-01-12 7:11 ` Sergey Senozhatsky
2023-01-12 7:14 ` [PATCH] zsmalloc: turn chain size config option into UL constant Sergey Senozhatsky
2023-01-13 19:02 ` [PATCHv2 3/4] zsmalloc: make zspage chain size configurable Minchan Kim
2023-01-09 3:38 ` [PATCHv2 4/4] zsmalloc: set default zspage chain size to 8 Sergey Senozhatsky
2023-01-13 19:02 ` Minchan Kim
2023-01-14 7:28 ` Sergey Senozhatsky
2023-01-13 19:57 ` [PATCHv2 0/4] zsmalloc: make zspage chain size configurable Mike Kravetz
2023-01-14 5:27 ` Sergey Senozhatsky
2023-01-14 6:34 ` Sergey Senozhatsky
2023-01-14 7:08 ` Sergey Senozhatsky
2023-01-14 21:34 ` Mike Kravetz
2023-01-15 4:21 ` Sergey Senozhatsky
2023-01-15 5:32 ` Sergey Senozhatsky
2023-01-15 7:18 ` Sergey Senozhatsky
2023-01-15 8:19 ` Sergey Senozhatsky
2023-01-16 1:27 ` Huang, Ying
2023-01-16 3:46 ` Sergey Senozhatsky
2023-01-15 13:04 ` Matthew Wilcox
2023-01-15 14:55 ` Sergey Senozhatsky
2023-01-16 3:15 ` Sergey Senozhatsky
2023-01-16 18:34 ` Mike Kravetz
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