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 Fri, 17 Jul 2020 09:18:07 +0300 (MSK)
Date: Fri, 17 Jul 2020 09:18:06 +0300
From: Kirill Yukhin <kyukhin@tarantool.org>
Message-ID: <20200717061806.fgxigglplle6wovp@tarantool.org>
References: <20200629121118.21596-1-arkholga@tarantool.org>
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In-Reply-To: <20200629121118.21596-1-arkholga@tarantool.org>
Subject: Re: [Tarantool-patches] [PATCH 0/1] fix box.info:memory()
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To: Olga Arkhangelskaia <arkholga@tarantool.org>
Cc: tarantool-patches@dev.tarantool.org, alexander.turenko@tarantool.org

Hello,

On 29 июн 15:11, Olga Arkhangelskaia wrote:
> The patch fixes the output of box.info:memory(). It used to return the same
> table as the box.info().
> 
> box.info.memory() can be written as box.info[“memory”](), that later has the only
> one argument on the stack - box.info.memory table we need to fill:
> box.info.memory() -> getmetatable(box.info.memory).__call(box.info.memory)[1]
> box.info:memory() call is the same as box.info[“memory”](box.info). So, it
> results in extra argument on the stack[1].
> box.info:mem()->getmetatable(box.info.memory).__call(box.info.memory, box.info).
> When function tries to fill box.info table - __call metamethod of box.info is
> trigged - resulting in box.info table returned as the result.
> 
> There are two options to get rid if extra box.info table:
> 1. Create new table in the beginning of the function(eg. box.info.gc).
> Every time box.info.memory is called it will generate new table with the fresh
> info.
> 2. The second way is to ignore box.info argument on the stack and fill
> directly box.info.memory table, that was passed as an argument.
> 
> I have implemented the first approach because there is box.info.gc works
> the same way and we only need to add one line of code.
> However, I do not know why it was done in such a way on the first place.
> So if you have pros for the second options, please share with me.
> 
> [1] https://www.lua.org/manual/5.1/manual.html#2.8
> 
> @Changelog:
> To retrieve information about memory usage box.info:memory() can be used.
> Olga Arkhangelskaia (1):
>   box: fixed box.info:memory()

I've checked your patch into master.

--
Regards, Kirill Yukhin