linux-kernel - RE: [PATCH 0/5] cramfs refresh for embedded usage

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Message-ID: <alpine.LFD.2.20.1708162111170.17016@knanqh.ubzr>
Date:   Wed, 16 Aug 2017 21:17:45 -0400 (EDT)
From:   Nicolas Pitre <nicolas.pitre@...aro.org>
To:     Chris Brandt <Chris.Brandt@...esas.com>
cc:     Alexander Viro <viro@...iv.linux.org.uk>,
        "linux-fsdevel@...r.kernel.org" <linux-fsdevel@...r.kernel.org>,
        "linux-embedded@...r.kernel.org" <linux-embedded@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH 0/5] cramfs refresh for embedded usage

On Wed, 16 Aug 2017, Chris Brandt wrote:

> I made an example once were all the graphics were RAW and uncompressed 
> and marked as XIP in AXFS. The result was a large saving of RAM because 
> as the graphics framework (DirectFB) would copy directly from Flash 
> whenever it needed to do a background erase or image re-draw (button press 
> animations).
> 
> Same went for playing MP3 files. The MP3 files were XIP in flash, so 
> mpg123 pulled from flash directly.

I wouldn't have expected mpg123 to mmap() its input files though.
If you use read() and not mmap() then you don't get the full benefit.


Nicolas