linux-kernel - Re: [PATCH RFC] initrd: resize /dev/ram as needed

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Message-ID: <20250321050146.GD1831@lst.de>
Date: Fri, 21 Mar 2025 06:01:46 +0100
From: Christoph Hellwig <hch@....de>
To: julian.stecklina@...erus-technology.de
Cc: Christoph Hellwig <hch@....de>, Al Viro <viro@...iv.linux.org.uk>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	"Rafael J. Wysocki" <rafael@...nel.org>,
	linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH RFC] initrd: resize /dev/ram as needed

On Thu, Mar 20, 2025 at 08:46:14PM +0100, Julian Stecklina via B4 Relay wrote:
> From: Julian Stecklina <julian.stecklina@...erus-technology.de>
> 
> When the initrd doesn't fit into the RAM disk, we currently just die.
> This is unfortunate, because users have to manually configure the RAM
> disk size for no good reason. It also means that the kernel command
> line needs to be changed for different initrds, which is sometimes
> cumbersome.
> 
> Attempt resizing /dev/ram to fit the RAM disk size instead. This makes
> initrd images work a bit more like initramfs images in that they just
> work.
> 
> Of course, this only works, because we know that /dev/ram is a RAM
> disk and we can resize it freely. I'm not sure whether I've used the
> blockdev APIs here in a sane way. If not, please advise!

Just use an initramfs and avoid all these problems.