From mboxrd@z Thu Jan 1 00:00:00 1970 From: "H. Peter Anvin" Subject: Re: [PATCH 0/5] initmpfs v2: use tmpfs instead of ramfs for rootfs Date: Thu, 18 Jul 2013 16:59:50 -0700 Message-ID: <51E88176.6040505@zytor.com> References: <20130715140135.0f896a584fec9f7861049b64@linux-foundation.org> <20130717160602.4b225ac80b1cb6121cbb489c@linux-foundation.org> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Cc: Rob Landley , linux-kernel@vger.kernel.org, Alexander Viro , "Eric W. Biederman" , Greg Kroah-Hartman , Hugh Dickins , Jeff Layton , Jens Axboe , Jim Cromie , linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, Rusty Russell , Sam Ravnborg , Stephen Warren To: Andrew Morton Return-path: In-Reply-To: <20130717160602.4b225ac80b1cb6121cbb489c@linux-foundation.org> Sender: owner-linux-mm@kvack.org List-Id: linux-fsdevel.vger.kernel.org On 07/17/2013 04:06 PM, Andrew Morton wrote: > On Tue, 16 Jul 2013 08:31:13 -0700 (PDT) Rob Landley wrote: > >> Use tmpfs for rootfs when CONFIG_TMPFS=y and there's no root=. >> Specify rootfstype=ramfs to get the old initramfs behavior. >> >> The previous initramfs code provided a fairly crappy root filesystem: >> didn't let you --bind mount directories out of it, reported zero >> size/usage so it didn't show up in "df" and couldn't run things like >> rpm that query available space before proceeding, would fill up all >> available memory and panic the system if you wrote too much to it... > > The df problem and the mount --bind thing are ramfs issues, are they > not? Can we fix them? If so, that's a less intrusive change, and we > also get a fixed ramfs. > mount --bind might be useful to fix for ramfs in general (as ramfs should provide minimal standard filesystem functionality, and that one counts, I believe), but honestly... we should have had tmpfs as a root filesystem option either as rootfs or as an automatic overmount a long time ago. The automatic overmount option (that is tmpfs on top of rootfs) is nice in some ways, as it makes garbage-collecting the inittmpfs trivial; this might save some boot time in the more conventional root scenarios. On the other hand, it doesn't exactly seem to be a big problem to just unlink everything. -hpa -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org