Messages in this thread | | | Date | Sun, 30 Jul 2006 11:48:41 -0700 | From | "H. Peter Anvin" <> | Subject | Re: [PATCH] initramfs: Allow rootfs to use tmpfs instead of ramfs |
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Hugh Dickins wrote: > On Sun, 30 Jul 2006, Al Boldi wrote: >> Replugs rootfs to use tmpfs instead of ramfs as a Kconfig option. > > Why? Looking further down we see what you should have explained here: >> + This option switches rootfs so that it uses tmpfs rather than ramfs >> + for its file storage. This makes rootfs swappable so having a large >> + initrd or initramfs image won't eat up valuable RAM. > > Now, I'm far from an expert on initramfs and early userspace, but my > understanding is that the "init" of a (properly designed) initramfs > would pretty much "rm -rf" everything in the initramfs before passing > control to the final "init". So (almost?) no valuable RAM is eaten > up, nor the less valuable swap if you do extend this to tmpfs (unless > something gets left open, which I think should not be the case). > > So I'm inclined to say that this patch is simply unnecessary. But > if people who know better think it's a good thing, I've no objection > (though I've not tried it): the Kconfiggery looks more likely to > provoke argument than the tmpfs/ramfs mods. >
Well...
There is some justification: embedded people would like to load inittmpfs and then continue running.
The main issue -- which I am not sure what effect this patch has -- is that we would really like to move initramfs initialization even earlier in the kernel, so that it can include firmware loading for built-in device drivers, for example.
Thus, if this patch makes it harder to push initramfs initialization earlier, it's probably a bad thing. If not, the author of the patch really needs to explain why it works and why it doesn't add new dependencies to the initialization order.
Saying "this is a trivial patch" and pushing it on the -stable tree doesn't inspire too much confidence, as initialization is subtle.
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