On Mon, 26 Mar 2007 12:25:18 +0100 David Howells <[EMAIL PROTECTED]> wrote:
> Andrew Morton <[EMAIL PROTECTED]> wrote: > > > Offending patch is > > ftp://ftp.kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.21-rc4/2.6.21-rc4-mm1/broken-out/nommu-hide-vm_mm-in-nommu-mode.patch, > > which seems rather dumb. Or at least, its changelog does a good job of > > making it look dumb. > > vm_mm is always NULL under NOMMU as it currently stands. As far as I know, > this has been true since the NOMMU mm stuff was first included (I'm not sure > the VMAs of the first NOMMU mm code *had* a vm_mm). Hugh (I think it was) > suggested that since this was always NULL, then it should be excised from the > struct in NOMMU-mode. > > The reason is that, at the moment, VMAs are a global *shared* resource in > NOMMU-mode. Each process has a list of global VMAs that it subscribes to, but > that's it. This (a) slightly reduces the amount of metadata allocated > (possibly), and (b) makes sharing of executables and libraries much easier. whoa. You live and learn. Logical, I guess. I agree that in that case, we just don't want vm_mm to exist in NOMMU builds - it's better to fail at compile time. I'll touch up the changelog for nommu-hide-vm_mm-in-nommu-mode.patch and then I'll temporarily drop it so the blackfin guys can test their work, I guess. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
