On Thu, Apr 14, 2011 at 01:03:37PM +0900, Tejun Heo wrote: > Hello, > > On Wed, Apr 13, 2011 at 07:33:40PM -0700, Linus Torvalds wrote: > > On Wednesday, April 13, 2011, Linus Torvalds > > <torvalds at linux-foundation.org> wrote: > > > On Wednesday, April 13, 2011, H. Peter Anvin <hpa at zytor.com> wrote: > > >> > > >> Yes. ?However, even if we *do* revert (and the time is running short on > > >> not reverting) I would like to understand this particular one, simply > > >> because I think it may very well be a problem that is manifesting itself > > >> in other ways on other systems. > > > > sorry, fingerfart. Anyway, I agree 100%. > > > > we definitely want to also understand the reason for things not > > working, even if we do revert.. > > There were (and still are) places where memblock callers implemented > ad-hoc top-down allocation by stepping down start limit until > allocation succeeds. Several of them have been removed since top-down > became the default behavior, so simply reverting the commit is likely > to cause subtle issues. Maybe the best approach is introducing > @topdown parameter and use it selectively for pure memory allocations.
Wouldn't it be better to provide a seperate memblock allocation function which operates top-down and use this one in the places that need it? This way it wouldn't break code that relies on bottom-up. Joerg