Re: [PATCH v3 4/5] powerpc/mm: restore top-down allocation when using movable_node

From: Reza Arbab
Date: Mon Sep 26 2016 - 16:49:04 EST

On Mon, Sep 26, 2016 at 09:17:43PM +0530, Aneesh Kumar K.V wrote:
+ /* bottom-up allocation may have been set by movable_node */
+ memblock_set_bottom_up(false);

By then we have done few memblock allocation right ?

Yes, some allocations do occur while bottom-up is set.

IMHO, we should do this early enough in prom.c after we do parse_early_param, with a comment there explaining that, we don't really support hotplug memblock and when we do that, this should be moved to a place where we can handle memblock allocation such that we avoid spreading memblock allocation to movable node.

Sure, we can do it earlier. The only consideration is that any potential calls to memblock_mark_hotplug() happen before we reset to top-down. Since we don't do that at all on power, the call can go anywhere.

Reza Arbab