Re: [PATCH v3 4/5] powerpc/mm: restore top-down allocation when using movable_node
From: Aneesh Kumar K.V <hidden>
Date: 2016-09-26 15:48:14
Also in:
linux-devicetree, linux-mm, lkml
Reza Arbab [off-list ref] writes:
quoted hunk ↗ jump to hunk
At boot, the movable_node option sets bottom-up memblock allocation. This reduces the chance that, in the window before movable memory has been identified, an allocation for the kernel might come from a movable node. By going bottom-up, early allocations will most likely come from the same node as the kernel image, which is necessarily in a nonmovable node. Then, once any known hotplug memory has been marked, allocation can be reset back to top-down. On x86, this is done in numa_init(). This patch does the same on power, in numa initmem_init(). Signed-off-by: Reza Arbab <redacted> --- arch/powerpc/mm/numa.c | 3 +++ 1 file changed, 3 insertions(+)diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c index d7ac419..fdf1e69 100644 --- a/arch/powerpc/mm/numa.c +++ b/arch/powerpc/mm/numa.c@@ -945,6 +945,9 @@ void __init initmem_init(void) max_low_pfn = memblock_end_of_DRAM() >> PAGE_SHIFT; max_pfn = max_low_pfn; + /* bottom-up allocation may have been set by movable_node */ + memblock_set_bottom_up(false); +
By then we have done few memblock allocation right ? 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.
if (parse_numa_properties()) setup_nonnuma(); else -- 1.8.3.1
-aneesh