From 39fa104d5b87655c1c19d4b1990ea63d190c4817 Mon Sep 17 00:00:00 2001 From: Reza Arbab Date: Mon, 12 Dec 2016 16:42:55 -0800 Subject: mm: remove x86-only restriction of movable_node In commit c5320926e370 ("mem-hotplug: introduce movable_node boot option"), the memblock allocation direction is changed to bottom-up and then back to top-down like this: 1. memblock_set_bottom_up(true), called by cmdline_parse_movable_node(). 2. memblock_set_bottom_up(false), called by x86's numa_init(). Even though (1) occurs in generic mm code, it is wrapped by #ifdef CONFIG_MOVABLE_NODE, which depends on X86_64. This means that when we extend CONFIG_MOVABLE_NODE to non-x86 arches, things will be unbalanced. (1) will happen for them, but (2) will not. This toggle was added in the first place because x86 has a delay between adding memblocks and marking them as hotpluggable. Since other arches do this marking either immediately or not at all, they do not require the bottom-up toggle. So, resolve things by moving (1) from cmdline_parse_movable_node() to x86's setup_arch(), immediately after the movable_node parameter has been parsed. Link: http://lkml.kernel.org/r/1479160961-25840-3-git-send-email-arbab@linux.vnet.ibm.com Signed-off-by: Reza Arbab Acked-by: Balbir Singh Cc: "Aneesh Kumar K.V" Cc: "H. Peter Anvin" Cc: Alistair Popple Cc: Aneesh Kumar K.V Cc: Benjamin Herrenschmidt Cc: Bharata B Rao Cc: Frank Rowand Cc: Ingo Molnar Cc: Michael Ellerman Cc: Nathan Fontenot Cc: Paul Mackerras Cc: Rob Herring Cc: Stewart Smith Cc: Thomas Gleixner Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/memory_hotplug.c | 20 -------------------- 1 file changed, 20 deletions(-) (limited to 'mm') diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index cad4b9125695..e43142c15631 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -1727,26 +1727,6 @@ static bool can_offline_normal(struct zone *zone, unsigned long nr_pages) static int __init cmdline_parse_movable_node(char *p) { #ifdef CONFIG_MOVABLE_NODE - /* - * Memory used by the kernel cannot be hot-removed because Linux - * cannot migrate the kernel pages. When memory hotplug is - * enabled, we should prevent memblock from allocating memory - * for the kernel. - * - * ACPI SRAT records all hotpluggable memory ranges. But before - * SRAT is parsed, we don't know about it. - * - * The kernel image is loaded into memory at very early time. We - * cannot prevent this anyway. So on NUMA system, we set any - * node the kernel resides in as un-hotpluggable. - * - * Since on modern servers, one node could have double-digit - * gigabytes memory, we can assume the memory around the kernel - * image is also un-hotpluggable. So before SRAT is parsed, just - * allocate memory near the kernel image to try the best to keep - * the kernel away from hotpluggable memory. - */ - memblock_set_bottom_up(true); movable_node_enabled = true; #else pr_warn("movable_node option not supported\n"); -- cgit v1.2.3-55-g7522