From 1f8d75c1b7dc62f017c542ca99e7da4a0839fb1e Mon Sep 17 00:00:00 2001 From: "Aneesh Kumar K.V" Date: Mon, 3 Feb 2020 17:34:06 -0800 Subject: [PATCH] mm/memmap_init: update variable name in memmap_init_zone Patch series "mm/memory_hotplug: Shrink zones before removing memory", v6. This series fixes the access of uninitialized memmaps when shrinking zones/nodes and when removing memory. Also, it contains all fixes for crashes that can be triggered when removing certain namespace using memunmap_pages() - ZONE_DEVICE, reported by Aneesh. We stop trying to shrink ZONE_DEVICE, as it's buggy, fixing it would be more involved (we don't have SECTION_IS_ONLINE as an indicator), and shrinking is only of limited use (set_zone_contiguous() cannot detect the ZONE_DEVICE as contiguous). We continue shrinking !ZONE_DEVICE zones, however, I reduced the amount of code to a minimum. Shrinking is especially necessary to keep zone->contiguous set where possible, especially, on memory unplug of DIMMs at zone boundaries. -------------------------------------------------------------------------- Zones are now properly shrunk when offlining memory blocks or when onlining failed. This allows to properly shrink zones on memory unplug even if the separate memory blocks of a DIMM were onlined to different zones or re-onlined to a different zone after offlining. Example: :/# cat /proc/zoneinfo Node 1, zone Movable spanned 0 present 0 managed 0 :/# echo "online_movable" > /sys/devices/system/memory/memory41/state :/# echo "online_movable" > /sys/devices/system/memory/memory43/state :/# cat /proc/zoneinfo Node 1, zone Movable spanned 98304 present 65536 managed 65536 :/# echo 0 > /sys/devices/system/memory/memory43/online :/# cat /proc/zoneinfo Node 1, zone Movable spanned 32768 present 32768 managed 32768 :/# echo 0 > /sys/devices/system/memory/memory41/online :/# cat /proc/zoneinfo Node 1, zone Movable spanned 0 present 0 managed 0 This patch (of 6): The third argument is actually number of pages. Change the variable name from size to nr_pages to indicate this better. No functional change in this patch. Link: http://lkml.kernel.org/r/20191006085646.5768-3-david@redhat.com Signed-off-by: Aneesh Kumar K.V Signed-off-by: David Hildenbrand Reviewed-by: Pankaj Gupta Reviewed-by: David Hildenbrand Cc: Michal Hocko Cc: "Matthew Wilcox (Oracle)" Cc: "Aneesh Kumar K.V" Cc: Pavel Tatashin Cc: Greg Kroah-Hartman Cc: Dan Williams Cc: Logan Gunthorpe Cc: Oscar Salvador Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/page_alloc.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 494f74a1725d..3c4eb750a199 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -5946,10 +5946,10 @@ void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone, #ifdef CONFIG_ZONE_DEVICE void __ref memmap_init_zone_device(struct zone *zone, unsigned long start_pfn, - unsigned long size, + unsigned long nr_pages, struct dev_pagemap *pgmap) { - unsigned long pfn, end_pfn = start_pfn + size; + unsigned long pfn, end_pfn = start_pfn + nr_pages; struct pglist_data *pgdat = zone->zone_pgdat; struct vmem_altmap *altmap = pgmap_altmap(pgmap); unsigned long zone_idx = zone_idx(zone); @@ -5966,7 +5966,7 @@ void __ref memmap_init_zone_device(struct zone *zone, */ if (altmap) { start_pfn = altmap->base_pfn + vmem_altmap_offset(altmap); - size = end_pfn - start_pfn; + nr_pages = end_pfn - start_pfn; } for (pfn = start_pfn; pfn < end_pfn; pfn++) { @@ -6013,7 +6013,7 @@ void __ref memmap_init_zone_device(struct zone *zone, } pr_info("%s initialised %lu pages in %ums\n", __func__, - size, jiffies_to_msecs(jiffies - start)); + nr_pages, jiffies_to_msecs(jiffies - start)); } #endif -- 2.11.0