From c246a213f5bad687c6c2cea27d7265eaf8f6f5d7 Mon Sep 17 00:00:00 2001 From: Michal Hocko Date: Thu, 6 Jul 2017 15:38:18 -0700 Subject: mm, memory_hotplug: do not assume ZONE_NORMAL is default kernel zone Heiko Carstens has noticed that he can generate overlapping zones for ZONE_DMA and ZONE_NORMAL: DMA [mem 0x0000000000000000-0x000000007fffffff] Normal [mem 0x0000000080000000-0x000000017fffffff] $ cat /sys/devices/system/memory/block_size_bytes 10000000 $ cat /sys/devices/system/memory/memory5/valid_zones DMA $ echo 0 > /sys/devices/system/memory/memory5/online $ cat /sys/devices/system/memory/memory5/valid_zones Normal $ echo 1 > /sys/devices/system/memory/memory5/online Normal $ cat /proc/zoneinfo Node 0, zone DMA spanned 524288 <----- present 458752 managed 455078 start_pfn: 0 <----- Node 0, zone Normal spanned 720896 present 589824 managed 571648 start_pfn: 327680 <----- The reason is that we assume that the default zone for kernel onlining is ZONE_NORMAL. This was a simplification introduced by the memory hotplug rework and it is easily fixable by checking the range overlap in the zone order and considering the first matching zone as the default one. If there is no such zone then assume ZONE_NORMAL as we have been doing so far. Fixes: "mm, memory_hotplug: do not associate hotadded memory to zones until online" Link: http://lkml.kernel.org/r/20170601083746.4924-3-mhocko@kernel.org Signed-off-by: Michal Hocko Reported-by: Heiko Carstens Tested-by: Heiko Carstens Acked-by: Vlastimil Babka Cc: Dan Williams Cc: Reza Arbab Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/base/memory.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/base') diff --git a/drivers/base/memory.c b/drivers/base/memory.c index b86fda30ce62..c7c4e0325cdb 100644 --- a/drivers/base/memory.c +++ b/drivers/base/memory.c @@ -419,7 +419,7 @@ static ssize_t show_valid_zones(struct device *dev, nid = pfn_to_nid(start_pfn); if (allow_online_pfn_range(nid, start_pfn, nr_pages, MMOP_ONLINE_KERNEL)) { - strcat(buf, NODE_DATA(nid)->node_zones[ZONE_NORMAL].name); + strcat(buf, default_zone_for_pfn(nid, start_pfn, nr_pages)->name); append = true; } -- cgit