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| author | Michal Hocko <mhocko@suse.com> | 2017-07-06 15:38:18 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-07-06 16:24:32 -0700 |
| commit | c246a213f5bad687c6c2cea27d7265eaf8f6f5d7 (patch) | |
| tree | f3d1f51d6eed2b3b97b5d85e981aa748e9bc70f9 /include/linux/memory_hotplug.h | |
| parent | a69578a154ee1c00b572171f5bb5da7a83f9cd77 (diff) | |
| download | linux-0-day-c246a213f5bad687c6c2cea27d7265eaf8f6f5d7.tar.gz linux-0-day-c246a213f5bad687c6c2cea27d7265eaf8f6f5d7.tar.xz | |
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 <mhocko@suse.com>
Reported-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Tested-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Reza Arbab <arbab@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/memory_hotplug.h')
| -rw-r--r-- | include/linux/memory_hotplug.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h index 8a07a49fd8dc2..4d65a2fcac150 100644 --- a/include/linux/memory_hotplug.h +++ b/include/linux/memory_hotplug.h @@ -311,4 +311,6 @@ extern struct page *sparse_decode_mem_map(unsigned long coded_mem_map, unsigned long pnum); extern bool allow_online_pfn_range(int nid, unsigned long pfn, unsigned long nr_pages, int online_type); +extern struct zone *default_zone_for_pfn(int nid, unsigned long pfn, + unsigned long nr_pages); #endif /* __LINUX_MEMORY_HOTPLUG_H */ |