From 95cf82ecc1fcb44df1768162343cc8eb88083b86 Mon Sep 17 00:00:00 2001 From: Tang Chen Date: Tue, 8 Sep 2015 15:02:03 -0700 Subject: [PATCH] mem-hotplug: handle node hole when initializing numa_meminfo. When parsing SRAT, all memory ranges are added into numa_meminfo. In numa_init(), before entering numa_cleanup_meminfo(), all possible memory ranges are in numa_meminfo. And numa_cleanup_meminfo() removes all ranges over max_pfn or empty. But, this only works if the nodes are continuous. Let's have a look at the following example: We have an SRAT like this: SRAT: Node 0 PXM 0 [mem 0x00000000-0x5fffffff] SRAT: Node 0 PXM 0 [mem 0x100000000-0x1ffffffffff] SRAT: Node 1 PXM 1 [mem 0x20000000000-0x3ffffffffff] SRAT: Node 4 PXM 2 [mem 0x40000000000-0x5ffffffffff] hotplug SRAT: Node 5 PXM 3 [mem 0x60000000000-0x7ffffffffff] hotplug SRAT: Node 2 PXM 4 [mem 0x80000000000-0x9ffffffffff] hotplug SRAT: Node 3 PXM 5 [mem 0xa0000000000-0xbffffffffff] hotplug SRAT: Node 6 PXM 6 [mem 0xc0000000000-0xdffffffffff] hotplug SRAT: Node 7 PXM 7 [mem 0xe0000000000-0xfffffffffff] hotplug On boot, only node 0,1,2,3 exist. And the numa_meminfo will look like this: numa_meminfo.nr_blks = 9 1. on node 0: [0, 60000000] 2. on node 0: [100000000, 20000000000] 3. on node 1: [20000000000, 40000000000] 4. on node 4: [40000000000, 60000000000] 5. on node 5: [60000000000, 80000000000] 6. on node 2: [80000000000, a0000000000] 7. on node 3: [a0000000000, a0800000000] 8. on node 6: [c0000000000, a0800000000] 9. on node 7: [e0000000000, a0800000000] And numa_cleanup_meminfo() will merge 1 and 2, and remove 8,9 because the end address is over max_pfn, which is a0800000000. But 4 and 5 are not removed because their end addresses are less then max_pfn. But in fact, node 4 and 5 don't exist. In a word, numa_cleanup_meminfo() is not able to handle holes between nodes. Since memory ranges in node 4 and 5 are in numa_meminfo, in numa_register_memblks(), node 4 and 5 will be mistakenly set to online. If you run lscpu, it will show: NUMA node0 CPU(s): 0-14,128-142 NUMA node1 CPU(s): 15-29,143-157 NUMA node2 CPU(s): NUMA node3 CPU(s): NUMA node4 CPU(s): 62-76,190-204 NUMA node5 CPU(s): 78-92,206-220 In this patch, we use memblock_overlaps_region() to check if ranges in numa_meminfo overlap with ranges in memory_block. Since memory_block contains all available memory at boot time, if they overlap, it means the ranges exist. If not, then remove them from numa_meminfo. After this patch, lscpu will show: NUMA node0 CPU(s): 0-14,128-142 NUMA node1 CPU(s): 15-29,143-157 NUMA node4 CPU(s): 62-76,190-204 NUMA node5 CPU(s): 78-92,206-220 Signed-off-by: Tang Chen Reviewed-by: Yasuaki Ishimatsu Cc: Thomas Gleixner Cc: Tejun Heo Cc: Luiz Capitulino Cc: Xishi Qiu Cc: Will Deacon Cc: Vladimir Murzin Cc: Fabian Frederick Cc: Alexander Kuleshov Cc: Baoquan He Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/x86/mm/numa.c | 6 ++++-- include/linux/memblock.h | 2 ++ mm/memblock.c | 2 +- 3 files changed, 7 insertions(+), 3 deletions(-) diff --git a/arch/x86/mm/numa.c b/arch/x86/mm/numa.c index 4053bb58bf92..c3b3f653ed0c 100644 --- a/arch/x86/mm/numa.c +++ b/arch/x86/mm/numa.c @@ -246,8 +246,10 @@ int __init numa_cleanup_meminfo(struct numa_meminfo *mi) bi->start = max(bi->start, low); bi->end = min(bi->end, high); - /* and there's no empty block */ - if (bi->start >= bi->end) + /* and there's no empty or non-exist block */ + if (bi->start >= bi->end || + !memblock_overlaps_region(&memblock.memory, + bi->start, bi->end - bi->start)) numa_remove_memblk_from(i--, mi); } diff --git a/include/linux/memblock.h b/include/linux/memblock.h index d312ae3b51fc..c518eb589260 100644 --- a/include/linux/memblock.h +++ b/include/linux/memblock.h @@ -77,6 +77,8 @@ int memblock_remove(phys_addr_t base, phys_addr_t size); int memblock_free(phys_addr_t base, phys_addr_t size); int memblock_reserve(phys_addr_t base, phys_addr_t size); void memblock_trim_memory(phys_addr_t align); +bool memblock_overlaps_region(struct memblock_type *type, + phys_addr_t base, phys_addr_t size); int memblock_mark_hotplug(phys_addr_t base, phys_addr_t size); int memblock_clear_hotplug(phys_addr_t base, phys_addr_t size); int memblock_mark_mirror(phys_addr_t base, phys_addr_t size); diff --git a/mm/memblock.c b/mm/memblock.c index 08a5126338db..509255223688 100644 --- a/mm/memblock.c +++ b/mm/memblock.c @@ -91,7 +91,7 @@ static unsigned long __init_memblock memblock_addrs_overlap(phys_addr_t base1, p return ((base1 < (base2 + size2)) && (base2 < (base1 + size1))); } -static bool __init_memblock memblock_overlaps_region(struct memblock_type *type, +bool __init_memblock memblock_overlaps_region(struct memblock_type *type, phys_addr_t base, phys_addr_t size) { unsigned long i; -- 2.20.1