Rather than splitting huge_cma in online nodes, it is better to do it in
nodes with memory.
For an ARM64 server with four numa nodes and only node0 has memory. If I
set hugetlb_cma=4G in bootargs,
without this patch, I got the below printk:
hugetlb_cma: reserve 4096 MiB, up to 1024 MiB per node
hugetlb_cma: reserved 1024 MiB on node 0
hugetlb_cma: reservation failed: err -12, node 1
hugetlb_cma: reservation failed: err -12, node 2
hugetlb_cma: reservation failed: err -12, node 3
hugetlb_cma size is broken once the system has nodes without memory.
With this patch, I got the below printk:
hugetlb_cma: reserve 4096 MiB, up to 4096 MiB per node
hugetlb_cma: reserved 4096 MiB on node 0
So this patch fixes the broken hugetlb_cma size on arm64.
Jonathan Cameron tested this patch on x86 platform. Jonathan figured out x86
is much different with arm64. hugetlb_cma size has never broken on x86.
On arm64 all nodes are marked online at the same time. On x86, only
nodes with memory are initially marked as online:
initmem_init()->x86_numa_init()->numa_init()->
numa_register_memblks()->alloc_node_data()->node_set_online()
So at time of the existing cma setup call only the memory containing nodes
are online. The other nodes are brought up much later.
Thus, the change is simply to fix ARM64. A change is needed to x86 only
because the inherent assumptions in cma_hugetlb_reserve() have changed.
Fixes: cf11e85fc08c ("mm: hugetlb: optionally allocate gigantic hugepages using
cma")
Cc: Roman Gushchin <g...@fb.com>
Cc: Catalin Marinas <catalin.mari...@arm.com>
Cc: Will Deacon <w...@kernel.org>
Cc: Thomas Gleixner <t...@linutronix.de>
Cc: Ingo Molnar <mi...@redhat.com>
Cc: Borislav Petkov <b...@alien8.de>
Cc: H. Peter Anvin <h...@zytor.com>
Cc: Mike Kravetz <mike.krav...@oracle.com>
Cc: Mike Rapoport <r...@linux.ibm.com>
Cc: Andrew Morton <a...@linux-foundation.org>
Cc: Anshuman Khandual <anshuman.khand...@arm.com>
Cc: Jonathan Cameron <jonathan.came...@huawei.com>
Signed-off-by: Barry Song <song.bao....@hisilicon.com>
---
arch/arm64/mm/init.c | 18 +++++++++---------
arch/x86/kernel/setup.c | 13 ++++++++++---
mm/hugetlb.c | 4 ++--
3 files changed, 21 insertions(+), 14 deletions(-)
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index 1e93cfc7c47a..f6090ef6812b 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -420,15 +420,6 @@ void __init bootmem_init(void)
arm64_numa_init();
- /*
- * must be done after arm64_numa_init() which calls numa_init() to
- * initialize node_online_map that gets used in hugetlb_cma_reserve()
- * while allocating required CMA size across online nodes.
- */
-#ifdef CONFIG_ARM64_4K_PAGES
- hugetlb_cma_reserve(PUD_SHIFT - PAGE_SHIFT);
-#endif
-
/*
* Sparsemem tries to allocate bootmem in memory_present(), so must be
* done after the fixed reservations.
@@ -438,6 +429,15 @@ void __init bootmem_init(void)
sparse_init();
zone_sizes_init(min, max);
+ /*
+ * must be done after zone_sizes_init() which calls node_set_state() to
+ * setup node_states[N_MEMORY] that gets used in hugetlb_cma_reserve()
+ * while allocating required CMA size across nodes with memory.
+ */
+#ifdef CONFIG_ARM64_4K_PAGES
+ hugetlb_cma_reserve(PUD_SHIFT - PAGE_SHIFT);
+#endif
+
memblock_dump_all();
}
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index a3767e74c758..fdb3a934b6c6 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -1164,9 +1164,6 @@ void __init setup_arch(char **cmdline_p)
initmem_init();
dma_contiguous_reserve(max_pfn_mapped << PAGE_SHIFT);
- if (boot_cpu_has(X86_FEATURE_GBPAGES))
- hugetlb_cma_reserve(PUD_SHIFT - PAGE_SHIFT);
-
/*
* Reserve memory for crash kernel after SRAT is parsed so that it
* won't consume hotpluggable memory.
@@ -1180,6 +1177,16 @@ void __init setup_arch(char **cmdline_p)
x86_init.paging.pagetable_init();
+ /*
+ * must be done after zone_sizes_init() which calls node_set_state() to
+ * setup node_states[N_MEMORY] that gets used in hugetlb_cma_reserve()
+ * while allocating required CMA size across nodes with memory.
+ * And zone_sizes_init() is done in x86_init.paging.pagetable_init()
+ * which is typically paging_init().
+ */
+ if (boot_cpu_has(X86_FEATURE_GBPAGES))
+ hugetlb_cma_reserve(PUD_SHIFT - PAGE_SHIFT);
+
kasan_init();
/*
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index d293c823121e..3a0ad49187e4 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -5699,12 +5699,12 @@ void __init hugetlb_cma_reserve(int order)
* If 3 GB area is requested on a machine with 4 numa nodes,
* let's allocate 1 GB on first three nodes and ignore the last one.
*/
- per_node = DIV_ROUND_UP(hugetlb_cma_size, nr_online_nodes);
+ per_node = DIV_ROUND_UP(hugetlb_cma_size, num_node_state(N_MEMORY));
pr_info("hugetlb_cma: reserve %lu MiB, up to %lu MiB per node\n",
hugetlb_cma_size / SZ_1M, per_node / SZ_1M);
reserved = 0;
- for_each_node_state(nid, N_ONLINE) {
+ for_each_node_state(nid, N_MEMORY) {
int res;
size = min(per_node, hugetlb_cma_size - reserved);
--
2.27.0
