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From:   Zhou Guanghui <zhouguanghui1@huawei.com>
To:     <akpm@linux-foundation.org>, <rppt@kernel.org>, <will@kernel.org>,
        <anshuman.khandual@arm.com>, <darren@os.amperecomputing.com>
CC:     <linux-kernel@vger.kernel.org>, <linux-mm@kvack.org>,
        <linux-arm-kernel@lists.infradead.org>, <xuqiang36@huawei.com>,
        <zhouguanghui1@huawei.com>
Subject: [PATCH v5] memblock,arm64: Expand the static memblock memory table
Date:   Wed, 15 Jun 2022 10:27:42 +0000
Message-ID: <20220615102742.96450-1-zhouguanghui1@huawei.com>
MIME-Version: 1.0
Content-Type: text/plain
Precedence: bulk

In a system(Huawei Ascend ARM64 SoC) using HBM, a multi-bit ECC error
occurs, and the BIOS will mark the corresponding area (for example, 2 MB)
as unusable. When the system restarts next time, these areas are not
reported or reported as EFI_UNUSABLE_MEMORY. Both cases lead to an
increase in the number of memblocks, whereas EFI_UNUSABLE_MEMORY
leads to a larger number of memblocks.

For example, if the EFI_UNUSABLE_MEMORY type is reported:
...
memory[0x92]    [0x0000200834a00000-0x0000200835bfffff], 0x0000000001200000 bytes on node 7 flags: 0x0
memory[0x93]    [0x0000200835c00000-0x0000200835dfffff], 0x0000000000200000 bytes on node 7 flags: 0x4
memory[0x94]    [0x0000200835e00000-0x00002008367fffff], 0x0000000000a00000 bytes on node 7 flags: 0x0
memory[0x95]    [0x0000200836800000-0x00002008369fffff], 0x0000000000200000 bytes on node 7 flags: 0x4
memory[0x96]    [0x0000200836a00000-0x0000200837bfffff], 0x0000000001200000 bytes on node 7 flags: 0x0
memory[0x97]    [0x0000200837c00000-0x0000200837dfffff], 0x0000000000200000 bytes on node 7 flags: 0x4
memory[0x98]    [0x0000200837e00000-0x000020087fffffff], 0x0000000048200000 bytes on node 7 flags: 0x0
memory[0x99]    [0x0000200880000000-0x0000200bcfffffff], 0x0000000350000000 bytes on node 6 flags: 0x0
memory[0x9a]    [0x0000200bd0000000-0x0000200bd01fffff], 0x0000000000200000 bytes on node 6 flags: 0x4
memory[0x9b]    [0x0000200bd0200000-0x0000200bd07fffff], 0x0000000000600000 bytes on node 6 flags: 0x0
memory[0x9c]    [0x0000200bd0800000-0x0000200bd09fffff], 0x0000000000200000 bytes on node 6 flags: 0x4
memory[0x9d]    [0x0000200bd0a00000-0x0000200fcfffffff], 0x00000003ff600000 bytes on node 6 flags: 0x0
memory[0x9e]    [0x0000200fd0000000-0x0000200fd01fffff], 0x0000000000200000 bytes on node 6 flags: 0x4
memory[0x9f]    [0x0000200fd0200000-0x0000200fffffffff], 0x000000002fe00000 bytes on node 6 flags: 0x0
...

The EFI memory map is parsed to construct the memblock arrays before
the memblock arrays can be resized. As the result, memory regions
beyond INIT_MEMBLOCK_REGIONS are lost.

Add a new macro INIT_MEMBLOCK_MEMORY_REGTIONS to replace
INIT_MEMBLOCK_REGTIONS to define the size of the static memblock.memory
array.

Allow overriding memblock.memory array size with architecture defined
INIT_MEMBLOCK_MEMORY_REGIONS and make arm64 to set
INIT_MEMBLOCK_MEMORY_REGIONS to 1024 when CONFIG_EFI is enabled.

Signed-off-by: Zhou Guanghui <zhouguanghui1@huawei.com>
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Tested-by: Darren Hart <darren@os.amperecomputing.com>
---
 arch/arm64/include/asm/memory.h |  9 +++++++++
 mm/memblock.c                   | 14 +++++++++-----
 2 files changed, 18 insertions(+), 5 deletions(-)

diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h
index 0af70d9abede..ce8614fa376a 100644
--- a/arch/arm64/include/asm/memory.h
+++ b/arch/arm64/include/asm/memory.h
@@ -364,6 +364,15 @@ void dump_mem_limit(void);
 # define INIT_MEMBLOCK_RESERVED_REGIONS	(INIT_MEMBLOCK_REGIONS + NR_CPUS + 1)
 #endif
 
+/*
+ * memory regions which marked with flag MEMBLOCK_NOMAP(for example, the memory
+ * of the EFI_UNUSABLE_MEMORY type) may divide a continuous memory block into
+ * multiple parts. As a result, the number of memory regions is large.
+ */
+#ifdef CONFIG_EFI
+#define INIT_MEMBLOCK_MEMORY_REGIONS	(INIT_MEMBLOCK_REGIONS * 8)
+#endif
+
 #include <asm-generic/memory_model.h>
 
 #endif /* __ASM_MEMORY_H */
diff --git a/mm/memblock.c b/mm/memblock.c
index e4f03a6e8e56..7c63571a69d7 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -29,6 +29,10 @@
 # define INIT_MEMBLOCK_RESERVED_REGIONS		INIT_MEMBLOCK_REGIONS
 #endif
 
+#ifndef INIT_MEMBLOCK_MEMORY_REGIONS
+#define INIT_MEMBLOCK_MEMORY_REGIONS		INIT_MEMBLOCK_REGIONS
+#endif
+
 /**
  * DOC: memblock overview
  *
@@ -55,9 +59,9 @@
  * the allocator metadata. The "memory" and "reserved" types are nicely
  * wrapped with struct memblock. This structure is statically
  * initialized at build time. The region arrays are initially sized to
- * %INIT_MEMBLOCK_REGIONS for "memory" and %INIT_MEMBLOCK_RESERVED_REGIONS
- * for "reserved". The region array for "physmem" is initially sized to
- * %INIT_PHYSMEM_REGIONS.
+ * %INIT_MEMBLOCK_MEMORY_REGIONS for "memory" and
+ * %INIT_MEMBLOCK_RESERVED_REGIONS for "reserved". The region array
+ * for "physmem" is initially sized to %INIT_PHYSMEM_REGIONS.
  * The memblock_allow_resize() enables automatic resizing of the region
  * arrays during addition of new regions. This feature should be used
  * with care so that memory allocated for the region array will not
@@ -102,7 +106,7 @@ unsigned long min_low_pfn;
 unsigned long max_pfn;
 unsigned long long max_possible_pfn;
 
-static struct memblock_region memblock_memory_init_regions[INIT_MEMBLOCK_REGIONS] __initdata_memblock;
+static struct memblock_region memblock_memory_init_regions[INIT_MEMBLOCK_MEMORY_REGIONS] __initdata_memblock;
 static struct memblock_region memblock_reserved_init_regions[INIT_MEMBLOCK_RESERVED_REGIONS] __initdata_memblock;
 #ifdef CONFIG_HAVE_MEMBLOCK_PHYS_MAP
 static struct memblock_region memblock_physmem_init_regions[INIT_PHYSMEM_REGIONS];
@@ -111,7 +115,7 @@ static struct memblock_region memblock_physmem_init_regions[INIT_PHYSMEM_REGIONS
 struct memblock memblock __initdata_memblock = {
 	.memory.regions		= memblock_memory_init_regions,
 	.memory.cnt		= 1,	/* empty dummy entry */
-	.memory.max		= INIT_MEMBLOCK_REGIONS,
+	.memory.max		= INIT_MEMBLOCK_MEMORY_REGIONS,
 	.memory.name		= "memory",
 
 	.reserved.regions	= memblock_reserved_init_regions,
-- 
2.17.1