memblock test: Add test to memblock_add() 129th region

Add 129th region into the memblock, and this will trigger the
memblock_double_array() function, this needs valid memory regions. So
using dummy_physical_memory_init() to allocate a large enough memory
region, and split it into a large enough memory which can be choosed by
memblock_double_array(), and the left memory will be split into small
memory region, and add them into the memblock. It make sure the
memblock_double_array() will always choose the valid memory region that
is allocated by the dummy_physical_memory_init().
So memblock_double_array() must success.

Another thing should be done is to restore the memory.regions after
memblock_double_array(), due to now the memory.regions is pointing to a
memory region allocated by dummy_physical_memory_init(). And it will
affect the subsequent tests if we don't restore the memory region. So
simply record the origin region, and restore it after the test.

Signed-off-by: Shaoqin Huang <[e-mail]>
Signed-off-by: Mike Rapoport <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

tools/testing/memblock/tests/basic_api.c

···
 	return 0;
 }
 
+/*
+ * A test that trying to add the 129th memory block.
+ * Expect to trigger memblock_double_array() to double the
+ * memblock.memory.max, find a new valid memory as
+ * memory.regions.
+ */
+static int memblock_add_many_check(void)
+{
+	int i;
+	void *orig_region;
+	struct region r = {
+		.base = SZ_16K,
+		.size = SZ_16K,
+	};
+	phys_addr_t new_memory_regions_size;
+	phys_addr_t base, size = SZ_64;
+	phys_addr_t gap_size = SZ_64;
+
+	PREFIX_PUSH();
+
+	reset_memblock_regions();
+	memblock_allow_resize();
+
+	dummy_physical_memory_init();
+	/*
+	 * We allocated enough memory by using dummy_physical_memory_init(), and
+	 * split it into small block. First we split a large enough memory block
+	 * as the memory region which will be choosed by memblock_double_array().
+	 */
+	base = PAGE_ALIGN(dummy_physical_memory_base());
+	new_memory_regions_size = PAGE_ALIGN(INIT_MEMBLOCK_REGIONS * 2 *
+					     sizeof(struct memblock_region));
+	memblock_add(base, new_memory_regions_size);
+
+	/* This is the base of small memory block. */
+	base += new_memory_regions_size + gap_size;
+
+	orig_region = memblock.memory.regions;
+
+	for (i = 0; i < INIT_MEMBLOCK_REGIONS; i++) {
+		/*
+		 * Add these small block to fulfill the memblock. We keep a
+		 * gap between the nearby memory to avoid being merged.
+		 */
+		memblock_add(base, size);
+		base += size + gap_size;
+
+		ASSERT_EQ(memblock.memory.cnt, i + 2);
+		ASSERT_EQ(memblock.memory.total_size, new_memory_regions_size +
+						      (i + 1) * size);
+	}
+
+	/*
+	 * At there, memblock_double_array() has been succeed, check if it
+	 * update the memory.max.
+	 */
+	ASSERT_EQ(memblock.memory.max, INIT_MEMBLOCK_REGIONS * 2);
+
+	/* memblock_double_array() will reserve the memory it used. Check it. */
+	ASSERT_EQ(memblock.reserved.cnt, 1);
+	ASSERT_EQ(memblock.reserved.total_size, new_memory_regions_size);
+
+	/*
+	 * Now memblock_double_array() works fine. Let's check after the
+	 * double_array(), the memblock_add() still works as normal.
+	 */
+	memblock_add(r.base, r.size);
+	ASSERT_EQ(memblock.memory.regions[0].base, r.base);
+	ASSERT_EQ(memblock.memory.regions[0].size, r.size);
+
+	ASSERT_EQ(memblock.memory.cnt, INIT_MEMBLOCK_REGIONS + 2);
+	ASSERT_EQ(memblock.memory.total_size, INIT_MEMBLOCK_REGIONS * size +
+					      new_memory_regions_size +
+					      r.size);
+	ASSERT_EQ(memblock.memory.max, INIT_MEMBLOCK_REGIONS * 2);
+
+	dummy_physical_memory_cleanup();
+
+	/*
+	 * The current memory.regions is occupying a range of memory that
+	 * allocated from dummy_physical_memory_init(). After free the memory,
+	 * we must not use it. So restore the origin memory region to make sure
+	 * the tests can run as normal and not affected by the double array.
+	 */
+	memblock.memory.regions = orig_region;
+	memblock.memory.cnt = INIT_MEMBLOCK_REGIONS;
+
+	test_pass_pop();
+
+	return 0;
+}
+
 static int memblock_add_checks(void)
 {
 	prefix_reset();
···
 	memblock_add_twice_check();
 	memblock_add_between_check();
 	memblock_add_near_max_check();
+	memblock_add_many_check();
 
 	prefix_pop();
 

tools/testing/memblock/tests/common.c

···
 #include <linux/memory_hotplug.h>
 #include <linux/build_bug.h>
 
-#define INIT_MEMBLOCK_REGIONS			128
-#define INIT_MEMBLOCK_RESERVED_REGIONS		INIT_MEMBLOCK_REGIONS
 #define PREFIXES_MAX				15
 #define DELIM					": "
 #define BASIS					10000
···
 void dummy_physical_memory_cleanup(void)
 {
 	free(memory_block.base);
+}
+
+phys_addr_t dummy_physical_memory_base(void)
+{
+	return (phys_addr_t)memory_block.base;
 }
 
 static void usage(const char *prog)

tools/testing/memblock/tests/common.h

···
 #include <linux/printk.h>
 #include <../selftests/kselftest.h>
 
-#define MEM_SIZE		SZ_16K
+#define MEM_SIZE		SZ_32K
 #define NUMA_NODES		8
+
+#define INIT_MEMBLOCK_REGIONS			128
+#define INIT_MEMBLOCK_RESERVED_REGIONS		INIT_MEMBLOCK_REGIONS
 
 enum test_flags {
 	/* No special request. */
···
 void setup_numa_memblock(const unsigned int node_fracs[]);
 void dummy_physical_memory_init(void);
 void dummy_physical_memory_cleanup(void);
+phys_addr_t dummy_physical_memory_base(void);
 void parse_args(int argc, char **argv);
 
 void test_fail(void);