Re: [PATCH v3 1/3] memblock test: Add test to memblock_add() 129th region

[Mike Rapoport]

On Tue, Sep 13, 2022 at 02:41:30PM +0800, shaoqin.huang@xxxxxxxxx wrote:
> From: Shaoqin Huang <shaoqin.huang@xxxxxxxxx>
> 
> 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 <shaoqin.huang@xxxxxxxxx>
> ---
>  tools/testing/memblock/tests/basic_api.c | 96 ++++++++++++++++++++++++
>  tools/testing/memblock/tests/common.c    |  7 +-
>  tools/testing/memblock/tests/common.h    |  3 +
>  3 files changed, 104 insertions(+), 2 deletions(-)
> 
> diff --git a/tools/testing/memblock/tests/basic_api.c b/tools/testing/memblock/tests/basic_api.c
> index a13a57ba0815..7120fd8e47b1 100644
> --- a/tools/testing/memblock/tests/basic_api.c
> +++ b/tools/testing/memblock/tests/basic_api.c
> @@ -423,6 +423,101 @@ static int memblock_add_near_max_check(void)
>  	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 = MEM_SIZE,
> +	};
> +	phys_addr_t new_memory_regions_size;
> +	phys_addr_t base, size, block_size;
> +
> +	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);

Why don't you simply increase MEM_SIZE, to say 1M?
This will make all the calculations here way simpler.

> +
> +	/*
> +	 * For the left memory, we split them into small block and add them into
> +	 * memblock later.
> +	 */
> +	base += new_memory_regions_size;
> +	size = MEM_SIZE - new_memory_regions_size;
> +	block_size = size / (INIT_MEMBLOCK_REGIONS * 2);
> +
> +	orig_region = memblock.memory.regions;
> +
> +	for (i = 0; i < INIT_MEMBLOCK_REGIONS; i++) {
> +		/*
> +		 * Add these small block to fulfill the memblock. We keep an
> +		 * interval between the nearby memory to avoid being merged.
> +		 */
> +		memblock_add(base + block_size * (2 * i + 1), block_size);
> +
> +		ASSERT_EQ(memblock.memory.cnt, i + 2);
> +		ASSERT_EQ(memblock.memory.total_size, new_memory_regions_size +
> +						      (i + 1) * block_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 * block_size +
> +					      new_memory_regions_size +
> +					      MEM_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();
> @@ -438,6 +533,7 @@ static int memblock_add_checks(void)
>  	memblock_add_twice_check();
>  	memblock_add_between_check();
>  	memblock_add_near_max_check();
> +	memblock_add_many_check();
>  
>  	prefix_pop();
>  
> diff --git a/tools/testing/memblock/tests/common.c b/tools/testing/memblock/tests/common.c
> index eec6901081af..2de6a2b6efd2 100644
> --- a/tools/testing/memblock/tests/common.c
> +++ b/tools/testing/memblock/tests/common.c
> @@ -5,8 +5,6 @@
>  #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					": "
>  
> @@ -84,6 +82,11 @@ 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)
>  {
>  	BUILD_BUG_ON(ARRAY_SIZE(help_opts) != ARRAY_SIZE(long_opts) - 1);
> diff --git a/tools/testing/memblock/tests/common.h b/tools/testing/memblock/tests/common.h
> index 78128e109a95..ba14dc989ae9 100644
> --- a/tools/testing/memblock/tests/common.h
> +++ b/tools/testing/memblock/tests/common.h
> @@ -11,6 +11,8 @@
>  #include <../selftests/kselftest.h>
>  
>  #define MEM_SIZE SZ_16K
> +#define INIT_MEMBLOCK_REGIONS			128
> +#define INIT_MEMBLOCK_RESERVED_REGIONS		INIT_MEMBLOCK_REGIONS
>  
>  enum test_flags {
>  	/* No special request. */
> @@ -104,6 +106,7 @@ void reset_memblock_attributes(void);
>  void setup_memblock(void);
>  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);
> -- 
> 2.34.1
> 
> 

-- 
Sincerely yours,
Mike.