Re: [PATCH v2] memblock test: Add test to memblock_add() 129th region

["Huang, Shaoqin" <shaoqin.huang@intel.com>]

On 8/2/2022 3:15 PM, Mike Rapoport wrote:
> On Mon, Aug 01, 2022 at 02:48:36PM +0800, shaoqin.huang@intel.com wrote:
>> From: Shaoqin Huang <shaoqin.huang@intel.com>
>>
>> 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 some valid memory, when
>> memblock_double_array() choose a new memory region from memory.regions,
>> it will always choose a valid memory region if we add all valid memory
>> region, so the 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@intel.com>
>> ---
>> Changelog:
>> ----------
>> v2:
>>    - Use ASSERT_EQ() to replace assert().
>>    - Not to expose memory_block, and add a function get_memory_block_base() to
>>    get the memory_block.base.
>>    - Add two functions for common usage, and now it has been used by this patch
>>    to allocate many valid memory regions and free them at the end.
>>
>>   tools/testing/memblock/tests/basic_api.c | 54 ++++++++++++++++++++++++
>>   tools/testing/memblock/tests/common.c    | 38 +++++++++++++++--
>>   tools/testing/memblock/tests/common.h    |  6 +++
>>   3 files changed, 95 insertions(+), 3 deletions(-)
>>
>> diff --git a/tools/testing/memblock/tests/basic_api.c b/tools/testing/memblock/tests/basic_api.c
>> index 66f46f261e66..46948d5a975e 100644
>> --- a/tools/testing/memblock/tests/basic_api.c
>> +++ b/tools/testing/memblock/tests/basic_api.c
>> @@ -326,6 +326,59 @@ static int memblock_add_twice_check(void)
>>   	return 0;
>>   }
>>   
>> +static int memblock_add_many_check(void)
>> +{
>> +	void *base[INIT_MEMBLOCK_REGIONS + 1];
>> +	void *orig_region;
>> +	struct region r = {
>> +		.base = SZ_16K,
>> +		.size = MEM_SIZE,
>> +	};
>> +
>> +	PREFIX_PUSH();
>> +
>> +	reset_memblock_regions();
>> +	memblock_allow_resize();
>> +
>> +	dummy_physical_memory_many_init(base, INIT_MEMBLOCK_REGIONS);
> 
> Why do we need this?

I want to memblock_add() 128 regions that every region has a valid 
"physical" memory. So it can make sure the memblock_double_array() 
success when add a 129-th region.

In the last patch, I didn't put this function here, I just 
memblock_add() 128 region at here. And after I think if we can 
encapsulate it to a function, later it can be used to init some valid 
memory regions into the memblock.

And if no others may be use this functions, the function is not needed.

> 
> dummy_physical_memory_init() allocates the "physical" memory, so to trigger
> memblock_double_array() it's enough to memblock_add() 129 non-intersecting
> chunks in the range [memory_block.base, memory_block.base + MEM_SIZE].
> If MEM_SIZE of 16k won't be enough, it can be increased.
> 

Yes. And now MEM_SIZE of 16k is enough, no need to increase it now.

>> +
>> +	orig_region = memblock.memory.regions;
>> +
>> +	/* This adds the 129 memory_region, and makes it double array. */
>> +	dummy_physical_memory_init();
>> +	append_memblock();
>> +	base[INIT_MEMBLOCK_REGIONS] = get_memory_block_base();
>> +
>> +	ASSERT_EQ(memblock.memory.cnt, INIT_MEMBLOCK_REGIONS + 1);
>> +	ASSERT_EQ(memblock.memory.total_size, (INIT_MEMBLOCK_REGIONS + 1) * MEM_SIZE);
>> +	ASSERT_EQ(memblock.memory.max, INIT_MEMBLOCK_REGIONS * 2);
>> +
>> +	/* The base is very small, so it should be insert to the first region. */
>> +	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 + 2) * MEM_SIZE);
>> +	ASSERT_EQ(memblock.memory.max, INIT_MEMBLOCK_REGIONS * 2);
>> +
>> +	/* Free these allocated memory. */
>> +	dummy_physical_memory_many_cleanup(base, INIT_MEMBLOCK_REGIONS + 1);
>> +
>> +	/*
>> +	 * 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();
>> @@ -339,6 +392,7 @@ static int memblock_add_checks(void)
>>   	memblock_add_overlap_bottom_check();
>>   	memblock_add_within_check();
>>   	memblock_add_twice_check();
>> +	memblock_add_many_check();
>>   
>>   	prefix_pop();
>>   
>> diff --git a/tools/testing/memblock/tests/common.c b/tools/testing/memblock/tests/common.c
>> index e43b2676af81..960b3ce07696 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					": "
>>   
>> @@ -58,10 +56,20 @@ void reset_memblock_attributes(void)
>>   	memblock.current_limit	= MEMBLOCK_ALLOC_ANYWHERE;
>>   }
>>   
>> +void *get_memory_block_base(void)
>> +{
>> +	return memory_block.base;
>> +}
>> +
>> +void append_memblock(void)
>> +{
>> +	memblock_add((phys_addr_t)memory_block.base, MEM_SIZE);
>> +}
>> +
>>   void setup_memblock(void)
>>   {
>>   	reset_memblock_regions();
>> -	memblock_add((phys_addr_t)memory_block.base, MEM_SIZE);
>> +	append_memblock();
>>   }
>>   
>>   void dummy_physical_memory_init(void)
>> @@ -75,6 +83,30 @@ void dummy_physical_memory_cleanup(void)
>>   	free(memory_block.base);
>>   }
>>   
>> +void dummy_physical_memory_many_init(void *base[], int cnt)
>> +{
>> +	int i;
>> +
>> +	for (i = 0; i < cnt; i++) {
>> +		dummy_physical_memory_init();
>> +		append_memblock();
>> +		base[i] = memory_block.base;
>> +
>> +		ASSERT_EQ(memblock.memory.cnt, i + 1);
>> +		ASSERT_EQ(memblock.memory.total_size, (i + 1) * MEM_SIZE);
>> +	}
>> +}
>> +
>> +void dummy_physical_memory_many_cleanup(void *base[], int cnt)
>> +{
>> +	int i;
>> +
>> +	for (i = 0; i < cnt; i++) {
>> +		memory_block.base = base[i];
>> +		dummy_physical_memory_cleanup();
>> +	}
>> +}
>> +
>>   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 3e7f23d341d7..848900aa8db6 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
>>   
>>   /**
>>    * ASSERT_EQ():
>> @@ -68,8 +70,12 @@ struct region {
>>   void reset_memblock_regions(void);
>>   void reset_memblock_attributes(void);
>>   void setup_memblock(void);
>> +void append_memblock(void);
>> +void *get_memory_block_base(void);
>>   void dummy_physical_memory_init(void);
>>   void dummy_physical_memory_cleanup(void);
>> +void dummy_physical_memory_many_init(void *base[], int cnt);
>> +void dummy_physical_memory_many_cleanup(void *base[], int cnt);
>>   void parse_args(int argc, char **argv);
>>   
>>   void test_fail(void);
>> -- 
>> 2.30.2
>>
>>
>