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

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

On 9/1/2022 4:02 PM, Mike Rapoport wrote:
> On Tue, Aug 30, 2022 at 09:49:17AM +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 a valid memory region, and
>> fake the other memory region, so 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@intel.com>
>> ---
>>   tools/testing/memblock/tests/basic_api.c | 82 ++++++++++++++++++++++++
>>   tools/testing/memblock/tests/common.c    |  7 +-
>>   tools/testing/memblock/tests/common.h    |  3 +
>>   3 files changed, 90 insertions(+), 2 deletions(-)
>>
>> diff --git a/tools/testing/memblock/tests/basic_api.c b/tools/testing/memblock/tests/basic_api.c
>> index 66f46f261e66..c8e201156cdc 100644
>> --- a/tools/testing/memblock/tests/basic_api.c
>> +++ b/tools/testing/memblock/tests/basic_api.c
>> @@ -326,6 +326,87 @@ static int memblock_add_twice_check(void)
>>   	return 0;
>>   }
>>   
>> +/*
>> + * A test that tries 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 memory_base = SZ_128K;
>> +
>> +	PREFIX_PUSH();
>> +
>> +	reset_memblock_regions();
>> +	memblock_allow_resize();
>> +
>> +	/*
>> +	 * Add one valid memory region, this will be choosed to be the memory
>> +	 * that new memory.regions occupied.
>> +	 */
>> +	dummy_physical_memory_init();
>> +	memblock_add((phys_addr_t)get_memory_block_base(), MEM_SIZE);
>> +
>> +	ASSERT_EQ(memblock.memory.cnt, 1);
>> +	ASSERT_EQ(memblock.memory.total_size, MEM_SIZE);
>> +
>> +	for (i = 1; i < INIT_MEMBLOCK_REGIONS; i++) {
>> +		/* Add some fakes memory region to fulfill the memblock. */
>> +		memblock_add(memory_base, MEM_SIZE);
> 
> I would rather prefer to memblock_add() ranges from the simulated memory
> created in dummy_physical_memory_init(). 16K will be probably too small,
> but I don't see problem with increasing MEM_SIZE.
> 

Yes. If we memblock_add() the memory both allocated from 
dummy_physical_memory_init(), It's no need to fake these memory regions. 
And with all valid memory region, it will always choose a valid memory 
region and double the array.

And now with calculation, 16K is enough. The doubled array will only use 
8KB, so it will success.

>> +
>> +		ASSERT_EQ(memblock.memory.cnt, i + 1);
>> +		ASSERT_EQ(memblock.memory.total_size, (i + 1) * MEM_SIZE);
>> +
>> +		/* Keep the gap so these memory region will not be merged. */
>> +		memory_base += MEM_SIZE * 2;
>> +	}
>> +
>> +	orig_region = memblock.memory.regions;
>> +
>> +	/* This adds the 129 memory_region, and makes it double array. */
>> +	memblock_add((phys_addr_t)memory_base, MEM_SIZE);
> 
> memory_base is already phys_addr_t, isn't it?
> 

Thanks for notice. Will delete it.

>> +
>> +	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);
>> +
>> +	ASSERT_EQ(memblock.reserved.cnt, 1);
>> +	/* This is the size used by new memory.regions. Check it. */
>> +	ASSERT_EQ(memblock.reserved.total_size, PAGE_ALIGN(INIT_MEMBLOCK_REGIONS * 2 *
>> +						sizeof(struct memblock_region)));
>> +
> 
> Can you please elaborate what does the following sequence test?
> 

Before this line, all checks is to make sure the double_array have 
successfully make the size doubled and reserved a new region as the new 
memory.regions.

Below I try to add a memory region which has a small base, so it will be 
added to the first region, if it succeed. We can prove the doubled 
memory.regions has a valid memory.

I will add the commends in the next version.

>> +	/* 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);
>> +
>> +	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();
>> @@ -339,6 +420,7 @@ 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 76a8ad818f3a..96fabd96ff31 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					": "
>>   
>> @@ -77,6 +75,11 @@ void dummy_physical_memory_cleanup(void)
>>   	free(memory_block.base);
>>   }
>>   
>> +void *get_memory_block_base(void)
>> +{
>> +	return 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 d396e5423a8e..d56af621c543 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():
>> @@ -73,6 +75,7 @@ void reset_memblock_attributes(void);
>>   void setup_memblock(void);
>>   void dummy_physical_memory_init(void);
>>   void dummy_physical_memory_cleanup(void);
>> +void *get_memory_block_base(void);
> 
> Let's make it
> 
> phys_addr_t dummy_physical_memory_base(void);
> 

Got it.

>>   void parse_args(int argc, char **argv);
>>   
>>   void test_fail(void);
>> -- 
>> 2.34.1
>>
>>
>