Re: [PATCH 2/6] memblock tests: add the 129th memory block at all possible position

[Mike Rapoport <rppt@kernel.org>]

On Fri, Apr 19, 2024 at 03:15:20AM +0000, Wei Yang wrote:
> On Wed, Apr 17, 2024 at 08:51:14AM +0300, Mike Rapoport wrote:
> >On Tue, Apr 16, 2024 at 12:55:31PM +0000, Wei Yang wrote:
> >> On Mon, Apr 15, 2024 at 06:19:42PM +0300, Mike Rapoport wrote:
> >> >On Sun, Apr 14, 2024 at 12:45:27AM +0000, Wei Yang wrote:
> >> >> After previous change, we may double the array based on the position of
> >> >> the new range.
> >> >> 
> >> >> Let's make sure the 129th memory block would double the size correctly
> >> >> at all possible position.
> >> >
> >> >Rather than rewrite an existing test, just add a new one.
> >> 
> >> Ok, will add a new one for this.
> >> 
> >> >Besides, it would be more interesting to test additions to
> >> >memblock.reserved and a mix of memblock_add() and memblock_reserve() that
> >> >will require resizing the memblock arrays.
> >> 
> >> I don't get this very clearly. Would you mind give more hint?
> >
> >There is memblock_reserve_many_check() that verifies that memblock.reserved
> >is properly resized. I think it's better to add test that adds 129th block
> >at multiple locations to memblock.reserved.
> > 
> 
> I come up with another version, which could address the bug fixed by commit
> 48c3b583bbdd ("mm/memblock: fix overlapping allocation when doubling reserved
> array").
> 
> Comment out the fix, the test failed since cnt mismatch after double array.
> 
> Not sure you prefer to have both or just leave this version by replacing
> current memblock_reserve_many_check().

Let's have both of them.
 
> diff --git a/tools/testing/memblock/tests/basic_api.c b/tools/testing/memblock/tests/basic_api.c
> index d2b8114921f9..fb76471108b2 100644
> --- a/tools/testing/memblock/tests/basic_api.c
> +++ b/tools/testing/memblock/tests/basic_api.c
> @@ -1006,6 +1006,119 @@ static int memblock_reserve_many_check(void)
>  	return 0;
>  }
>  
> +/* Keep the gap so these memory region will not be merged. */
> +#define MEMORY_BASE_OFFSET(idx, offset) ((offset) + (MEM_SIZE * 2) * (idx))
> +static int memblock_reserve_many_conflict_check(void)
> +{
> +	int i, skip;
> +	void *orig_region;
> +	struct region r = {
> +		.base = SZ_16K,
> +		.size = SZ_16K,
> +	};
> +	phys_addr_t new_reserved_regions_size;
> +
> +	/*
> +	 *  0        1          129
> +	 *  +---+    +---+      +---+
> +	 *  |32K|    |32K|  ..  |32K|
> +	 *  +---+    +---+      +---+
> +	 *
> +	 * Pre-allocate the range for 129 memory block + one range for double
> +	 * memblock.reserved.regions at idx 0.
> +	 * See commit 48c3b583bbdd ("mm/memblock: fix overlapping allocation
> +	 * when doubling reserved array")
> +	 */
> +	phys_addr_t memory_base = (phys_addr_t)malloc(130 * (2 * SZ_32K));

Just increase MEM_SIZE to, say, SZ_1M and use dummy_physical_memory_init()
etc

> +	phys_addr_t offset = PAGE_ALIGN(memory_base);
> +
> +	PREFIX_PUSH();
> +
> +	/* Reserve the 129th memory block for all possible positions*/
> +	for (skip = 1; skip <= INIT_MEMBLOCK_REGIONS + 1; skip++)
> +	{
> +		reset_memblock_regions();
> +		memblock_allow_resize();
> +
> +		reset_memblock_attributes();
> +		/* Add a valid memory region used by double_array(). */
> +		memblock_add(MEMORY_BASE_OFFSET(0, offset), MEM_SIZE);
> +		/*
> +		 * Add a memory region which will be reserved as 129th memory
> +		 * region. This is not expected to be used by double_array().
> +		 */
> +		memblock_add(MEMORY_BASE_OFFSET(skip, offset), MEM_SIZE);
> +
> +		for (i = 1; i <= INIT_MEMBLOCK_REGIONS + 1; i++) {
> +			if (i == skip)
> +				continue;
> +
> +			/* Reserve some fakes memory region to fulfill the memblock. */
> +			memblock_reserve(MEMORY_BASE_OFFSET(i, offset), MEM_SIZE);
> +
> +			if (i < skip) {
> +				ASSERT_EQ(memblock.reserved.cnt, i);
> +				ASSERT_EQ(memblock.reserved.total_size, i * MEM_SIZE);
> +			} else {
> +				ASSERT_EQ(memblock.reserved.cnt, i - 1);
> +				ASSERT_EQ(memblock.reserved.total_size, (i - 1) * MEM_SIZE);
> +			}
> +		}
> +
> +		orig_region = memblock.reserved.regions;
> +
> +		/* This reserve the 129 memory_region, and makes it double array. */
> +		memblock_reserve(MEMORY_BASE_OFFSET(skip, offset), MEM_SIZE);
> +
> +		/*
> +		 * This is the memory region size used by the doubled reserved.regions,
> +		 * and it has been reserved due to it has been used. The size is used to
> +		 * calculate the total_size that the memblock.reserved have now.
> +		 */
> +		new_reserved_regions_size = PAGE_ALIGN((INIT_MEMBLOCK_REGIONS * 2) *
> +						sizeof(struct memblock_region));
> +		/*
> +		 * The double_array() will find a free memory region as the new
> +		 * reserved.regions, and the used memory region will be reserved, so
> +		 * there will be one more region exist in the reserved memblock. And the
> +		 * one more reserved region's size is new_reserved_regions_size.
> +		 */
> +		ASSERT_EQ(memblock.reserved.cnt, INIT_MEMBLOCK_REGIONS + 2);
> +		ASSERT_EQ(memblock.reserved.total_size, (INIT_MEMBLOCK_REGIONS + 1) * MEM_SIZE +
> +							new_reserved_regions_size);
> +		ASSERT_EQ(memblock.reserved.max, INIT_MEMBLOCK_REGIONS * 2);
> +
> +		/*
> +		 * Now memblock_double_array() works fine. Let's check after the
> +		 * double_array(), the memblock_reserve() still works as normal.
> +		 */
> +		memblock_reserve(r.base, r.size);
> +		ASSERT_EQ(memblock.reserved.regions[0].base, r.base);
> +		ASSERT_EQ(memblock.reserved.regions[0].size, r.size);
> +
> +		ASSERT_EQ(memblock.reserved.cnt, INIT_MEMBLOCK_REGIONS + 3);
> +		ASSERT_EQ(memblock.reserved.total_size, (INIT_MEMBLOCK_REGIONS + 1) * MEM_SIZE +
> +							new_reserved_regions_size +
> +							r.size);
> +		ASSERT_EQ(memblock.reserved.max, INIT_MEMBLOCK_REGIONS * 2);
> +
> +		/*
> +		 * The current reserved.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.reserved.regions = orig_region;
> +		memblock.reserved.cnt = INIT_MEMBLOCK_RESERVED_REGIONS;
> +	}
> +
> +	free((void *)memory_base);
> +
> +	test_pass_pop();
> +
> +	return 0;
> +}
> +
>  static int memblock_reserve_checks(void)
>  {
>  	prefix_reset();
> @@ -1021,6 +1134,7 @@ static int memblock_reserve_checks(void)
>  	memblock_reserve_between_check();
>  	memblock_reserve_near_max_check();
>  	memblock_reserve_many_check();
> +	memblock_reserve_many_conflict_check();
>  
>  	prefix_pop();
>  
> -- 
> 2.34.1

-- 
Sincerely yours,
Mike.