Re: [PATCH 2/3] memblock test: Add test to memblock_reserve() 129th region

[Huang, Shaoqin]

On 9/1/2022 4:08 PM, Mike Rapoport wrote:
> On Tue, Aug 30, 2022 at 09:49:18AM +0800, shaoqin.huang@xxxxxxxxx wrote:
> > From: Shaoqin Huang <shaoqin.huang@xxxxxxxxx>
> >
> > Reserve 129th region in 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.
> > At the same time, reserve 128 faked memory region, and make sure these
> > reserved region not intersect with the valid memory region. So
> > memblock_double_array() will choose the valid memory region, and it will
> > success.
> >
> > Also need to restore the reserved.regions after memblock_double_array(),
> > to make sure the subsequent tests can run as normal.
> >
> > Signed-off-by: Shaoqin Huang <shaoqin.huang@xxxxxxxxx>
> > ---
> >   tools/testing/memblock/tests/basic_api.c | 87 ++++++++++++++++++++++++
> >   1 file changed, 87 insertions(+)
> >
> > diff --git a/tools/testing/memblock/tests/basic_api.c b/tools/testing/memblock/tests/basic_api.c
> > index c8e201156cdc..d8defc9866cb 100644
> > --- a/tools/testing/memblock/tests/basic_api.c
> > +++ b/tools/testing/memblock/tests/basic_api.c
> > @@ -686,6 +686,92 @@ static int memblock_reserve_twice_check(void)
> >   	return 0;
> >   }
> >   
> > +/*
> > + * A test that tries to reserve the 129th memory block.
> > + * Expect to trigger memblock_double_array() to double the
> > + * memblock.memory.max, find a new valid memory as
> > + * reserved.regions.
> > + */
> > +static int memblock_reserve_many_check(void)
> > +{
> > +	int i;
> > +	void *orig_region;
> > +	struct region r = {
> > +		.base = SZ_16K,
> > +		.size = MEM_SIZE,
> > +	};
> > +	phys_addr_t memory_base = SZ_128K;
> > +	phys_addr_t new_reserved_regions_size;
> > +
> > +	PREFIX_PUSH();
> > +
> > +	reset_memblock_regions();
> > +	memblock_allow_resize();
> > +
> > +	/* Add a valid memory region used by double_array(). */
> > +	dummy_physical_memory_init();
> > +	memblock_add((phys_addr_t)get_memory_block_base(), MEM_SIZE);
> > +
> > +	for (i = 0; i < INIT_MEMBLOCK_REGIONS; i++) {
> > +		/* Reserve some fakes memory region to fulfill the memblock. */
> > +		memblock_reserve(memory_base, MEM_SIZE);
> > +
> > +		ASSERT_EQ(memblock.reserved.cnt, i + 1);
> > +		ASSERT_EQ(memblock.reserved.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.reserved.regions;
> > +
> > +	/* This reserve the 129 memory_region, and makes it double array. */
> > +	memblock_reserve(memory_base, 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 + 1 + 1);
>
>                                                     +2 would be fine ^

Yes. It actually is +2. first +1 is the 129th region, second +1 is the 
reserved region used by double_array().

> > +	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);
> > +
>
> Can you please elaborate what does the below sequence check?

After the double_array(), we can reserve more memory region. The below 
is aimed to check it can reserve more. So this reserve a memory region 
with small base which will be put at the first reserved.regions, and I 
checked if it will be reserved ok.

> > +	/* The base is very small, so it should be insert to the first region. */
> > +	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 + 2 + 1);
> > +	ASSERT_EQ(memblock.reserved.total_size, (INIT_MEMBLOCK_REGIONS + 2) * MEM_SIZE +
> > +						new_reserved_regions_size);
> > +	ASSERT_EQ(memblock.reserved.max, INIT_MEMBLOCK_REGIONS * 2);
> > +
> > +	dummy_physical_memory_cleanup();
> > +
> > +	/*
> > +	 * 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_REGIONS;
> > +
> > +	test_pass_pop();
> > +
> > +	return 0;
> > +}
> > +
> >   static int memblock_reserve_checks(void)
> >   {
> >   	prefix_reset();
> > @@ -698,6 +784,7 @@ static int memblock_reserve_checks(void)
> >   	memblock_reserve_overlap_bottom_check();
> >   	memblock_reserve_within_check();
> >   	memblock_reserve_twice_check();
> > +	memblock_reserve_many_check();
> >   
> >   	prefix_pop();
> >   
> > --
> > 2.34.1