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Date: Thu, 1 Sep 2022 16:35:04 +0800
From: "Huang, Shaoqin" <shaoqin.huang@...el.com>
To: Mike Rapoport <rppt@...nel.org>
CC: Karolina Drobnik <karolinadrobnik@...il.com>,
David Hildenbrand <david@...hat.com>,
Rebecca Mckeever <remckee0@...il.com>, <linux-mm@...ck.org>,
<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/3] memblock test: Add test to memblock_add() 129th
region
On 9/1/2022 4:02 PM, Mike Rapoport wrote:
> On Tue, Aug 30, 2022 at 09:49:17AM +0800, shaoqin.huang@...el.com wrote:
>> From: Shaoqin Huang <shaoqin.huang@...el.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@...el.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
>>
>>
>
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