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Date: Sun, 18 Sep 2022 17:48:47 +0800
From: "Huang, Shaoqin" <shaoqin.huang@...el.com>
To: Mike Rapoport <rppt@...nel.org>
CC: Karolina Drobnik <karolinadrobnik@...il.com>,
Rebecca Mckeever <remckee0@...il.com>,
David Hildenbrand <david@...hat.com>, <linux-mm@...ck.org>,
<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v3 1/3] memblock test: Add test to memblock_add() 129th
region
On 9/18/2022 5:25 PM, Mike Rapoport wrote:
> On Tue, Sep 13, 2022 at 02:41:30PM +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 large enough memory
>> region, and split it into a large enough memory which can be choosed by
>> memblock_double_array(), and the left memory will be split into small
>> memory region, and add them into the memblock. 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 | 96 ++++++++++++++++++++++++
>> tools/testing/memblock/tests/common.c | 7 +-
>> tools/testing/memblock/tests/common.h | 3 +
>> 3 files changed, 104 insertions(+), 2 deletions(-)
>>
>> diff --git a/tools/testing/memblock/tests/basic_api.c b/tools/testing/memblock/tests/basic_api.c
>> index a13a57ba0815..7120fd8e47b1 100644
>> --- a/tools/testing/memblock/tests/basic_api.c
>> +++ b/tools/testing/memblock/tests/basic_api.c
>> @@ -423,6 +423,101 @@ static int memblock_add_near_max_check(void)
>> return 0;
>> }
>>
>> +/*
>> + * A test that trying 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 new_memory_regions_size;
>> + phys_addr_t base, size, block_size;
>> +
>> + PREFIX_PUSH();
>> +
>> + reset_memblock_regions();
>> + memblock_allow_resize();
>> +
>> + dummy_physical_memory_init();
>> + /*
>> + * We allocated enough memory by using dummy_physical_memory_init(), and
>> + * split it into small block. First we split a large enough memory block
>> + * as the memory region which will be choosed by memblock_double_array().
>> + */
>> + base = PAGE_ALIGN(dummy_physical_memory_base());
>> + new_memory_regions_size = PAGE_ALIGN(INIT_MEMBLOCK_REGIONS * 2 *
>> + sizeof(struct memblock_region));
>> + memblock_add(base, new_memory_regions_size);
>
> Why don't you simply increase MEM_SIZE, to say 1M?
> This will make all the calculations here way simpler.
>
Ok. I will increase MEM_SIZE. That can clean the calculation.
>> +
>> + /*
>> + * For the left memory, we split them into small block and add them into
>> + * memblock later.
>> + */
>> + base += new_memory_regions_size;
>> + size = MEM_SIZE - new_memory_regions_size;
>> + block_size = size / (INIT_MEMBLOCK_REGIONS * 2);
>> +
>> + orig_region = memblock.memory.regions;
>> +
>> + for (i = 0; i < INIT_MEMBLOCK_REGIONS; i++) {
>> + /*
>> + * Add these small block to fulfill the memblock. We keep an
>> + * interval between the nearby memory to avoid being merged.
>> + */
>> + memblock_add(base + block_size * (2 * i + 1), block_size);
>> +
>> + ASSERT_EQ(memblock.memory.cnt, i + 2);
>> + ASSERT_EQ(memblock.memory.total_size, new_memory_regions_size +
>> + (i + 1) * block_size);
>> + }
>> +
>> + /*
>> + * At there, memblock_double_array() has been succeed, check if it
>> + * update the memory.max.
>> + */
>> + ASSERT_EQ(memblock.memory.max, INIT_MEMBLOCK_REGIONS * 2);
>> +
>> + /* memblock_double_array() will reserve the memory it used. Check it. */
>> + ASSERT_EQ(memblock.reserved.cnt, 1);
>> + ASSERT_EQ(memblock.reserved.total_size, new_memory_regions_size);
>> +
>> + /*
>> + * Now memblock_double_array() works fine. Let's check after the
>> + * double_array(), the memblock_add() still works as normal.
>> + */
>> + 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 * block_size +
>> + new_memory_regions_size +
>> + 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();
>> @@ -438,6 +533,7 @@ static int memblock_add_checks(void)
>> memblock_add_twice_check();
>> memblock_add_between_check();
>> memblock_add_near_max_check();
>> + memblock_add_many_check();
>>
>> prefix_pop();
>>
>> diff --git a/tools/testing/memblock/tests/common.c b/tools/testing/memblock/tests/common.c
>> index eec6901081af..2de6a2b6efd2 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 ": "
>>
>> @@ -84,6 +82,11 @@ void dummy_physical_memory_cleanup(void)
>> free(memory_block.base);
>> }
>>
>> +phys_addr_t dummy_physical_memory_base(void)
>> +{
>> + return (phys_addr_t)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 78128e109a95..ba14dc989ae9 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
>>
>> enum test_flags {
>> /* No special request. */
>> @@ -104,6 +106,7 @@ void reset_memblock_attributes(void);
>> void setup_memblock(void);
>> void dummy_physical_memory_init(void);
>> void dummy_physical_memory_cleanup(void);
>> +phys_addr_t dummy_physical_memory_base(void);
>> void parse_args(int argc, char **argv);
>>
>> void test_fail(void);
>> --
>> 2.34.1
>>
>>
>
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