Re: [PATCH V2] selftest/vm: Add test case for mmap across 128TB boundary.

[Anshuman Khandual <khandual@linux.vnet.ibm.com>]

On 11/23/2017 08:33 AM, Aneesh Kumar K.V wrote:
> From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
> 
> This patch add a self-test that covers a few corner cases of the interface.
> 
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
> ---
> 
> Changes from V1:
> * Add the test to run_vmtests script
> 
>  tools/testing/selftests/vm/Makefile         |   1 +
>  tools/testing/selftests/vm/run_vmtests      |  11 ++
>  tools/testing/selftests/vm/va_128TBswitch.c | 297 ++++++++++++++++++++++++++++
>  3 files changed, 309 insertions(+)
>  create mode 100644 tools/testing/selftests/vm/va_128TBswitch.c
> 
> diff --git a/tools/testing/selftests/vm/Makefile b/tools/testing/selftests/vm/Makefile
> index cbb29e41ef2b..b1fb3cd7cf52 100644
> --- a/tools/testing/selftests/vm/Makefile
> +++ b/tools/testing/selftests/vm/Makefile
> @@ -17,6 +17,7 @@ TEST_GEN_FILES += transhuge-stress
>  TEST_GEN_FILES += userfaultfd
>  TEST_GEN_FILES += mlock-random-test
>  TEST_GEN_FILES += virtual_address_range
> +TEST_GEN_FILES += va_128TBswitch

This will conflict with a test case for mremap clone functionality
which might have been queued in Shuah's tree.

https://patchwork.kernel.org/patch/10031943/

>  
>  TEST_PROGS := run_vmtests
>  
> diff --git a/tools/testing/selftests/vm/run_vmtests b/tools/testing/selftests/vm/run_vmtests
> index 07548a1fa901..d8305fb83125 100755
> --- a/tools/testing/selftests/vm/run_vmtests
> +++ b/tools/testing/selftests/vm/run_vmtests
> @@ -176,4 +176,15 @@ else
>  	echo "[PASS]"
>  fi
>  
> +echo "-----------------------------"
> +echo "running virtual address 128TB switch test"
> +echo "-----------------------------"
> +./va_128TBswitch
> +if [ $? -ne 0 ]; then
> +    echo "[FAIL]"
> +    exitcode=1
> +else
> +    echo "[PASS]"
> +fi
> +
>  exit $exitcode
> diff --git a/tools/testing/selftests/vm/va_128TBswitch.c b/tools/testing/selftests/vm/va_128TBswitch.c
> new file mode 100644
> index 000000000000..2fdb84ab94b1
> --- /dev/null
> +++ b/tools/testing/selftests/vm/va_128TBswitch.c
> @@ -0,0 +1,297 @@
> +/*
> + *
> + * Authors: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> + * Authors: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms of version 2.1 of the GNU Lesser General Public License
> + * as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it would be useful, but
> + * WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
> + *
> + */
> +
> +#include <stdio.h>
> +#include <sys/mman.h>
> +#include <string.h>
> +
> +#define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]))
> +
> +#ifdef __powerpc64__
> +#define PAGE_SIZE	(64 << 10)
> +/*
> + * This will work with 16M and 2M hugepage size
> + */
> +#define HUGETLB_SIZE	(16 << 20)
> +#else
> +#define PAGE_SIZE	(4 << 10)
> +#define HUGETLB_SIZE	(2 << 20)
> +#endif
> +
> +/*
> + * >= 128TB is the hint addr value we used to select
> + * large address space.
> + */
> +#define ADDR_SWITCH_HINT (1UL << 47)
> +#define LOW_ADDR	((void *) (1UL << 30))
> +#define HIGH_ADDR	((void *) (1UL << 48))

Is there any particular reason for choosing 1GB as low and 256TB
as high address ?

> +
> +struct testcase {
> +	void *addr;
> +	unsigned long size;
> +	unsigned long flags;
> +	const char *msg;
> +	unsigned int low_addr_required:1;
> +	unsigned int keep_mapped:1;
> +};
> +
> +static struct testcase testcases[] = {
> +	{
> +		/*
> +		 * If stack is moved, we could possibly allocate
> +		 * this at the requested address.
> +		 */
> +		.addr = ((void *)(ADDR_SWITCH_HINT - PAGE_SIZE)),
> +		.size = PAGE_SIZE,
> +		.flags = MAP_PRIVATE | MAP_ANONYMOUS,
> +		.msg = "mmap(ADDR_SWITCH_HINT - PAGE_SIZE, PAGE_SIZE)",
> +		.low_addr_required = 1,
> +	},
> +	{
> +		/*
> +		 * We should never allocate at the requested address or above it
> +		 * The len cross the 128TB boundary. Without MAP_FIXED
> +		 * we will always search in the lower address space.
> +		 */
> +		.addr = ((void *)(ADDR_SWITCH_HINT - PAGE_SIZE)),
> +		.size = 2 * PAGE_SIZE,
> +		.flags = MAP_PRIVATE | MAP_ANONYMOUS,
> +		.msg = "mmap(ADDR_SWITCH_HINT - PAGE_SIZE, (2 * PAGE_SIZE))",
> +		.low_addr_required = 1,
> +	},
> +	{
> +		/*
> +		 * Exact mapping at 128TB, the area is free we should get that
> +		 * even without MAP_FIXED.
> +		 */
> +		.addr = ((void *)(ADDR_SWITCH_HINT)),
> +		.size = PAGE_SIZE,
> +		.flags = MAP_PRIVATE | MAP_ANONYMOUS,
> +		.msg = "mmap(ADDR_SWITCH_HINT, PAGE_SIZE)",
> +		.keep_mapped = 1,
> +	},
> +	{
> +		.addr = (void *)(ADDR_SWITCH_HINT),
> +		.size = 2 * PAGE_SIZE,
> +		.flags = MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED,
> +		.msg = "mmap(ADDR_SWITCH_HINT, 2 * PAGE_SIZE, MAP_FIXED)",
> +	},
> +	{
> +		.addr = NULL,
> +		.size = 2 * PAGE_SIZE,
> +		.flags = MAP_PRIVATE | MAP_ANONYMOUS,
> +		.msg = "mmap(NULL)",
> +		.low_addr_required = 1,
> +	},
> +	{
> +		.addr = LOW_ADDR,
> +		.size = 2 * PAGE_SIZE,
> +		.flags = MAP_PRIVATE | MAP_ANONYMOUS,
> +		.msg = "mmap(LOW_ADDR)",
> +		.low_addr_required = 1,
> +	},
> +	{
> +		.addr = HIGH_ADDR,
> +		.size = 2 * PAGE_SIZE,
> +		.flags = MAP_PRIVATE | MAP_ANONYMOUS,
> +		.msg = "mmap(HIGH_ADDR)",
> +		.keep_mapped = 1,
> +	},
> +	{
> +		.addr = HIGH_ADDR,
> +		.size = 2 * PAGE_SIZE,
> +		.flags = MAP_PRIVATE | MAP_ANONYMOUS,
> +		.msg = "mmap(HIGH_ADDR) again",
> +		.keep_mapped = 1,
> +	},
> +	{
> +		.addr = HIGH_ADDR,
> +		.size = 2 * PAGE_SIZE,
> +		.flags = MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED,
> +		.msg = "mmap(HIGH_ADDR, MAP_FIXED)",
> +	},
> +	{
> +		.addr = (void *) -1,
> +		.size = 2 * PAGE_SIZE,
> +		.flags = MAP_PRIVATE | MAP_ANONYMOUS,
> +		.msg = "mmap(-1)",
> +		.keep_mapped = 1,
> +	},
> +	{
> +		.addr = (void *) -1,
> +		.size = 2 * PAGE_SIZE,
> +		.flags = MAP_PRIVATE | MAP_ANONYMOUS,
> +		.msg = "mmap(-1) again",
> +	},
> +	{
> +		.addr = ((void *)(ADDR_SWITCH_HINT - PAGE_SIZE)),
> +		.size = PAGE_SIZE,
> +		.flags = MAP_PRIVATE | MAP_ANONYMOUS,
> +		.msg = "mmap(ADDR_SWITCH_HINT - PAGE_SIZE, PAGE_SIZE)",
> +		.low_addr_required = 1,
> +	},
> +	{
> +		.addr = (void *)(ADDR_SWITCH_HINT - PAGE_SIZE),
> +		.size = 2 * PAGE_SIZE,
> +		.flags = MAP_PRIVATE | MAP_ANONYMOUS,
> +		.msg = "mmap(ADDR_SWITCH_HINT - PAGE_SIZE, 2 * PAGE_SIZE)",
> +		.low_addr_required = 1,
> +		.keep_mapped = 1,
> +	},
> +	{
> +		.addr = (void *)(ADDR_SWITCH_HINT - PAGE_SIZE / 2),
> +		.size = 2 * PAGE_SIZE,
> +		.flags = MAP_PRIVATE | MAP_ANONYMOUS,
> +		.msg = "mmap(ADDR_SWITCH_HINT - PAGE_SIZE/2 , 2 * PAGE_SIZE)",
> +		.low_addr_required = 1,
> +		.keep_mapped = 1,
> +	},
> +	{
> +		.addr = ((void *)(ADDR_SWITCH_HINT)),
> +		.size = PAGE_SIZE,
> +		.flags = MAP_PRIVATE | MAP_ANONYMOUS,
> +		.msg = "mmap(ADDR_SWITCH_HINT, PAGE_SIZE)",
> +	},
> +	{
> +		.addr = (void *)(ADDR_SWITCH_HINT),
> +		.size = 2 * PAGE_SIZE,
> +		.flags = MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED,
> +		.msg = "mmap(ADDR_SWITCH_HINT, 2 * PAGE_SIZE, MAP_FIXED)",
> +	},
> +};
> +
> +static struct testcase hugetlb_testcases[] = {
> +	{
> +		.addr = NULL,
> +		.size = HUGETLB_SIZE,
> +		.flags = MAP_HUGETLB | MAP_PRIVATE | MAP_ANONYMOUS,
> +		.msg = "mmap(NULL, MAP_HUGETLB)",
> +		.low_addr_required = 1,
> +	},
> +	{
> +		.addr = LOW_ADDR,
> +		.size = HUGETLB_SIZE,
> +		.flags = MAP_HUGETLB | MAP_PRIVATE | MAP_ANONYMOUS,
> +		.msg = "mmap(LOW_ADDR, MAP_HUGETLB)",
> +		.low_addr_required = 1,
> +	},
> +	{
> +		.addr = HIGH_ADDR,
> +		.size = HUGETLB_SIZE,
> +		.flags = MAP_HUGETLB | MAP_PRIVATE | MAP_ANONYMOUS,
> +		.msg = "mmap(HIGH_ADDR, MAP_HUGETLB)",
> +		.keep_mapped = 1,
> +	},
> +	{
> +		.addr = HIGH_ADDR,
> +		.size = HUGETLB_SIZE,
> +		.flags = MAP_HUGETLB | MAP_PRIVATE | MAP_ANONYMOUS,
> +		.msg = "mmap(HIGH_ADDR, MAP_HUGETLB) again",
> +		.keep_mapped = 1,
> +	},
> +	{
> +		.addr = HIGH_ADDR,
> +		.size = HUGETLB_SIZE,
> +		.flags = MAP_HUGETLB | MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED,
> +		.msg = "mmap(HIGH_ADDR, MAP_FIXED | MAP_HUGETLB)",
> +	},
> +	{
> +		.addr = (void *) -1,
> +		.size = HUGETLB_SIZE,
> +		.flags = MAP_HUGETLB | MAP_PRIVATE | MAP_ANONYMOUS,
> +		.msg = "mmap(-1, MAP_HUGETLB)",
> +		.keep_mapped = 1,
> +	},
> +	{
> +		.addr = (void *) -1,
> +		.size = HUGETLB_SIZE,
> +		.flags = MAP_HUGETLB | MAP_PRIVATE | MAP_ANONYMOUS,
> +		.msg = "mmap(-1, MAP_HUGETLB) again",
> +	},
> +	{
> +		.addr = (void *)(ADDR_SWITCH_HINT - PAGE_SIZE),
> +		.size = 2 * HUGETLB_SIZE,
> +		.flags = MAP_HUGETLB | MAP_PRIVATE | MAP_ANONYMOUS,
> +		.msg = "mmap(ADDR_SWITCH_HINT - PAGE_SIZE, 2*HUGETLB_SIZE, MAP_HUGETLB)",
> +		.low_addr_required = 1,
> +		.keep_mapped = 1,
> +	},
> +	{
> +		.addr = (void *)(ADDR_SWITCH_HINT),
> +		.size = 2 * HUGETLB_SIZE,
> +		.flags = MAP_HUGETLB | MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED,
> +		.msg = "mmap(ADDR_SWITCH_HINT , 2*HUGETLB_SIZE, MAP_FIXED | MAP_HUGETLB)",
> +	},
> +};

Does the test permutations with 'keep_mapped' form some sort of corner
case for later test cases ? If yes, could you please describe it.

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