Subject: Re: [PATCH] selftests/powerpc/mm: Add a test for virtual address mapping

From: "Aneesh Kumar K.V" <[email-masked]>
Date: Mon, 17 Apr 2017 10:56:44 +0530

Anshuman Khandual <[email-masked]> writes:

> This verifies virtual address mapping below and above the
> 128TB range and makes sure that address returned are within
> the expected range depending upon the hint passed from the
> user space.
>
> Signed-off-by: Anshuman Khandual <[email-masked]>
> ---
> Tested this on latest ppc-next with Aneesh's yesterday's patch
> which can be found at https://patchwork.ozlabs.org/patch/749510/
>
>  tools/testing/selftests/powerpc/mm/.gitignore |  3 +-
>  tools/testing/selftests/powerpc/mm/Makefile   |  2 +-
>  tools/testing/selftests/powerpc/mm/vaddr.c    | 89 +++++++++++++++++++++++++++
>  3 files changed, 92 insertions(+), 2 deletions(-)
>  create mode 100644 tools/testing/selftests/powerpc/mm/vaddr.c
>
> diff --git a/tools/testing/selftests/powerpc/mm/.gitignore b/tools/testing/selftests/powerpc/mm/.gitignore
> index e715a3f..af1f31f 100644
> --- a/tools/testing/selftests/powerpc/mm/.gitignore
> +++ b/tools/testing/selftests/powerpc/mm/.gitignore
> @@ -1,4 +1,5 @@
>  hugetlb_vs_thp_test
>  subpage_prot
>  tempfile
> -prot_sao
> \ No newline at end of file
> +prot_sao
> +vaddr
> diff --git a/tools/testing/selftests/powerpc/mm/Makefile b/tools/testing/selftests/powerpc/mm/Makefile
> index 1cffe54..7345db2 100644
> --- a/tools/testing/selftests/powerpc/mm/Makefile
> +++ b/tools/testing/selftests/powerpc/mm/Makefile
> @@ -1,7 +1,7 @@
>  noarg:
>  	$(MAKE) -C ../
>
> -TEST_GEN_PROGS := hugetlb_vs_thp_test subpage_prot prot_sao
> +TEST_GEN_PROGS := hugetlb_vs_thp_test subpage_prot prot_sao vaddr
>  TEST_GEN_FILES := tempfile
>
>  include ../../lib.mk
> diff --git a/tools/testing/selftests/powerpc/mm/vaddr.c b/tools/testing/selftests/powerpc/mm/vaddr.c
> new file mode 100644
> index 0000000..d6485e9
> --- /dev/null
> +++ b/tools/testing/selftests/powerpc/mm/vaddr.c
> @@ -0,0 +1,89 @@
> +/*
> + * Copyright 2017, Anshuman Khandual, IBM Corp.
> + * Licensed under GPLv2.
> + */
> +
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include <string.h>
> +#include <unistd.h>
> +#include <errno.h>
> +#include <numaif.h>
> +#include <sys/mman.h>
> +#include <sys/time.h>
> +#include "utils.h"
> +
> +#define PAGE_SIZE        65536UL  /* 64KB */
> +#define MAP_SIZE_16GB    262144UL /* 16GB  */

can we make it MMAP_CHUNK_SIZE ?

> +#define NR_SLICES_128TB  8192UL   /* 128TB */

NR_CHUNK_128TB ?

> +#define NR_SLICES_384TB  24576UL  /* 384TB */

Can you add more comments around that. Those numbers/names have special
meaning on powerpc. I guess you are not doing anything related that.
Hence rename slices to something else or add a comment saying how many
16GB slices. Also explain why you are taking 16GB as the size.

> +#define ADDR_MARK_128TB  0x800000000000UL /* Beyond 128TB */
> +
> +static char *hind_addr(void)
> +{
> +	int bits = 48 + rand() % 15;
> +
> +	return (char *) (1UL << bits);
> +}
> +
> +static int validate_addr(char *ptr, int high_addr)
> +{
> +	unsigned long addr = (unsigned long) ptr;
> +
> +	if (high_addr) {
> +		if (addr < ADDR_MARK_128TB) {
> +			printf("Bad address %lx\n", addr);
> +			return 1;
> +		}
> +		return 0;
> +	}
> +
> +	if (addr > ADDR_MARK_128TB) {
> +		printf("Bad address %lx\n", addr);
> +		return 1;
> +	}
> +	return 0;
> +}
> +
> +int vaddr(void)
> +{
> +	char *ptr[NR_SLICES_128TB];
> +	char *hptr[NR_SLICES_384TB];
> +	char *hint;
> +	int  i;
> +
> +	for (i = 0; i < NR_SLICES_128TB; i++) {
> +		ptr[i] = mmap(NULL, MAP_SIZE_16GB, PROT_READ | PROT_WRITE,
> +					MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
> +
> +		if (ptr[i] == MAP_FAILED)
> +			break;
> +
> +		if (validate_addr(ptr[i], 0))
> +			return 1;
> +	}
> +
> +	for (i = 0; i < NR_SLICES_384TB; i++) {
> +		hint = hind_addr();

Why add rand() why not a constant value ?

> +		hptr[i] = mmap(hint, MAP_SIZE_16GB, PROT_READ | PROT_WRITE,
> +					MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
> +
> +		if (hptr[i] == MAP_FAILED)
> +			break;
> +
> +		if (validate_addr(hptr[i], 1))
> +			return 1;
> +	}

We can also add check to make sure mmap fail if we passed a hint addr
below 128TB ? 

> +
> +	for (i = 0; i < NR_SLICES_128TB; i++)
> +		munmap(ptr[i], MAP_SIZE_16GB);
> +
> +	for (i = 0; i < NR_SLICES_384TB; i++)
> +		munmap(hptr[i], MAP_SIZE_16GB);
> +	return 0;
> +}
> +
> +int main(int argc, char *argv[])
> +{
> +	return test_harness(vaddr, "vaddr-range");
> +}
> -- 
> 1.8.5.2