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Date: Wed, 3 Jan 2024 15:21:56 +0900
From: Itaru Kitayama <itaru.kitayama@linux.dev>
To: Ryan Roberts <ryan.roberts@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Matthew Wilcox <willy@infradead.org>,
	Yin Fengwei <fengwei.yin@intel.com>,
	David Hildenbrand <david@redhat.com>, Yu Zhao <yuzhao@google.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Anshuman Khandual <anshuman.khandual@arm.com>,
	Yang Shi <shy828301@gmail.com>,
	"Huang, Ying" <ying.huang@intel.com>, Zi Yan <ziy@nvidia.com>,
	Luis Chamberlain <mcgrof@kernel.org>,
	Itaru Kitayama <itaru.kitayama@gmail.com>,
	"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
	John Hubbard <jhubbard@nvidia.com>,
	David Rientjes <rientjes@google.com>,
	Vlastimil Babka <vbabka@suse.cz>, Hugh Dickins <hughd@google.com>,
	Kefeng Wang <wangkefeng.wang@huawei.com>,
	Barry Song <21cnbao@gmail.com>,
	Alistair Popple <apopple@nvidia.com>, linux-mm@kvack.org,
	linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v9 09/10] selftests/mm/cow: Generalize do_run_with_thp()
 helper
Message-ID: <ZZT9BHVU0+lyKNJF@vm3>
References: <20231207161211.2374093-1-ryan.roberts@arm.com>
 <20231207161211.2374093-10-ryan.roberts@arm.com>
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In-Reply-To: <20231207161211.2374093-10-ryan.roberts@arm.com>

On Thu, Dec 07, 2023 at 04:12:10PM +0000, Ryan Roberts wrote:
> do_run_with_thp() prepares (PMD-sized) THP memory into different states
> before running tests. With the introduction of multi-size THP, we would
> like to reuse this logic to also test those smaller THP sizes. So let's
> add a thpsize parameter which tells the function what size THP it should
> operate on.
> 
> A separate commit will utilize this change to add new tests for
> multi-size THP, where available.
> 
> Reviewed-by: David Hildenbrand <david@redhat.com>
> Tested-by: Kefeng Wang <wangkefeng.wang@huawei.com>
> Tested-by: John Hubbard <jhubbard@nvidia.com>
> Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>

Tested-by: Itaru Kitayama <itaru.kitayama@linux.dev>

I am replying to all this time; Ryan, do you think it's okay to run
700 of selftests/mm/cow tests? Even on FVP, they did not take longer
though.

> ---
>  tools/testing/selftests/mm/cow.c | 121 +++++++++++++++++--------------
>  1 file changed, 67 insertions(+), 54 deletions(-)
> 
> diff --git a/tools/testing/selftests/mm/cow.c b/tools/testing/selftests/mm/cow.c
> index 7324ce5363c0..4d0b5a125d3c 100644
> --- a/tools/testing/selftests/mm/cow.c
> +++ b/tools/testing/selftests/mm/cow.c
> @@ -32,7 +32,7 @@
>  
>  static size_t pagesize;
>  static int pagemap_fd;
> -static size_t thpsize;
> +static size_t pmdsize;
>  static int nr_hugetlbsizes;
>  static size_t hugetlbsizes[10];
>  static int gup_fd;
> @@ -734,7 +734,7 @@ enum thp_run {
>  	THP_RUN_PARTIAL_SHARED,
>  };
>  
> -static void do_run_with_thp(test_fn fn, enum thp_run thp_run)
> +static void do_run_with_thp(test_fn fn, enum thp_run thp_run, size_t thpsize)
>  {
>  	char *mem, *mmap_mem, *tmp, *mremap_mem = MAP_FAILED;
>  	size_t size, mmap_size, mremap_size;
> @@ -759,11 +759,11 @@ static void do_run_with_thp(test_fn fn, enum thp_run thp_run)
>  	}
>  
>  	/*
> -	 * Try to populate a THP. Touch the first sub-page and test if we get
> -	 * another sub-page populated automatically.
> +	 * Try to populate a THP. Touch the first sub-page and test if
> +	 * we get the last sub-page populated automatically.
>  	 */
>  	mem[0] = 0;
> -	if (!pagemap_is_populated(pagemap_fd, mem + pagesize)) {
> +	if (!pagemap_is_populated(pagemap_fd, mem + thpsize - pagesize)) {
>  		ksft_test_result_skip("Did not get a THP populated\n");
>  		goto munmap;
>  	}
> @@ -773,12 +773,14 @@ static void do_run_with_thp(test_fn fn, enum thp_run thp_run)
>  	switch (thp_run) {
>  	case THP_RUN_PMD:
>  	case THP_RUN_PMD_SWAPOUT:
> +		assert(thpsize == pmdsize);
>  		break;
>  	case THP_RUN_PTE:
>  	case THP_RUN_PTE_SWAPOUT:
>  		/*
>  		 * Trigger PTE-mapping the THP by temporarily mapping a single
> -		 * subpage R/O.
> +		 * subpage R/O. This is a noop if the THP is not pmdsize (and
> +		 * therefore already PTE-mapped).
>  		 */
>  		ret = mprotect(mem + pagesize, pagesize, PROT_READ);
>  		if (ret) {
> @@ -875,52 +877,60 @@ static void do_run_with_thp(test_fn fn, enum thp_run thp_run)
>  		munmap(mremap_mem, mremap_size);
>  }
>  
> -static void run_with_thp(test_fn fn, const char *desc)
> +static void run_with_thp(test_fn fn, const char *desc, size_t size)
>  {
> -	ksft_print_msg("[RUN] %s ... with THP\n", desc);
> -	do_run_with_thp(fn, THP_RUN_PMD);
> +	ksft_print_msg("[RUN] %s ... with THP (%zu kB)\n",
> +		desc, size / 1024);
> +	do_run_with_thp(fn, THP_RUN_PMD, size);
>  }
>  
> -static void run_with_thp_swap(test_fn fn, const char *desc)
> +static void run_with_thp_swap(test_fn fn, const char *desc, size_t size)
>  {
> -	ksft_print_msg("[RUN] %s ... with swapped-out THP\n", desc);
> -	do_run_with_thp(fn, THP_RUN_PMD_SWAPOUT);
> +	ksft_print_msg("[RUN] %s ... with swapped-out THP (%zu kB)\n",
> +		desc, size / 1024);
> +	do_run_with_thp(fn, THP_RUN_PMD_SWAPOUT, size);
>  }
>  
> -static void run_with_pte_mapped_thp(test_fn fn, const char *desc)
> +static void run_with_pte_mapped_thp(test_fn fn, const char *desc, size_t size)
>  {
> -	ksft_print_msg("[RUN] %s ... with PTE-mapped THP\n", desc);
> -	do_run_with_thp(fn, THP_RUN_PTE);
> +	ksft_print_msg("[RUN] %s ... with PTE-mapped THP (%zu kB)\n",
> +		desc, size / 1024);
> +	do_run_with_thp(fn, THP_RUN_PTE, size);
>  }
>  
> -static void run_with_pte_mapped_thp_swap(test_fn fn, const char *desc)
> +static void run_with_pte_mapped_thp_swap(test_fn fn, const char *desc, size_t size)
>  {
> -	ksft_print_msg("[RUN] %s ... with swapped-out, PTE-mapped THP\n", desc);
> -	do_run_with_thp(fn, THP_RUN_PTE_SWAPOUT);
> +	ksft_print_msg("[RUN] %s ... with swapped-out, PTE-mapped THP (%zu kB)\n",
> +		desc, size / 1024);
> +	do_run_with_thp(fn, THP_RUN_PTE_SWAPOUT, size);
>  }
>  
> -static void run_with_single_pte_of_thp(test_fn fn, const char *desc)
> +static void run_with_single_pte_of_thp(test_fn fn, const char *desc, size_t size)
>  {
> -	ksft_print_msg("[RUN] %s ... with single PTE of THP\n", desc);
> -	do_run_with_thp(fn, THP_RUN_SINGLE_PTE);
> +	ksft_print_msg("[RUN] %s ... with single PTE of THP (%zu kB)\n",
> +		desc, size / 1024);
> +	do_run_with_thp(fn, THP_RUN_SINGLE_PTE, size);
>  }
>  
> -static void run_with_single_pte_of_thp_swap(test_fn fn, const char *desc)
> +static void run_with_single_pte_of_thp_swap(test_fn fn, const char *desc, size_t size)
>  {
> -	ksft_print_msg("[RUN] %s ... with single PTE of swapped-out THP\n", desc);
> -	do_run_with_thp(fn, THP_RUN_SINGLE_PTE_SWAPOUT);
> +	ksft_print_msg("[RUN] %s ... with single PTE of swapped-out THP (%zu kB)\n",
> +		desc, size / 1024);
> +	do_run_with_thp(fn, THP_RUN_SINGLE_PTE_SWAPOUT, size);
>  }
>  
> -static void run_with_partial_mremap_thp(test_fn fn, const char *desc)
> +static void run_with_partial_mremap_thp(test_fn fn, const char *desc, size_t size)
>  {
> -	ksft_print_msg("[RUN] %s ... with partially mremap()'ed THP\n", desc);
> -	do_run_with_thp(fn, THP_RUN_PARTIAL_MREMAP);
> +	ksft_print_msg("[RUN] %s ... with partially mremap()'ed THP (%zu kB)\n",
> +		desc, size / 1024);
> +	do_run_with_thp(fn, THP_RUN_PARTIAL_MREMAP, size);
>  }
>  
> -static void run_with_partial_shared_thp(test_fn fn, const char *desc)
> +static void run_with_partial_shared_thp(test_fn fn, const char *desc, size_t size)
>  {
> -	ksft_print_msg("[RUN] %s ... with partially shared THP\n", desc);
> -	do_run_with_thp(fn, THP_RUN_PARTIAL_SHARED);
> +	ksft_print_msg("[RUN] %s ... with partially shared THP (%zu kB)\n",
> +		desc, size / 1024);
> +	do_run_with_thp(fn, THP_RUN_PARTIAL_SHARED, size);
>  }
>  
>  static void run_with_hugetlb(test_fn fn, const char *desc, size_t hugetlbsize)
> @@ -1091,15 +1101,15 @@ static void run_anon_test_case(struct test_case const *test_case)
>  
>  	run_with_base_page(test_case->fn, test_case->desc);
>  	run_with_base_page_swap(test_case->fn, test_case->desc);
> -	if (thpsize) {
> -		run_with_thp(test_case->fn, test_case->desc);
> -		run_with_thp_swap(test_case->fn, test_case->desc);
> -		run_with_pte_mapped_thp(test_case->fn, test_case->desc);
> -		run_with_pte_mapped_thp_swap(test_case->fn, test_case->desc);
> -		run_with_single_pte_of_thp(test_case->fn, test_case->desc);
> -		run_with_single_pte_of_thp_swap(test_case->fn, test_case->desc);
> -		run_with_partial_mremap_thp(test_case->fn, test_case->desc);
> -		run_with_partial_shared_thp(test_case->fn, test_case->desc);
> +	if (pmdsize) {
> +		run_with_thp(test_case->fn, test_case->desc, pmdsize);
> +		run_with_thp_swap(test_case->fn, test_case->desc, pmdsize);
> +		run_with_pte_mapped_thp(test_case->fn, test_case->desc, pmdsize);
> +		run_with_pte_mapped_thp_swap(test_case->fn, test_case->desc, pmdsize);
> +		run_with_single_pte_of_thp(test_case->fn, test_case->desc, pmdsize);
> +		run_with_single_pte_of_thp_swap(test_case->fn, test_case->desc, pmdsize);
> +		run_with_partial_mremap_thp(test_case->fn, test_case->desc, pmdsize);
> +		run_with_partial_shared_thp(test_case->fn, test_case->desc, pmdsize);
>  	}
>  	for (i = 0; i < nr_hugetlbsizes; i++)
>  		run_with_hugetlb(test_case->fn, test_case->desc,
> @@ -1120,7 +1130,7 @@ static int tests_per_anon_test_case(void)
>  {
>  	int tests = 2 + nr_hugetlbsizes;
>  
> -	if (thpsize)
> +	if (pmdsize)
>  		tests += 8;
>  	return tests;
>  }
> @@ -1329,7 +1339,7 @@ static void run_anon_thp_test_cases(void)
>  {
>  	int i;
>  
> -	if (!thpsize)
> +	if (!pmdsize)
>  		return;
>  
>  	ksft_print_msg("[INFO] Anonymous THP tests\n");
> @@ -1338,13 +1348,13 @@ static void run_anon_thp_test_cases(void)
>  		struct test_case const *test_case = &anon_thp_test_cases[i];
>  
>  		ksft_print_msg("[RUN] %s\n", test_case->desc);
> -		do_run_with_thp(test_case->fn, THP_RUN_PMD);
> +		do_run_with_thp(test_case->fn, THP_RUN_PMD, pmdsize);
>  	}
>  }
>  
>  static int tests_per_anon_thp_test_case(void)
>  {
> -	return thpsize ? 1 : 0;
> +	return pmdsize ? 1 : 0;
>  }
>  
>  typedef void (*non_anon_test_fn)(char *mem, const char *smem, size_t size);
> @@ -1419,7 +1429,7 @@ static void run_with_huge_zeropage(non_anon_test_fn fn, const char *desc)
>  	}
>  
>  	/* For alignment purposes, we need twice the thp size. */
> -	mmap_size = 2 * thpsize;
> +	mmap_size = 2 * pmdsize;
>  	mmap_mem = mmap(NULL, mmap_size, PROT_READ | PROT_WRITE,
>  			MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
>  	if (mmap_mem == MAP_FAILED) {
> @@ -1434,11 +1444,11 @@ static void run_with_huge_zeropage(non_anon_test_fn fn, const char *desc)
>  	}
>  
>  	/* We need a THP-aligned memory area. */
> -	mem = (char *)(((uintptr_t)mmap_mem + thpsize) & ~(thpsize - 1));
> -	smem = (char *)(((uintptr_t)mmap_smem + thpsize) & ~(thpsize - 1));
> +	mem = (char *)(((uintptr_t)mmap_mem + pmdsize) & ~(pmdsize - 1));
> +	smem = (char *)(((uintptr_t)mmap_smem + pmdsize) & ~(pmdsize - 1));
>  
> -	ret = madvise(mem, thpsize, MADV_HUGEPAGE);
> -	ret |= madvise(smem, thpsize, MADV_HUGEPAGE);
> +	ret = madvise(mem, pmdsize, MADV_HUGEPAGE);
> +	ret |= madvise(smem, pmdsize, MADV_HUGEPAGE);
>  	if (ret) {
>  		ksft_test_result_fail("MADV_HUGEPAGE failed\n");
>  		goto munmap;
> @@ -1457,7 +1467,7 @@ static void run_with_huge_zeropage(non_anon_test_fn fn, const char *desc)
>  		goto munmap;
>  	}
>  
> -	fn(mem, smem, thpsize);
> +	fn(mem, smem, pmdsize);
>  munmap:
>  	munmap(mmap_mem, mmap_size);
>  	if (mmap_smem != MAP_FAILED)
> @@ -1650,7 +1660,7 @@ static void run_non_anon_test_case(struct non_anon_test_case const *test_case)
>  	run_with_zeropage(test_case->fn, test_case->desc);
>  	run_with_memfd(test_case->fn, test_case->desc);
>  	run_with_tmpfile(test_case->fn, test_case->desc);
> -	if (thpsize)
> +	if (pmdsize)
>  		run_with_huge_zeropage(test_case->fn, test_case->desc);
>  	for (i = 0; i < nr_hugetlbsizes; i++)
>  		run_with_memfd_hugetlb(test_case->fn, test_case->desc,
> @@ -1671,7 +1681,7 @@ static int tests_per_non_anon_test_case(void)
>  {
>  	int tests = 3 + nr_hugetlbsizes;
>  
> -	if (thpsize)
> +	if (pmdsize)
>  		tests += 1;
>  	return tests;
>  }
> @@ -1681,10 +1691,13 @@ int main(int argc, char **argv)
>  	int err;
>  
>  	pagesize = getpagesize();
> -	thpsize = read_pmd_pagesize();
> -	if (thpsize)
> +	pmdsize = read_pmd_pagesize();
> +	if (pmdsize) {
> +		ksft_print_msg("[INFO] detected PMD size: %zu KiB\n",
> +			       pmdsize / 1024);
>  		ksft_print_msg("[INFO] detected THP size: %zu KiB\n",
> -			       thpsize / 1024);
> +			       pmdsize / 1024);
> +	}
>  	nr_hugetlbsizes = detect_hugetlb_page_sizes(hugetlbsizes,
>  						    ARRAY_SIZE(hugetlbsizes));
>  	detect_huge_zeropage();
> -- 
> 2.25.1
>