From nobody Mon Feb 9 07:19:14 2026 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 70BFE3D0C6; Sat, 30 Mar 2024 17:37:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711820268; cv=none; b=ikL6KX/bCwvc9rOobvIGDVLGZ/TgdfaTlls9Z2lPPYXOyiOew0TNok9Us9ihzLbfYHp2Nf0Q+RMC+lQIe0aKVY/IqDVNyqb521edGKy8zdxqrboJ3QJP4NJTB4SDYI9SLej4pg/6Hm8zJ2hNDDx5z/qTNIqIyr158VdfkocUFOE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711820268; c=relaxed/simple; bh=86LynxX/Wa5mVbZP8ibHc/96NXH3pPQppzNPOikiI/U=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=FWbtpzHBETvvBhxhBWQnrE2gEheYkvLCum9F6oLtZIYolr4S4nngi//ZANlMNY6zP9nmTVPWksUCtDj8EnNPrT0B3kfTV/ePrrXgP3shgrVk8Dz6G+q0bCPUjRxXHnsuFlhRNmhCITjX+VEYeIjqVSXl4WdX2fcgo79I4pG2OiI= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 824DE11FB; Sat, 30 Mar 2024 10:38:12 -0700 (PDT) Received: from e116581.. (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 2C7803F7B4; Sat, 30 Mar 2024 10:37:35 -0700 (PDT) From: Dev Jain To: akpm@linux-foundation.org Cc: shuah@kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, kaleshsingh@google.com, jhubbard@nvidia.com, Anshuman.Khandual@arm.com, Dev Jain Subject: [PATCH 1/3] selftests/mm: mremap_test: Optimize using pre-filled random array and memcpy Date: Sat, 30 Mar 2024 23:05:55 +0530 Message-Id: <20240330173557.2697684-2-dev.jain@arm.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20240330173557.2697684-1-dev.jain@arm.com> References: <20240330173557.2697684-1-dev.jain@arm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Allocate a pre-filled random buffer using the seed. Replace iterative copyi= ng of the random sequence to buffers using the highly optimized library function memcpy(). Signed-off-by: Dev Jain --- tools/testing/selftests/mm/mremap_test.c | 78 ++++++++++++++++-------- 1 file changed, 53 insertions(+), 25 deletions(-) diff --git a/tools/testing/selftests/mm/mremap_test.c b/tools/testing/selft= ests/mm/mremap_test.c index 2f8b991f78cb..7fed9cc3911e 100644 --- a/tools/testing/selftests/mm/mremap_test.c +++ b/tools/testing/selftests/mm/mremap_test.c @@ -23,6 +23,7 @@ #define VALIDATION_NO_THRESHOLD 0 /* Verify the entire region */ =20 #define MIN(X, Y) ((X) < (Y) ? (X) : (Y)) +#define MAX(X, Y) ((X) > (Y) ? (X) : (Y)) #define SIZE_MB(m) ((size_t)m * (1024 * 1024)) #define SIZE_KB(k) ((size_t)k * 1024) =20 @@ -296,7 +297,7 @@ static void mremap_expand_merge_offset(FILE *maps_fp, u= nsigned long page_size) * * |DDDDddddSSSSssss| */ -static void mremap_move_within_range(char pattern_seed) +static void mremap_move_within_range(unsigned int pattern_seed, char *rand= _addr) { char *test_name =3D "mremap mremap move within range"; void *src, *dest; @@ -316,10 +317,7 @@ static void mremap_move_within_range(char pattern_seed) src =3D (void *)((unsigned long)src & ~(SIZE_MB(2) - 1)); =20 /* Set byte pattern for source block. */ - srand(pattern_seed); - for (i =3D 0; i < SIZE_MB(2); i++) { - ((char *)src)[i] =3D (char) rand(); - } + memcpy(src, rand_addr, SIZE_MB(2)); =20 dest =3D src - SIZE_MB(2); =20 @@ -357,7 +355,7 @@ static void mremap_move_within_range(char pattern_seed) =20 /* Returns the time taken for the remap on success else returns -1. */ static long long remap_region(struct config c, unsigned int threshold_mb, - char pattern_seed) + unsigned int pattern_seed, char *rand_addr) { void *addr, *src_addr, *dest_addr, *dest_preamble_addr; int d; @@ -378,9 +376,7 @@ static long long remap_region(struct config c, unsigned= int threshold_mb, } =20 /* Set byte pattern for source block. */ - srand(pattern_seed); - for (t =3D 0; t < threshold; t++) - memset((char *) src_addr + t, (char) rand(), 1); + memcpy(src_addr, rand_addr, threshold); =20 /* Mask to zero out lower bits of address for alignment */ align_mask =3D ~(c.dest_alignment - 1); @@ -420,9 +416,7 @@ static long long remap_region(struct config c, unsigned= int threshold_mb, } =20 /* Set byte pattern for the dest preamble block. */ - srand(pattern_seed); - for (d =3D 0; d < c.dest_preamble_size; d++) - memset((char *) dest_preamble_addr + d, (char) rand(), 1); + memcpy(dest_preamble_addr, rand_addr, c.dest_preamble_size); } =20 clock_gettime(CLOCK_MONOTONIC, &t_start); @@ -494,7 +488,8 @@ static long long remap_region(struct config c, unsigned= int threshold_mb, * the beginning of the mapping just because the aligned * down address landed on a mapping that maybe does not exist. */ -static void mremap_move_1mb_from_start(char pattern_seed) +static void mremap_move_1mb_from_start(unsigned int pattern_seed, + char *rand_addr) { char *test_name =3D "mremap move 1mb from start at 1MB+256KB aligned src"; void *src =3D NULL, *dest =3D NULL; @@ -520,10 +515,7 @@ static void mremap_move_1mb_from_start(char pattern_se= ed) } =20 /* Set byte pattern for source block. */ - srand(pattern_seed); - for (i =3D 0; i < SIZE_MB(2); i++) { - ((char *)src)[i] =3D (char) rand(); - } + memcpy(src, rand_addr, SIZE_MB(2)); =20 /* * Unmap the beginning of dest so that the aligned address @@ -568,10 +560,10 @@ static void mremap_move_1mb_from_start(char pattern_s= eed) =20 static void run_mremap_test_case(struct test test_case, int *failures, unsigned int threshold_mb, - unsigned int pattern_seed) + unsigned int pattern_seed, char *rand_addr) { long long remap_time =3D remap_region(test_case.config, threshold_mb, - pattern_seed); + pattern_seed, rand_addr); =20 if (remap_time < 0) { if (test_case.expect_failure) @@ -642,7 +634,15 @@ int main(int argc, char **argv) int failures =3D 0; int i, run_perf_tests; unsigned int threshold_mb =3D VALIDATION_DEFAULT_THRESHOLD; + + /* hard-coded test configs */ + size_t max_test_variable_region_size =3D _2GB; + size_t max_test_constant_region_size =3D _2MB; + size_t dest_preamble_size =3D 10 * _4MB; + unsigned int pattern_seed; + char *rand_addr; + size_t rand_size; int num_expand_tests =3D 2; int num_misc_tests =3D 2; struct test test_cases[MAX_TEST] =3D {}; @@ -659,6 +659,31 @@ int main(int argc, char **argv) ksft_print_msg("Test configs:\n\tthreshold_mb=3D%u\n\tpattern_seed=3D%u\n= \n", threshold_mb, pattern_seed); =20 + /* + * set preallocated random array according to test configs; see the + * functions for the logic of setting the size + */ + if (!threshold_mb) + rand_size =3D MAX(max_test_variable_region_size, + max_test_constant_region_size); + else + rand_size =3D MAX(MIN(threshold_mb * _1MB, + max_test_variable_region_size), + max_test_constant_region_size); + rand_size =3D MAX(dest_preamble_size, rand_size); + + rand_addr =3D (char *)mmap(NULL, rand_size, PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); + if (rand_addr =3D=3D MAP_FAILED) { + perror("mmap"); + ksft_exit_fail_msg("cannot mmap rand_addr\n"); + } + + /* fill stream of random bytes */ + srand(pattern_seed); + for (unsigned long i =3D 0; i < rand_size; ++i) + rand_addr[i] =3D (char) rand(); + page_size =3D sysconf(_SC_PAGESIZE); =20 /* Expected mremap failures */ @@ -730,13 +755,13 @@ int main(int argc, char **argv) =20 for (i =3D 0; i < ARRAY_SIZE(test_cases); i++) run_mremap_test_case(test_cases[i], &failures, threshold_mb, - pattern_seed); + pattern_seed, rand_addr); =20 maps_fp =3D fopen("/proc/self/maps", "r"); =20 if (maps_fp =3D=3D NULL) { - ksft_print_msg("Failed to read /proc/self/maps: %s\n", strerror(errno)); - exit(KSFT_FAIL); + munmap(rand_addr, rand_size); + ksft_exit_fail_msg("Failed to read /proc/self/maps: %s\n", strerror(errn= o)); } =20 mremap_expand_merge(maps_fp, page_size); @@ -744,17 +769,20 @@ int main(int argc, char **argv) =20 fclose(maps_fp); =20 - mremap_move_within_range(pattern_seed); - mremap_move_1mb_from_start(pattern_seed); + mremap_move_within_range(pattern_seed, rand_addr); + mremap_move_1mb_from_start(pattern_seed, rand_addr); =20 if (run_perf_tests) { ksft_print_msg("\n%s\n", "mremap HAVE_MOVE_PMD/PUD optimization time comparison for 1GB region:"= ); for (i =3D 0; i < ARRAY_SIZE(perf_test_cases); i++) run_mremap_test_case(perf_test_cases[i], &failures, - threshold_mb, pattern_seed); + threshold_mb, pattern_seed, + rand_addr); } =20 + munmap(rand_addr, rand_size); + if (failures > 0) ksft_exit_fail(); else --=20 2.34.1