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Fri, 13 Dec 2024 09:55:53 +0000 (UTC) Received: from gmonaco-thinkpadt14gen3.rmtit.com (unknown [10.39.192.43]) by mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id F02EC195394B; Fri, 13 Dec 2024 09:55:48 +0000 (UTC) From: Gabriele Monaco To: Mathieu Desnoyers , Ingo Molnar , Peter Zijlstra , Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: Juri Lelli , Vincent Guittot , Mel Gorman , Shuah Khan , linux-kselftest@vger.kernel.org, Gabriele Monaco Subject: [PATCH v2 4/4] rseq/selftests: Add test for mm_cid compaction Date: Fri, 13 Dec 2024 10:54:07 +0100 Message-ID: <20241213095407.271357-5-gmonaco@redhat.com> In-Reply-To: <20241213095407.271357-1-gmonaco@redhat.com> References: <20241213095407.271357-1-gmonaco@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.0 on 10.30.177.12 X-Rspamd-Queue-Id: 2B2F98000F X-Rspam-User: X-Rspamd-Server: rspam07 X-Stat-Signature: 7i63qh6u3mz8qfft9mnoma87iwzzg3jr X-HE-Tag: 1734083711-363568 X-HE-Meta: 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 nK7jrMX6 acfcZEavzNUDOJGZG3qAT32jQ9dHo3IIkSro9Feazoww5sA1HxGIagqA6NMnfq5VOg/pxGgF0Agy2EvZ7RZ2vX0wCwt6WSwQh+qzgf5fmSL3ATJDkjt41yxg097t99DZPNL3VOmHk0VHDshKLsC5TAOfKWR0v8vDsLYP6gEBp3xRyovFK1SPxoi3ZY93Ekp5Wlyb3aA8jFP0chGSKIcKMyXLgNB/S6m0TvI0RsJ5uJUvNWEODwjjP8I/hOZKfOgJ4LyGphGPHOtpTvrLwgLUuchql0kmfGeYgj/i9QiY55RUej1Uf9s9rPnavFLc7jF//EKODq3U+JZm8ZoRYjQ0jtXhyrVRrYYavKdwZOJxROJcyKA5Q0QUGhHoWHrQYN/uMHpJPHyNhnk9ImKSsvz063Z3NWQ== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: A task in the kernel (task_mm_cid_work) runs somewhat periodically to compact the mm_cid for each process, this test tries to validate that it runs correctly and timely. The test spawns 1 thread pinned to each CPU, then each thread, including the main one, run in short bursts for some time. During this period, the mm_cids should be spanning all numbers between 0 and nproc. At the end of this phase, a thread with high enough mm_cid (> nproc/2) is selected to be the new leader, all other threads terminate. After some time, the only running thread should see 0 as mm_cid, if that doesn't happen, the compaction mechanism didn't work and the test fails. The test never fails if only 1 core is available, in which case, we cannot test anything as the only available mm_cid is 0. Signed-off-by: Gabriele Monaco --- tools/testing/selftests/rseq/.gitignore | 1 + tools/testing/selftests/rseq/Makefile | 2 +- .../selftests/rseq/mm_cid_compaction_test.c | 157 ++++++++++++++++++ 3 files changed, 159 insertions(+), 1 deletion(-) create mode 100644 tools/testing/selftests/rseq/mm_cid_compaction_test.c diff --git a/tools/testing/selftests/rseq/.gitignore b/tools/testing/selftests/rseq/.gitignore index 16496de5f6ce..2c89f97e4f73 100644 --- a/tools/testing/selftests/rseq/.gitignore +++ b/tools/testing/selftests/rseq/.gitignore @@ -3,6 +3,7 @@ basic_percpu_ops_test basic_percpu_ops_mm_cid_test basic_test basic_rseq_op_test +mm_cid_compaction_test param_test param_test_benchmark param_test_compare_twice diff --git a/tools/testing/selftests/rseq/Makefile b/tools/testing/selftests/rseq/Makefile index 5a3432fceb58..ce1b38f46a35 100644 --- a/tools/testing/selftests/rseq/Makefile +++ b/tools/testing/selftests/rseq/Makefile @@ -16,7 +16,7 @@ OVERRIDE_TARGETS = 1 TEST_GEN_PROGS = basic_test basic_percpu_ops_test basic_percpu_ops_mm_cid_test param_test \ param_test_benchmark param_test_compare_twice param_test_mm_cid \ - param_test_mm_cid_benchmark param_test_mm_cid_compare_twice + param_test_mm_cid_benchmark param_test_mm_cid_compare_twice mm_cid_compaction_test TEST_GEN_PROGS_EXTENDED = librseq.so diff --git a/tools/testing/selftests/rseq/mm_cid_compaction_test.c b/tools/testing/selftests/rseq/mm_cid_compaction_test.c new file mode 100644 index 000000000000..9bc7310c3cb5 --- /dev/null +++ b/tools/testing/selftests/rseq/mm_cid_compaction_test.c @@ -0,0 +1,157 @@ +// SPDX-License-Identifier: LGPL-2.1 +#define _GNU_SOURCE +#include +#include +#include +#include +#include +#include +#include +#include + +#include "../kselftest.h" +#include "rseq.h" + +#define VERBOSE 0 +#define printf_verbose(fmt, ...) \ + do { \ + if (VERBOSE) \ + printf(fmt, ##__VA_ARGS__); \ + } while (0) + +/* 0.5 s */ +#define RUNNER_PERIOD 500000 +/* Number of runs before we terminate or get the token */ +#define THREAD_RUNS 5 + +/* + * Number of times we check that the mm_cid were compacted. + * Checks are repeated every RUNNER_PERIOD + */ +#define MM_CID_CLEANUP_TIMEOUT 10 + +struct thread_args { + int num_cpus; + pthread_mutex_t token; + pthread_t *tinfo; +}; + +static void *thread_runner(void *arg) +{ + struct thread_args *args = arg; + int i, ret, curr_mm_cid; + + for (i = 0; i < THREAD_RUNS; i++) + usleep(RUNNER_PERIOD); + curr_mm_cid = rseq_current_mm_cid(); + /* + * We select one thread with high enough mm_cid to be the new leader + * all other threads (including the main thread) will terminate + * After some time, the mm_cid of the only remaining thread should + * converge to 0, if not, the test fails + */ + if (curr_mm_cid > args->num_cpus / 2 && + !pthread_mutex_trylock(&args->token)) { + printf_verbose("cpu%d has %d and will be the new leader\n", + sched_getcpu(), curr_mm_cid); + for (i = 0; i < args->num_cpus; i++) { + if (args->tinfo[i] == pthread_self()) + continue; + ret = pthread_join(args->tinfo[i], NULL); + if (ret) { + fprintf(stderr, + "Error: failed to join thread %d (%d): %s\n", + i, ret, strerror(ret)); + assert(ret == 0); + } + } + free(args->tinfo); + + for (i = 0; i < MM_CID_CLEANUP_TIMEOUT; i++) { + curr_mm_cid = rseq_current_mm_cid(); + printf_verbose("run %d: mm_cid %d on cpu%d\n", i, + curr_mm_cid, sched_getcpu()); + if (curr_mm_cid == 0) { + printf_verbose( + "mm_cids successfully compacted, exiting\n"); + pthread_exit(NULL); + } + usleep(RUNNER_PERIOD); + } + assert(false); + } + printf_verbose("cpu%d has %d and is going to terminate\n", + sched_getcpu(), curr_mm_cid); + pthread_exit(NULL); +} + +void test_mm_cid_compaction(void) +{ + cpu_set_t affinity, test_affinity; + int i, j, ret, num_threads; + pthread_t *tinfo; + struct thread_args args = { .token = PTHREAD_MUTEX_INITIALIZER }; + + sched_getaffinity(0, sizeof(affinity), &affinity); + CPU_ZERO(&test_affinity); + num_threads = CPU_COUNT(&affinity); + tinfo = calloc(num_threads, sizeof(*tinfo)); + if (!tinfo) { + fprintf(stderr, "Error: failed to allocate tinfo(%d): %s\n", + errno, strerror(errno)); + assert(ret == 0); + } + args.num_cpus = num_threads; + args.tinfo = tinfo; + if (num_threads == 1) { + printf_verbose( + "Running on a single cpu, cannot test anything\n"); + return; + } + for (i = 0, j = 0; i < CPU_SETSIZE && j < num_threads; i++) { + if (CPU_ISSET(i, &affinity)) { + ret = pthread_create(&tinfo[j], NULL, thread_runner, + &args); + if (ret) { + fprintf(stderr, + "Error: failed to create thread(%d): %s\n", + ret, strerror(ret)); + assert(ret == 0); + } + CPU_SET(i, &test_affinity); + pthread_setaffinity_np(tinfo[j], sizeof(test_affinity), + &test_affinity); + CPU_CLR(i, &test_affinity); + ++j; + } + } + printf_verbose("Started %d threads\n", num_threads); + + /* Also main thread will terminate if it is not selected as leader */ + thread_runner(&args); +} + +int main(int argc, char **argv) +{ + if (rseq_register_current_thread()) { + fprintf(stderr, + "Error: rseq_register_current_thread(...) failed(%d): %s\n", + errno, strerror(errno)); + goto error; + } + if (!rseq_mm_cid_available()) { + fprintf(stderr, "Error: rseq_mm_cid unavailable\n"); + goto error; + } + test_mm_cid_compaction(); + if (rseq_unregister_current_thread()) { + fprintf(stderr, + "Error: rseq_unregister_current_thread(...) failed(%d): %s\n", + errno, strerror(errno)); + goto error; + } + return 0; + +error: + return -1; +}