From nobody Wed Dec 17 21:28:57 2025 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id F3D56205AAF for ; Mon, 16 Dec 2024 13:09:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734354574; cv=none; b=LkBTDU+SwIOJzocaqe1E8wbsoBXv/53HH7Gl872rMyFkQpg0n63uY4xUPz2twCjLBCeWRPJqUWLf2E3bsEuZU14Yi6TUT50UGiZ7VPS/2FaaCvaqhjuD2O8kotxHhmqlcby5h+KYVP3NH6TyibShea4x2by+hZANCzm44/ePoiQ= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734354574; c=relaxed/simple; bh=T70vG6L8jn8l8he2hnx4huyfOdSMAiIoBEhRIs90Qaw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=b3/nduBzwDt1oce4AqKCQwQ8fMEqtsjR3ccgQ+fksFc/Fftj/7owsvERNSYw/roaWU1MolQdnrsjxZFALjgj0VTb+Wae8vEd4q9x01qc0AYi6+r/bK6x9oatpoiRDG+T2rqJ18UUlrtaUi0SHNe93cJMjdYsSrLyPtsCz4gc8Y0= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=fbli0Etb; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="fbli0Etb" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1734354572; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=uZtDN64Xh2i1EouKa8fldcRUrzUUze6qMnOFRIwRqYA=; b=fbli0Etb69xd47RyS7Jvx34l+cvwN+zS0JYqfzeyqmPvxpLa0zJ3IsEnTJ21xAMGC4MGGj UQ6IeuVFaRRDsg2qlG54wsSnH5u4IuecA/a8kTzolY5dZaN6ApksGiTXPR8fODP1Rq4qsi /KwT2t/5h3DudZVg0VARVDvjqZbRfD0= Received: from mx-prod-mc-04.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-70-MiaLR4PnNt-nwN18nbzrrQ-1; Mon, 16 Dec 2024 08:09:29 -0500 X-MC-Unique: MiaLR4PnNt-nwN18nbzrrQ-1 X-Mimecast-MFC-AGG-ID: MiaLR4PnNt-nwN18nbzrrQ Received: from mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.17]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-04.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 101CD19560B3; Mon, 16 Dec 2024 13:09:28 +0000 (UTC) Received: from gmonaco-thinkpadt14gen3.rmtit.com (unknown [10.39.193.102]) by mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id E51BA1956052; Mon, 16 Dec 2024 13:09:24 +0000 (UTC) From: Gabriele Monaco To: Mathieu Desnoyers , Peter Zijlstra , Ingo Molnar , linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: Juri Lelli , Gabriele Monaco , Shuah Khan Subject: [PATCH v3 3/3] rseq/selftests: Add test for mm_cid compaction Date: Mon, 16 Dec 2024 14:09:09 +0100 Message-ID: <20241216130909.240042-4-gmonaco@redhat.com> In-Reply-To: <20241216130909.240042-1-gmonaco@redhat.com> References: <20241216130909.240042-1-gmonaco@redhat.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 X-Scanned-By: MIMEDefang 3.0 on 10.30.177.17 Content-Type: text/plain; charset="utf-8" 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, runs 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 (>=3D 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. To: Mathieu Desnoyers Cc: Shuah Khan Signed-off-by: Gabriele Monaco --- tools/testing/selftests/rseq/.gitignore | 1 + tools/testing/selftests/rseq/Makefile | 2 +- .../selftests/rseq/mm_cid_compaction_test.c | 190 ++++++++++++++++++ 3 files changed, 192 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/selfte= sts/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/selftest= s/rseq/Makefile index 5a3432fceb58..ce1b38f46a35 100644 --- a/tools/testing/selftests/rseq/Makefile +++ b/tools/testing/selftests/rseq/Makefile @@ -16,7 +16,7 @@ OVERRIDE_TARGETS =3D 1 =20 TEST_GEN_PROGS =3D basic_test basic_percpu_ops_test basic_percpu_ops_mm_ci= d_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_compa= ction_test =20 TEST_GEN_PROGS_EXTENDED =3D librseq.so =20 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..e5557b38a4e9 --- /dev/null +++ b/tools/testing/selftests/rseq/mm_cid_compaction_test.c @@ -0,0 +1,190 @@ +// 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_COMPACT_TIMEOUT 10 + +struct thread_args { + int cpu; + int num_cpus; + pthread_mutex_t *token; + pthread_t *tinfo; + struct thread_args *args_head; +}; + +static void *thread_runner(void *arg) +{ + struct thread_args *args =3D arg; + int i, ret, curr_mm_cid; + cpu_set_t affinity; + + CPU_ZERO(&affinity); + CPU_SET(args->cpu, &affinity); + ret =3D pthread_setaffinity_np(pthread_self(), sizeof(affinity), &affinit= y); + if (ret) { + fprintf(stderr, + "Error: failed to set affinity to thread %d (%d): %s\n", + args->cpu, ret, strerror(ret)); + assert(ret =3D=3D 0); + } + for (i =3D 0; i < THREAD_RUNS; i++) + usleep(RUNNER_PERIOD); + curr_mm_cid =3D 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 >=3D 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 =3D 0; i < args->num_cpus; i++) { + if (args->tinfo[i] =3D=3D pthread_self()) + continue; + ret =3D 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 =3D=3D 0); + } + } + free(args->tinfo); + free(args->token); + free(args->args_head); + + for (i =3D 0; i < MM_CID_COMPACT_TIMEOUT; i++) { + curr_mm_cid =3D 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 =3D=3D 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; + int i, j, ret, num_threads; + pthread_t *tinfo; + pthread_mutex_t *token; + struct thread_args *args; + + sched_getaffinity(0, sizeof(affinity), &affinity); + num_threads =3D CPU_COUNT(&affinity); + tinfo =3D calloc(num_threads, sizeof(*tinfo)); + if (!tinfo) { + fprintf(stderr, "Error: failed to allocate tinfo(%d): %s\n", + errno, strerror(errno)); + assert(ret =3D=3D 0); + } + args =3D calloc(num_threads, sizeof(*args)); + if (!args) { + fprintf(stderr, "Error: failed to allocate args(%d): %s\n", + errno, strerror(errno)); + assert(ret =3D=3D 0); + } + token =3D calloc(num_threads, sizeof(*token)); + if (!token) { + fprintf(stderr, "Error: failed to allocate token(%d): %s\n", + errno, strerror(errno)); + assert(ret =3D=3D 0); + } + if (num_threads =3D=3D 1) { + printf_verbose( + "Running on a single cpu, cannot test anything\n"); + return; + } + pthread_mutex_init(token, NULL); + /* The main thread runs on CPU0 */ + for (i =3D 0, j =3D 0; i < CPU_SETSIZE && j < num_threads; i++) { + if (CPU_ISSET(i, &affinity)) { + args[j].num_cpus =3D num_threads; + args[j].tinfo =3D tinfo; + args[j].token =3D token; + args[j].cpu =3D i; + args[j].args_head =3D args; + if (!j) { + /* The first thread is the main one */ + tinfo[0] =3D pthread_self(); + ++j; + continue; + } + ret =3D pthread_create(&tinfo[j], NULL, thread_runner, + &args[j]); + if (ret) { + fprintf(stderr, + "Error: failed to create thread(%d): %s\n", + ret, strerror(ret)); + assert(ret =3D=3D 0); + } + ++j; + } + } + printf_verbose("Started %d threads\n", num_threads); + + /* Also main thread will terminate if it is not selected as leader */ + thread_runner(&args[0]); +} + +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; +} --=20 2.47.1