From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 A6C7E430CD5 for ; Mon, 31 Aug 2026 13:25:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788182743; cv=none; b=EB2Jhfwfbhyt3Km9pVeocINznJ3y1I8W/fi6AiDCwlM7OMu6Sihcu9p2+s2FBgW97v95JgPaxmABper3l6S1qdiLPR/Rsn9kVsWS1xcQpIlY5wsP5sIwEJmFrf8p3S0Dkdmom98Is+JeFcKe3L+9xlvf9d4xPIrqGDHZV3Z7iRI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788182743; c=relaxed/simple; bh=3+VoVKeZv3gsnQJua4pDGn0oOb/kZqlkTYmTWEKGOg4=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=Ik0rdW++KqvpGirujBI2P9clfN1aOhO0lesrKnH4oSqo84huBXzY0UE9gFOhRYmJB49QCCpJAK27gWl1As0MTKpcN8J0jlbuCl98KvaLNngW/rFW/iTBMgvdQRff4QH3grRep15px9I14uayvJcOfL9ehFhxQk8zcoH8A9KmvFs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine 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=Z6FuOvBx; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine 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="Z6FuOvBx" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1788182740; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=obgsA+wmkoM83ZDQQaFWaWOWiW1c97++AGpx79Oxzms=; b=Z6FuOvBxMORUlxGo/p2VFpiN6SnssmOQPs4rlCK3VWKLqfmbV/tAa5Dgdqbc6X9N/Hh0eX 9/b/6j8puHZDD9HofRlz1wkmIK9CNAdIIFHcVdbGcwXzn4ZiqsG7ivgYBntfueTN6zQE8B iber5zpDJcmb4x1hD6qHB0NICdEcm2A= Received: from mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-97-bT7zN3AnMdqPTgtdrhG5Bw-1; Mon, 31 Aug 2026 09:25:35 -0400 X-MC-Unique: bT7zN3AnMdqPTgtdrhG5Bw-1 X-Mimecast-MFC-AGG-ID: bT7zN3AnMdqPTgtdrhG5Bw_1788182734 Received: from mx-prod-int-10.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-10.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.95]) (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-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id E093D190B693; Mon, 31 Aug 2026 13:25:19 +0000 (UTC) Received: from aesteve-thinkpadp1gen8.rmtes.csb (headnet03.pony-001.prod.iad2.dc.redhat.com [10.2.32.114]) by mx-prod-int-10.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 3DFA440E; Mon, 31 Aug 2026 13:25:18 +0000 (UTC) From: Albert Esteve Date: Mon, 31 Aug 2026 15:25:11 +0200 Subject: [PATCH v6 1/3] selftests: cgroup: Add dmem_selftest helper module Precedence: bulk X-Mailing-List: cgroups@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260831-kunit_cgroups-v6-1-63b6c7695287@redhat.com> References: <20260831-kunit_cgroups-v6-0-63b6c7695287@redhat.com> In-Reply-To: <20260831-kunit_cgroups-v6-0-63b6c7695287@redhat.com> To: Tejun Heo , Johannes Weiner , =?utf-8?q?Michal_Koutn=C3=BD?= , Shuah Khan Cc: linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, linux-kselftest@vger.kernel.org, Albert Esteve X-Developer-Signature: v=1; a=ed25519-sha256; t=1788182715; l=7299; i=aesteve@redhat.com; s=20260827; h=from:subject:message-id; bh=3+VoVKeZv3gsnQJua4pDGn0oOb/kZqlkTYmTWEKGOg4=; b=vzcM11inmXYQJkP5+sVqbEHqX+yOkuj7JFbrCgN1VQ40GNiWP1dcwgS+MsRWbvpQhk6yEeQP0 VUvNrwb8SYICR+1Zf98G68PvpIDkyeOQs/ssTUa7l9E33T/oGqjJM04 X-Developer-Key: i=aesteve@redhat.com; a=ed25519; pk=zI2RBeZgocwYm3AkJW4CtjoJnKoDZrfBl1xe5Ed6h+U= X-Scanned-By: MIMEDefang 3.6 on 10.30.177.95 Currently, dmem charging is driver-driven through direct calls to dmem_cgroup_try_charge() (for example TTM). That does not give cgroup selftests a generic way to trigger alloc/free paths from userspace in a chosen cgroup, so coverage of nested dmem.max still needs a synthetic region. Add tools/testing/selftests/cgroup/test_modules/dmem_selftest.c as an OOT helper, built like other test_modules (no extra Kconfig needed). Tests can insmod the .ko module to register a "dmem_selftest" region. Module parameters drive a single outstanding allocation against the calling task's cgroup: /sys/module/dmem_selftest/parameters/alloc /sys/module/dmem_selftest/parameters/free Writing a size to alloc triggers dmem_cgroup_try_charge() for the calling task's cgroup. Writing to free with no argument releases the outstanding charge via dmem_cgroup_uncharge(). Only a single outstanding charge is supported. This provides a deterministic, driver-independent mechanism for exercising dmem accounting paths in selftests. Signed-off-by: Albert Esteve --- tools/testing/selftests/cgroup/Makefile | 1 + tools/testing/selftests/cgroup/config | 1 + .../testing/selftests/cgroup/test_modules/Makefile | 17 +++ .../selftests/cgroup/test_modules/dmem_selftest.c | 146 +++++++++++++++++++++ 4 files changed, 165 insertions(+) diff --git a/tools/testing/selftests/cgroup/Makefile b/tools/testing/selftests/cgroup/Makefile index e01584c2189a..a08661320a07 100644 --- a/tools/testing/selftests/cgroup/Makefile +++ b/tools/testing/selftests/cgroup/Makefile @@ -6,6 +6,7 @@ all: ${HELPER_PROGS} TEST_FILES := with_stress.sh TEST_PROGS := test_stress.sh test_cpuset_prs.sh test_cpuset_v1_hp.sh TEST_GEN_FILES := wait_inotify +TEST_GEN_MODS_DIR := test_modules # Keep the lists lexicographically sorted TEST_GEN_PROGS = test_core TEST_GEN_PROGS += test_cpu diff --git a/tools/testing/selftests/cgroup/config b/tools/testing/selftests/cgroup/config index 39f979690dd3..2ee0488c3d65 100644 --- a/tools/testing/selftests/cgroup/config +++ b/tools/testing/selftests/cgroup/config @@ -1,5 +1,6 @@ CONFIG_CGROUPS=y CONFIG_CGROUP_CPUACCT=y +CONFIG_CGROUP_DMEM=y CONFIG_CGROUP_FREEZER=y CONFIG_CGROUP_SCHED=y CONFIG_MEMCG=y diff --git a/tools/testing/selftests/cgroup/test_modules/Makefile b/tools/testing/selftests/cgroup/test_modules/Makefile new file mode 100644 index 000000000000..dd8a17313cec --- /dev/null +++ b/tools/testing/selftests/cgroup/test_modules/Makefile @@ -0,0 +1,17 @@ +# SPDX-License-Identifier: GPL-2.0 +TESTMODS_DIR := $(realpath $(dir $(abspath $(lastword $(MAKEFILE_LIST))))) +KDIR ?= /lib/modules/$(shell uname -r)/build + +obj-m += dmem_selftest.o + +# Ensure that KDIR exists, otherwise skip the compilation +modules: +ifneq ("$(wildcard $(KDIR))", "") + $(Q)$(MAKE) -C $(KDIR) modules KBUILD_EXTMOD=$(TESTMODS_DIR) +endif + +# Ensure that KDIR exists, otherwise skip the clean target +clean: +ifneq ("$(wildcard $(KDIR))", "") + $(Q)$(MAKE) -C $(KDIR) clean KBUILD_EXTMOD=$(TESTMODS_DIR) +endif diff --git a/tools/testing/selftests/cgroup/test_modules/dmem_selftest.c b/tools/testing/selftests/cgroup/test_modules/dmem_selftest.c new file mode 100644 index 000000000000..a763a156f13f --- /dev/null +++ b/tools/testing/selftests/cgroup/test_modules/dmem_selftest.c @@ -0,0 +1,146 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Kselftest helper for the dmem cgroup controller. + * + * Registers a synthetic dmem region so tests can trigger allocations + * from the calling task's cgroup via module parameters: + * /sys/module/dmem_selftest/parameters/alloc + * /sys/module/dmem_selftest/parameters/free + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include +#include +#include +#include +#include +#include +#include + +#define DM_SELFTEST_REGION_NAME "dmem_selftest" +#define DM_SELFTEST_REGION_SIZE (256ULL * 1024 * 1024) + +static struct dmem_cgroup_region *selftest_region; +static struct dmem_cgroup_pool_state *alloc_pool; +static u64 alloc_size; +static DEFINE_MUTEX(alloc_lock); + +static int param_set_alloc(const char *val, const struct kernel_param *kp) +{ + struct dmem_cgroup_pool_state *pool = NULL, *limit = NULL; + u64 size; + int ret; + + if (!selftest_region) + return -ENODEV; + + ret = kstrtou64(val, 0, &size); + if (ret) + return ret; + if (!size || size > DM_SELFTEST_REGION_SIZE) + return -EINVAL; + + mutex_lock(&alloc_lock); + if (alloc_pool) { + mutex_unlock(&alloc_lock); + return -EBUSY; + } + + ret = dmem_cgroup_try_charge(selftest_region, size, &pool, &limit); + if (ret == -EAGAIN && limit) + dmem_cgroup_pool_state_put(limit); + if (ret) { + mutex_unlock(&alloc_lock); + return ret; + } + + alloc_pool = pool; + alloc_size = size; + mutex_unlock(&alloc_lock); + return 0; +} + +static int param_get_alloc(char *buffer, const struct kernel_param *kp) +{ + u64 size; + + mutex_lock(&alloc_lock); + size = alloc_size; + mutex_unlock(&alloc_lock); + return sysfs_emit(buffer, "%llu\n", size); +} + +static const struct kernel_param_ops alloc_ops = { + .set = param_set_alloc, + .get = param_get_alloc, +}; + +module_param_cb(alloc, &alloc_ops, NULL, 0644); +MODULE_PARM_DESC(alloc, "Allocate (charge) SIZE bytes against the calling task's dmem cgroup"); + +static int param_set_free(const char *val, const struct kernel_param *kp) +{ + mutex_lock(&alloc_lock); + if (!alloc_pool) { + mutex_unlock(&alloc_lock); + return -EINVAL; + } + + dmem_cgroup_uncharge(alloc_pool, alloc_size); + alloc_pool = NULL; + alloc_size = 0; + mutex_unlock(&alloc_lock); + return 0; +} + +static const struct kernel_param_ops free_ops = { + .flags = KERNEL_PARAM_OPS_FL_NOARG, + .set = param_set_free, +}; + +module_param_cb(free, &free_ops, NULL, 0200); +MODULE_PARM_DESC(free, "Free the outstanding dmem selftest allocation"); + +static int __init dmem_selftest_init(void) +{ + static const struct dmem_cgroup_init init = { + .size = DM_SELFTEST_REGION_SIZE, + }; + + selftest_region = dmem_cgroup_register_region(&init, DM_SELFTEST_REGION_NAME); + if (IS_ERR(selftest_region)) + return PTR_ERR(selftest_region); + if (!selftest_region) + return -EINVAL; + + add_taint(TAINT_TEST, LOCKDEP_STILL_OK); + pr_info("region '%s' registered; parameters alloc/free\n", + DM_SELFTEST_REGION_NAME); + return 0; +} + +static void __exit dmem_selftest_exit(void) +{ + mutex_lock(&alloc_lock); + if (alloc_pool) { + dmem_cgroup_uncharge(alloc_pool, alloc_size); + alloc_pool = NULL; + alloc_size = 0; + } + mutex_unlock(&alloc_lock); + + if (selftest_region) { + dmem_cgroup_unregister_region(selftest_region); + selftest_region = NULL; + } + pr_info("unloaded.\n"); +} + +module_init(dmem_selftest_init); +module_exit(dmem_selftest_exit); + +MODULE_AUTHOR("Albert Esteve "); +MODULE_DESCRIPTION("Kselftest helper for cgroup dmem controller"); +MODULE_LICENSE("GPL"); +MODULE_INFO(test, "Y"); -- 2.55.0