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 B96DC43149D for ; Mon, 31 Aug 2026 13:25:39 +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=1788182741; cv=none; b=euOzMkZBNKXj8vLoDRAhq4Lx830aRdFlp78TZKI6n4yk9i7yLTBCimmfJr75TV1DM97j94oJxMMJGtvNZHsxfPqcvdTZqfKGUi0K7b0wERlf/SyT9sNsTbhhC4i2Z3XySvVhgOuKPs0y3SHHYw7sh0ZRfxGn00KkI6oDBpoTh/U= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788182741; c=relaxed/simple; bh=8Kr2YZNNSN192SnAtC2dKJKhWLemLjQtnhC6rdjd7ao=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=ZzAFveI9iMmcCqzFPD4JNbLkdr1uwaAsSqQxAcHz9uq3T59h07b/I9VTHBe1DlKCQH/VmuhSt7pcObWo+iBg3jQn4VL4akZdLs4Pz6gN0NQvPoSkrDEyWIFlMDU+s+AOtqY90tmf4cXOi7IwS4KuTPSq9XbJQ21bAIDpGK/2WuE= 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=P3XK6IYx; 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="P3XK6IYx" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1788182738; 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=3fAt4QX4GgLPNS42ubuGBQ665ezuuMkEG/rcgHIK/9M=; b=P3XK6IYxaQUTmSDj0wtP6m8f2h4siR9nWnumdLeIt2kh/8MIp3XS41fB4rqK7a653MCZqP pEWOxjJFj1wbLoeFOJXyFXapfrU40PI9SSFeAVGsl3xgbhemr9b65DbDTyS7LDpZ1xJx00 S/AoqdqHan5ZahSctZGKdwADyqs5E6I= Received: from mx-prod-mc-01.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-227-wtKlriVgO4uE57ic7aKn9Q-1; Mon, 31 Aug 2026 09:25:35 -0400 X-MC-Unique: wtKlriVgO4uE57ic7aKn9Q-1 X-Mimecast-MFC-AGG-ID: wtKlriVgO4uE57ic7aKn9Q_1788182733 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-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id BB3C61945CBE; Mon, 31 Aug 2026 13:25:24 +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 AC70840E; Mon, 31 Aug 2026 13:25:22 +0000 (UTC) From: Albert Esteve Date: Mon, 31 Aug 2026 15:25:13 +0200 Subject: [PATCH v6 3/3] selftests: cgroup: Add dmem selftest coverage Precedence: bulk X-Mailing-List: linux-kselftest@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-v6-3-63b6c7695287@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=10309; i=aesteve@redhat.com; s=20260827; h=from:subject:message-id; bh=8Kr2YZNNSN192SnAtC2dKJKhWLemLjQtnhC6rdjd7ao=; b=QN0ZJ18d5Obu5q1QBi7Es7NtzGNR4ZIUKCF682UWwvKNZA7VX9ER9Zyw/+D6S0KqRrn6EWJFx lzOOjLFgko8AnmHLAK5wF8aT9/bIDTPJPKguL/zs+Keucprco+ajnsw X-Developer-Key: i=aesteve@redhat.com; a=ed25519; pk=zI2RBeZgocwYm3AkJW4CtjoJnKoDZrfBl1xe5Ed6h+U= X-Scanned-By: MIMEDefang 3.6 on 10.30.177.95 Currently, tools/testing/selftests/cgroup/ has no dmem-specific test. This leaves dmem accounting and dmem.max enforcement largely unvalidated without a production driver. Add test_dmem, driven by the dmem_selftest helper module parameters (alloc/free) on the dmem_selftest region. insmod the helper before running the tests. The tests cover: - test_dmem_max: nested hierarchy with per-leaf dmem.max values and verifies that over-limit charges fail while in-limit charges succeed in dmem.current. - test_dmem_alloc_byte_granularity: non-page-aligned alloc sizes, dmem.current equals the requested byte count, and free-to-zero behavior. Limits are read with cg_read_key_long(). The helper is stat'd in main() so a missing module skips the whole test instead of each subtest. Signed-off-by: Albert Esteve --- tools/testing/selftests/cgroup/.gitignore | 1 + tools/testing/selftests/cgroup/Makefile | 2 + tools/testing/selftests/cgroup/test_dmem.c | 314 +++++++++++++++++++++++++++++ 3 files changed, 317 insertions(+) diff --git a/tools/testing/selftests/cgroup/.gitignore b/tools/testing/selftests/cgroup/.gitignore index 952e4448bf07..ea2322598217 100644 --- a/tools/testing/selftests/cgroup/.gitignore +++ b/tools/testing/selftests/cgroup/.gitignore @@ -2,6 +2,7 @@ test_core test_cpu test_cpuset +test_dmem test_freezer test_hugetlb_memcg test_kill diff --git a/tools/testing/selftests/cgroup/Makefile b/tools/testing/selftests/cgroup/Makefile index a08661320a07..d01e8eb1ead2 100644 --- a/tools/testing/selftests/cgroup/Makefile +++ b/tools/testing/selftests/cgroup/Makefile @@ -11,6 +11,7 @@ TEST_GEN_MODS_DIR := test_modules TEST_GEN_PROGS = test_core TEST_GEN_PROGS += test_cpu TEST_GEN_PROGS += test_cpuset +TEST_GEN_PROGS += test_dmem TEST_GEN_PROGS += test_freezer TEST_GEN_PROGS += test_hugetlb_memcg TEST_GEN_PROGS += test_kill @@ -27,6 +28,7 @@ include lib/libcgroup.mk $(OUTPUT)/test_core: $(LIBCGROUP_O) $(OUTPUT)/test_cpu: $(LIBCGROUP_O) $(OUTPUT)/test_cpuset: $(LIBCGROUP_O) +$(OUTPUT)/test_dmem: $(LIBCGROUP_O) $(OUTPUT)/test_freezer: $(LIBCGROUP_O) $(OUTPUT)/test_hugetlb_memcg: $(LIBCGROUP_O) $(OUTPUT)/test_kill: $(LIBCGROUP_O) diff --git a/tools/testing/selftests/cgroup/test_dmem.c b/tools/testing/selftests/cgroup/test_dmem.c new file mode 100644 index 000000000000..3793664678b9 --- /dev/null +++ b/tools/testing/selftests/cgroup/test_dmem.c @@ -0,0 +1,314 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Test the dmem (device memory) cgroup controller. + * + * Depends on the dmem_selftest helper module + * (tools/testing/selftests/cgroup/test_modules/dmem_selftest.c). + */ + +#define _GNU_SOURCE + +#include +#include +#include +#include +#include +#include +#include + +#include "kselftest.h" +#include "cgroup_util.h" + +#define DM_SELFTEST_REGION "dmem_selftest" +#define DM_SELFTEST_ALLOC "/sys/module/dmem_selftest/parameters/alloc" +#define DM_SELFTEST_FREE "/sys/module/dmem_selftest/parameters/free" + +static long dmem_read_limit(const char *cgroup, const char *ctrl) +{ + return cg_read_key_long(cgroup, ctrl, DM_SELFTEST_REGION " "); +} + +static int dmem_write_limit(const char *cgroup, const char *ctrl, long val) +{ + char wr[64]; + + snprintf(wr, sizeof(wr), "%s %ld", DM_SELFTEST_REGION, val); + return cg_write(cgroup, ctrl, wr); +} + +static int dmem_selftest_alloc(long bytes) +{ + char wr[32]; + + snprintf(wr, sizeof(wr), "%ld", bytes); + return write_text(DM_SELFTEST_ALLOC, wr, strlen(wr)); +} + +static int dmem_selftest_free(void) +{ + char wr[] = "1"; + + return write_text(DM_SELFTEST_FREE, wr, strlen(wr)); +} + +/* + * First, this test creates the following hierarchy: + * A + * A/B dmem.max=8M + * A/B/C dmem.max=2M + * A/B/D dmem.max=1M + * A/B/E dmem.max=75K + * A/B/F dmem.max=25K + * A/B/G dmem.max=8K + * A/B/H dmem.max=0 + * + * Then for each leaf cgroup it tries to alloc above dmem.max + * and expects the request to fail and dmem.current to remain + * unchanged. + * + * For leaves with non-zero dmem.max, it additionally allocs a + * smaller amount and verifies dmem.current matches the requested + * size exactly (the controller accounts in bytes, with no page + * rounding), then frees and verifies dmem.current returns + * to the previous value. + */ +static int test_dmem_max(const char *root) +{ + static const long leaf_max[] = { + MB(2), MB(1), KB(75), KB(25), KB(8), 0 + }; + static const long pass_sz[] = { + MB(1), MB(1), KB(4), KB(4), KB(4), 0 + }; + char *parent[2] = {NULL}; + char *children[ARRAY_SIZE(leaf_max)] = {NULL}; + + _Static_assert(ARRAY_SIZE(pass_sz) == ARRAY_SIZE(leaf_max), + "pass_sz doesn't match leaf_max length"); + long cur_before, cur_after; + int ret = KSFT_FAIL; + int charged = 0; + int in_child = 0; + long v; + int i; + + parent[0] = cg_name(root, "dmem_prot_0"); + if (!parent[0]) + goto cleanup; + + parent[1] = cg_name(parent[0], "dmem_prot_1"); + if (!parent[1]) + goto cleanup; + + if (cg_create(parent[0])) + goto cleanup; + + if (cg_write(parent[0], "cgroup.subtree_control", "+dmem")) + goto cleanup; + + if (cg_create(parent[1])) + goto cleanup; + + if (cg_write(parent[1], "cgroup.subtree_control", "+dmem")) + goto cleanup; + + for (i = 0; i < ARRAY_SIZE(children); i++) { + children[i] = cg_name_indexed(parent[1], "dmem_child", i); + if (!children[i]) + goto cleanup; + if (cg_create(children[i])) + goto cleanup; + } + + if (dmem_write_limit(parent[1], "dmem.max", MB(8))) + goto cleanup; + for (i = 0; i < ARRAY_SIZE(children); i++) + if (dmem_write_limit(children[i], "dmem.max", leaf_max[i])) + goto cleanup; + + v = dmem_read_limit(parent[1], "dmem.max"); + if (v != MB(8)) + goto cleanup; + for (i = 0; i < ARRAY_SIZE(children); i++) { + v = dmem_read_limit(children[i], "dmem.max"); + if (v != leaf_max[i]) + goto cleanup; + } + + for (i = 0; i < ARRAY_SIZE(children); i++) { + if (cg_enter_current(children[i])) + goto cleanup; + in_child = 1; + + cur_before = dmem_read_limit(children[i], "dmem.current"); + if (cur_before < 0) + goto cleanup; + + if (dmem_selftest_alloc(leaf_max[i] + 1) >= 0) { + charged = 1; + goto cleanup; + } + + cur_after = dmem_read_limit(children[i], "dmem.current"); + if (cur_after != cur_before) + goto cleanup; + + if (pass_sz[i] > 0) { + if (dmem_selftest_alloc(pass_sz[i]) < 0) + goto cleanup; + charged = 1; + + cur_after = dmem_read_limit(children[i], "dmem.current"); + if (cur_after != cur_before + pass_sz[i]) + goto cleanup; + + if (dmem_selftest_free() < 0) + goto cleanup; + charged = 0; + + cur_after = dmem_read_limit(children[i], "dmem.current"); + if (cur_after != cur_before) + goto cleanup; + } + + if (cg_enter_current(root)) + goto cleanup; + in_child = 0; + } + + ret = KSFT_PASS; + +cleanup: + if (charged) + dmem_selftest_free(); + if (in_child) + cg_enter_current(root); + for (i = ARRAY_SIZE(children) - 1; i >= 0; i--) { + if (!children[i]) + continue; + cg_destroy(children[i]); + free(children[i]); + } + for (i = ARRAY_SIZE(parent) - 1; i >= 0; i--) { + if (!parent[i]) + continue; + cg_destroy(parent[i]); + free(parent[i]); + } + return ret; +} + +/* + * Alloc non-page-aligned byte sizes and verify dmem.current matches + * the requested size exactly. The controller charges the byte count + * passed to dmem_cgroup_try_charge() with no page rounding, for this + * helper and for production drivers. Then free must return usage to 0. + */ +static int test_dmem_alloc_byte_granularity(const char *root) +{ + static const long sizes[] = { + 1, 4095, 4097, KB(75) + 1, MB(1), MB(1) + 1 + }; + char *cg = NULL; + long cur; + int ret = KSFT_FAIL; + int charged = 0; + int in_child = 0; + size_t i; + + cg = cg_name(root, "dmem_dbg_byte_gran"); + if (!cg) + goto cleanup; + + if (cg_create(cg)) + goto cleanup; + + if (dmem_write_limit(cg, "dmem.max", MB(16))) + goto cleanup; + + if (cg_enter_current(cg)) + goto cleanup; + in_child = 1; + + for (i = 0; i < ARRAY_SIZE(sizes); i++) { + if (dmem_selftest_alloc(sizes[i]) < 0) + goto cleanup; + charged = 1; + + cur = dmem_read_limit(cg, "dmem.current"); + if (cur != sizes[i]) + goto cleanup; + + if (dmem_selftest_free() < 0) + goto cleanup; + charged = 0; + + cur = dmem_read_limit(cg, "dmem.current"); + if (cur != 0) + goto cleanup; + } + + ret = KSFT_PASS; + +cleanup: + if (charged) + dmem_selftest_free(); + if (in_child) + cg_enter_current(root); + if (cg) { + cg_destroy(cg); + free(cg); + } + return ret; +} + +#define T(x) { x, #x } +struct dmem_test { + int (*fn)(const char *root); + const char *name; +} tests[] = { + T(test_dmem_max), + T(test_dmem_alloc_byte_granularity), +}; +#undef T + +int main(int argc, char **argv) +{ + char root[PATH_MAX]; + struct stat st; + int i; + + ksft_print_header(); + + if (cg_find_unified_root(root, sizeof(root), NULL)) + ksft_exit_skip("cgroup v2 isn't mounted\n"); + + if (cg_read_strstr(root, "cgroup.controllers", "dmem")) + ksft_exit_skip("dmem controller isn't available (CONFIG_CGROUP_DMEM?)\n"); + + if (cg_read_strstr(root, "cgroup.subtree_control", "dmem")) + if (cg_write(root, "cgroup.subtree_control", "+dmem")) + ksft_exit_skip("Failed to enable dmem controller\n"); + + if (stat(DM_SELFTEST_ALLOC, &st) < 0) + ksft_exit_skip( + "dmem_selftest helper not loaded (insmod test_modules/dmem_selftest.ko)\n"); + + if (dmem_read_limit(root, "dmem.capacity") < 0) + ksft_exit_skip("dmem_selftest region not registered\n"); + + ksft_set_plan(ARRAY_SIZE(tests)); + + for (i = 0; i < ARRAY_SIZE(tests); i++) { + switch (tests[i].fn(root)) { + case KSFT_PASS: + ksft_test_result_pass("%s\n", tests[i].name); + break; + default: + ksft_test_result_fail("%s\n", tests[i].name); + break; + } + } + + ksft_finished(); +} -- 2.55.0