From nobody Mon Oct 6 04:56:06 2025 Received: from mail-qt1-f178.google.com (mail-qt1-f178.google.com [209.85.160.178]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 68C712EFD99; Fri, 25 Jul 2025 16:23:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.160.178 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753460590; cv=none; b=ltYG6WW2Y2XBPGNcNbymWWVl0g56919Oi0IOdrwfFoVXQu7o45jwBc62/gbNru8rRKFT61Fq56AbJH3B2kGuyzeOqjhLZzshzmWWGPnfnSfXKRixWNhil5JAc00/9zTHDOJD0q9Ypzh7VCV1/bCHNkYESGGf21go6RoB3vGN9e8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753460590; c=relaxed/simple; bh=LkB88lWIbkM8o0a2fZPfu3489tAdfyFV07pwUyZ9Z0E=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=lFOkBDrV5nnNkPbAWDwUpnVzgN5OSEj73LeZx6EcnADL2Bqf6/9zh5ab6rWMyIbbrlptS49DmExmTngb9SponnBTjasO+vP8hcu2GK3Co2ZRktiLhLlIGW9lbEek4GHop6qKM05b+7DySrV7YaMwg821MUvyzSaWmiEftb1Uawc= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=HH4sfpqZ; arc=none smtp.client-ip=209.85.160.178 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="HH4sfpqZ" Received: by mail-qt1-f178.google.com with SMTP id d75a77b69052e-4ab81d0169cso29277111cf.2; Fri, 25 Jul 2025 09:23:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1753460586; x=1754065386; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=c2nMfW+8EG0yHdd/y9pp9Ykp4/bgoGWX5aUFmAoHq2k=; b=HH4sfpqZl54F0KoL0ccU32DeF235n+JQF607FyDRzumLVnGKopXawOVrsncpUbq0vi dDyQjJEzic9dQHM9UK6iJbqzSpfdIyA4dNxCLJ2e4oldOQsPvOzq7ysGgxMo4Z+wuHCN BgJOA49fmefS3zrj20BsZKVTjopEtznwrn/drAKucmE02XKWqYNzTwiuRTTOydm9ZdAZ kfSAxm9oCpZIkIA+Mou7fhABPo6h1yqZ1JVIi+XmE988mS+g6Rw2b2N68JypwnwwXKZ7 5jdlMODs3sPExBUEOX6KzU1w+Lfhmxiva6oPZOjDMpPvoa2dzUaGyJQRrt6UvdSMMBmJ N+9w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1753460586; x=1754065386; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=c2nMfW+8EG0yHdd/y9pp9Ykp4/bgoGWX5aUFmAoHq2k=; b=csD+f2E6LVjun+Gz+aCNnWMnlul/C2m7XDHhPKeRelWML+zG7NW69TAKTj3kCojqWQ aaLJOcbkENwuqUIQkFvO20TniODXZNedC+wAwIQ1PmrHPB0obuy9gWDQzXZKTFoQHO3f ov7ztPF0mmhYrx47TYCNuehw+Cjsvmk5+MX5jHnDTFXjc6tTDHkhGHDD3TpiaAeHrzxZ oAnhGJlySD4r35MACpAcdDhFe7SUGnAZu/wfLxlwc+NsYL9MCHcMd+e5cLKoqk9MRHZt LNGnFFe+YRgjGQ2ZvCboFyyJShEe8AKqkScsMIfmjpqDPIpfcY1OIxWuhqkrCsNOwuDA htgg== X-Forwarded-Encrypted: i=1; AJvYcCWa9gDy5pwLfg6YuseLHweYtlKSN8kjyvSx52seHd/QNSf/xQLwAiq03WiigTJwc7zdaZwJAEYCq3W595go@vger.kernel.org, AJvYcCX0pwnnRBJuRWA3A7V/rF9Qm2tQcAsAXqHb62Eqbm9gpDkE2jWhpcE3zMy6efZD/Kl15MbjvZWDOYw=@vger.kernel.org X-Gm-Message-State: AOJu0YxHx3kXHA/IjFhQ2KoKWl6eJ8U0G6kbLk9BXZfuNhwJA2cQ6eDN NCo3CSB4qWTeRl7INvXIZ2qHRp6m3BDSl4PJbttaijzGKmzKZFrx3GRv+SRsCaS1 X-Gm-Gg: ASbGncsuBT8qtwOSOpsuiCdgML/7dDODivRiaLkg0O6cJC8XW8HSTu76HAUSwjFHZrk duz6KZk+5XEth7TzzOch5EMOzHbFk10Jt36jTkhoh8s5WrQCKk2Z5tYgi4hGpuhO9tA9ML018ae vlyc3CLgYWSWAgbvycPEZBXOTj9q9kYK85j0YSBl45U7V/g2Y8rKhMpa9gO65irrPhlH2wkfQQY tTRdUVszxf10+SUbYzOQzfnaFIlBpPOkqytpMJqm9eg4nPvGvXh5S1OIdnUtc16Vqdm5opoaDYB kmDI2zL+tBafl+5RtoXaS0c8XAFXdar1gQskT0+8lI8wBOl1ZmpaSvhog3YvGmsq+ArpOjPqmzm 1kjgHSYg2hfWIZjTgQusWYmFhIli5Ww== X-Google-Smtp-Source: AGHT+IGhB0ODduWZoA0stvQcbydiYz6AaKK3E3SHNDplUWRJe9PTwU9UCJc3fawE6uOksSdsUztLVA== X-Received: by 2002:a05:622a:1348:b0:4ab:6a1e:ea51 with SMTP id d75a77b69052e-4ae8edcdf0bmr33885121cf.11.1753460586010; Fri, 25 Jul 2025 09:23:06 -0700 (PDT) Received: from localhost ([2a03:2880:20ff:6::]) by smtp.gmail.com with ESMTPSA id d75a77b69052e-4ae99516fcesm1906231cf.9.2025.07.25.09.23.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 25 Jul 2025 09:23:05 -0700 (PDT) From: Usama Arif To: Andrew Morton , david@redhat.com, linux-mm@kvack.org Cc: linux-fsdevel@vger.kernel.org, corbet@lwn.net, rppt@kernel.org, surenb@google.com, mhocko@suse.com, hannes@cmpxchg.org, baohua@kernel.org, shakeel.butt@linux.dev, riel@surriel.com, ziy@nvidia.com, laoar.shao@gmail.com, dev.jain@arm.com, baolin.wang@linux.alibaba.com, npache@redhat.com, lorenzo.stoakes@oracle.com, Liam.Howlett@oracle.com, ryan.roberts@arm.com, vbabka@suse.cz, jannh@google.com, Arnd Bergmann , sj@kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, kernel-team@meta.com, Usama Arif Subject: [PATCH 4/5] selftests: prctl: introduce tests for disabling THPs completely Date: Fri, 25 Jul 2025 17:22:43 +0100 Message-ID: <20250725162258.1043176-5-usamaarif642@gmail.com> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20250725162258.1043176-1-usamaarif642@gmail.com> References: <20250725162258.1043176-1-usamaarif642@gmail.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" The test will set the global system THP setting to madvise and the 2M setting to inherit before it starts (and reset to original at teardown) This tests if the process can: - successfully set and get the policy to disable THPs completely. - never get a hugepage when the THPs are completely disabled, including with MADV_HUGE and MADV_COLLAPSE. - successfully reset the policy of the process. - get hugepages only on MADV_HUGE and MADV_COLLAPSE after reset. - repeat the above tests in a forked process to make sure the policy is carried across forks. Signed-off-by: Usama Arif --- tools/testing/selftests/mm/.gitignore | 1 + tools/testing/selftests/mm/Makefile | 1 + .../testing/selftests/mm/prctl_thp_disable.c | 162 ++++++++++++++++++ 3 files changed, 164 insertions(+) create mode 100644 tools/testing/selftests/mm/prctl_thp_disable.c diff --git a/tools/testing/selftests/mm/.gitignore b/tools/testing/selftest= s/mm/.gitignore index e7b23a8a05fe..eb023ea857b3 100644 --- a/tools/testing/selftests/mm/.gitignore +++ b/tools/testing/selftests/mm/.gitignore @@ -58,3 +58,4 @@ pkey_sighandler_tests_32 pkey_sighandler_tests_64 guard-regions merge +prctl_thp_disable diff --git a/tools/testing/selftests/mm/Makefile b/tools/testing/selftests/= mm/Makefile index d13b3cef2a2b..2bb8d3ebc17c 100644 --- a/tools/testing/selftests/mm/Makefile +++ b/tools/testing/selftests/mm/Makefile @@ -86,6 +86,7 @@ TEST_GEN_FILES +=3D on-fault-limit TEST_GEN_FILES +=3D pagemap_ioctl TEST_GEN_FILES +=3D pfnmap TEST_GEN_FILES +=3D process_madv +TEST_GEN_FILES +=3D prctl_thp_disable TEST_GEN_FILES +=3D thuge-gen TEST_GEN_FILES +=3D transhuge-stress TEST_GEN_FILES +=3D uffd-stress diff --git a/tools/testing/selftests/mm/prctl_thp_disable.c b/tools/testing= /selftests/mm/prctl_thp_disable.c new file mode 100644 index 000000000000..52f7e6659b1f --- /dev/null +++ b/tools/testing/selftests/mm/prctl_thp_disable.c @@ -0,0 +1,162 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Basic tests for PR_GET/SET_THP_DISABLE prctl calls + * + * Author(s): Usama Arif + */ +#include +#include +#include +#include +#include +#include +#include + +#include "../kselftest_harness.h" +#include "thp_settings.h" +#include "vm_util.h" + +#ifndef PR_THP_DISABLE_EXCEPT_ADVISED +#define PR_THP_DISABLE_EXCEPT_ADVISED (1 << 1) +#endif + +#define NR_HUGEPAGES 6 + +static int sz2ord(size_t size, size_t pagesize) +{ + return __builtin_ctzll(size / pagesize); +} + +enum madvise_buffer { + NONE, + HUGE, + COLLAPSE +}; + +/* + * Function to mmap a buffer, fault it in, madvise it appropriately (before + * page fault for MADV_HUGE, and after for MADV_COLLAPSE), and check if the + * mmap region is huge. + * returns: + * 0 if test doesn't give hugepage + * 1 if test gives a hugepage + * -1 if mmap fails + */ +static int test_mmap_thp(enum madvise_buffer madvise_buf, size_t pmdsize) +{ + int ret; + int buf_size =3D NR_HUGEPAGES * pmdsize; + + char *buffer =3D (char *)mmap(NULL, buf_size, PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); + if (buffer =3D=3D MAP_FAILED) + return -1; + + if (madvise_buf =3D=3D HUGE) + madvise(buffer, buf_size, MADV_HUGEPAGE); + + /* Ensure memory is allocated */ + memset(buffer, 1, buf_size); + + if (madvise_buf =3D=3D COLLAPSE) + madvise(buffer, buf_size, MADV_COLLAPSE); + + ret =3D check_huge_anon(buffer, NR_HUGEPAGES, pmdsize); + munmap(buffer, buf_size); + return ret; +} +FIXTURE(prctl_thp_disable_completely) +{ + struct thp_settings settings; + size_t pmdsize; +}; + +FIXTURE_SETUP(prctl_thp_disable_completely) +{ + if (!thp_is_enabled()) + SKIP(return, "Transparent Hugepages not available\n"); + + self->pmdsize =3D read_pmd_pagesize(); + if (!self->pmdsize) + SKIP(return, "Unable to read PMD size\n"); + + thp_read_settings(&self->settings); + self->settings.thp_enabled =3D THP_MADVISE; + self->settings.hugepages[sz2ord(self->pmdsize, getpagesize())].enabled = =3D THP_INHERIT; + thp_save_settings(); + thp_push_settings(&self->settings); +} + +FIXTURE_TEARDOWN(prctl_thp_disable_completely) +{ + thp_restore_settings(); +} + +/* prctl_thp_disable_except_madvise fixture sets system THP setting to mad= vise */ +static void prctl_thp_disable_completely(struct __test_metadata *const _me= tadata, + size_t pmdsize) +{ + int res =3D 0; + + res =3D prctl(PR_GET_THP_DISABLE, NULL, NULL, NULL, NULL); + ASSERT_EQ(res, 1); + + /* global =3D madvise, process =3D never, we shouldn't get HPs even with = madvise */ + res =3D test_mmap_thp(NONE, pmdsize); + ASSERT_EQ(res, 0); + + res =3D test_mmap_thp(HUGE, pmdsize); + ASSERT_EQ(res, 0); + + res =3D test_mmap_thp(COLLAPSE, pmdsize); + ASSERT_EQ(res, 0); + + /* Reset to system policy */ + res =3D prctl(PR_SET_THP_DISABLE, 0, NULL, NULL, NULL); + ASSERT_EQ(res, 0); + + /* global =3D madvise */ + res =3D test_mmap_thp(NONE, pmdsize); + ASSERT_EQ(res, 0); + + res =3D test_mmap_thp(HUGE, pmdsize); + ASSERT_EQ(res, 1); + + res =3D test_mmap_thp(COLLAPSE, pmdsize); + ASSERT_EQ(res, 1); +} + +TEST_F(prctl_thp_disable_completely, nofork) +{ + int res =3D 0; + + res =3D prctl(PR_SET_THP_DISABLE, 1, NULL, NULL, NULL); + ASSERT_EQ(res, 0); + + prctl_thp_disable_completely(_metadata, self->pmdsize); +} + +TEST_F(prctl_thp_disable_completely, fork) +{ + int res =3D 0, ret =3D 0; + pid_t pid; + + res =3D prctl(PR_SET_THP_DISABLE, 1, NULL, NULL, NULL); + ASSERT_EQ(res, 0); + + /* Make sure prctl changes are carried across fork */ + pid =3D fork(); + ASSERT_GE(pid, 0); + + if (!pid) + prctl_thp_disable_completely(_metadata, self->pmdsize); + + wait(&ret); + if (WIFEXITED(ret)) + ret =3D WEXITSTATUS(ret); + else + ret =3D -EINVAL; + ASSERT_EQ(ret, 0); +} + +TEST_HARNESS_MAIN --=20 2.47.3