Add some basic tests of mlock/mmap cgroup accounting for pinned memory.

Signed-off-by: Alistair Popple apopple@nvidia.com Cc: Shuah Khan shuah@kernel.org Cc: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org Cc: linux-kselftest@vger.kernel.org Cc: cgroups@vger.kernel.org --- MAINTAINERS | 1 +- tools/testing/selftests/vm/Makefile | 1 +- tools/testing/selftests/vm/pins-cgroup.c | 271 ++++++++++++++++++++++++- 3 files changed, 273 insertions(+) create mode 100644 tools/testing/selftests/vm/pins-cgroup.c

diff --git a/MAINTAINERS b/MAINTAINERS index f8526e2..4c4eed9 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -5387,6 +5387,7 @@ L: cgroups@vger.kernel.org L: linux-mm@kvack.org S: Maintained F: mm/pins_cgroup.c +F: tools/testing/selftests/vm/pins-cgroup.c

CORETEMP HARDWARE MONITORING DRIVER M: Fenghua Yu fenghua.yu@intel.com diff --git a/tools/testing/selftests/vm/Makefile b/tools/testing/selftests/vm/Makefile index 89c14e4..0653720 100644 --- a/tools/testing/selftests/vm/Makefile +++ b/tools/testing/selftests/vm/Makefile @@ -56,6 +56,7 @@ TEST_GEN_PROGS += soft-dirty TEST_GEN_PROGS += split_huge_page_test TEST_GEN_FILES += ksm_tests TEST_GEN_PROGS += ksm_functional_tests +TEST_GEN_FILES += pins-cgroup

ifeq ($(MACHINE),x86_64) CAN_BUILD_I386 := $(shell ./../x86/check_cc.sh "$(CC)" ../x86/trivial_32bit_program.c -m32) diff --git a/tools/testing/selftests/vm/pins-cgroup.c b/tools/testing/selftests/vm/pins-cgroup.c new file mode 100644 index 0000000..c2eabc2 --- /dev/null +++ b/tools/testing/selftests/vm/pins-cgroup.c @@ -0,0 +1,271 @@ +// SPDX-License-Identifier: GPL-2.0 +#include "../kselftest_harness.h" + +#define _GNU_SOURCE +#include <fcntl.h> +#include <assert.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <sys/mman.h> +#include <sys/types.h> +#include <sys/stat.h> +#include <sys/ioctl.h> +#include <sys/prctl.h> +#include <sys/resource.h> +#include <sys/capability.h> +#include <unistd.h> + +#define CGROUP_TEMP "/sys/fs/cgroup/pins_XXXXXX" +#define PINS_MAX (-1UL) + +FIXTURE(pins_cg) +{ + char *cg_path; + long page_size; +}; + +static char *cgroup_new(void) +{ + char *cg; + + cg = malloc(sizeof(CGROUP_TEMP)); + strcpy(cg, CGROUP_TEMP); + if (!mkdtemp(cg)) { + perror("Failed to create cgroup"); + return NULL; + } + + return cg; +} + +static int cgroup_add_proc(char *cg, pid_t pid) +{ + char *cg_proc; + FILE *f; + int ret = 0; + + if (asprintf(&cg_proc, "%s/cgroup.procs", cg) < 0) + return -1; + + f = fopen(cg_proc, "w"); + free(cg_proc); + if (!f) + return -1; + + if (fprintf(f, "%ld\n", (long) pid) < 0) + ret = -1; + + fclose(f); + return ret; +} + +static int cgroup_set_limit(char *cg, unsigned long limit) +{ + char *cg_pins_max; + FILE *f; + int ret = 0; + + if (asprintf(&cg_pins_max, "%s/pins.max", cg) < 0) + return -1; + + f = fopen(cg_pins_max, "w"); + free(cg_pins_max); + if (!f) + return -1; + + if (limit != PINS_MAX) { + if (fprintf(f, "%ld\n", limit) < 0) + ret = -1; + } else { + if (fprintf(f, "max\n") < 0) + ret = -1; + } + + fclose(f); + return ret; +} + +FIXTURE_SETUP(pins_cg) +{ + char *cg_subtree_control; + FILE *f; + + if (asprintf(&cg_subtree_control, + "/sys/fs/cgroup/cgroup.subtree_control") < 0) + return; + + f = fopen(cg_subtree_control, "w"); + free(cg_subtree_control); + if (!f) + return; + + fprintf(f, "+pins\n"); + fclose(f); + + self->cg_path = cgroup_new(); + self->page_size = sysconf(_SC_PAGE_SIZE); +} + +FIXTURE_TEARDOWN(pins_cg) +{ + cgroup_add_proc("/sys/fs/cgroup", getpid()); + + rmdir(self->cg_path); + free(self->cg_path); +} + +static long cgroup_pins(char *cg) +{ + long pin_count; + char *cg_pins_current; + FILE *f; + int ret; + + if (asprintf(&cg_pins_current, "%s/pins.current", cg) < 0) + return -1; + + f = fopen(cg_pins_current, "r"); + if (!f) { + printf("Can't open %s\n", cg_pins_current); + getchar(); + free(cg_pins_current); + return -2; + } + + free(cg_pins_current); + + if (fscanf(f, "%ld", &pin_count) == EOF) + ret = -3; + else + ret = pin_count; + + fclose(f); + return ret; +} + +static int set_rlim_memlock(unsigned long size) +{ + struct rlimit rlim_memlock = { + .rlim_cur = size, + .rlim_max = size, + }; + cap_t cap; + cap_value_t capability[1] = { CAP_IPC_LOCK }; + + /* + * Many of the rlimit checks are skipped if a process has + * CAP_IP_LOCK. As this test should be run as root we need to + * explicitly drop it. + */ + cap = cap_get_proc(); + if (!cap) + return -1; + if (cap_set_flag(cap, CAP_EFFECTIVE, 1, capability, CAP_CLEAR)) + return -1; + if (cap_set_proc(cap)) + return -1; + return setrlimit(RLIMIT_MEMLOCK, &rlim_memlock); +} + +TEST_F(pins_cg, basic) +{ + pid_t child_pid; + long page_size = self->page_size; + char *p; + + ASSERT_EQ(cgroup_add_proc(self->cg_path, getpid()), 0); + p = mmap(NULL, 32*page_size, PROT_READ | PROT_WRITE, + MAP_ANONYMOUS | MAP_PRIVATE, -1, 0); + ASSERT_NE(p, MAP_FAILED); + + ASSERT_EQ(cgroup_pins(self->cg_path), 0); + memset(p, 0, 16*page_size); + ASSERT_EQ(mlock(p, page_size), 0); + ASSERT_EQ(cgroup_pins(self->cg_path), 1); + ASSERT_EQ(mlock(p + page_size, page_size), 0); + ASSERT_EQ(cgroup_pins(self->cg_path), 2); + ASSERT_EQ(mlock(p, page_size), 0); + ASSERT_EQ(cgroup_pins(self->cg_path), 2); + ASSERT_EQ(mlock(p, 4*page_size), 0); + ASSERT_EQ(cgroup_pins(self->cg_path), 4); + ASSERT_EQ(munlock(p + 2*page_size, 2*page_size), 0); + ASSERT_EQ(cgroup_pins(self->cg_path), 2); + ASSERT_EQ(cgroup_set_limit(self->cg_path, 8), 0); + ASSERT_EQ(mlock(p, 16*page_size), -1); + ASSERT_EQ(errno, ENOMEM); + ASSERT_EQ(cgroup_pins(self->cg_path), 2); + ASSERT_EQ(cgroup_set_limit(self->cg_path, PINS_MAX), 0); + + /* check mremap() a locked region correctly accounts locked pages */ + ASSERT_EQ(mlock(p, 32*page_size), 0); + ASSERT_EQ(cgroup_pins(self->cg_path), 32); + p = mremap(p, 32*page_size, 64*page_size, MREMAP_MAYMOVE); + ASSERT_NE(p, MAP_FAILED); + ASSERT_EQ(cgroup_pins(self->cg_path), 64); + ASSERT_EQ(munmap(p + 32*page_size, 32*page_size), 0) + ASSERT_EQ(cgroup_pins(self->cg_path), 32); + p = mremap(p, 32*page_size, 32*page_size, MREMAP_MAYMOVE | MREMAP_DONTUNMAP); + ASSERT_NE(p, MAP_FAILED); + ASSERT_EQ(cgroup_pins(self->cg_path), 32); + ASSERT_EQ(munlock(p, 32*page_size), 0); + + /* mremap() a locked region should fail if limit exceeded */ + ASSERT_EQ(set_rlim_memlock(32*page_size), 0); + ASSERT_EQ(mlock(p, 32*page_size), 0); + ASSERT_EQ(mremap(p, 32*page_size, 64*page_size, 0), MAP_FAILED); + ASSERT_EQ(munlock(p, 32*page_size), 0); + + /* Exceeds rlimit, expected to fail */ + ASSERT_EQ(set_rlim_memlock(16*page_size), 0); + ASSERT_EQ(mlock(p, 32*page_size), -1); + ASSERT_EQ(errno, ENOMEM); + + /* memory in the child isn't locked so shouldn't increase pin_cg count */ + ASSERT_EQ(mlock(p, 16*page_size), 0); + child_pid = fork(); + if (!child_pid) { + ASSERT_EQ(cgroup_pins(self->cg_path), 16); + ASSERT_EQ(mlock(p, 16*page_size), 0); + ASSERT_EQ(cgroup_pins(self->cg_path), 32); + return; + + } + waitpid(child_pid, NULL, 0); + + /* check that child exit uncharged the pins */ + ASSERT_EQ(cgroup_pins(self->cg_path), 16); +} + +TEST_F(pins_cg, mmap) +{ + char *p; + + ASSERT_EQ(cgroup_add_proc(self->cg_path, getpid()), 0); + p = mmap(NULL, 4*self->page_size, PROT_READ | PROT_WRITE, + MAP_ANONYMOUS | MAP_PRIVATE | MAP_LOCKED, -1, 0); + ASSERT_NE(p, MAP_FAILED); + ASSERT_EQ(cgroup_pins(self->cg_path), 4); +} + +/* + * Test moving to a different cgroup. + */ +TEST_F(pins_cg, move_cg) +{ + char *p, *new_cg; + + ASSERT_EQ(cgroup_add_proc(self->cg_path, getpid()), 0); + p = mmap(NULL, 16*self->page_size, PROT_READ | PROT_WRITE, + MAP_ANONYMOUS | MAP_PRIVATE, -1, 0); + ASSERT_NE(p, MAP_FAILED); + memset(p, 0, 16*self->page_size); + ASSERT_EQ(mlock(p, 16*self->page_size), 0); + ASSERT_EQ(cgroup_pins(self->cg_path), 16); + ASSERT_NE(new_cg = cgroup_new(), NULL); + ASSERT_EQ(cgroup_add_proc(new_cg, getpid()), 0); + ASSERT_EQ(cgroup_pins(new_cg), 16); + ASSERT_EQ(cgroup_add_proc(self->cg_path, getpid()), 0); + rmdir(new_cg); +} +TEST_HARNESS_MAIN