| Message ID | 20230810081319.65668-5-zhouchuyi@bytedance.com (mailing list archive) |
|---|---|
| State | RFC |
| Delegated to: | BPF |
| Headers | show |
| Series | mm: Select victim using bpf_oom_evaluate_task | expand |
| Context | Check | Description |
|---|---|---|
| bpf/vmtest-bpf-next-PR | success | PR summary |
| bpf/vmtest-bpf-next-VM_Test-1 | success | Logs for ${{ matrix.test }} on ${{ matrix.arch }} with ${{ matrix.toolchain_full }} |
| bpf/vmtest-bpf-next-VM_Test-2 | success | Logs for ShellCheck |
| bpf/vmtest-bpf-next-VM_Test-3 | fail | Logs for build for aarch64 with gcc |
| bpf/vmtest-bpf-next-VM_Test-4 | fail | Logs for build for s390x with gcc |
| bpf/vmtest-bpf-next-VM_Test-5 | fail | Logs for build for x86_64 with gcc |
| bpf/vmtest-bpf-next-VM_Test-6 | fail | Logs for build for x86_64 with llvm-16 |
| bpf/vmtest-bpf-next-VM_Test-7 | success | Logs for set-matrix |
| bpf/vmtest-bpf-next-VM_Test-8 | success | Logs for veristat |
| netdev/tree_selection | success | Not a local patch, async |
On 10/08/2023 09:13, Chuyi Zhou wrote: > This patch adds a test which implements a priority-based policy through > bpf_oom_evaluate_task. > > The BPF program, oom_policy.c, compares the cgroup priority of two tasks > and select the lower one. The userspace program test_oom_policy.c > maintains a priority map by using cgroup id as the keys and priority as > the values. We could protect certain cgroups from oom-killer by setting > higher priority. > > Signed-off-by: Chuyi Zhou <zhouchuyi@bytedance.com> > --- > .../bpf/prog_tests/test_oom_policy.c | 140 ++++++++++++++++++ > .../testing/selftests/bpf/progs/oom_policy.c | 104 +++++++++++++ > 2 files changed, 244 insertions(+) > create mode 100644 tools/testing/selftests/bpf/prog_tests/test_oom_policy.c > create mode 100644 tools/testing/selftests/bpf/progs/oom_policy.c > > diff --git a/tools/testing/selftests/bpf/prog_tests/test_oom_policy.c b/tools/testing/selftests/bpf/prog_tests/test_oom_policy.c > new file mode 100644 > index 000000000000..bea61ff22603 > --- /dev/null > +++ b/tools/testing/selftests/bpf/prog_tests/test_oom_policy.c > @@ -0,0 +1,140 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +#define _GNU_SOURCE > + > +#include <stdio.h> > +#include <fcntl.h> > +#include <unistd.h> > +#include <stdlib.h> > +#include <signal.h> > +#include <sys/stat.h> > +#include <test_progs.h> > +#include <bpf/btf.h> > +#include <bpf/bpf.h> > + > +#include "cgroup_helpers.h" > +#include "oom_policy.skel.h" > + > +static int map_fd; > +static int cg_nr; > +struct { > + const char *path; > + int fd; > + unsigned long long id; > +} cgs[] = { > + { "/cg1" }, > + { "/cg2" }, > +}; > + > + > +static struct oom_policy *open_load_oom_policy_skel(void) > +{ > + struct oom_policy *skel; > + int err; > + > + skel = oom_policy__open(); > + if (!ASSERT_OK_PTR(skel, "skel_open")) > + return NULL; > + > + err = oom_policy__load(skel); > + if (!ASSERT_OK(err, "skel_load")) > + goto cleanup; > + > + return skel; > + > +cleanup: > + oom_policy__destroy(skel); > + return NULL; > +} > + > +static void run_memory_consume(unsigned long long consume_size, int idx) > +{ > + char *buf; > + > + join_parent_cgroup(cgs[idx].path); > + buf = malloc(consume_size); > + memset(buf, 0, consume_size); > + sleep(2); > + exit(0); > +} > + > +static int set_cgroup_prio(unsigned long long cg_id, int prio) > +{ > + int err; > + > + err = bpf_map_update_elem(map_fd, &cg_id, &prio, BPF_ANY); > + ASSERT_EQ(err, 0, "update_map"); > + return err; > +} > + > +static int prepare_cgroup_environment(void) > +{ > + int err; > + > + err = setup_cgroup_environment(); > + if (err) > + goto clean_cg_env; > + for (int i = 0; i < cg_nr; i++) { > + err = cgs[i].fd = create_and_get_cgroup(cgs[i].path); > + if (!ASSERT_GE(cgs[i].fd, 0, "cg_create")) > + goto clean_cg_env; > + cgs[i].id = get_cgroup_id(cgs[i].path); > + } > + return 0; > +clean_cg_env: > + cleanup_cgroup_environment(); > + return err; > +} > + > +void test_oom_policy(void) > +{ > + struct oom_policy *skel; > + struct bpf_link *link; > + int err; > + int victim_pid; > + unsigned long long victim_cg_id; > + > + link = NULL; > + cg_nr = ARRAY_SIZE(cgs); > + > + skel = open_load_oom_policy_skel(); > + err = oom_policy__attach(skel); > + if (!ASSERT_OK(err, "oom_policy__attach")) > + goto cleanup; > + > + map_fd = bpf_object__find_map_fd_by_name(skel->obj, "cg_map"); > + if (!ASSERT_GE(map_fd, 0, "find map")) > + goto cleanup; > + > + err = prepare_cgroup_environment(); > + if (!ASSERT_EQ(err, 0, "prepare cgroup env")) > + goto cleanup; > + > + write_cgroup_file("/", "memory.max", "10M"); > + > + /* > + * Set higher priority to cg2 and lower to cg1, so we would select > + * task under cg1 as victim.(see oom_policy.c) > + */ > + set_cgroup_prio(cgs[0].id, 10); > + set_cgroup_prio(cgs[1].id, 50); > + > + victim_cg_id = cgs[0].id; > + victim_pid = fork(); > + > + if (victim_pid == 0) > + run_memory_consume(1024 * 1024 * 4, 0); > + > + if (fork() == 0) > + run_memory_consume(1024 * 1024 * 8, 1); > + > + while (wait(NULL) > 0) > + ; > + > + ASSERT_EQ(skel->bss->victim_pid, victim_pid, "victim_pid"); > + ASSERT_EQ(skel->bss->victim_cg_id, victim_cg_id, "victim_cgid"); > + ASSERT_EQ(skel->bss->failed_cnt, 1, "failed_cnt"); > +cleanup: > + bpf_link__destroy(link); > + oom_policy__destroy(skel); > + cleanup_cgroup_environment(); > +} > diff --git a/tools/testing/selftests/bpf/progs/oom_policy.c b/tools/testing/selftests/bpf/progs/oom_policy.c > new file mode 100644 > index 000000000000..fc9efc93914e > --- /dev/null > +++ b/tools/testing/selftests/bpf/progs/oom_policy.c > @@ -0,0 +1,104 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +#include <vmlinux.h> > +#include <bpf/bpf_tracing.h> > +#include <bpf/bpf_helpers.h> > + > +char _license[] SEC("license") = "GPL"; > + > +struct { > + __uint(type, BPF_MAP_TYPE_HASH); > + __type(key, int); > + __type(value, int); > + __uint(max_entries, 24); > +} cg_map SEC(".maps"); > + > +unsigned int victim_pid; > +u64 victim_cg_id; > +int failed_cnt; > + > +#define EOPNOTSUPP 95 > + > +enum { > + NO_BPF_POLICY, > + BPF_EVAL_ABORT, > + BPF_EVAL_NEXT, > + BPF_EVAL_SELECT, > +}; When I built a kernel using this series and tried building the associated test for that kernel I saw: progs/oom_policy.c:22:2: error: redefinition of enumerator 'NO_BPF_POLICY' NO_BPF_POLICY, ^ /home/opc/src/bpf-next/tools/testing/selftests/bpf/tools/include/vmlinux.h:75894:2: note: previous definition is here NO_BPF_POLICY = 0, ^ progs/oom_policy.c:23:2: error: redefinition of enumerator 'BPF_EVAL_ABORT' BPF_EVAL_ABORT, ^ /home/opc/src/bpf-next/tools/testing/selftests/bpf/tools/include/vmlinux.h:75895:2: note: previous definition is here BPF_EVAL_ABORT = 1, ^ progs/oom_policy.c:24:2: error: redefinition of enumerator 'BPF_EVAL_NEXT' BPF_EVAL_NEXT, ^ /home/opc/src/bpf-next/tools/testing/selftests/bpf/tools/include/vmlinux.h:75896:2: note: previous definition is here BPF_EVAL_NEXT = 2, ^ progs/oom_policy.c: CLNG-BPF [test_maps] tailcall_bpf2bpf4.bpf.o 25:2: error: redefinition of enumerator 'BPF_EVAL_SELECT' BPF_EVAL_SELECT, ^ /home/opc/src/bpf-next/tools/testing/selftests/bpf/tools/include/vmlinux.h:75897:2: note: previous definition is here BPF_EVAL_SELECT = 3, ^ 4 errors generated. So you shouldn't need the enum definition since it already makes it into vmlinux.h. I also ran into test failures when I removed the above (and compilation succeeded): test_oom_policy:PASS:prepare cgroup env 0 nsec (cgroup_helpers.c:130: errno: No such file or directory) Opening /mnt/cgroup-test-work-dir23054//memory.max set_cgroup_prio:PASS:update_map 0 nsec set_cgroup_prio:PASS:update_map 0 nsec test_oom_policy:FAIL:victim_pid unexpected victim_pid: actual 0 != expected 23058 test_oom_policy:FAIL:victim_cgid unexpected victim_cgid: actual 0 != expected 68 test_oom_policy:FAIL:failed_cnt unexpected failed_cnt: actual 0 != expected 1 #154 oom_policy:FAIL Summary: 1/0 PASSED, 0 SKIPPED, 1 FAILED So it seems that because my system was using the cgroupv1 memory controller, it could not be used for v2 unless I rebooted with systemd.unified_cgroup_hierarchy=1 ...on the boot commandline. It would be good to note any such requirements for this test in the selftests/bpf/README.rst. Might also be worth adding write_cgroup_file("", "cgroup.subtree_control", "+memory"); ...to ensure the memory controller is enabled for the root cgroup. At that point the test still failed: set_cgroup_prio:PASS:update_map 0 nsec test_oom_policy:FAIL:victim_pid unexpected victim_pid: actual 0 != expected 12649 test_oom_policy:FAIL:victim_cgid unexpected victim_cgid: actual 0 != expected 9583 test_oom_policy:FAIL:failed_cnt unexpected failed_cnt: actual 0 != expected 1 #154 oom_policy:FAIL Summary: 0/0 PASSED, 0 SKIPPED, 1 FAILED Successfully unloaded bpf_testmod.ko. Are there other implicit assumptions about configuration that cause this test to fail perhaps? Alan
Hello, 在 2023/8/16 19:53, Alan Maguire 写道: > On 10/08/2023 09:13, Chuyi Zhou wrote: >> This patch adds a test which implements a priority-based policy through >> bpf_oom_evaluate_task. >> >> The BPF program, oom_policy.c, compares the cgroup priority of two tasks >> and select the lower one. The userspace program test_oom_policy.c >> maintains a priority map by using cgroup id as the keys and priority as >> the values. We could protect certain cgroups from oom-killer by setting >> higher priority. >> >> Signed-off-by: Chuyi Zhou <zhouchuyi@bytedance.com> >> --- >> .../bpf/prog_tests/test_oom_policy.c | 140 ++++++++++++++++++ >> .../testing/selftests/bpf/progs/oom_policy.c | 104 +++++++++++++ >> 2 files changed, 244 insertions(+) >> create mode 100644 tools/testing/selftests/bpf/prog_tests/test_oom_policy.c >> create mode 100644 tools/testing/selftests/bpf/progs/oom_policy.c >> >> diff --git a/tools/testing/selftests/bpf/prog_tests/test_oom_policy.c b/tools/testing/selftests/bpf/prog_tests/test_oom_policy.c >> new file mode 100644 >> index 000000000000..bea61ff22603 >> --- /dev/null >> +++ b/tools/testing/selftests/bpf/prog_tests/test_oom_policy.c >> @@ -0,0 +1,140 @@ >> +// SPDX-License-Identifier: GPL-2.0-only >> +#define _GNU_SOURCE >> + >> +#include <stdio.h> >> +#include <fcntl.h> >> +#include <unistd.h> >> +#include <stdlib.h> >> +#include <signal.h> >> +#include <sys/stat.h> >> +#include <test_progs.h> >> +#include <bpf/btf.h> >> +#include <bpf/bpf.h> >> + >> +#include "cgroup_helpers.h" >> +#include "oom_policy.skel.h" >> + >> +static int map_fd; >> +static int cg_nr; >> +struct { >> + const char *path; >> + int fd; >> + unsigned long long id; >> +} cgs[] = { >> + { "/cg1" }, >> + { "/cg2" }, >> +}; >> + >> + >> +static struct oom_policy *open_load_oom_policy_skel(void) >> +{ >> + struct oom_policy *skel; >> + int err; >> + >> + skel = oom_policy__open(); >> + if (!ASSERT_OK_PTR(skel, "skel_open")) >> + return NULL; >> + >> + err = oom_policy__load(skel); >> + if (!ASSERT_OK(err, "skel_load")) >> + goto cleanup; >> + >> + return skel; >> + >> +cleanup: >> + oom_policy__destroy(skel); >> + return NULL; >> +} >> + >> +static void run_memory_consume(unsigned long long consume_size, int idx) >> +{ >> + char *buf; >> + >> + join_parent_cgroup(cgs[idx].path); >> + buf = malloc(consume_size); >> + memset(buf, 0, consume_size); >> + sleep(2); >> + exit(0); >> +} >> + >> +static int set_cgroup_prio(unsigned long long cg_id, int prio) >> +{ >> + int err; >> + >> + err = bpf_map_update_elem(map_fd, &cg_id, &prio, BPF_ANY); >> + ASSERT_EQ(err, 0, "update_map"); >> + return err; >> +} >> + >> +static int prepare_cgroup_environment(void) >> +{ >> + int err; >> + >> + err = setup_cgroup_environment(); >> + if (err) >> + goto clean_cg_env; >> + for (int i = 0; i < cg_nr; i++) { >> + err = cgs[i].fd = create_and_get_cgroup(cgs[i].path); >> + if (!ASSERT_GE(cgs[i].fd, 0, "cg_create")) >> + goto clean_cg_env; >> + cgs[i].id = get_cgroup_id(cgs[i].path); >> + } >> + return 0; >> +clean_cg_env: >> + cleanup_cgroup_environment(); >> + return err; >> +} >> + >> +void test_oom_policy(void) >> +{ >> + struct oom_policy *skel; >> + struct bpf_link *link; >> + int err; >> + int victim_pid; >> + unsigned long long victim_cg_id; >> + >> + link = NULL; >> + cg_nr = ARRAY_SIZE(cgs); >> + >> + skel = open_load_oom_policy_skel(); >> + err = oom_policy__attach(skel); >> + if (!ASSERT_OK(err, "oom_policy__attach")) >> + goto cleanup; >> + >> + map_fd = bpf_object__find_map_fd_by_name(skel->obj, "cg_map"); >> + if (!ASSERT_GE(map_fd, 0, "find map")) >> + goto cleanup; >> + >> + err = prepare_cgroup_environment(); >> + if (!ASSERT_EQ(err, 0, "prepare cgroup env")) >> + goto cleanup; >> + >> + write_cgroup_file("/", "memory.max", "10M"); >> + >> + /* >> + * Set higher priority to cg2 and lower to cg1, so we would select >> + * task under cg1 as victim.(see oom_policy.c) >> + */ >> + set_cgroup_prio(cgs[0].id, 10); >> + set_cgroup_prio(cgs[1].id, 50); >> + >> + victim_cg_id = cgs[0].id; >> + victim_pid = fork(); >> + >> + if (victim_pid == 0) >> + run_memory_consume(1024 * 1024 * 4, 0); >> + >> + if (fork() == 0) >> + run_memory_consume(1024 * 1024 * 8, 1); >> + >> + while (wait(NULL) > 0) >> + ; >> + >> + ASSERT_EQ(skel->bss->victim_pid, victim_pid, "victim_pid"); >> + ASSERT_EQ(skel->bss->victim_cg_id, victim_cg_id, "victim_cgid"); >> + ASSERT_EQ(skel->bss->failed_cnt, 1, "failed_cnt"); >> +cleanup: >> + bpf_link__destroy(link); >> + oom_policy__destroy(skel); >> + cleanup_cgroup_environment(); >> +} >> diff --git a/tools/testing/selftests/bpf/progs/oom_policy.c b/tools/testing/selftests/bpf/progs/oom_policy.c >> new file mode 100644 >> index 000000000000..fc9efc93914e >> --- /dev/null >> +++ b/tools/testing/selftests/bpf/progs/oom_policy.c >> @@ -0,0 +1,104 @@ >> +// SPDX-License-Identifier: GPL-2.0-only >> +#include <vmlinux.h> >> +#include <bpf/bpf_tracing.h> >> +#include <bpf/bpf_helpers.h> >> + >> +char _license[] SEC("license") = "GPL"; >> + >> +struct { >> + __uint(type, BPF_MAP_TYPE_HASH); >> + __type(key, int); >> + __type(value, int); >> + __uint(max_entries, 24); >> +} cg_map SEC(".maps"); >> + >> +unsigned int victim_pid; >> +u64 victim_cg_id; >> +int failed_cnt; >> + >> +#define EOPNOTSUPP 95 >> + >> +enum { >> + NO_BPF_POLICY, >> + BPF_EVAL_ABORT, >> + BPF_EVAL_NEXT, >> + BPF_EVAL_SELECT, >> +}; > > When I built a kernel using this series and tried building the > associated test for that kernel I saw: > > progs/oom_policy.c:22:2: error: redefinition of enumerator 'NO_BPF_POLICY' > NO_BPF_POLICY, > ^ > /home/opc/src/bpf-next/tools/testing/selftests/bpf/tools/include/vmlinux.h:75894:2: > note: previous definition is here > NO_BPF_POLICY = 0, > ^ > progs/oom_policy.c:23:2: error: redefinition of enumerator 'BPF_EVAL_ABORT' > BPF_EVAL_ABORT, > ^ > /home/opc/src/bpf-next/tools/testing/selftests/bpf/tools/include/vmlinux.h:75895:2: > note: previous definition is here > BPF_EVAL_ABORT = 1, > ^ > progs/oom_policy.c:24:2: error: redefinition of enumerator 'BPF_EVAL_NEXT' > BPF_EVAL_NEXT, > ^ > /home/opc/src/bpf-next/tools/testing/selftests/bpf/tools/include/vmlinux.h:75896:2: > note: previous definition is here > BPF_EVAL_NEXT = 2, > ^ > progs/oom_policy.c: CLNG-BPF [test_maps] tailcall_bpf2bpf4.bpf.o > 25:2: error: redefinition of enumerator 'BPF_EVAL_SELECT' > BPF_EVAL_SELECT, > ^ > /home/opc/src/bpf-next/tools/testing/selftests/bpf/tools/include/vmlinux.h:75897:2: > note: previous definition is here > BPF_EVAL_SELECT = 3, > ^ > 4 errors generated. > > > So you shouldn't need the enum definition since it already makes it into > vmlinux.h. > OK. It seems my vmlinux.h doesn't contain these enum... > I also ran into test failures when I removed the above (and compilation > succeeded): > > > test_oom_policy:PASS:prepare cgroup env 0 nsec > (cgroup_helpers.c:130: errno: No such file or directory) Opening > /mnt/cgroup-test-work-dir23054//memory.max > set_cgroup_prio:PASS:update_map 0 nsec > set_cgroup_prio:PASS:update_map 0 nsec > test_oom_policy:FAIL:victim_pid unexpected victim_pid: actual 0 != > expected 23058 > test_oom_policy:FAIL:victim_cgid unexpected victim_cgid: actual 0 != > expected 68 > test_oom_policy:FAIL:failed_cnt unexpected failed_cnt: actual 0 != > expected 1 > #154 oom_policy:FAIL > Summary: 1/0 PASSED, 0 SKIPPED, 1 FAILED > > So it seems that because my system was using the cgroupv1 memory > controller, it could not be used for v2 unless I rebooted with > > systemd.unified_cgroup_hierarchy=1 > > ...on the boot commandline. It would be good to note any such > requirements for this test in the selftests/bpf/README.rst. > Might also be worth adding > > write_cgroup_file("", "cgroup.subtree_control", "+memory"); > > ...to ensure the memory controller is enabled for the root cgroup. > > At that point the test still failed: > > set_cgroup_prio:PASS:update_map 0 nsec > test_oom_policy:FAIL:victim_pid unexpected victim_pid: actual 0 != > expected 12649 > test_oom_policy:FAIL:victim_cgid unexpected victim_cgid: actual 0 != > expected 9583 > test_oom_policy:FAIL:failed_cnt unexpected failed_cnt: actual 0 != > expected 1 > #154 oom_policy:FAIL > Summary: 0/0 PASSED, 0 SKIPPED, 1 FAILED > Successfully unloaded bpf_testmod.ko. > > It seems that OOM is not invoked in your environment(you can check it in demsg). If the memcg OOM is invoked by the test, we would record the *victim_pid* and *victim_cgid* and they would not be zero. I guess the reason is memory_control is not enabled in cgroup "/mnt/cgroup-test-work-dir23054/", because I see the error message: (cgroup_helpers.c:130: errno: No such file or directory) Opening > /mnt/cgroup-test-work-dir23054//memory.max Thanks for your review and test! > Are there other implicit assumptions about configuration that cause this > test to fail perhaps? > > Alan
On 16/08/2023 13:31, Chuyi Zhou wrote: > Hello, > > 在 2023/8/16 19:53, Alan Maguire 写道: >> On 10/08/2023 09:13, Chuyi Zhou wrote: >>> This patch adds a test which implements a priority-based policy through >>> bpf_oom_evaluate_task. >>> >>> The BPF program, oom_policy.c, compares the cgroup priority of two tasks >>> and select the lower one. The userspace program test_oom_policy.c >>> maintains a priority map by using cgroup id as the keys and priority as >>> the values. We could protect certain cgroups from oom-killer by setting >>> higher priority. >>> >>> Signed-off-by: Chuyi Zhou <zhouchuyi@bytedance.com> >>> --- >>> .../bpf/prog_tests/test_oom_policy.c | 140 ++++++++++++++++++ >>> .../testing/selftests/bpf/progs/oom_policy.c | 104 +++++++++++++ >>> 2 files changed, 244 insertions(+) >>> create mode 100644 >>> tools/testing/selftests/bpf/prog_tests/test_oom_policy.c >>> create mode 100644 tools/testing/selftests/bpf/progs/oom_policy.c >>> >>> diff --git a/tools/testing/selftests/bpf/prog_tests/test_oom_policy.c >>> b/tools/testing/selftests/bpf/prog_tests/test_oom_policy.c >>> new file mode 100644 >>> index 000000000000..bea61ff22603 >>> --- /dev/null >>> +++ b/tools/testing/selftests/bpf/prog_tests/test_oom_policy.c >>> @@ -0,0 +1,140 @@ >>> +// SPDX-License-Identifier: GPL-2.0-only >>> +#define _GNU_SOURCE >>> + >>> +#include <stdio.h> >>> +#include <fcntl.h> >>> +#include <unistd.h> >>> +#include <stdlib.h> >>> +#include <signal.h> >>> +#include <sys/stat.h> >>> +#include <test_progs.h> >>> +#include <bpf/btf.h> >>> +#include <bpf/bpf.h> >>> + >>> +#include "cgroup_helpers.h" >>> +#include "oom_policy.skel.h" >>> + >>> +static int map_fd; >>> +static int cg_nr; >>> +struct { >>> + const char *path; >>> + int fd; >>> + unsigned long long id; >>> +} cgs[] = { >>> + { "/cg1" }, >>> + { "/cg2" }, >>> +}; >>> + >>> + >>> +static struct oom_policy *open_load_oom_policy_skel(void) >>> +{ >>> + struct oom_policy *skel; >>> + int err; >>> + >>> + skel = oom_policy__open(); >>> + if (!ASSERT_OK_PTR(skel, "skel_open")) >>> + return NULL; >>> + >>> + err = oom_policy__load(skel); >>> + if (!ASSERT_OK(err, "skel_load")) >>> + goto cleanup; >>> + >>> + return skel; >>> + >>> +cleanup: >>> + oom_policy__destroy(skel); >>> + return NULL; >>> +} >>> + >>> +static void run_memory_consume(unsigned long long consume_size, int >>> idx) >>> +{ >>> + char *buf; >>> + >>> + join_parent_cgroup(cgs[idx].path); >>> + buf = malloc(consume_size); >>> + memset(buf, 0, consume_size); >>> + sleep(2); >>> + exit(0); >>> +} >>> + >>> +static int set_cgroup_prio(unsigned long long cg_id, int prio) >>> +{ >>> + int err; >>> + >>> + err = bpf_map_update_elem(map_fd, &cg_id, &prio, BPF_ANY); >>> + ASSERT_EQ(err, 0, "update_map"); >>> + return err; >>> +} >>> + >>> +static int prepare_cgroup_environment(void) >>> +{ >>> + int err; >>> + >>> + err = setup_cgroup_environment(); >>> + if (err) >>> + goto clean_cg_env; >>> + for (int i = 0; i < cg_nr; i++) { >>> + err = cgs[i].fd = create_and_get_cgroup(cgs[i].path); >>> + if (!ASSERT_GE(cgs[i].fd, 0, "cg_create")) >>> + goto clean_cg_env; >>> + cgs[i].id = get_cgroup_id(cgs[i].path); >>> + } >>> + return 0; >>> +clean_cg_env: >>> + cleanup_cgroup_environment(); >>> + return err; >>> +} >>> + >>> +void test_oom_policy(void) >>> +{ >>> + struct oom_policy *skel; >>> + struct bpf_link *link; >>> + int err; >>> + int victim_pid; >>> + unsigned long long victim_cg_id; >>> + >>> + link = NULL; >>> + cg_nr = ARRAY_SIZE(cgs); >>> + >>> + skel = open_load_oom_policy_skel(); >>> + err = oom_policy__attach(skel); >>> + if (!ASSERT_OK(err, "oom_policy__attach")) >>> + goto cleanup; >>> + >>> + map_fd = bpf_object__find_map_fd_by_name(skel->obj, "cg_map"); >>> + if (!ASSERT_GE(map_fd, 0, "find map")) >>> + goto cleanup; >>> + >>> + err = prepare_cgroup_environment(); >>> + if (!ASSERT_EQ(err, 0, "prepare cgroup env")) >>> + goto cleanup; >>> + >>> + write_cgroup_file("/", "memory.max", "10M"); >>> + >>> + /* >>> + * Set higher priority to cg2 and lower to cg1, so we would select >>> + * task under cg1 as victim.(see oom_policy.c) >>> + */ >>> + set_cgroup_prio(cgs[0].id, 10); >>> + set_cgroup_prio(cgs[1].id, 50); >>> + >>> + victim_cg_id = cgs[0].id; >>> + victim_pid = fork(); >>> + >>> + if (victim_pid == 0) >>> + run_memory_consume(1024 * 1024 * 4, 0); >>> + >>> + if (fork() == 0) >>> + run_memory_consume(1024 * 1024 * 8, 1); >>> + >>> + while (wait(NULL) > 0) >>> + ; >>> + >>> + ASSERT_EQ(skel->bss->victim_pid, victim_pid, "victim_pid"); >>> + ASSERT_EQ(skel->bss->victim_cg_id, victim_cg_id, "victim_cgid"); >>> + ASSERT_EQ(skel->bss->failed_cnt, 1, "failed_cnt"); >>> +cleanup: >>> + bpf_link__destroy(link); >>> + oom_policy__destroy(skel); >>> + cleanup_cgroup_environment(); >>> +} >>> diff --git a/tools/testing/selftests/bpf/progs/oom_policy.c >>> b/tools/testing/selftests/bpf/progs/oom_policy.c >>> new file mode 100644 >>> index 000000000000..fc9efc93914e >>> --- /dev/null >>> +++ b/tools/testing/selftests/bpf/progs/oom_policy.c >>> @@ -0,0 +1,104 @@ >>> +// SPDX-License-Identifier: GPL-2.0-only >>> +#include <vmlinux.h> >>> +#include <bpf/bpf_tracing.h> >>> +#include <bpf/bpf_helpers.h> >>> + >>> +char _license[] SEC("license") = "GPL"; >>> + >>> +struct { >>> + __uint(type, BPF_MAP_TYPE_HASH); >>> + __type(key, int); >>> + __type(value, int); >>> + __uint(max_entries, 24); >>> +} cg_map SEC(".maps"); >>> + >>> +unsigned int victim_pid; >>> +u64 victim_cg_id; >>> +int failed_cnt; >>> + >>> +#define EOPNOTSUPP 95 >>> + >>> +enum { >>> + NO_BPF_POLICY, >>> + BPF_EVAL_ABORT, >>> + BPF_EVAL_NEXT, >>> + BPF_EVAL_SELECT, >>> +}; >> >> When I built a kernel using this series and tried building the >> associated test for that kernel I saw: >> >> progs/oom_policy.c:22:2: error: redefinition of enumerator >> 'NO_BPF_POLICY' >> NO_BPF_POLICY, >> ^ >> /home/opc/src/bpf-next/tools/testing/selftests/bpf/tools/include/vmlinux.h:75894:2: >> note: previous definition is here >> NO_BPF_POLICY = 0, >> ^ >> progs/oom_policy.c:23:2: error: redefinition of enumerator >> 'BPF_EVAL_ABORT' >> BPF_EVAL_ABORT, >> ^ >> /home/opc/src/bpf-next/tools/testing/selftests/bpf/tools/include/vmlinux.h:75895:2: >> note: previous definition is here >> BPF_EVAL_ABORT = 1, >> ^ >> progs/oom_policy.c:24:2: error: redefinition of enumerator >> 'BPF_EVAL_NEXT' >> BPF_EVAL_NEXT, >> ^ >> /home/opc/src/bpf-next/tools/testing/selftests/bpf/tools/include/vmlinux.h:75896:2: >> note: previous definition is here >> BPF_EVAL_NEXT = 2, >> ^ >> progs/oom_policy.c: CLNG-BPF [test_maps] tailcall_bpf2bpf4.bpf.o >> 25:2: error: redefinition of enumerator 'BPF_EVAL_SELECT' >> BPF_EVAL_SELECT, >> ^ >> /home/opc/src/bpf-next/tools/testing/selftests/bpf/tools/include/vmlinux.h:75897:2: >> note: previous definition is here >> BPF_EVAL_SELECT = 3, >> ^ >> 4 errors generated. >> >> >> So you shouldn't need the enum definition since it already makes it into >> vmlinux.h. >> OK. It seems my vmlinux.h doesn't contain these enum... >> I also ran into test failures when I removed the above (and compilation >> succeeded): >> >> >> test_oom_policy:PASS:prepare cgroup env 0 nsec >> (cgroup_helpers.c:130: errno: No such file or directory) Opening >> /mnt/cgroup-test-work-dir23054//memory.max >> set_cgroup_prio:PASS:update_map 0 nsec >> set_cgroup_prio:PASS:update_map 0 nsec >> test_oom_policy:FAIL:victim_pid unexpected victim_pid: actual 0 != >> expected 23058 >> test_oom_policy:FAIL:victim_cgid unexpected victim_cgid: actual 0 != >> expected 68 >> test_oom_policy:FAIL:failed_cnt unexpected failed_cnt: actual 0 != >> expected 1 >> #154 oom_policy:FAIL >> Summary: 1/0 PASSED, 0 SKIPPED, 1 FAILED >> >> So it seems that because my system was using the cgroupv1 memory >> controller, it could not be used for v2 unless I rebooted with >> >> systemd.unified_cgroup_hierarchy=1 >> >> ...on the boot commandline. It would be good to note any such >> requirements for this test in the selftests/bpf/README.rst. >> Might also be worth adding >> >> write_cgroup_file("", "cgroup.subtree_control", "+memory"); >> >> ...to ensure the memory controller is enabled for the root cgroup. >> >> At that point the test still failed: >> >> set_cgroup_prio:PASS:update_map 0 nsec >> test_oom_policy:FAIL:victim_pid unexpected victim_pid: actual 0 != >> expected 12649 >> test_oom_policy:FAIL:victim_cgid unexpected victim_cgid: actual 0 != >> expected 9583 >> test_oom_policy:FAIL:failed_cnt unexpected failed_cnt: actual 0 != >> expected 1 >> #154 oom_policy:FAIL >> Summary: 0/0 PASSED, 0 SKIPPED, 1 FAILED >> Successfully unloaded bpf_testmod.ko. >> >> > It seems that OOM is not invoked in your environment(you can check it in > demsg). If the memcg OOM is invoked by the test, we would record the > *victim_pid* and *victim_cgid* and they would not be zero. I guess the > reason is memory_control is not enabled in cgroup > "/mnt/cgroup-test-work-dir23054/", because I see the error message: > (cgroup_helpers.c:130: errno: No such file or directory) Opening >> /mnt/cgroup-test-work-dir23054//memory.max Right, but after I set up unified cgroup hierarchy and rebooted, that message disappeared and cgroup setup succeeded, _but_ the test still failed with 0 victim_pid/cgid. I see nothing OOM-related in dmesg, but the toplevel cgroupv2 cgroup.controllers file contains: cpuset cpu io memory hugetlb pids rdma Is there something else that needs to be done to enable OOM scanning? I see the oom_reaper process: root 72 2 0 11:30 ? 00:00:00 [oom_reaper] This test will need to pass BPF CI, so any assumptions about configuration need to be ironed out. For example, I think you should probably have diff --git a/tools/testing/selftests/bpf/prog_tests/test_oom_policy.c b/tools/testing/selftests/bpf/prog_tests/test_oom_policy.c index bea61ff22603..54fdb8a59816 100644 --- a/tools/testing/selftests/bpf/prog_tests/test_oom_policy.c +++ b/tools/testing/selftests/bpf/prog_tests/test_oom_policy.c @@ -109,6 +109,7 @@ void test_oom_policy(void) if (!ASSERT_EQ(err, 0, "prepare cgroup env")) goto cleanup; + write_cgroup_file("/", "cgroup.subtree_control", "+memory"); write_cgroup_file("/", "memory.max", "10M"); /* ...to be safe, since https://docs.kernel.org/admin-guide/cgroup-v2.html#organizing-processes-and-threads ...says "No controller is enabled by default. Controllers can be enabled and disabled by writing to the "cgroup.subtree_control" file: # echo "+cpu +memory -io" > cgroup.subtree_control " Are there any other aspects of configuration like that which might explain why the test passes for you but fails for me? Alan
Hello, 在 2023/8/16 21:49, Alan Maguire 写道: > On 16/08/2023 13:31, Chuyi Zhou wrote: >> Hello, >> >> 在 2023/8/16 19:53, Alan Maguire 写道: >>> On 10/08/2023 09:13, Chuyi Zhou wrote: >>>> This patch adds a test which implements a priority-based policy through >>>> bpf_oom_evaluate_task. >>>> >>>> The BPF program, oom_policy.c, compares the cgroup priority of two tasks >>>> and select the lower one. The userspace program test_oom_policy.c >>>> maintains a priority map by using cgroup id as the keys and priority as >>>> the values. We could protect certain cgroups from oom-killer by setting >>>> higher priority. >>>> >>>> Signed-off-by: Chuyi Zhou <zhouchuyi@bytedance.com> >>>> --- >>>> .../bpf/prog_tests/test_oom_policy.c | 140 ++++++++++++++++++ >>>> .../testing/selftests/bpf/progs/oom_policy.c | 104 +++++++++++++ >>>> 2 files changed, 244 insertions(+) >>>> create mode 100644 >>>> tools/testing/selftests/bpf/prog_tests/test_oom_policy.c >>>> create mode 100644 tools/testing/selftests/bpf/progs/oom_policy.c >>>> >>>> diff --git a/tools/testing/selftests/bpf/prog_tests/test_oom_policy.c >>>> b/tools/testing/selftests/bpf/prog_tests/test_oom_policy.c >>>> new file mode 100644 >>>> index 000000000000..bea61ff22603 >>>> --- /dev/null >>>> +++ b/tools/testing/selftests/bpf/prog_tests/test_oom_policy.c >>>> @@ -0,0 +1,140 @@ >>>> +// SPDX-License-Identifier: GPL-2.0-only >>>> +#define _GNU_SOURCE >>>> + >>>> +#include <stdio.h> >>>> +#include <fcntl.h> >>>> +#include <unistd.h> >>>> +#include <stdlib.h> >>>> +#include <signal.h> >>>> +#include <sys/stat.h> >>>> +#include <test_progs.h> >>>> +#include <bpf/btf.h> >>>> +#include <bpf/bpf.h> >>>> + >>>> +#include "cgroup_helpers.h" >>>> +#include "oom_policy.skel.h" >>>> + >>>> +static int map_fd; >>>> +static int cg_nr; >>>> +struct { >>>> + const char *path; >>>> + int fd; >>>> + unsigned long long id; >>>> +} cgs[] = { >>>> + { "/cg1" }, >>>> + { "/cg2" }, >>>> +}; >>>> + >>>> + >>>> +static struct oom_policy *open_load_oom_policy_skel(void) >>>> +{ >>>> + struct oom_policy *skel; >>>> + int err; >>>> + >>>> + skel = oom_policy__open(); >>>> + if (!ASSERT_OK_PTR(skel, "skel_open")) >>>> + return NULL; >>>> + >>>> + err = oom_policy__load(skel); >>>> + if (!ASSERT_OK(err, "skel_load")) >>>> + goto cleanup; >>>> + >>>> + return skel; >>>> + >>>> +cleanup: >>>> + oom_policy__destroy(skel); >>>> + return NULL; >>>> +} >>>> + >>>> +static void run_memory_consume(unsigned long long consume_size, int >>>> idx) >>>> +{ >>>> + char *buf; >>>> + >>>> + join_parent_cgroup(cgs[idx].path); >>>> + buf = malloc(consume_size); >>>> + memset(buf, 0, consume_size); >>>> + sleep(2); >>>> + exit(0); >>>> +} >>>> + >>>> +static int set_cgroup_prio(unsigned long long cg_id, int prio) >>>> +{ >>>> + int err; >>>> + >>>> + err = bpf_map_update_elem(map_fd, &cg_id, &prio, BPF_ANY); >>>> + ASSERT_EQ(err, 0, "update_map"); >>>> + return err; >>>> +} >>>> + >>>> +static int prepare_cgroup_environment(void) >>>> +{ >>>> + int err; >>>> + >>>> + err = setup_cgroup_environment(); >>>> + if (err) >>>> + goto clean_cg_env; >>>> + for (int i = 0; i < cg_nr; i++) { >>>> + err = cgs[i].fd = create_and_get_cgroup(cgs[i].path); >>>> + if (!ASSERT_GE(cgs[i].fd, 0, "cg_create")) >>>> + goto clean_cg_env; >>>> + cgs[i].id = get_cgroup_id(cgs[i].path); >>>> + } >>>> + return 0; >>>> +clean_cg_env: >>>> + cleanup_cgroup_environment(); >>>> + return err; >>>> +} >>>> + >>>> +void test_oom_policy(void) >>>> +{ >>>> + struct oom_policy *skel; >>>> + struct bpf_link *link; >>>> + int err; >>>> + int victim_pid; >>>> + unsigned long long victim_cg_id; >>>> + >>>> + link = NULL; >>>> + cg_nr = ARRAY_SIZE(cgs); >>>> + >>>> + skel = open_load_oom_policy_skel(); >>>> + err = oom_policy__attach(skel); >>>> + if (!ASSERT_OK(err, "oom_policy__attach")) >>>> + goto cleanup; >>>> + >>>> + map_fd = bpf_object__find_map_fd_by_name(skel->obj, "cg_map"); >>>> + if (!ASSERT_GE(map_fd, 0, "find map")) >>>> + goto cleanup; >>>> + >>>> + err = prepare_cgroup_environment(); >>>> + if (!ASSERT_EQ(err, 0, "prepare cgroup env")) >>>> + goto cleanup; >>>> + >>>> + write_cgroup_file("/", "memory.max", "10M"); >>>> + >>>> + /* >>>> + * Set higher priority to cg2 and lower to cg1, so we would select >>>> + * task under cg1 as victim.(see oom_policy.c) >>>> + */ >>>> + set_cgroup_prio(cgs[0].id, 10); >>>> + set_cgroup_prio(cgs[1].id, 50); >>>> + >>>> + victim_cg_id = cgs[0].id; >>>> + victim_pid = fork(); >>>> + >>>> + if (victim_pid == 0) >>>> + run_memory_consume(1024 * 1024 * 4, 0); >>>> + >>>> + if (fork() == 0) >>>> + run_memory_consume(1024 * 1024 * 8, 1); >>>> + >>>> + while (wait(NULL) > 0) >>>> + ; >>>> + >>>> + ASSERT_EQ(skel->bss->victim_pid, victim_pid, "victim_pid"); >>>> + ASSERT_EQ(skel->bss->victim_cg_id, victim_cg_id, "victim_cgid"); >>>> + ASSERT_EQ(skel->bss->failed_cnt, 1, "failed_cnt"); >>>> +cleanup: >>>> + bpf_link__destroy(link); >>>> + oom_policy__destroy(skel); >>>> + cleanup_cgroup_environment(); >>>> +} >>>> diff --git a/tools/testing/selftests/bpf/progs/oom_policy.c >>>> b/tools/testing/selftests/bpf/progs/oom_policy.c >>>> new file mode 100644 >>>> index 000000000000..fc9efc93914e >>>> --- /dev/null >>>> +++ b/tools/testing/selftests/bpf/progs/oom_policy.c >>>> @@ -0,0 +1,104 @@ >>>> +// SPDX-License-Identifier: GPL-2.0-only >>>> +#include <vmlinux.h> >>>> +#include <bpf/bpf_tracing.h> >>>> +#include <bpf/bpf_helpers.h> >>>> + >>>> +char _license[] SEC("license") = "GPL"; >>>> + >>>> +struct { >>>> + __uint(type, BPF_MAP_TYPE_HASH); >>>> + __type(key, int); >>>> + __type(value, int); >>>> + __uint(max_entries, 24); >>>> +} cg_map SEC(".maps"); >>>> + >>>> +unsigned int victim_pid; >>>> +u64 victim_cg_id; >>>> +int failed_cnt; >>>> + >>>> +#define EOPNOTSUPP 95 >>>> + >>>> +enum { >>>> + NO_BPF_POLICY, >>>> + BPF_EVAL_ABORT, >>>> + BPF_EVAL_NEXT, >>>> + BPF_EVAL_SELECT, >>>> +}; >>> >>> When I built a kernel using this series and tried building the >>> associated test for that kernel I saw: >>> >>> progs/oom_policy.c:22:2: error: redefinition of enumerator >>> 'NO_BPF_POLICY' >>> NO_BPF_POLICY, >>> ^ >>> /home/opc/src/bpf-next/tools/testing/selftests/bpf/tools/include/vmlinux.h:75894:2: >>> note: previous definition is here >>> NO_BPF_POLICY = 0, >>> ^ >>> progs/oom_policy.c:23:2: error: redefinition of enumerator >>> 'BPF_EVAL_ABORT' >>> BPF_EVAL_ABORT, >>> ^ >>> /home/opc/src/bpf-next/tools/testing/selftests/bpf/tools/include/vmlinux.h:75895:2: >>> note: previous definition is here >>> BPF_EVAL_ABORT = 1, >>> ^ >>> progs/oom_policy.c:24:2: error: redefinition of enumerator >>> 'BPF_EVAL_NEXT' >>> BPF_EVAL_NEXT, >>> ^ >>> /home/opc/src/bpf-next/tools/testing/selftests/bpf/tools/include/vmlinux.h:75896:2: >>> note: previous definition is here >>> BPF_EVAL_NEXT = 2, >>> ^ >>> progs/oom_policy.c: CLNG-BPF [test_maps] tailcall_bpf2bpf4.bpf.o >>> 25:2: error: redefinition of enumerator 'BPF_EVAL_SELECT' >>> BPF_EVAL_SELECT, >>> ^ >>> /home/opc/src/bpf-next/tools/testing/selftests/bpf/tools/include/vmlinux.h:75897:2: >>> note: previous definition is here >>> BPF_EVAL_SELECT = 3, >>> ^ >>> 4 errors generated. >>> >>> >>> So you shouldn't need the enum definition since it already makes it into >>> vmlinux.h. >>> OK. It seems my vmlinux.h doesn't contain these enum... >>> I also ran into test failures when I removed the above (and compilation >>> succeeded): >>> >>> >>> test_oom_policy:PASS:prepare cgroup env 0 nsec >>> (cgroup_helpers.c:130: errno: No such file or directory) Opening >>> /mnt/cgroup-test-work-dir23054//memory.max >>> set_cgroup_prio:PASS:update_map 0 nsec >>> set_cgroup_prio:PASS:update_map 0 nsec >>> test_oom_policy:FAIL:victim_pid unexpected victim_pid: actual 0 != >>> expected 23058 >>> test_oom_policy:FAIL:victim_cgid unexpected victim_cgid: actual 0 != >>> expected 68 >>> test_oom_policy:FAIL:failed_cnt unexpected failed_cnt: actual 0 != >>> expected 1 >>> #154 oom_policy:FAIL >>> Summary: 1/0 PASSED, 0 SKIPPED, 1 FAILED >>> >>> So it seems that because my system was using the cgroupv1 memory >>> controller, it could not be used for v2 unless I rebooted with >>> >>> systemd.unified_cgroup_hierarchy=1 >>> >>> ...on the boot commandline. It would be good to note any such >>> requirements for this test in the selftests/bpf/README.rst. >>> Might also be worth adding >>> >>> write_cgroup_file("", "cgroup.subtree_control", "+memory"); >>> >>> ...to ensure the memory controller is enabled for the root cgroup. >>> >>> At that point the test still failed: >>> >>> set_cgroup_prio:PASS:update_map 0 nsec >>> test_oom_policy:FAIL:victim_pid unexpected victim_pid: actual 0 != >>> expected 12649 >>> test_oom_policy:FAIL:victim_cgid unexpected victim_cgid: actual 0 != >>> expected 9583 >>> test_oom_policy:FAIL:failed_cnt unexpected failed_cnt: actual 0 != >>> expected 1 >>> #154 oom_policy:FAIL >>> Summary: 0/0 PASSED, 0 SKIPPED, 1 FAILED >>> Successfully unloaded bpf_testmod.ko. >>> >>> >> It seems that OOM is not invoked in your environment(you can check it in >> demsg). If the memcg OOM is invoked by the test, we would record the >> *victim_pid* and *victim_cgid* and they would not be zero. I guess the >> reason is memory_control is not enabled in cgroup >> "/mnt/cgroup-test-work-dir23054/", because I see the error message: >> (cgroup_helpers.c:130: errno: No such file or directory) Opening >>> /mnt/cgroup-test-work-dir23054//memory.max > > Right, but after I set up unified cgroup hierarchy and rebooted, that > message disappeared and cgroup setup succeeded, _but_ the test still > failed with 0 victim_pid/cgid. I see nothing OOM-related in dmesg, but > the toplevel cgroupv2 cgroup.controllers file contains: > > cpuset cpu io memory hugetlb pids rdma > Dose the toplevel cgroupv2's *cgroup.subtree_control* looks like that? /sys/fs/cgroup$ cat cgroup.subtree_control cpuset cpu io memory hugetlb pids This prog test would mkdir a test cgroup dir under the toplevel's cgroupv2 and rmdir after the test finishing. In my env, the test cgroup path looks like: /sys/fs/cgroup/cgroup-test-work-dirxxx/ This test would run in cgroup-test-work-dirxxx. If we want to enable memory controller in cgroup-test-work-dirxxx, we should guarantee that /sys/fs/cgroup/cgroup.subtree_control contanins "memory". > Is there something else that needs to be done to enable OOM scanning? > I see the oom_reaper process: > > root 72 2 0 11:30 ? 00:00:00 [oom_reaper] > > > This test will need to pass BPF CI, so any assumptions about > configuration need to be ironed out. For example, I think you should > probably have > > diff --git a/tools/testing/selftests/bpf/prog_tests/test_oom_policy.c > b/tools/testing/selftests/bpf/prog_tests/test_oom_policy.c > index bea61ff22603..54fdb8a59816 100644 > --- a/tools/testing/selftests/bpf/prog_tests/test_oom_policy.c > +++ b/tools/testing/selftests/bpf/prog_tests/test_oom_policy.c > @@ -109,6 +109,7 @@ void test_oom_policy(void) > if (!ASSERT_EQ(err, 0, "prepare cgroup env")) > goto cleanup; > > + write_cgroup_file("/", "cgroup.subtree_control", "+memory"); > write_cgroup_file("/", "memory.max", "10M"); Yes, you are right. We do need something to guarantee that the memory controller is enabled in cgroup-test-work-dir. write_cgroup_file("/", "cgroup.subtree_control", "+memory"); This code actually dose something like: echo "+memory" > /sys/fs/cgroup/cgroup-test-work-dir/cgroup.subtree_control What we need actually is echo "+memory" > /sys/fs/cgroup/cgroup.subtree_control Thanks! > > /* > > ...to be safe, since > > https://docs.kernel.org/admin-guide/cgroup-v2.html#organizing-processes-and-threads > > ...says > > "No controller is enabled by default. Controllers can be enabled and > disabled by writing to the "cgroup.subtree_control" file: > > # echo "+cpu +memory -io" > cgroup.subtree_control > > " > > Are there any other aspects of configuration like that which might > explain why the test passes for you but fails for me? > > Alan
在 2023/8/10 16:13, Chuyi Zhou 写道: > + +void test_oom_policy(void) +{ + struct oom_policy *skel; + struct > bpf_link *link; 'link' doesn't seem to be used. Thanks Bixuan Cui
在 2023/8/16 22:34, Chuyi Zhou 写道: > Hello, > > 在 2023/8/16 21:49, Alan Maguire 写道: >> On 16/08/2023 13:31, Chuyi Zhou wrote: >>> Hello, >>> >>> 在 2023/8/16 19:53, Alan Maguire 写道: >>>> On 10/08/2023 09:13, Chuyi Zhou wrote: >>>>> This patch adds a test which implements a priority-based policy >>>>> through >>>>> bpf_oom_evaluate_task. >>>>> >>>>> The BPF program, oom_policy.c, compares the cgroup priority of two >>>>> tasks >>>>> and select the lower one. The userspace program test_oom_policy.c >>>>> maintains a priority map by using cgroup id as the keys and >>>>> priority as >>>>> the values. We could protect certain cgroups from oom-killer by >>>>> setting >>>>> higher priority. >>>>> >>>>> Signed-off-by: Chuyi Zhou <zhouchuyi@bytedance.com> >>>>> --- >>>>> .../bpf/prog_tests/test_oom_policy.c | 140 >>>>> ++++++++++++++++++ >>>>> .../testing/selftests/bpf/progs/oom_policy.c | 104 +++++++++++++ >>>>> 2 files changed, 244 insertions(+) >>>>> create mode 100644 >>>>> tools/testing/selftests/bpf/prog_tests/test_oom_policy.c >>>>> create mode 100644 tools/testing/selftests/bpf/progs/oom_policy.c >>>>> >>>>> diff --git a/tools/testing/selftests/bpf/prog_tests/test_oom_policy.c >>>>> b/tools/testing/selftests/bpf/prog_tests/test_oom_policy.c >>>>> new file mode 100644 >>>>> index 000000000000..bea61ff22603 >>>>> --- /dev/null >>>>> +++ b/tools/testing/selftests/bpf/prog_tests/test_oom_policy.c >>>>> @@ -0,0 +1,140 @@ >>>>> +// SPDX-License-Identifier: GPL-2.0-only >>>>> +#define _GNU_SOURCE >>>>> + >>>>> +#include <stdio.h> >>>>> +#include <fcntl.h> >>>>> +#include <unistd.h> >>>>> +#include <stdlib.h> >>>>> +#include <signal.h> >>>>> +#include <sys/stat.h> >>>>> +#include <test_progs.h> >>>>> +#include <bpf/btf.h> >>>>> +#include <bpf/bpf.h> >>>>> + >>>>> +#include "cgroup_helpers.h" >>>>> +#include "oom_policy.skel.h" >>>>> + >>>>> +static int map_fd; >>>>> +static int cg_nr; >>>>> +struct { >>>>> + const char *path; >>>>> + int fd; >>>>> + unsigned long long id; >>>>> +} cgs[] = { >>>>> + { "/cg1" }, >>>>> + { "/cg2" }, >>>>> +}; >>>>> + >>>>> + >>>>> +static struct oom_policy *open_load_oom_policy_skel(void) >>>>> +{ >>>>> + struct oom_policy *skel; >>>>> + int err; >>>>> + >>>>> + skel = oom_policy__open(); >>>>> + if (!ASSERT_OK_PTR(skel, "skel_open")) >>>>> + return NULL; >>>>> + >>>>> + err = oom_policy__load(skel); >>>>> + if (!ASSERT_OK(err, "skel_load")) >>>>> + goto cleanup; >>>>> + >>>>> + return skel; >>>>> + >>>>> +cleanup: >>>>> + oom_policy__destroy(skel); >>>>> + return NULL; >>>>> +} >>>>> + >>>>> +static void run_memory_consume(unsigned long long consume_size, int >>>>> idx) >>>>> +{ >>>>> + char *buf; >>>>> + >>>>> + join_parent_cgroup(cgs[idx].path); >>>>> + buf = malloc(consume_size); >>>>> + memset(buf, 0, consume_size); >>>>> + sleep(2); >>>>> + exit(0); >>>>> +} >>>>> + >>>>> +static int set_cgroup_prio(unsigned long long cg_id, int prio) >>>>> +{ >>>>> + int err; >>>>> + >>>>> + err = bpf_map_update_elem(map_fd, &cg_id, &prio, BPF_ANY); >>>>> + ASSERT_EQ(err, 0, "update_map"); >>>>> + return err; >>>>> +} >>>>> + >>>>> +static int prepare_cgroup_environment(void) >>>>> +{ >>>>> + int err; >>>>> + >>>>> + err = setup_cgroup_environment(); >>>>> + if (err) >>>>> + goto clean_cg_env; >>>>> + for (int i = 0; i < cg_nr; i++) { >>>>> + err = cgs[i].fd = create_and_get_cgroup(cgs[i].path); >>>>> + if (!ASSERT_GE(cgs[i].fd, 0, "cg_create")) >>>>> + goto clean_cg_env; >>>>> + cgs[i].id = get_cgroup_id(cgs[i].path); >>>>> + } >>>>> + return 0; >>>>> +clean_cg_env: >>>>> + cleanup_cgroup_environment(); >>>>> + return err; >>>>> +} >>>>> + >>>>> +void test_oom_policy(void) >>>>> +{ >>>>> + struct oom_policy *skel; >>>>> + struct bpf_link *link; >>>>> + int err; >>>>> + int victim_pid; >>>>> + unsigned long long victim_cg_id; >>>>> + >>>>> + link = NULL; >>>>> + cg_nr = ARRAY_SIZE(cgs); >>>>> + >>>>> + skel = open_load_oom_policy_skel(); >>>>> + err = oom_policy__attach(skel); >>>>> + if (!ASSERT_OK(err, "oom_policy__attach")) >>>>> + goto cleanup; >>>>> + >>>>> + map_fd = bpf_object__find_map_fd_by_name(skel->obj, "cg_map"); >>>>> + if (!ASSERT_GE(map_fd, 0, "find map")) >>>>> + goto cleanup; >>>>> + >>>>> + err = prepare_cgroup_environment(); >>>>> + if (!ASSERT_EQ(err, 0, "prepare cgroup env")) >>>>> + goto cleanup; >>>>> + >>>>> + write_cgroup_file("/", "memory.max", "10M"); >>>>> + >>>>> + /* >>>>> + * Set higher priority to cg2 and lower to cg1, so we would >>>>> select >>>>> + * task under cg1 as victim.(see oom_policy.c) >>>>> + */ >>>>> + set_cgroup_prio(cgs[0].id, 10); >>>>> + set_cgroup_prio(cgs[1].id, 50); >>>>> + >>>>> + victim_cg_id = cgs[0].id; >>>>> + victim_pid = fork(); >>>>> + >>>>> + if (victim_pid == 0) >>>>> + run_memory_consume(1024 * 1024 * 4, 0); >>>>> + >>>>> + if (fork() == 0) >>>>> + run_memory_consume(1024 * 1024 * 8, 1); >>>>> + >>>>> + while (wait(NULL) > 0) >>>>> + ; >>>>> + >>>>> + ASSERT_EQ(skel->bss->victim_pid, victim_pid, "victim_pid"); >>>>> + ASSERT_EQ(skel->bss->victim_cg_id, victim_cg_id, "victim_cgid"); >>>>> + ASSERT_EQ(skel->bss->failed_cnt, 1, "failed_cnt"); >>>>> +cleanup: >>>>> + bpf_link__destroy(link); >>>>> + oom_policy__destroy(skel); >>>>> + cleanup_cgroup_environment(); >>>>> +} >>>>> diff --git a/tools/testing/selftests/bpf/progs/oom_policy.c >>>>> b/tools/testing/selftests/bpf/progs/oom_policy.c >>>>> new file mode 100644 >>>>> index 000000000000..fc9efc93914e >>>>> --- /dev/null >>>>> +++ b/tools/testing/selftests/bpf/progs/oom_policy.c >>>>> @@ -0,0 +1,104 @@ >>>>> +// SPDX-License-Identifier: GPL-2.0-only >>>>> +#include <vmlinux.h> >>>>> +#include <bpf/bpf_tracing.h> >>>>> +#include <bpf/bpf_helpers.h> >>>>> + >>>>> +char _license[] SEC("license") = "GPL"; >>>>> + >>>>> +struct { >>>>> + __uint(type, BPF_MAP_TYPE_HASH); >>>>> + __type(key, int); >>>>> + __type(value, int); >>>>> + __uint(max_entries, 24); >>>>> +} cg_map SEC(".maps"); >>>>> + >>>>> +unsigned int victim_pid; >>>>> +u64 victim_cg_id; >>>>> +int failed_cnt; >>>>> + >>>>> +#define EOPNOTSUPP 95 >>>>> + >>>>> +enum { >>>>> + NO_BPF_POLICY, >>>>> + BPF_EVAL_ABORT, >>>>> + BPF_EVAL_NEXT, >>>>> + BPF_EVAL_SELECT, >>>>> +}; >>>> >>>> When I built a kernel using this series and tried building the >>>> associated test for that kernel I saw: >>>> >>>> progs/oom_policy.c:22:2: error: redefinition of enumerator >>>> 'NO_BPF_POLICY' >>>> NO_BPF_POLICY, >>>> ^ >>>> /home/opc/src/bpf-next/tools/testing/selftests/bpf/tools/include/vmlinux.h:75894:2: >>>> >>>> note: previous definition is here >>>> NO_BPF_POLICY = 0, >>>> ^ >>>> progs/oom_policy.c:23:2: error: redefinition of enumerator >>>> 'BPF_EVAL_ABORT' >>>> BPF_EVAL_ABORT, >>>> ^ >>>> /home/opc/src/bpf-next/tools/testing/selftests/bpf/tools/include/vmlinux.h:75895:2: >>>> >>>> note: previous definition is here >>>> BPF_EVAL_ABORT = 1, >>>> ^ >>>> progs/oom_policy.c:24:2: error: redefinition of enumerator >>>> 'BPF_EVAL_NEXT' >>>> BPF_EVAL_NEXT, >>>> ^ >>>> /home/opc/src/bpf-next/tools/testing/selftests/bpf/tools/include/vmlinux.h:75896:2: >>>> >>>> note: previous definition is here >>>> BPF_EVAL_NEXT = 2, >>>> ^ >>>> progs/oom_policy.c: CLNG-BPF [test_maps] tailcall_bpf2bpf4.bpf.o >>>> 25:2: error: redefinition of enumerator 'BPF_EVAL_SELECT' >>>> BPF_EVAL_SELECT, >>>> ^ >>>> /home/opc/src/bpf-next/tools/testing/selftests/bpf/tools/include/vmlinux.h:75897:2: >>>> >>>> note: previous definition is here >>>> BPF_EVAL_SELECT = 3, >>>> ^ >>>> 4 errors generated. >>>> >>>> >>>> So you shouldn't need the enum definition since it already makes it >>>> into >>>> vmlinux.h. >>>> OK. It seems my vmlinux.h doesn't contain these enum... >>>> I also ran into test failures when I removed the above (and >>>> compilation >>>> succeeded): >>>> >>>> >>>> test_oom_policy:PASS:prepare cgroup env 0 nsec >>>> (cgroup_helpers.c:130: errno: No such file or directory) Opening >>>> /mnt/cgroup-test-work-dir23054//memory.max >>>> set_cgroup_prio:PASS:update_map 0 nsec >>>> set_cgroup_prio:PASS:update_map 0 nsec >>>> test_oom_policy:FAIL:victim_pid unexpected victim_pid: actual 0 != >>>> expected 23058 >>>> test_oom_policy:FAIL:victim_cgid unexpected victim_cgid: actual 0 != >>>> expected 68 >>>> test_oom_policy:FAIL:failed_cnt unexpected failed_cnt: actual 0 != >>>> expected 1 >>>> #154 oom_policy:FAIL >>>> Summary: 1/0 PASSED, 0 SKIPPED, 1 FAILED >>>> >>>> So it seems that because my system was using the cgroupv1 memory >>>> controller, it could not be used for v2 unless I rebooted with >>>> >>>> systemd.unified_cgroup_hierarchy=1 >>>> >>>> ...on the boot commandline. It would be good to note any such >>>> requirements for this test in the selftests/bpf/README.rst. >>>> Might also be worth adding >>>> >>>> write_cgroup_file("", "cgroup.subtree_control", "+memory"); >>>> >>>> ...to ensure the memory controller is enabled for the root cgroup. >>>> >>>> At that point the test still failed: >>>> >>>> set_cgroup_prio:PASS:update_map 0 nsec >>>> test_oom_policy:FAIL:victim_pid unexpected victim_pid: actual 0 != >>>> expected 12649 >>>> test_oom_policy:FAIL:victim_cgid unexpected victim_cgid: actual 0 != >>>> expected 9583 >>>> test_oom_policy:FAIL:failed_cnt unexpected failed_cnt: actual 0 != >>>> expected 1 >>>> #154 oom_policy:FAIL >>>> Summary: 0/0 PASSED, 0 SKIPPED, 1 FAILED >>>> Successfully unloaded bpf_testmod.ko. >>>> >>>> >>> It seems that OOM is not invoked in your environment(you can check >>> it in >>> demsg). If the memcg OOM is invoked by the test, we would record the >>> *victim_pid* and *victim_cgid* and they would not be zero. I guess the >>> reason is memory_control is not enabled in cgroup >>> "/mnt/cgroup-test-work-dir23054/", because I see the error message: >>> (cgroup_helpers.c:130: errno: No such file or directory) Opening >>>> /mnt/cgroup-test-work-dir23054//memory.max >> >> Right, but after I set up unified cgroup hierarchy and rebooted, that >> message disappeared and cgroup setup succeeded, _but_ the test still >> failed with 0 victim_pid/cgid. I see nothing OOM-related in dmesg, but >> the toplevel cgroupv2 cgroup.controllers file contains: >> >> cpuset cpu io memory hugetlb pids rdma >> > > Dose the toplevel cgroupv2's *cgroup.subtree_control* looks like that? > /sys/fs/cgroup$ cat cgroup.subtree_control > > cpuset cpu io memory hugetlb pids > > This prog test would mkdir a test cgroup dir under the toplevel's > cgroupv2 and rmdir after the test finishing. In my env, the test > cgroup path looks like: > > /sys/fs/cgroup/cgroup-test-work-dirxxx/ > > This test would run in cgroup-test-work-dirxxx. > > If we want to enable memory controller in cgroup-test-work-dirxxx, we > should guarantee that /sys/fs/cgroup/cgroup.subtree_control contanins > "memory". > > >> Is there something else that needs to be done to enable OOM scanning? >> I see the oom_reaper process: >> >> root 72 2 0 11:30 ? 00:00:00 [oom_reaper] >> >> >> This test will need to pass BPF CI, so any assumptions about >> configuration need to be ironed out. For example, I think you should >> probably have >> >> diff --git a/tools/testing/selftests/bpf/prog_tests/test_oom_policy.c >> b/tools/testing/selftests/bpf/prog_tests/test_oom_policy.c >> index bea61ff22603..54fdb8a59816 100644 >> --- a/tools/testing/selftests/bpf/prog_tests/test_oom_policy.c >> +++ b/tools/testing/selftests/bpf/prog_tests/test_oom_policy.c >> @@ -109,6 +109,7 @@ void test_oom_policy(void) >> if (!ASSERT_EQ(err, 0, "prepare cgroup env")) >> goto cleanup; >> >> + write_cgroup_file("/", "cgroup.subtree_control", "+memory"); >> write_cgroup_file("/", "memory.max", "10M"); > > Yes, you are right. We do need something to guarantee that the memory > controller is enabled in cgroup-test-work-dir. > write_cgroup_file("/", "cgroup.subtree_control", "+memory"); > This code actually dose something like: > > echo "+memory" > > /sys/fs/cgroup/cgroup-test-work-dir/cgroup.subtree_control > > What we need actually is > echo "+memory" > /sys/fs/cgroup/cgroup.subtree_control > > Thanks! Hello! I confirmed that I have the memory and other necessary options in cgroup.subtree_control you mentioned. cat /sys/fs/cgroup/cgroup.subtree_control cpuset cpu io memory hugetlb pids rdma misc I almost exactly reproduced the problem Alan encountered. make => redefinition of enumerator XXX => delete the enum => start the bpf selftest with "make run_tests" In the end, three Fails also appeared, with victim_pid, victim_cgid, and failed_cnt all being 0. My environment: - I installed the necessary software for bpf on Ubuntu 22.04. - I downloaded "linux-source-6.2.0 - Linux kernel source for version 6.2.0 with Ubuntu patches" from apt source. - I have applied your series of patches on this version of the kernel source code. - I compiled and installed this patched kernel and installed its linux-tools - Finally I reproduced the above error. Could you please provide an exact environment in which your success can be replicated? Perhaps this requires a more precise environment, including which version of the kernel source code your patch needs to be based on, which distribution of operating system, which necessary software needs to be installed, and which features need to be enabled. If you can help solve the problem, I would be very grateful! >> >> /* >> >> ...to be safe, since >> >> https://docs.kernel.org/admin-guide/cgroup-v2.html#organizing-processes-and-threads >> >> >> ...says >> >> "No controller is enabled by default. Controllers can be enabled and >> disabled by writing to the "cgroup.subtree_control" file: >> >> # echo "+cpu +memory -io" > cgroup.subtree_control >> >> " >> >> Are there any other aspects of configuration like that which might >> explain why the test passes for you but fails for me? >> >> Alan > >
diff --git a/tools/testing/selftests/bpf/prog_tests/test_oom_policy.c b/tools/testing/selftests/bpf/prog_tests/test_oom_policy.c new file mode 100644 index 000000000000..bea61ff22603 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/test_oom_policy.c @@ -0,0 +1,140 @@ +// SPDX-License-Identifier: GPL-2.0-only +#define _GNU_SOURCE + +#include <stdio.h> +#include <fcntl.h> +#include <unistd.h> +#include <stdlib.h> +#include <signal.h> +#include <sys/stat.h> +#include <test_progs.h> +#include <bpf/btf.h> +#include <bpf/bpf.h> + +#include "cgroup_helpers.h" +#include "oom_policy.skel.h" + +static int map_fd; +static int cg_nr; +struct { + const char *path; + int fd; + unsigned long long id; +} cgs[] = { + { "/cg1" }, + { "/cg2" }, +}; + + +static struct oom_policy *open_load_oom_policy_skel(void) +{ + struct oom_policy *skel; + int err; + + skel = oom_policy__open(); + if (!ASSERT_OK_PTR(skel, "skel_open")) + return NULL; + + err = oom_policy__load(skel); + if (!ASSERT_OK(err, "skel_load")) + goto cleanup; + + return skel; + +cleanup: + oom_policy__destroy(skel); + return NULL; +} + +static void run_memory_consume(unsigned long long consume_size, int idx) +{ + char *buf; + + join_parent_cgroup(cgs[idx].path); + buf = malloc(consume_size); + memset(buf, 0, consume_size); + sleep(2); + exit(0); +} + +static int set_cgroup_prio(unsigned long long cg_id, int prio) +{ + int err; + + err = bpf_map_update_elem(map_fd, &cg_id, &prio, BPF_ANY); + ASSERT_EQ(err, 0, "update_map"); + return err; +} + +static int prepare_cgroup_environment(void) +{ + int err; + + err = setup_cgroup_environment(); + if (err) + goto clean_cg_env; + for (int i = 0; i < cg_nr; i++) { + err = cgs[i].fd = create_and_get_cgroup(cgs[i].path); + if (!ASSERT_GE(cgs[i].fd, 0, "cg_create")) + goto clean_cg_env; + cgs[i].id = get_cgroup_id(cgs[i].path); + } + return 0; +clean_cg_env: + cleanup_cgroup_environment(); + return err; +} + +void test_oom_policy(void) +{ + struct oom_policy *skel; + struct bpf_link *link; + int err; + int victim_pid; + unsigned long long victim_cg_id; + + link = NULL; + cg_nr = ARRAY_SIZE(cgs); + + skel = open_load_oom_policy_skel(); + err = oom_policy__attach(skel); + if (!ASSERT_OK(err, "oom_policy__attach")) + goto cleanup; + + map_fd = bpf_object__find_map_fd_by_name(skel->obj, "cg_map"); + if (!ASSERT_GE(map_fd, 0, "find map")) + goto cleanup; + + err = prepare_cgroup_environment(); + if (!ASSERT_EQ(err, 0, "prepare cgroup env")) + goto cleanup; + + write_cgroup_file("/", "memory.max", "10M"); + + /* + * Set higher priority to cg2 and lower to cg1, so we would select + * task under cg1 as victim.(see oom_policy.c) + */ + set_cgroup_prio(cgs[0].id, 10); + set_cgroup_prio(cgs[1].id, 50); + + victim_cg_id = cgs[0].id; + victim_pid = fork(); + + if (victim_pid == 0) + run_memory_consume(1024 * 1024 * 4, 0); + + if (fork() == 0) + run_memory_consume(1024 * 1024 * 8, 1); + + while (wait(NULL) > 0) + ; + + ASSERT_EQ(skel->bss->victim_pid, victim_pid, "victim_pid"); + ASSERT_EQ(skel->bss->victim_cg_id, victim_cg_id, "victim_cgid"); + ASSERT_EQ(skel->bss->failed_cnt, 1, "failed_cnt"); +cleanup: + bpf_link__destroy(link); + oom_policy__destroy(skel); + cleanup_cgroup_environment(); +} diff --git a/tools/testing/selftests/bpf/progs/oom_policy.c b/tools/testing/selftests/bpf/progs/oom_policy.c new file mode 100644 index 000000000000..fc9efc93914e --- /dev/null +++ b/tools/testing/selftests/bpf/progs/oom_policy.c @@ -0,0 +1,104 @@ +// SPDX-License-Identifier: GPL-2.0-only +#include <vmlinux.h> +#include <bpf/bpf_tracing.h> +#include <bpf/bpf_helpers.h> + +char _license[] SEC("license") = "GPL"; + +struct { + __uint(type, BPF_MAP_TYPE_HASH); + __type(key, int); + __type(value, int); + __uint(max_entries, 24); +} cg_map SEC(".maps"); + +unsigned int victim_pid; +u64 victim_cg_id; +int failed_cnt; + +#define EOPNOTSUPP 95 + +enum { + NO_BPF_POLICY, + BPF_EVAL_ABORT, + BPF_EVAL_NEXT, + BPF_EVAL_SELECT, +}; + +extern void set_oom_policy_name(struct oom_control *oc, const char *buf, size_t sz) __ksym; + +static __always_inline u64 task_cgroup_id(struct task_struct *task) +{ + struct kernfs_node *node; + struct task_group *tg; + + if (!task) + return 0; + + tg = task->sched_task_group; + node = tg->css.cgroup->kn; + + return node->id; +} + +SEC("fentry/oom_kill_process") +int BPF_PROG(oom_kill_process_k, struct oom_control *oc, const char *message) +{ + struct task_struct *victim = oc->chosen; + + if (victim) { + victim_cg_id = task_cgroup_id(victim); + victim_pid = victim->pid; + } + + return 0; +} + +SEC("fentry/bpf_set_policy_name") +int BPF_PROG(set_police_name_k, struct oom_control *oc) +{ + char name[] = "cg_prio"; + set_oom_policy_name(oc, name, sizeof(name)); + return 0; +} + +SEC("tp_btf/select_bad_process_end") +int BPF_PROG(record_failed, struct oom_control *oc) +{ + failed_cnt += 1; + return 0; +} + +SEC("fmod_ret/bpf_oom_evaluate_task") +int BPF_PROG(bpf_oom_evaluate_task, struct task_struct *task, struct oom_control *oc) +{ + int chosen_cg_prio, task_cg_prio; + u64 chosen_cg_id, task_cg_id; + struct task_struct *chosen; + int *val; + + if (!failed_cnt) + return BPF_EVAL_NEXT; + + chosen = oc->chosen; + if (!chosen) + return BPF_EVAL_SELECT; + + chosen_cg_id = task_cgroup_id(chosen); + task_cg_id = task_cgroup_id(task); + chosen_cg_prio = task_cg_prio = 0; + val = bpf_map_lookup_elem(&cg_map, &chosen_cg_id); + if (val) + chosen_cg_prio = *val; + val = bpf_map_lookup_elem(&cg_map, &task_cg_id); + if (val) + task_cg_prio = *val; + + if (chosen_cg_prio > task_cg_prio) + return BPF_EVAL_SELECT; + if (chosen_cg_prio < task_cg_prio) + return BPF_EVAL_NEXT; + + return NO_BPF_POLICY; +} +
This patch adds a test which implements a priority-based policy through bpf_oom_evaluate_task. The BPF program, oom_policy.c, compares the cgroup priority of two tasks and select the lower one. The userspace program test_oom_policy.c maintains a priority map by using cgroup id as the keys and priority as the values. We could protect certain cgroups from oom-killer by setting higher priority. Signed-off-by: Chuyi Zhou <zhouchuyi@bytedance.com> --- .../bpf/prog_tests/test_oom_policy.c | 140 ++++++++++++++++++ .../testing/selftests/bpf/progs/oom_policy.c | 104 +++++++++++++ 2 files changed, 244 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/test_oom_policy.c create mode 100644 tools/testing/selftests/bpf/progs/oom_policy.c