Allocate and free arena pages, both from BPF and via user-space fault-in, and check that the map's memlock in fdinfo tracks the number of pages that are actually populated.
Like the other arena tests it runs serially. test: ./test_progs -a arena_mem_usage #5 arena_mem_usage:OK Summary: 1/0 PASSED, 0 SKIPPED, 0 FAILED Signed-off-by: Jiayuan Chen <[email protected]> --- .../bpf/prog_tests/arena_mem_usage.c | 122 ++++++++++++++++++ .../selftests/bpf/progs/arena_mem_usage.c | 39 ++++++ 2 files changed, 161 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/arena_mem_usage.c create mode 100644 tools/testing/selftests/bpf/progs/arena_mem_usage.c diff --git a/tools/testing/selftests/bpf/prog_tests/arena_mem_usage.c b/tools/testing/selftests/bpf/prog_tests/arena_mem_usage.c new file mode 100644 index 000000000000..14c2d1a1d673 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/arena_mem_usage.c @@ -0,0 +1,122 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include <test_progs.h> +#include <sys/user.h> +#ifndef PAGE_SIZE /* on some archs it comes in sys/user.h */ +#include <unistd.h> +#define PAGE_SIZE getpagesize() +#endif + +#include "arena_mem_usage.skel.h" + +/* + * arena_map_mem_usage() is surfaced to user space through the map's + * /proc/<pid>/fdinfo/<fd> "memlock:" line (the same value bpftool map show + * prints). Read it directly so the test has no external dependency. + */ +static long map_memlock(int map_fd) +{ + char path[64], line[128]; + long memlock = -1; + FILE *f; + + snprintf(path, sizeof(path), "/proc/self/fdinfo/%d", map_fd); + f = fopen(path, "r"); + if (!ASSERT_OK_PTR(f, "open_fdinfo")) + return -1; + while (fgets(line, sizeof(line), f)) { + if (sscanf(line, "memlock:\t%ld", &memlock) == 1) + break; + } + fclose(f); + ASSERT_NEQ(memlock, -1, "parse_memlock"); + return memlock; +} + +static int run(struct bpf_program *prog, const char *name) +{ + LIBBPF_OPTS(bpf_test_run_opts, opts); + int err = bpf_prog_test_run_opts(bpf_program__fd(prog), &opts); + + if (!ASSERT_OK(err, name)) + return -1; + if (!ASSERT_OK(opts.retval, name)) + return -1; + return 0; +} + +void serial_test_arena_mem_usage(void) +{ + struct arena_mem_usage *skel; + const long ps = PAGE_SIZE; + char *base; + size_t sz; + int fd, i; + + skel = arena_mem_usage__open_and_load(); + if (!ASSERT_OK_PTR(skel, "open_load")) + return; + fd = bpf_map__fd(skel->maps.arena); + + /* Fresh arena: no data pages, and the scratch page is not counted. */ + ASSERT_EQ(map_memlock(fd), 0, "initial"); + + /* BPF-side allocation of 17 pages. */ + skel->bss->alloc_cnt = 17; + if (run(skel->progs.alloc, "alloc")) + goto out; + /* + * A NULL ptr means bpf_arena_alloc_pages() itself failed (e.g. the host + * is under memory pressure), not a miscount -- flag it distinctly so a + * red CI run is not mistaken for a counting bug. + */ + if (!ASSERT_OK_PTR(skel->bss->ptr, "arena_alloc_pages")) + goto out; + ASSERT_EQ(map_memlock(fd), 17 * ps, "after_alloc"); + + /* Free a single page (arena_free_pages page_cnt==1 path). */ + skel->bss->free_byte_off = 0; + skel->bss->free_cnt = 1; + if (run(skel->progs.free_pages, "free_one")) + goto out; + ASSERT_EQ(map_memlock(fd), 16 * ps, "after_free_one"); + + /* Free ten pages in one call (bulk path); only the freed pages count. */ + skel->bss->free_byte_off = 1 * ps; + skel->bss->free_cnt = 10; + if (run(skel->progs.free_pages, "free_bulk")) + goto out; + ASSERT_EQ(map_memlock(fd), 6 * ps, "after_free_bulk"); + + /* Free the remaining six -> arena empty again. */ + skel->bss->free_byte_off = 11 * ps; + skel->bss->free_cnt = 6; + if (run(skel->progs.free_pages, "free_rest")) + goto out; + ASSERT_EQ(map_memlock(fd), 0, "after_free_rest"); + + /* + * User-space fault-in: touching unallocated arena pages allocates them + * through arena_vm_fault(). libbpf mmap()s the arena at map_extra during + * load, so bpf_map__initial_value() hands back that base. + */ + base = bpf_map__initial_value(skel->maps.arena, &sz); + if (!ASSERT_OK_PTR(base, "arena_base")) + goto out; + for (i = 0; i < 8; i++) + base[i * ps] = 1; + ASSERT_EQ(map_memlock(fd), 8 * ps, "after_faultin"); + + /* + * Free the faulted-in pages from BPF. They are mapped into the user vma + * (elevated refcount), so this also exercises the zap path. + */ + skel->bss->ptr = base; + skel->bss->free_byte_off = 0; + skel->bss->free_cnt = 8; + if (run(skel->progs.free_pages, "free_faulted")) + goto out; + ASSERT_EQ(map_memlock(fd), 0, "after_free_faulted"); +out: + arena_mem_usage__destroy(skel); +} diff --git a/tools/testing/selftests/bpf/progs/arena_mem_usage.c b/tools/testing/selftests/bpf/progs/arena_mem_usage.c new file mode 100644 index 000000000000..50d9d6ac86f6 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/arena_mem_usage.c @@ -0,0 +1,39 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include <vmlinux.h> +#include <bpf/bpf_helpers.h> +#include "bpf_arena_common.h" + +struct { + __uint(type, BPF_MAP_TYPE_ARENA); + __uint(map_flags, BPF_F_MMAPABLE); + __uint(max_entries, 1000); /* number of pages */ +#ifdef __TARGET_ARCH_arm64 + __ulong(map_extra, 0x1ull << 32); /* start of mmap() region */ +#else + __ulong(map_extra, 0x1ull << 44); /* start of mmap() region */ +#endif +} arena SEC(".maps"); + +void __arena *ptr; +int alloc_cnt; /* in: pages to allocate */ +long free_byte_off; /* in: byte offset within ptr to start freeing */ +int free_cnt; /* in: pages to free */ + +SEC("syscall") +int alloc(void *ctx) +{ + ptr = bpf_arena_alloc_pages(&arena, NULL, alloc_cnt, NUMA_NO_NODE, 0); + return ptr ? 0 : 1; +} + +SEC("syscall") +int free_pages(void *ctx) +{ + if (!ptr) + return 1; + bpf_arena_free_pages(&arena, (char __arena *)ptr + free_byte_off, free_cnt); + return 0; +} + +char _license[] SEC("license") = "GPL"; -- 2.43.0
