[PATCH bpf-next v10 0/8] bpf: Introduce BPF_F_CPU and BPF_F_ALL_CPUS flags for percpu maps
This patch set introduces the BPF_F_CPU and BPF_F_ALL_CPUS flags for percpu maps, as the requirement of BPF_F_ALL_CPUS flag for percpu_array maps was discussed in the thread of "[PATCH bpf-next v3 0/4] bpf: Introduce global percpu data"[1].
The goal of BPF_F_ALL_CPUS flag is to reduce data caching overhead in light skeletons by allowing a single value to be reused to update values across all CPUs. This avoids the M:N problem where M cached values are used to update a map on N CPUs kernel.
The BPF_F_CPU flag is accompanied by *flags*-embedded cpu info, which specifies the target CPU for the operation:
* For lookup operations: the flag field alongside cpu info enable querying a value on the specified CPU. * For update operations: the flag field alongside cpu info enable updating value for specified CPU.
Links: [1] https://lore.kernel.org/bpf/20250526162146.24429-1-leon.hwang@linux.dev/
Changes: v9 -> v10: * Add tests to verify array and hash maps do not support BPF_F_CPU and BPF_F_ALL_CPUS flags. * Address comment from Andrii: * Copy map value using copy_map_value_long for percpu_cgroup_storage maps in a separate patch.
v8 -> v9: * Change value type from u64 to u32 in selftests. * Address comments from Andrii: * Keep value_size unaligned and update everywhere for consistency when cpu flags are specified. * Update value by getting pointer for percpu hash and percpu cgroup_storage maps.
v7 -> v8: * Address comments from Andrii: * Check BPF_F_LOCK when update percpu_array, percpu_hash and lru_percpu_hash maps. * Refactor flags check in __htab_map_lookup_and_delete_batch(). * Keep value_size unaligned and copy value using copy_map_value() in __htab_map_lookup_and_delete_batch() when BPF_F_CPU is specified. * Update warn message in libbpf's validate_map_op(). * Update comment of libbpf's bpf_map__lookup_elem().
v6 -> v7: * Get correct value size for percpu_hash and lru_percpu_hash in update_batch API. * Set 'count' as 'max_entries' in test cases for lookup_batch API. * Address comment from Alexei: * Move cpu flags check into bpf_map_check_op_flags().
v5 -> v6: * Move bpf_map_check_op_flags() from 'bpf.h' to 'syscall.c'. * Address comments from Alexei: * Drop the refactoring code of data copying logic for percpu maps. * Drop bpf_map_check_op_flags() wrappers.
v4 -> v5: * Address comments from Andrii: * Refactor data copying logic for all percpu maps. * Drop this_cpu_ptr() micro-optimization. * Drop cpu check in libbpf's validate_map_op(). * Enhance bpf_map_check_op_flags() using *allowed flags* instead of 'extra_flags_mask'.
v3 -> v4: * Address comments from Andrii: * Remove unnecessary map_type check in bpf_map_value_size(). * Reduce code churn. * Remove unnecessary do_delete check in __htab_map_lookup_and_delete_batch(). * Introduce bpf_percpu_copy_to_user() and bpf_percpu_copy_from_user(). * Rename check_map_flags() to bpf_map_check_op_flags() with extra_flags_mask. * Add human-readable pr_warn() explanations in validate_map_op(). * Use flags in bpf_map__delete_elem() and bpf_map__lookup_and_delete_elem(). * Drop "for alignment reasons". v3 link: https://lore.kernel.org/bpf/20250821160817.70285-1-leon.hwang@linux.dev/
v2 -> v3: * Address comments from Alexei: * Use BPF_F_ALL_CPUS instead of BPF_ALL_CPUS magic. * Introduce these two cpu flags for all percpu maps. * Address comments from Jiri: * Reduce some unnecessary u32 cast. * Refactor more generic map flags check function. * A code style issue. v2 link: https://lore.kernel.org/bpf/20250805163017.17015-1-leon.hwang@linux.dev/
v1 -> v2: * Address comments from Andrii: * Embed cpu info as high 32 bits of *flags* totally. * Use ERANGE instead of E2BIG. * Few format issues.
Leon Hwang (8): bpf: Introduce internal bpf_map_check_op_flags helper function bpf: Introduce BPF_F_CPU and BPF_F_ALL_CPUS flags bpf: Add BPF_F_CPU and BPF_F_ALL_CPUS flags support for percpu_array maps bpf: Add BPF_F_CPU and BPF_F_ALL_CPUS flags support for percpu_hash and lru_percpu_hash maps bpf: Copy map value using copy_map_value_long for percpu_cgroup_storage maps bpf: Add BPF_F_CPU and BPF_F_ALL_CPUS flags support for percpu_cgroup_storage maps libbpf: Add BPF_F_CPU and BPF_F_ALL_CPUS flags support for percpu maps selftests/bpf: Add cases to test BPF_F_CPU and BPF_F_ALL_CPUS flags
include/linux/bpf-cgroup.h | 4 +- include/linux/bpf.h | 44 ++- include/uapi/linux/bpf.h | 2 + kernel/bpf/arraymap.c | 29 +- kernel/bpf/hashtab.c | 94 ++++-- kernel/bpf/local_storage.c | 27 +- kernel/bpf/syscall.c | 65 ++-- tools/include/uapi/linux/bpf.h | 2 + tools/lib/bpf/bpf.h | 8 + tools/lib/bpf/libbpf.c | 26 +- tools/lib/bpf/libbpf.h | 21 +- .../selftests/bpf/prog_tests/percpu_alloc.c | 312 ++++++++++++++++++ .../selftests/bpf/progs/percpu_alloc_array.c | 32 ++ 13 files changed, 562 insertions(+), 104 deletions(-)
-- 2.51.2
It is to unify map flags checking for lookup_elem, update_elem, lookup_batch and update_batch APIs.
Therefore, it will be convenient to check BPF_F_CPU and BPF_F_ALL_CPUS flags in it for these APIs in next patch.
Acked-by: Andrii Nakryiko andrii@kernel.org Signed-off-by: Leon Hwang leon.hwang@linux.dev --- include/linux/bpf.h | 11 +++++++++++ kernel/bpf/syscall.c | 34 +++++++++++----------------------- 2 files changed, 22 insertions(+), 23 deletions(-)
diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 09d5dc541d1ce..a900bc022b1cc 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -3813,4 +3813,15 @@ bpf_prog_update_insn_ptrs(struct bpf_prog *prog, u32 *offsets, void *image) } #endif
+static inline int bpf_map_check_op_flags(struct bpf_map *map, u64 flags, u64 allowed_flags) +{ + if (flags & ~allowed_flags) + return -EINVAL; + + if ((flags & BPF_F_LOCK) && !btf_record_has_field(map->record, BPF_SPIN_LOCK)) + return -EINVAL; + + return 0; +} + #endif /* _LINUX_BPF_H */ diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index a2a441185f810..f3dc6e2c82411 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -1725,9 +1725,6 @@ static int map_lookup_elem(union bpf_attr *attr) if (CHECK_ATTR(BPF_MAP_LOOKUP_ELEM)) return -EINVAL;
- if (attr->flags & ~BPF_F_LOCK) - return -EINVAL; - CLASS(fd, f)(attr->map_fd); map = __bpf_map_get(f); if (IS_ERR(map)) @@ -1735,9 +1732,9 @@ static int map_lookup_elem(union bpf_attr *attr) if (!(map_get_sys_perms(map, f) & FMODE_CAN_READ)) return -EPERM;
- if ((attr->flags & BPF_F_LOCK) && - !btf_record_has_field(map->record, BPF_SPIN_LOCK)) - return -EINVAL; + err = bpf_map_check_op_flags(map, attr->flags, BPF_F_LOCK); + if (err) + return err;
key = __bpf_copy_key(ukey, map->key_size); if (IS_ERR(key)) @@ -1800,11 +1797,9 @@ static int map_update_elem(union bpf_attr *attr, bpfptr_t uattr) goto err_put; }
- if ((attr->flags & BPF_F_LOCK) && - !btf_record_has_field(map->record, BPF_SPIN_LOCK)) { - err = -EINVAL; + err = bpf_map_check_op_flags(map, attr->flags, ~0); + if (err) goto err_put; - }
key = ___bpf_copy_key(ukey, map->key_size); if (IS_ERR(key)) { @@ -2008,13 +2003,9 @@ int generic_map_update_batch(struct bpf_map *map, struct file *map_file, void *key, *value; int err = 0;
- if (attr->batch.elem_flags & ~BPF_F_LOCK) - return -EINVAL; - - if ((attr->batch.elem_flags & BPF_F_LOCK) && - !btf_record_has_field(map->record, BPF_SPIN_LOCK)) { - return -EINVAL; - } + err = bpf_map_check_op_flags(map, attr->batch.elem_flags, BPF_F_LOCK); + if (err) + return err;
value_size = bpf_map_value_size(map);
@@ -2071,12 +2062,9 @@ int generic_map_lookup_batch(struct bpf_map *map, u32 value_size, cp, max_count; int err;
- if (attr->batch.elem_flags & ~BPF_F_LOCK) - return -EINVAL; - - if ((attr->batch.elem_flags & BPF_F_LOCK) && - !btf_record_has_field(map->record, BPF_SPIN_LOCK)) - return -EINVAL; + err = bpf_map_check_op_flags(map, attr->batch.elem_flags, BPF_F_LOCK); + if (err) + return err;
value_size = bpf_map_value_size(map);
Introduce BPF_F_CPU and BPF_F_ALL_CPUS flags and check them for following APIs:
* 'map_lookup_elem()' * 'map_update_elem()' * 'generic_map_lookup_batch()' * 'generic_map_update_batch()'
And, get the correct value size for these APIs.
Acked-by: Andrii Nakryiko andrii@kernel.org Signed-off-by: Leon Hwang leon.hwang@linux.dev --- include/linux/bpf.h | 23 ++++++++++++++++++++++- include/uapi/linux/bpf.h | 2 ++ kernel/bpf/syscall.c | 31 +++++++++++++++++-------------- tools/include/uapi/linux/bpf.h | 2 ++ 4 files changed, 43 insertions(+), 15 deletions(-)
diff --git a/include/linux/bpf.h b/include/linux/bpf.h index a900bc022b1cc..65737870f2ea6 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -3813,14 +3813,35 @@ bpf_prog_update_insn_ptrs(struct bpf_prog *prog, u32 *offsets, void *image) } #endif
+static inline bool bpf_map_supports_cpu_flags(enum bpf_map_type map_type) +{ + return false; +} + static inline int bpf_map_check_op_flags(struct bpf_map *map, u64 flags, u64 allowed_flags) { - if (flags & ~allowed_flags) + u32 cpu; + + if ((u32)flags & ~allowed_flags) return -EINVAL;
if ((flags & BPF_F_LOCK) && !btf_record_has_field(map->record, BPF_SPIN_LOCK)) return -EINVAL;
+ if (!(flags & BPF_F_CPU) && flags >> 32) + return -EINVAL; + + if (flags & (BPF_F_CPU | BPF_F_ALL_CPUS)) { + if (!bpf_map_supports_cpu_flags(map->map_type)) + return -EINVAL; + if ((flags & BPF_F_CPU) && (flags & BPF_F_ALL_CPUS)) + return -EINVAL; + + cpu = flags >> 32; + if ((flags & BPF_F_CPU) && cpu >= num_possible_cpus()) + return -ERANGE; + } + return 0; }
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index f5713f59ac10a..8b6279ca6e662 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -1373,6 +1373,8 @@ enum { BPF_NOEXIST = 1, /* create new element if it didn't exist */ BPF_EXIST = 2, /* update existing element */ BPF_F_LOCK = 4, /* spin_lock-ed map_lookup/map_update */ + BPF_F_CPU = 8, /* cpu flag for percpu maps, upper 32-bit of flags is a cpu number */ + BPF_F_ALL_CPUS = 16, /* update value across all CPUs for percpu maps */ };
/* flags for BPF_MAP_CREATE command */ diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index f3dc6e2c82411..6edaab858b326 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -133,12 +133,14 @@ bool bpf_map_write_active(const struct bpf_map *map) return atomic64_read(&map->writecnt) != 0; }
-static u32 bpf_map_value_size(const struct bpf_map *map) -{ - if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH || - map->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH || - map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY || - map->map_type == BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE) +static u32 bpf_map_value_size(const struct bpf_map *map, u64 flags) +{ + if (flags & (BPF_F_CPU | BPF_F_ALL_CPUS)) + return map->value_size; + else if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH || + map->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH || + map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY || + map->map_type == BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE) return round_up(map->value_size, 8) * num_possible_cpus(); else if (IS_FD_MAP(map)) return sizeof(u32); @@ -1732,7 +1734,7 @@ static int map_lookup_elem(union bpf_attr *attr) if (!(map_get_sys_perms(map, f) & FMODE_CAN_READ)) return -EPERM;
- err = bpf_map_check_op_flags(map, attr->flags, BPF_F_LOCK); + err = bpf_map_check_op_flags(map, attr->flags, BPF_F_LOCK | BPF_F_CPU); if (err) return err;
@@ -1740,7 +1742,7 @@ static int map_lookup_elem(union bpf_attr *attr) if (IS_ERR(key)) return PTR_ERR(key);
- value_size = bpf_map_value_size(map); + value_size = bpf_map_value_size(map, attr->flags);
err = -ENOMEM; value = kvmalloc(value_size, GFP_USER | __GFP_NOWARN); @@ -1807,7 +1809,7 @@ static int map_update_elem(union bpf_attr *attr, bpfptr_t uattr) goto err_put; }
- value_size = bpf_map_value_size(map); + value_size = bpf_map_value_size(map, attr->flags); value = kvmemdup_bpfptr(uvalue, value_size); if (IS_ERR(value)) { err = PTR_ERR(value); @@ -2003,11 +2005,12 @@ int generic_map_update_batch(struct bpf_map *map, struct file *map_file, void *key, *value; int err = 0;
- err = bpf_map_check_op_flags(map, attr->batch.elem_flags, BPF_F_LOCK); + err = bpf_map_check_op_flags(map, attr->batch.elem_flags, + BPF_F_LOCK | BPF_F_CPU | BPF_F_ALL_CPUS); if (err) return err;
- value_size = bpf_map_value_size(map); + value_size = bpf_map_value_size(map, attr->batch.elem_flags);
max_count = attr->batch.count; if (!max_count) @@ -2062,11 +2065,11 @@ int generic_map_lookup_batch(struct bpf_map *map, u32 value_size, cp, max_count; int err;
- err = bpf_map_check_op_flags(map, attr->batch.elem_flags, BPF_F_LOCK); + err = bpf_map_check_op_flags(map, attr->batch.elem_flags, BPF_F_LOCK | BPF_F_CPU); if (err) return err;
- value_size = bpf_map_value_size(map); + value_size = bpf_map_value_size(map, attr->batch.elem_flags);
max_count = attr->batch.count; if (!max_count) @@ -2188,7 +2191,7 @@ static int map_lookup_and_delete_elem(union bpf_attr *attr) goto err_put; }
- value_size = bpf_map_value_size(map); + value_size = bpf_map_value_size(map, 0);
err = -ENOMEM; value = kvmalloc(value_size, GFP_USER | __GFP_NOWARN); diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index f5713f59ac10a..8b6279ca6e662 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -1373,6 +1373,8 @@ enum { BPF_NOEXIST = 1, /* create new element if it didn't exist */ BPF_EXIST = 2, /* update existing element */ BPF_F_LOCK = 4, /* spin_lock-ed map_lookup/map_update */ + BPF_F_CPU = 8, /* cpu flag for percpu maps, upper 32-bit of flags is a cpu number */ + BPF_F_ALL_CPUS = 16, /* update value across all CPUs for percpu maps */ };
/* flags for BPF_MAP_CREATE command */
Introduce support for the BPF_F_ALL_CPUS flag in percpu_array maps to allow updating values for all CPUs with a single value for both update_elem and update_batch APIs.
Introduce support for the BPF_F_CPU flag in percpu_array maps to allow:
* update value for specified CPU for both update_elem and update_batch APIs. * lookup value for specified CPU for both lookup_elem and lookup_batch APIs.
The BPF_F_CPU flag is passed via:
* map_flags of lookup_elem and update_elem APIs along with embedded cpu info. * elem_flags of lookup_batch and update_batch APIs along with embedded cpu info.
Signed-off-by: Leon Hwang leon.hwang@linux.dev --- include/linux/bpf.h | 9 +++++++-- kernel/bpf/arraymap.c | 29 +++++++++++++++++++++++------ kernel/bpf/syscall.c | 2 +- 3 files changed, 31 insertions(+), 9 deletions(-)
diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 65737870f2ea6..c43cdd90bfb12 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -2748,7 +2748,7 @@ int map_set_for_each_callback_args(struct bpf_verifier_env *env, struct bpf_func_state *callee);
int bpf_percpu_hash_copy(struct bpf_map *map, void *key, void *value); -int bpf_percpu_array_copy(struct bpf_map *map, void *key, void *value); +int bpf_percpu_array_copy(struct bpf_map *map, void *key, void *value, u64 flags); int bpf_percpu_hash_update(struct bpf_map *map, void *key, void *value, u64 flags); int bpf_percpu_array_update(struct bpf_map *map, void *key, void *value, @@ -3815,7 +3815,12 @@ bpf_prog_update_insn_ptrs(struct bpf_prog *prog, u32 *offsets, void *image)
static inline bool bpf_map_supports_cpu_flags(enum bpf_map_type map_type) { - return false; + switch (map_type) { + case BPF_MAP_TYPE_PERCPU_ARRAY: + return true; + default: + return false; + } }
static inline int bpf_map_check_op_flags(struct bpf_map *map, u64 flags, u64 allowed_flags) diff --git a/kernel/bpf/arraymap.c b/kernel/bpf/arraymap.c index 1eeb31c5b317d..67e9e811de3a7 100644 --- a/kernel/bpf/arraymap.c +++ b/kernel/bpf/arraymap.c @@ -307,7 +307,7 @@ static void *percpu_array_map_lookup_percpu_elem(struct bpf_map *map, void *key, return per_cpu_ptr(array->pptrs[index & array->index_mask], cpu); }
-int bpf_percpu_array_copy(struct bpf_map *map, void *key, void *value) +int bpf_percpu_array_copy(struct bpf_map *map, void *key, void *value, u64 map_flags) { struct bpf_array *array = container_of(map, struct bpf_array, map); u32 index = *(u32 *)key; @@ -325,11 +325,18 @@ int bpf_percpu_array_copy(struct bpf_map *map, void *key, void *value) size = array->elem_size; rcu_read_lock(); pptr = array->pptrs[index & array->index_mask]; + if (map_flags & BPF_F_CPU) { + cpu = map_flags >> 32; + copy_map_value(map, value, per_cpu_ptr(pptr, cpu)); + check_and_init_map_value(map, value); + goto unlock; + } for_each_possible_cpu(cpu) { copy_map_value_long(map, value + off, per_cpu_ptr(pptr, cpu)); check_and_init_map_value(map, value + off); off += size; } +unlock: rcu_read_unlock(); return 0; } @@ -398,10 +405,11 @@ int bpf_percpu_array_update(struct bpf_map *map, void *key, void *value, struct bpf_array *array = container_of(map, struct bpf_array, map); u32 index = *(u32 *)key; void __percpu *pptr; - int cpu, off = 0; + void *ptr, *val; u32 size; + int cpu;
- if (unlikely(map_flags > BPF_EXIST)) + if (unlikely((map_flags & BPF_F_LOCK) || (u32)map_flags > BPF_F_ALL_CPUS)) /* unknown flags */ return -EINVAL;
@@ -422,11 +430,20 @@ int bpf_percpu_array_update(struct bpf_map *map, void *key, void *value, size = array->elem_size; rcu_read_lock(); pptr = array->pptrs[index & array->index_mask]; + if (map_flags & BPF_F_CPU) { + cpu = map_flags >> 32; + ptr = per_cpu_ptr(pptr, cpu); + copy_map_value(map, ptr, value); + bpf_obj_free_fields(array->map.record, ptr); + goto unlock; + } for_each_possible_cpu(cpu) { - copy_map_value_long(map, per_cpu_ptr(pptr, cpu), value + off); - bpf_obj_free_fields(array->map.record, per_cpu_ptr(pptr, cpu)); - off += size; + ptr = per_cpu_ptr(pptr, cpu); + val = (map_flags & BPF_F_ALL_CPUS) ? value : value + size * cpu; + copy_map_value(map, ptr, val); + bpf_obj_free_fields(array->map.record, ptr); } +unlock: rcu_read_unlock(); return 0; } diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 6edaab858b326..edb7462a34f13 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -318,7 +318,7 @@ static int bpf_map_copy_value(struct bpf_map *map, void *key, void *value, map->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH) { err = bpf_percpu_hash_copy(map, key, value); } else if (map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY) { - err = bpf_percpu_array_copy(map, key, value); + err = bpf_percpu_array_copy(map, key, value, flags); } else if (map->map_type == BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE) { err = bpf_percpu_cgroup_storage_copy(map, key, value); } else if (map->map_type == BPF_MAP_TYPE_STACK_TRACE) {
Introduce BPF_F_ALL_CPUS flag support for percpu_hash and lru_percpu_hash maps to allow updating values for all CPUs with a single value for both update_elem and update_batch APIs.
Introduce BPF_F_CPU flag support for percpu_hash and lru_percpu_hash maps to allow:
* update value for specified CPU for both update_elem and update_batch APIs. * lookup value for specified CPU for both lookup_elem and lookup_batch APIs.
The BPF_F_CPU flag is passed via:
* map_flags along with embedded cpu info. * elem_flags along with embedded cpu info.
Signed-off-by: Leon Hwang leon.hwang@linux.dev --- include/linux/bpf.h | 4 +- kernel/bpf/hashtab.c | 94 ++++++++++++++++++++++++++++++-------------- kernel/bpf/syscall.c | 2 +- 3 files changed, 68 insertions(+), 32 deletions(-)
diff --git a/include/linux/bpf.h b/include/linux/bpf.h index c43cdd90bfb12..1fc0afb7f547f 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -2747,7 +2747,7 @@ int map_set_for_each_callback_args(struct bpf_verifier_env *env, struct bpf_func_state *caller, struct bpf_func_state *callee);
-int bpf_percpu_hash_copy(struct bpf_map *map, void *key, void *value); +int bpf_percpu_hash_copy(struct bpf_map *map, void *key, void *value, u64 flags); int bpf_percpu_array_copy(struct bpf_map *map, void *key, void *value, u64 flags); int bpf_percpu_hash_update(struct bpf_map *map, void *key, void *value, u64 flags); @@ -3817,6 +3817,8 @@ static inline bool bpf_map_supports_cpu_flags(enum bpf_map_type map_type) { switch (map_type) { case BPF_MAP_TYPE_PERCPU_ARRAY: + case BPF_MAP_TYPE_PERCPU_HASH: + case BPF_MAP_TYPE_LRU_PERCPU_HASH: return true; default: return false; diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c index c8a9b27f8663b..441ff5bc54ac2 100644 --- a/kernel/bpf/hashtab.c +++ b/kernel/bpf/hashtab.c @@ -932,7 +932,7 @@ static void free_htab_elem(struct bpf_htab *htab, struct htab_elem *l) }
static void pcpu_copy_value(struct bpf_htab *htab, void __percpu *pptr, - void *value, bool onallcpus) + void *value, bool onallcpus, u64 map_flags) { void *ptr;
@@ -943,19 +943,28 @@ static void pcpu_copy_value(struct bpf_htab *htab, void __percpu *pptr, bpf_obj_free_fields(htab->map.record, ptr); } else { u32 size = round_up(htab->map.value_size, 8); - int off = 0, cpu; + void *val; + int cpu; + + if (map_flags & BPF_F_CPU) { + cpu = map_flags >> 32; + ptr = per_cpu_ptr(pptr, cpu); + copy_map_value(&htab->map, ptr, value); + bpf_obj_free_fields(htab->map.record, ptr); + return; + }
for_each_possible_cpu(cpu) { ptr = per_cpu_ptr(pptr, cpu); - copy_map_value_long(&htab->map, ptr, value + off); + val = (map_flags & BPF_F_ALL_CPUS) ? value : value + size * cpu; + copy_map_value(&htab->map, ptr, val); bpf_obj_free_fields(htab->map.record, ptr); - off += size; } } }
static void pcpu_init_value(struct bpf_htab *htab, void __percpu *pptr, - void *value, bool onallcpus) + void *value, bool onallcpus, u64 map_flags) { /* When not setting the initial value on all cpus, zero-fill element * values for other cpus. Otherwise, bpf program has no way to ensure @@ -973,7 +982,7 @@ static void pcpu_init_value(struct bpf_htab *htab, void __percpu *pptr, zero_map_value(&htab->map, per_cpu_ptr(pptr, cpu)); } } else { - pcpu_copy_value(htab, pptr, value, onallcpus); + pcpu_copy_value(htab, pptr, value, onallcpus, map_flags); } }
@@ -985,7 +994,7 @@ static bool fd_htab_map_needs_adjust(const struct bpf_htab *htab) static struct htab_elem *alloc_htab_elem(struct bpf_htab *htab, void *key, void *value, u32 key_size, u32 hash, bool percpu, bool onallcpus, - struct htab_elem *old_elem) + struct htab_elem *old_elem, u64 map_flags) { u32 size = htab->map.value_size; bool prealloc = htab_is_prealloc(htab); @@ -1043,7 +1052,7 @@ static struct htab_elem *alloc_htab_elem(struct bpf_htab *htab, void *key, pptr = *(void __percpu **)ptr; }
- pcpu_init_value(htab, pptr, value, onallcpus); + pcpu_init_value(htab, pptr, value, onallcpus, map_flags);
if (!prealloc) htab_elem_set_ptr(l_new, key_size, pptr); @@ -1147,7 +1156,7 @@ static long htab_map_update_elem(struct bpf_map *map, void *key, void *value, }
l_new = alloc_htab_elem(htab, key, value, key_size, hash, false, false, - l_old); + l_old, map_flags); if (IS_ERR(l_new)) { /* all pre-allocated elements are in use or memory exhausted */ ret = PTR_ERR(l_new); @@ -1249,6 +1258,15 @@ static long htab_lru_map_update_elem(struct bpf_map *map, void *key, void *value return ret; }
+static int htab_map_check_update_flags(bool onallcpus, u64 map_flags) +{ + if (unlikely(!onallcpus && map_flags > BPF_EXIST)) + return -EINVAL; + if (unlikely(onallcpus && ((map_flags & BPF_F_LOCK) || (u32)map_flags > BPF_F_ALL_CPUS))) + return -EINVAL; + return 0; +} + static long htab_map_update_elem_in_place(struct bpf_map *map, void *key, void *value, u64 map_flags, bool percpu, bool onallcpus) @@ -1262,9 +1280,9 @@ static long htab_map_update_elem_in_place(struct bpf_map *map, void *key, u32 key_size, hash; int ret;
- if (unlikely(map_flags > BPF_EXIST)) - /* unknown flags */ - return -EINVAL; + ret = htab_map_check_update_flags(onallcpus, map_flags); + if (unlikely(ret)) + return ret;
WARN_ON_ONCE(!bpf_rcu_lock_held());
@@ -1289,7 +1307,7 @@ static long htab_map_update_elem_in_place(struct bpf_map *map, void *key, /* Update value in-place */ if (percpu) { pcpu_copy_value(htab, htab_elem_get_ptr(l_old, key_size), - value, onallcpus); + value, onallcpus, map_flags); } else { void **inner_map_pptr = htab_elem_value(l_old, key_size);
@@ -1298,7 +1316,7 @@ static long htab_map_update_elem_in_place(struct bpf_map *map, void *key, } } else { l_new = alloc_htab_elem(htab, key, value, key_size, - hash, percpu, onallcpus, NULL); + hash, percpu, onallcpus, NULL, map_flags); if (IS_ERR(l_new)) { ret = PTR_ERR(l_new); goto err; @@ -1324,9 +1342,9 @@ static long __htab_lru_percpu_map_update_elem(struct bpf_map *map, void *key, u32 key_size, hash; int ret;
- if (unlikely(map_flags > BPF_EXIST)) - /* unknown flags */ - return -EINVAL; + ret = htab_map_check_update_flags(onallcpus, map_flags); + if (unlikely(ret)) + return ret;
WARN_ON_ONCE(!bpf_rcu_lock_held());
@@ -1363,10 +1381,10 @@ static long __htab_lru_percpu_map_update_elem(struct bpf_map *map, void *key,
/* per-cpu hash map can update value in-place */ pcpu_copy_value(htab, htab_elem_get_ptr(l_old, key_size), - value, onallcpus); + value, onallcpus, map_flags); } else { pcpu_init_value(htab, htab_elem_get_ptr(l_new, key_size), - value, onallcpus); + value, onallcpus, map_flags); hlist_nulls_add_head_rcu(&l_new->hash_node, head); l_new = NULL; } @@ -1678,9 +1696,9 @@ __htab_map_lookup_and_delete_batch(struct bpf_map *map, void __user *ukeys = u64_to_user_ptr(attr->batch.keys); void __user *ubatch = u64_to_user_ptr(attr->batch.in_batch); u32 batch, max_count, size, bucket_size, map_id; + u64 elem_map_flags, map_flags, allowed_flags; u32 bucket_cnt, total, key_size, value_size; struct htab_elem *node_to_free = NULL; - u64 elem_map_flags, map_flags; struct hlist_nulls_head *head; struct hlist_nulls_node *n; unsigned long flags = 0; @@ -1690,9 +1708,12 @@ __htab_map_lookup_and_delete_batch(struct bpf_map *map, int ret = 0;
elem_map_flags = attr->batch.elem_flags; - if ((elem_map_flags & ~BPF_F_LOCK) || - ((elem_map_flags & BPF_F_LOCK) && !btf_record_has_field(map->record, BPF_SPIN_LOCK))) - return -EINVAL; + allowed_flags = BPF_F_LOCK; + if (!do_delete && is_percpu) + allowed_flags |= BPF_F_CPU; + ret = bpf_map_check_op_flags(map, elem_map_flags, allowed_flags); + if (ret) + return ret;
map_flags = attr->batch.flags; if (map_flags) @@ -1715,7 +1736,7 @@ __htab_map_lookup_and_delete_batch(struct bpf_map *map, key_size = htab->map.key_size; value_size = htab->map.value_size; size = round_up(value_size, 8); - if (is_percpu) + if (is_percpu && !(elem_map_flags & BPF_F_CPU)) value_size = size * num_possible_cpus(); total = 0; /* while experimenting with hash tables with sizes ranging from 10 to @@ -1798,10 +1819,17 @@ __htab_map_lookup_and_delete_batch(struct bpf_map *map, void __percpu *pptr;
pptr = htab_elem_get_ptr(l, map->key_size); - for_each_possible_cpu(cpu) { - copy_map_value_long(&htab->map, dst_val + off, per_cpu_ptr(pptr, cpu)); - check_and_init_map_value(&htab->map, dst_val + off); - off += size; + if (elem_map_flags & BPF_F_CPU) { + cpu = elem_map_flags >> 32; + copy_map_value(&htab->map, dst_val, per_cpu_ptr(pptr, cpu)); + check_and_init_map_value(&htab->map, dst_val); + } else { + for_each_possible_cpu(cpu) { + copy_map_value_long(&htab->map, dst_val + off, + per_cpu_ptr(pptr, cpu)); + check_and_init_map_value(&htab->map, dst_val + off); + off += size; + } } } else { value = htab_elem_value(l, key_size); @@ -2357,7 +2385,7 @@ static void *htab_lru_percpu_map_lookup_percpu_elem(struct bpf_map *map, void *k return NULL; }
-int bpf_percpu_hash_copy(struct bpf_map *map, void *key, void *value) +int bpf_percpu_hash_copy(struct bpf_map *map, void *key, void *value, u64 map_flags) { struct htab_elem *l; void __percpu *pptr; @@ -2374,16 +2402,22 @@ int bpf_percpu_hash_copy(struct bpf_map *map, void *key, void *value) l = __htab_map_lookup_elem(map, key); if (!l) goto out; + ret = 0; /* We do not mark LRU map element here in order to not mess up * eviction heuristics when user space does a map walk. */ pptr = htab_elem_get_ptr(l, map->key_size); + if (map_flags & BPF_F_CPU) { + cpu = map_flags >> 32; + copy_map_value(map, value, per_cpu_ptr(pptr, cpu)); + check_and_init_map_value(map, value); + goto out; + } for_each_possible_cpu(cpu) { copy_map_value_long(map, value + off, per_cpu_ptr(pptr, cpu)); check_and_init_map_value(map, value + off); off += size; } - ret = 0; out: rcu_read_unlock(); return ret; diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index edb7462a34f13..3cff19a4be527 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -316,7 +316,7 @@ static int bpf_map_copy_value(struct bpf_map *map, void *key, void *value, bpf_disable_instrumentation(); if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH || map->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH) { - err = bpf_percpu_hash_copy(map, key, value); + err = bpf_percpu_hash_copy(map, key, value, flags); } else if (map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY) { err = bpf_percpu_array_copy(map, key, value, flags); } else if (map->map_type == BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE) {
Copy map value using 'copy_map_value_long()'. It's to keep consistent style with the way of other percpu maps.
No functional change intended.
Signed-off-by: Leon Hwang leon.hwang@linux.dev --- kernel/bpf/local_storage.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-)
diff --git a/kernel/bpf/local_storage.c b/kernel/bpf/local_storage.c index c93a756e035c0..2ab4b60ffe61f 100644 --- a/kernel/bpf/local_storage.c +++ b/kernel/bpf/local_storage.c @@ -200,8 +200,7 @@ int bpf_percpu_cgroup_storage_copy(struct bpf_map *_map, void *key, */ size = round_up(_map->value_size, 8); for_each_possible_cpu(cpu) { - bpf_long_memcpy(value + off, - per_cpu_ptr(storage->percpu_buf, cpu), size); + copy_map_value_long(_map, value + off, per_cpu_ptr(storage->percpu_buf, cpu)); off += size; } rcu_read_unlock(); @@ -234,8 +233,7 @@ int bpf_percpu_cgroup_storage_update(struct bpf_map *_map, void *key, */ size = round_up(_map->value_size, 8); for_each_possible_cpu(cpu) { - bpf_long_memcpy(per_cpu_ptr(storage->percpu_buf, cpu), - value + off, size); + copy_map_value_long(_map, per_cpu_ptr(storage->percpu_buf, cpu), value + off); off += size; } rcu_read_unlock();
Introduce BPF_F_ALL_CPUS flag support for percpu_cgroup_storage maps to allow updating values for all CPUs with a single value for update_elem API.
Introduce BPF_F_CPU flag support for percpu_cgroup_storage maps to allow:
* update value for specified CPU for update_elem API. * lookup value for specified CPU for lookup_elem API.
The BPF_F_CPU flag is passed via map_flags along with embedded cpu info.
Signed-off-by: Leon Hwang leon.hwang@linux.dev --- include/linux/bpf-cgroup.h | 4 ++-- include/linux/bpf.h | 1 + kernel/bpf/local_storage.c | 23 ++++++++++++++++++----- kernel/bpf/syscall.c | 2 +- 4 files changed, 22 insertions(+), 8 deletions(-)
diff --git a/include/linux/bpf-cgroup.h b/include/linux/bpf-cgroup.h index aedf573bdb426..013f4db9903fd 100644 --- a/include/linux/bpf-cgroup.h +++ b/include/linux/bpf-cgroup.h @@ -172,7 +172,7 @@ void bpf_cgroup_storage_link(struct bpf_cgroup_storage *storage, void bpf_cgroup_storage_unlink(struct bpf_cgroup_storage *storage); int bpf_cgroup_storage_assign(struct bpf_prog_aux *aux, struct bpf_map *map);
-int bpf_percpu_cgroup_storage_copy(struct bpf_map *map, void *key, void *value); +int bpf_percpu_cgroup_storage_copy(struct bpf_map *map, void *key, void *value, u64 flags); int bpf_percpu_cgroup_storage_update(struct bpf_map *map, void *key, void *value, u64 flags);
@@ -467,7 +467,7 @@ static inline struct bpf_cgroup_storage *bpf_cgroup_storage_alloc( static inline void bpf_cgroup_storage_free( struct bpf_cgroup_storage *storage) {} static inline int bpf_percpu_cgroup_storage_copy(struct bpf_map *map, void *key, - void *value) { + void *value, u64 flags) { return 0; } static inline int bpf_percpu_cgroup_storage_update(struct bpf_map *map, diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 1fc0afb7f547f..e87779d3c5927 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -3819,6 +3819,7 @@ static inline bool bpf_map_supports_cpu_flags(enum bpf_map_type map_type) case BPF_MAP_TYPE_PERCPU_ARRAY: case BPF_MAP_TYPE_PERCPU_HASH: case BPF_MAP_TYPE_LRU_PERCPU_HASH: + case BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE: return true; default: return false; diff --git a/kernel/bpf/local_storage.c b/kernel/bpf/local_storage.c index 2ab4b60ffe61f..1ccbf28b2ad9f 100644 --- a/kernel/bpf/local_storage.c +++ b/kernel/bpf/local_storage.c @@ -180,7 +180,7 @@ static long cgroup_storage_update_elem(struct bpf_map *map, void *key, }
int bpf_percpu_cgroup_storage_copy(struct bpf_map *_map, void *key, - void *value) + void *value, u64 map_flags) { struct bpf_cgroup_storage_map *map = map_to_storage(_map); struct bpf_cgroup_storage *storage; @@ -198,11 +198,17 @@ int bpf_percpu_cgroup_storage_copy(struct bpf_map *_map, void *key, * access 'value_size' of them, so copying rounded areas * will not leak any kernel data */ + if (map_flags & BPF_F_CPU) { + cpu = map_flags >> 32; + copy_map_value(_map, value, per_cpu_ptr(storage->percpu_buf, cpu)); + goto unlock; + } size = round_up(_map->value_size, 8); for_each_possible_cpu(cpu) { copy_map_value_long(_map, value + off, per_cpu_ptr(storage->percpu_buf, cpu)); off += size; } +unlock: rcu_read_unlock(); return 0; } @@ -212,10 +218,11 @@ int bpf_percpu_cgroup_storage_update(struct bpf_map *_map, void *key, { struct bpf_cgroup_storage_map *map = map_to_storage(_map); struct bpf_cgroup_storage *storage; - int cpu, off = 0; + void *val; u32 size; + int cpu;
- if (map_flags != BPF_ANY && map_flags != BPF_EXIST) + if ((u32)map_flags & ~(BPF_ANY | BPF_EXIST | BPF_F_CPU | BPF_F_ALL_CPUS)) return -EINVAL;
rcu_read_lock(); @@ -231,11 +238,17 @@ int bpf_percpu_cgroup_storage_update(struct bpf_map *_map, void *key, * returned or zeros which were zero-filled by percpu_alloc, * so no kernel data leaks possible */ + if (map_flags & BPF_F_CPU) { + cpu = map_flags >> 32; + copy_map_value(_map, per_cpu_ptr(storage->percpu_buf, cpu), value); + goto unlock; + } size = round_up(_map->value_size, 8); for_each_possible_cpu(cpu) { - copy_map_value_long(_map, per_cpu_ptr(storage->percpu_buf, cpu), value + off); - off += size; + val = (map_flags & BPF_F_ALL_CPUS) ? value : value + size * cpu; + copy_map_value(_map, per_cpu_ptr(storage->percpu_buf, cpu), val); } +unlock: rcu_read_unlock(); return 0; } diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 3cff19a4be527..643e589c10231 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -320,7 +320,7 @@ static int bpf_map_copy_value(struct bpf_map *map, void *key, void *value, } else if (map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY) { err = bpf_percpu_array_copy(map, key, value, flags); } else if (map->map_type == BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE) { - err = bpf_percpu_cgroup_storage_copy(map, key, value); + err = bpf_percpu_cgroup_storage_copy(map, key, value, flags); } else if (map->map_type == BPF_MAP_TYPE_STACK_TRACE) { err = bpf_stackmap_extract(map, key, value, false); } else if (IS_FD_ARRAY(map) || IS_FD_PROG_ARRAY(map)) {
Add libbpf support for the BPF_F_CPU flag for percpu maps by embedding the cpu info into the high 32 bits of:
1. **flags**: bpf_map_lookup_elem_flags(), bpf_map__lookup_elem(), bpf_map_update_elem() and bpf_map__update_elem() 2. **opts->elem_flags**: bpf_map_lookup_batch() and bpf_map_update_batch()
And the flag can be BPF_F_ALL_CPUS, but cannot be 'BPF_F_CPU | BPF_F_ALL_CPUS'.
Behavior:
* If the flag is BPF_F_ALL_CPUS, the update is applied across all CPUs. * If the flag is BPF_F_CPU, it updates value only to the specified CPU. * If the flag is BPF_F_CPU, lookup value only from the specified CPU. * lookup does not support BPF_F_ALL_CPUS.
Acked-by: Andrii Nakryiko andrii@kernel.org Signed-off-by: Leon Hwang leon.hwang@linux.dev --- tools/lib/bpf/bpf.h | 8 ++++++++ tools/lib/bpf/libbpf.c | 26 ++++++++++++++++++++------ tools/lib/bpf/libbpf.h | 21 ++++++++------------- 3 files changed, 36 insertions(+), 19 deletions(-)
diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h index e983a3e40d612..ffd93feffd71d 100644 --- a/tools/lib/bpf/bpf.h +++ b/tools/lib/bpf/bpf.h @@ -289,6 +289,14 @@ LIBBPF_API int bpf_map_lookup_and_delete_batch(int fd, void *in_batch, * Update spin_lock-ed map elements. This must be * specified if the map value contains a spinlock. * + * **BPF_F_CPU** + * As for percpu maps, update value on the specified CPU. And the cpu + * info is embedded into the high 32 bits of **opts->elem_flags**. + * + * **BPF_F_ALL_CPUS** + * As for percpu maps, update value across all CPUs. This flag cannot + * be used with BPF_F_CPU at the same time. + * * @param fd BPF map file descriptor * @param keys pointer to an array of *count* keys * @param values pointer to an array of *count* values diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 706e7481bdf6b..65b9b5e955449 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -10913,7 +10913,7 @@ bpf_object__find_map_fd_by_name(const struct bpf_object *obj, const char *name) }
static int validate_map_op(const struct bpf_map *map, size_t key_sz, - size_t value_sz, bool check_value_sz) + size_t value_sz, bool check_value_sz, __u64 flags) { if (!map_is_created(map)) /* map is not yet created */ return -ENOENT; @@ -10940,6 +10940,20 @@ static int validate_map_op(const struct bpf_map *map, size_t key_sz, int num_cpu = libbpf_num_possible_cpus(); size_t elem_sz = roundup(map->def.value_size, 8);
+ if (flags & (BPF_F_CPU | BPF_F_ALL_CPUS)) { + if ((flags & BPF_F_CPU) && (flags & BPF_F_ALL_CPUS)) { + pr_warn("map '%s': BPF_F_CPU and BPF_F_ALL_CPUS are mutually exclusive\n", + map->name); + return -EINVAL; + } + if (map->def.value_size != value_sz) { + pr_warn("map '%s': unexpected value size %zu provided for either BPF_F_CPU or BPF_F_ALL_CPUS, expected %u\n", + map->name, value_sz, map->def.value_size); + return -EINVAL; + } + break; + } + if (value_sz != num_cpu * elem_sz) { pr_warn("map '%s': unexpected value size %zu provided for per-CPU map, expected %d * %zu = %zd\n", map->name, value_sz, num_cpu, elem_sz, num_cpu * elem_sz); @@ -10964,7 +10978,7 @@ int bpf_map__lookup_elem(const struct bpf_map *map, { int err;
- err = validate_map_op(map, key_sz, value_sz, true); + err = validate_map_op(map, key_sz, value_sz, true, flags); if (err) return libbpf_err(err);
@@ -10977,7 +10991,7 @@ int bpf_map__update_elem(const struct bpf_map *map, { int err;
- err = validate_map_op(map, key_sz, value_sz, true); + err = validate_map_op(map, key_sz, value_sz, true, flags); if (err) return libbpf_err(err);
@@ -10989,7 +11003,7 @@ int bpf_map__delete_elem(const struct bpf_map *map, { int err;
- err = validate_map_op(map, key_sz, 0, false /* check_value_sz */); + err = validate_map_op(map, key_sz, 0, false /* check_value_sz */, flags); if (err) return libbpf_err(err);
@@ -11002,7 +11016,7 @@ int bpf_map__lookup_and_delete_elem(const struct bpf_map *map, { int err;
- err = validate_map_op(map, key_sz, value_sz, true); + err = validate_map_op(map, key_sz, value_sz, true, flags); if (err) return libbpf_err(err);
@@ -11014,7 +11028,7 @@ int bpf_map__get_next_key(const struct bpf_map *map, { int err;
- err = validate_map_op(map, key_sz, 0, false /* check_value_sz */); + err = validate_map_op(map, key_sz, 0, false /* check_value_sz */, 0); if (err) return libbpf_err(err);
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h index 5118d0a90e243..7c38b2e546080 100644 --- a/tools/lib/bpf/libbpf.h +++ b/tools/lib/bpf/libbpf.h @@ -1196,12 +1196,13 @@ LIBBPF_API struct bpf_map *bpf_map__inner_map(struct bpf_map *map); * @param key_sz size in bytes of key data, needs to match BPF map definition's **key_size** * @param value pointer to memory in which looked up value will be stored * @param value_sz size in byte of value data memory; it has to match BPF map - * definition's **value_size**. For per-CPU BPF maps value size has to be - * a product of BPF map value size and number of possible CPUs in the system - * (could be fetched with **libbpf_num_possible_cpus()**). Note also that for - * per-CPU values value size has to be aligned up to closest 8 bytes for - * alignment reasons, so expected size is: `round_up(value_size, 8) - * * libbpf_num_possible_cpus()`. + * definition's **value_size**. For per-CPU BPF maps, value size can be + * `value_size` if either **BPF_F_CPU** or **BPF_F_ALL_CPUS** is specified + * in **flags**, otherwise a product of BPF map value size and number of + * possible CPUs in the system (could be fetched with + * **libbpf_num_possible_cpus()**). Note also that for per-CPU values value + * size has to be aligned up to closest 8 bytes, so expected size is: + * `round_up(value_size, 8) * libbpf_num_possible_cpus()`. * @flags extra flags passed to kernel for this operation * @return 0, on success; negative error, otherwise * @@ -1219,13 +1220,7 @@ LIBBPF_API int bpf_map__lookup_elem(const struct bpf_map *map, * @param key pointer to memory containing bytes of the key * @param key_sz size in bytes of key data, needs to match BPF map definition's **key_size** * @param value pointer to memory containing bytes of the value - * @param value_sz size in byte of value data memory; it has to match BPF map - * definition's **value_size**. For per-CPU BPF maps value size has to be - * a product of BPF map value size and number of possible CPUs in the system - * (could be fetched with **libbpf_num_possible_cpus()**). Note also that for - * per-CPU values value size has to be aligned up to closest 8 bytes for - * alignment reasons, so expected size is: `round_up(value_size, 8) - * * libbpf_num_possible_cpus()`. + * @param value_sz refer to **bpf_map__lookup_elem**'s description.' * @flags extra flags passed to kernel for this operation * @return 0, on success; negative error, otherwise *
Add test coverage for the new BPF_F_CPU and BPF_F_ALL_CPUS flags support in percpu maps. The following APIs are exercised:
* bpf_map_update_batch() * bpf_map_lookup_batch() * bpf_map_update_elem() * bpf_map__update_elem() * bpf_map_lookup_elem_flags() * bpf_map__lookup_elem()
Add tests to verify that array and hash maps do not support BPF_F_CPU and BPF_F_ALL_CPUS flags.
Signed-off-by: Leon Hwang leon.hwang@linux.dev --- .../selftests/bpf/prog_tests/percpu_alloc.c | 312 ++++++++++++++++++ .../selftests/bpf/progs/percpu_alloc_array.c | 32 ++ 2 files changed, 344 insertions(+)
diff --git a/tools/testing/selftests/bpf/prog_tests/percpu_alloc.c b/tools/testing/selftests/bpf/prog_tests/percpu_alloc.c index 343da65864d6d..b9c3f5f6cd9c3 100644 --- a/tools/testing/selftests/bpf/prog_tests/percpu_alloc.c +++ b/tools/testing/selftests/bpf/prog_tests/percpu_alloc.c @@ -1,5 +1,6 @@ // SPDX-License-Identifier: GPL-2.0 #include <test_progs.h> +#include "cgroup_helpers.h" #include "percpu_alloc_array.skel.h" #include "percpu_alloc_cgrp_local_storage.skel.h" #include "percpu_alloc_fail.skel.h" @@ -115,6 +116,305 @@ static void test_failure(void) { RUN_TESTS(percpu_alloc_fail); }
+static void test_percpu_map_op_cpu_flag(struct bpf_map *map, void *keys, size_t key_sz, + u32 max_entries, bool test_batch) +{ + size_t value_sz = sizeof(u32), value_sz_cpus, value_sz_total; + u32 *values = NULL, *values_percpu = NULL; + int i, j, cpu, map_fd, nr_cpus, err; + const u32 value = 0xDEADC0DE; + u32 count = max_entries, v; + u64 batch = 0, flags; + void *values_row; + LIBBPF_OPTS(bpf_map_batch_opts, batch_opts); + + nr_cpus = libbpf_num_possible_cpus(); + if (!ASSERT_GT(nr_cpus, 0, "libbpf_num_possible_cpus")) + return; + + value_sz_cpus = value_sz * nr_cpus; + values = calloc(max_entries, value_sz_cpus); + if (!ASSERT_OK_PTR(values, "calloc values")) + return; + + values_percpu = calloc(max_entries, roundup(value_sz, 8) * nr_cpus); + if (!ASSERT_OK_PTR(values_percpu, "calloc values_percpu")) { + free(values); + return; + } + + value_sz_total = value_sz_cpus * max_entries; + memset(values, 0, value_sz_total); + + map_fd = bpf_map__fd(map); + flags = BPF_F_CPU | BPF_F_ALL_CPUS; + err = bpf_map_lookup_elem_flags(map_fd, keys, values, flags); + if (!ASSERT_ERR(err, "bpf_map_lookup_elem_flags cpu|all_cpus")) + goto out; + + err = bpf_map_update_elem(map_fd, keys, values, flags); + if (!ASSERT_ERR(err, "bpf_map_update_elem cpu|all_cpus")) + goto out; + + flags = BPF_F_ALL_CPUS; + err = bpf_map_lookup_elem_flags(map_fd, keys, values, flags); + if (!ASSERT_ERR(err, "bpf_map_lookup_elem_flags all_cpus")) + goto out; + + flags = BPF_F_LOCK | BPF_F_CPU; + err = bpf_map_lookup_elem_flags(map_fd, keys, values, flags); + if (!ASSERT_ERR(err, "bpf_map_lookup_elem_flags BPF_F_LOCK")) + goto out; + + flags = BPF_F_LOCK | BPF_F_ALL_CPUS; + err = bpf_map_update_elem(map_fd, keys, values, flags); + if (!ASSERT_ERR(err, "bpf_map_update_elem BPF_F_LOCK")) + goto out; + + flags = (u64)nr_cpus << 32 | BPF_F_CPU; + err = bpf_map_update_elem(map_fd, keys, values, flags); + if (!ASSERT_EQ(err, -ERANGE, "bpf_map_update_elem -ERANGE")) + goto out; + + err = bpf_map__update_elem(map, keys, key_sz, values, value_sz, flags); + if (!ASSERT_EQ(err, -ERANGE, "bpf_map__update_elem -ERANGE")) + goto out; + + err = bpf_map_lookup_elem_flags(map_fd, keys, values, flags); + if (!ASSERT_EQ(err, -ERANGE, "bpf_map_lookup_elem_flags -ERANGE")) + goto out; + + err = bpf_map__lookup_elem(map, keys, key_sz, values, value_sz, flags); + if (!ASSERT_EQ(err, -ERANGE, "bpf_map__lookup_elem -ERANGE")) + goto out; + + for (cpu = 0; cpu < nr_cpus; cpu++) { + /* clear value on all cpus */ + values[0] = 0; + flags = BPF_F_ALL_CPUS; + for (i = 0; i < max_entries; i++) { + err = bpf_map__update_elem(map, keys + i * key_sz, key_sz, values, + value_sz, flags); + if (!ASSERT_OK(err, "bpf_map__update_elem all_cpus")) + goto out; + } + + /* update value on specified cpu */ + for (i = 0; i < max_entries; i++) { + values[0] = value; + flags = (u64)cpu << 32 | BPF_F_CPU; + err = bpf_map__update_elem(map, keys + i * key_sz, key_sz, values, + value_sz, flags); + if (!ASSERT_OK(err, "bpf_map__update_elem specified cpu")) + goto out; + + /* lookup then check value on CPUs */ + for (j = 0; j < nr_cpus; j++) { + flags = (u64)j << 32 | BPF_F_CPU; + err = bpf_map__lookup_elem(map, keys + i * key_sz, key_sz, values, + value_sz, flags); + if (!ASSERT_OK(err, "bpf_map__lookup_elem specified cpu")) + goto out; + if (!ASSERT_EQ(values[0], j != cpu ? 0 : value, + "bpf_map__lookup_elem value on specified cpu")) + goto out; + } + } + } + + if (!test_batch) + goto out; + + batch_opts.elem_flags = (u64)nr_cpus << 32 | BPF_F_CPU; + err = bpf_map_update_batch(map_fd, keys, values, &max_entries, &batch_opts); + if (!ASSERT_EQ(err, -ERANGE, "bpf_map_update_batch -ERANGE")) + goto out; + + for (cpu = 0; cpu < nr_cpus; cpu++) { + memset(values, 0, value_sz_total); + + /* clear values across all CPUs */ + batch_opts.elem_flags = BPF_F_ALL_CPUS; + err = bpf_map_update_batch(map_fd, keys, values, &max_entries, &batch_opts); + if (!ASSERT_OK(err, "bpf_map_update_batch all_cpus")) + goto out; + + /* update values on specified CPU */ + for (i = 0; i < max_entries; i++) + values[i] = value; + + batch_opts.elem_flags = (u64)cpu << 32 | BPF_F_CPU; + err = bpf_map_update_batch(map_fd, keys, values, &max_entries, &batch_opts); + if (!ASSERT_OK(err, "bpf_map_update_batch specified cpu")) + goto out; + + /* lookup values on specified CPU */ + memset(values, 0, max_entries * value_sz); + err = bpf_map_lookup_batch(map_fd, NULL, &batch, keys, values, &count, &batch_opts); + if (!ASSERT_TRUE(!err || err == -ENOENT, "bpf_map_lookup_batch specified cpu")) + goto out; + + for (i = 0; i < max_entries; i++) + if (!ASSERT_EQ(values[i], value, + "bpf_map_lookup_batch value on specified cpu")) + goto out; + + /* lookup values from all CPUs */ + batch = 0; + count = max_entries; + batch_opts.elem_flags = 0; + memset(values_percpu, 0, roundup(value_sz, 8) * nr_cpus * max_entries); + err = bpf_map_lookup_batch(map_fd, NULL, &batch, keys, values_percpu, &count, + &batch_opts); + if (!ASSERT_TRUE(!err || err == -ENOENT, "bpf_map_lookup_batch all_cpus")) + goto out; + + for (i = 0; i < max_entries; i++) { + values_row = (void *) values_percpu + + roundup(value_sz, 8) * i * nr_cpus; + for (j = 0; j < nr_cpus; j++) { + v = *(u32 *) (values_row + roundup(value_sz, 8) * j); + if (!ASSERT_EQ(v, j != cpu ? 0 : value, + "bpf_map_lookup_batch value all_cpus")) + goto out; + } + } + } + +out: + free(values_percpu); + free(values); +} + +static void test_percpu_map_cpu_flag(enum bpf_map_type map_type) +{ + struct percpu_alloc_array *skel; + size_t key_sz = sizeof(int); + int *keys = NULL, i, err; + struct bpf_map *map; + u32 max_entries; + + skel = percpu_alloc_array__open(); + if (!ASSERT_OK_PTR(skel, "percpu_alloc_array__open")) + return; + + map = skel->maps.percpu; + bpf_map__set_type(map, map_type); + + err = percpu_alloc_array__load(skel); + if (!ASSERT_OK(err, "test_percpu_alloc__load")) + goto out; + + max_entries = bpf_map__max_entries(map); + keys = calloc(max_entries, key_sz); + if (!ASSERT_OK_PTR(keys, "calloc keys")) + goto out; + + for (i = 0; i < max_entries; i++) + keys[i] = i; + + test_percpu_map_op_cpu_flag(map, keys, key_sz, max_entries, true); +out: + if (keys) + free(keys); + percpu_alloc_array__destroy(skel); +} + +static void test_percpu_array_cpu_flag(void) +{ + test_percpu_map_cpu_flag(BPF_MAP_TYPE_PERCPU_ARRAY); +} + +static void test_percpu_hash_cpu_flag(void) +{ + test_percpu_map_cpu_flag(BPF_MAP_TYPE_PERCPU_HASH); +} + +static void test_lru_percpu_hash_cpu_flag(void) +{ + test_percpu_map_cpu_flag(BPF_MAP_TYPE_LRU_PERCPU_HASH); +} + +static void test_percpu_cgroup_storage_cpu_flag(void) +{ + struct percpu_alloc_array *skel = NULL; + struct bpf_cgroup_storage_key key; + int cgroup, prog_fd, err; + struct bpf_map *map; + + cgroup = create_and_get_cgroup("/cg_percpu"); + if (!ASSERT_GE(cgroup, 0, "create_and_get_cgroup")) { + cleanup_cgroup_environment(); + return; + } + + err = join_cgroup("/cg_percpu"); + if (!ASSERT_OK(err, "join_cgroup")) + goto out; + + skel = percpu_alloc_array__open_and_load(); + if (!ASSERT_OK_PTR(skel, "percpu_alloc_array__open_and_load")) + goto out; + + prog_fd = bpf_program__fd(skel->progs.cgroup_egress); + err = bpf_prog_attach(prog_fd, cgroup, BPF_CGROUP_INET_EGRESS, 0); + if (!ASSERT_OK(err, "bpf_prog_attach")) + goto out; + + map = skel->maps.percpu_cgroup_storage; + err = bpf_map_get_next_key(bpf_map__fd(map), NULL, &key); + if (!ASSERT_OK(err, "bpf_map_get_next_key")) + goto out; + + test_percpu_map_op_cpu_flag(map, &key, sizeof(key), 1, false); +out: + bpf_prog_detach2(-1, cgroup, BPF_CGROUP_INET_EGRESS); + close(cgroup); + cleanup_cgroup_environment(); + percpu_alloc_array__destroy(skel); +} + +static void test_map_op_cpu_flag(enum bpf_map_type map_type) +{ + u32 max_entries = 1, count = max_entries; + u64 flags, batch = 0, val = 0; + int err, map_fd, key = 0; + LIBBPF_OPTS(bpf_map_batch_opts, batch_opts); + + map_fd = bpf_map_create(map_type, "test_cpu_flag", sizeof(int), sizeof(u64), max_entries, + NULL); + if (!ASSERT_GE(map_fd, 0, "bpf_map_create")) + return; + + flags = BPF_F_ALL_CPUS; + err = bpf_map_update_elem(map_fd, &key, &val, flags); + ASSERT_ERR(err, "bpf_map_update_elem all_cpus"); + + batch_opts.elem_flags = BPF_F_ALL_CPUS; + err = bpf_map_update_batch(map_fd, &key, &val, &count, &batch_opts); + ASSERT_ERR(err, "bpf_map_update_batch all_cpus"); + + flags = BPF_F_CPU; + err = bpf_map_lookup_elem_flags(map_fd, &key, &val, flags); + ASSERT_ERR(err, "bpf_map_lookup_elem_flags cpu"); + + batch_opts.elem_flags = BPF_F_CPU; + err = bpf_map_lookup_batch(map_fd, NULL, &batch, &key, &val, &count, &batch_opts); + ASSERT_ERR(err, "bpf_map_lookup_batch cpu"); + + close(map_fd); +} + +static void test_array_cpu_flag(void) +{ + test_map_op_cpu_flag(BPF_MAP_TYPE_ARRAY); +} + +static void test_hash_cpu_flag(void) +{ + test_map_op_cpu_flag(BPF_MAP_TYPE_HASH); +} + void test_percpu_alloc(void) { if (test__start_subtest("array")) @@ -125,4 +425,16 @@ void test_percpu_alloc(void) test_cgrp_local_storage(); if (test__start_subtest("failure_tests")) test_failure(); + if (test__start_subtest("cpu_flag_percpu_array")) + test_percpu_array_cpu_flag(); + if (test__start_subtest("cpu_flag_percpu_hash")) + test_percpu_hash_cpu_flag(); + if (test__start_subtest("cpu_flag_lru_percpu_hash")) + test_lru_percpu_hash_cpu_flag(); + if (test__start_subtest("cpu_flag_percpu_cgroup_storage")) + test_percpu_cgroup_storage_cpu_flag(); + if (test__start_subtest("cpu_flag_array")) + test_array_cpu_flag(); + if (test__start_subtest("cpu_flag_hash")) + test_hash_cpu_flag(); } diff --git a/tools/testing/selftests/bpf/progs/percpu_alloc_array.c b/tools/testing/selftests/bpf/progs/percpu_alloc_array.c index 37c2d2608ec0b..ed6a2a93d5a51 100644 --- a/tools/testing/selftests/bpf/progs/percpu_alloc_array.c +++ b/tools/testing/selftests/bpf/progs/percpu_alloc_array.c @@ -187,4 +187,36 @@ int BPF_PROG(test_array_map_10) return 0; }
+struct { + __uint(type, BPF_MAP_TYPE_PERCPU_ARRAY); + __uint(max_entries, 2); + __type(key, int); + __type(value, u32); +} percpu SEC(".maps"); + +SEC("?fentry/bpf_fentry_test1") +int BPF_PROG(test_percpu_array, int x) +{ + u64 value = 0xDEADC0DE; + int key = 0; + + bpf_map_update_elem(&percpu, &key, &value, BPF_ANY); + return 0; +} + +struct { + __uint(type, BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE); + __type(key, struct bpf_cgroup_storage_key); + __type(value, u32); +} percpu_cgroup_storage SEC(".maps"); + +SEC("cgroup_skb/egress") +int cgroup_egress(struct __sk_buff *skb) +{ + u32 *val = bpf_get_local_storage(&percpu_cgroup_storage, 0); + + *val = 1; + return 1; +} + char _license[] SEC("license") = "GPL";
linux-kselftest-mirror@lists.linaro.org
-
Leon Hwang