From: Jiri Olsa <jolsa@kernel.org>
To: Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Andrii Nakryiko <andrii@kernel.org>
Cc: bpf@vger.kernel.org, Martin KaFai Lau <martin.lau@linux.dev>,
Eduard Zingerman <eddyz87@gmail.com>,
Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
Quentin Monnet <qmo@kernel.org>, Tao Chen <chen.dylane@linux.dev>,
STAR Labs SG <info@starlabs.sg>
Subject: [PATCH bpf-next 3/9] bpf: Factor stackid_new_bucket from __bpf_get_stackid
Date: Mon, 20 Jul 2026 10:53:45 +0200 [thread overview]
Message-ID: <20260720085351.655075-4-jolsa@kernel.org> (raw)
In-Reply-To: <20260720085351.655075-1-jolsa@kernel.org>
The new stackid_new_bucket allocates the new bucket and initializes it
with the trace data.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
kernel/bpf/stackmap.c | 49 +++++++++++++++++++++++++++----------------
1 file changed, 31 insertions(+), 18 deletions(-)
diff --git a/kernel/bpf/stackmap.c b/kernel/bpf/stackmap.c
index 7bc2a966e3e8..48a2e28f0c68 100644
--- a/kernel/bpf/stackmap.c
+++ b/kernel/bpf/stackmap.c
@@ -559,31 +559,53 @@ static int stackid_fastpath(struct stackid *stackid, struct bpf_map *map,
return -ENOENT;
}
+static struct stack_map_bucket *
+stackid_new_bucket(struct stackid *stackid, struct bpf_map *map,
+ struct perf_callchain_entry *trace, u64 flags)
+{
+ struct bpf_stack_map *smap = container_of(map, struct bpf_stack_map, map);
+ struct bpf_stack_build_id *id_offs;
+ struct stack_map_bucket *bucket;
+ u32 i;
+
+ bucket = (struct stack_map_bucket *) pcpu_freelist_pop(&smap->freelist);
+ if (unlikely(!bucket))
+ return NULL;
+
+ if (stack_map_use_build_id(map)) {
+ id_offs = (struct bpf_stack_build_id *)bucket->data;
+ for (i = 0; i < stackid->nr; i++)
+ id_offs[i].ip = stackid->ips[i];
+ } else {
+ memcpy(bucket->data, stackid->ips, stackid->len);
+ }
+
+ bucket->hash = stackid->hash;
+ bucket->nr = stackid->nr;
+ return bucket;
+}
+
static long __bpf_get_stackid(struct stackid *stackid, struct bpf_map *map,
struct perf_callchain_entry *trace, u64 flags)
{
struct bpf_stack_map *smap = container_of(map, struct bpf_stack_map, map);
struct stack_map_bucket *new_bucket, *old_bucket;
bool user = flags & BPF_F_USER_STACK;
- u32 trace_len, i;
+ u32 trace_len;
int err;
err = stackid_fastpath(stackid, map, trace, flags);
if (err != -ENOENT)
return err;
+ new_bucket = stackid_new_bucket(stackid, map, trace, flags);
+ if (!new_bucket)
+ return -ENOMEM;
+
if (stack_map_use_build_id(map)) {
struct bpf_stack_build_id *id_offs;
- /* for build_id+offset, pop a bucket before slow cmp */
- new_bucket = (struct stack_map_bucket *)
- pcpu_freelist_pop(&smap->freelist);
- if (unlikely(!new_bucket))
- return -ENOMEM;
- new_bucket->nr = stackid->nr;
id_offs = (struct bpf_stack_build_id *)new_bucket->data;
- for (i = 0; i < stackid->nr; i++)
- id_offs[i].ip = stackid->ips[i];
stack_map_get_build_id_offset(id_offs, stackid->nr, user, false /* !may_fault */);
trace_len = stackid->nr * sizeof(struct bpf_stack_build_id);
if (stackid->hash_matches && stackid->bucket->nr == stackid->nr &&
@@ -595,17 +617,8 @@ static long __bpf_get_stackid(struct stackid *stackid, struct bpf_map *map,
pcpu_freelist_push(&smap->freelist, &new_bucket->fnode);
return -EEXIST;
}
- } else {
- new_bucket = (struct stack_map_bucket *)
- pcpu_freelist_pop(&smap->freelist);
- if (unlikely(!new_bucket))
- return -ENOMEM;
- memcpy(new_bucket->data, stackid->ips, stackid->len);
}
- new_bucket->hash = stackid->hash;
- new_bucket->nr = stackid->nr;
-
old_bucket = xchg(&smap->buckets[stackid->id], new_bucket);
if (old_bucket)
pcpu_freelist_push(&smap->freelist, &old_bucket->fnode);
--
2.54.0
next prev parent reply other threads:[~2026-07-20 8:54 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-20 8:53 [PATCH bpf-next 0/9] bpf: Disable preemption in stack map code Jiri Olsa
2026-07-20 8:53 ` [PATCH bpf-next 1/9] bpf: Factor stackid_init function from __bpf_get_stackid Jiri Olsa
2026-07-20 8:53 ` [PATCH bpf-next 2/9] bpf: Factor stackid_fastpath " Jiri Olsa
2026-07-20 9:09 ` sashiko-bot
2026-07-20 20:31 ` Jiri Olsa
2026-07-20 8:53 ` Jiri Olsa [this message]
2026-07-20 9:01 ` [PATCH bpf-next 3/9] bpf: Factor stackid_new_bucket " sashiko-bot
2026-07-20 20:31 ` Jiri Olsa
2026-07-20 8:53 ` [PATCH bpf-next 4/9] bpf: Use stack id functions instead of __bpf_get_stackid Jiri Olsa
2026-07-20 8:53 ` [PATCH bpf-next 5/9] bpf: Disable preemption in bpf_get_stackid Jiri Olsa
2026-07-20 9:04 ` sashiko-bot
2026-07-20 20:31 ` Jiri Olsa
2026-07-20 8:53 ` [PATCH bpf-next 6/9] bpf: Factor callchain_store function from __bpf_get_stack Jiri Olsa
2026-07-20 9:07 ` sashiko-bot
2026-07-20 20:31 ` Jiri Olsa
2026-07-20 8:53 ` [PATCH bpf-next 7/9] bpf: Factor callchain_finalize " Jiri Olsa
2026-07-20 9:08 ` sashiko-bot
2026-07-20 20:31 ` Jiri Olsa
2026-07-20 8:53 ` [PATCH bpf-next 8/9] bpf: Remove trace_in argument " Jiri Olsa
2026-07-20 9:09 ` sashiko-bot
2026-07-20 20:31 ` Jiri Olsa
2026-07-20 8:53 ` [PATCH bpf-next 9/9] bpf: Disable preemption in __bpf_get_stack Jiri Olsa
2026-07-20 9:18 ` sashiko-bot
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