From: Daniel Borkmann <daniel@iogearbox.net>
To: Song Liu <songliubraving@fb.com>,
netdev@vger.kernel.org, bpf@vger.kernel.org
Cc: kernel-team@fb.com, ast@kernel.org, john.fastabend@gmail.com,
kpsingh@chromium.org
Subject: Re: [PATCH v2 bpf-next 1/2] bpf: introduce BPF_F_PRESERVE_ELEMS for perf event array
Date: Wed, 30 Sep 2020 16:49:27 +0200 [thread overview]
Message-ID: <c7b572d4-df22-db9d-6c01-d2b577c47116@iogearbox.net> (raw)
In-Reply-To: <20200929215659.3938706-2-songliubraving@fb.com>
On 9/29/20 11:56 PM, Song Liu wrote:
[...]
>
> +static void bpf_fd_array_map_clear(struct bpf_map *map);
> +
> +static void perf_event_fd_array_map_free(struct bpf_map *map)
> +{
> + if (map->map_flags & BPF_F_PRESERVE_ELEMS)
> + bpf_fd_array_map_clear(map);
> + fd_array_map_free(map);
> +}
Not quite sure why you place that here and added the fwd declaration? If you
place perf_event_fd_array_map_free() near perf_event_array_map_ops, then you
also don't need the additional bpf_fd_array_map_clear declaration.
> static void *prog_fd_array_get_ptr(struct bpf_map *map,
> struct file *map_file, int fd)
> {
> @@ -1134,6 +1148,9 @@ static void perf_event_fd_array_release(struct bpf_map *map,
> struct bpf_event_entry *ee;
> int i;
>
> + if (map->map_flags & BPF_F_PRESERVE_ELEMS)
> + return;
> +
> rcu_read_lock();
> for (i = 0; i < array->map.max_entries; i++) {
> ee = READ_ONCE(array->ptrs[i]);
> @@ -1148,7 +1165,7 @@ const struct bpf_map_ops perf_event_array_map_ops = {
> .map_meta_equal = bpf_map_meta_equal,
> .map_alloc_check = fd_array_map_alloc_check,
> .map_alloc = array_map_alloc,
> - .map_free = fd_array_map_free,
> + .map_free = perf_event_fd_array_map_free,
> .map_get_next_key = array_map_get_next_key,
> .map_lookup_elem = fd_array_map_lookup_elem,
> .map_delete_elem = fd_array_map_delete_elem,
> diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
> index 82522f05c0213..ea78eb89f8d67 100644
> --- a/tools/include/uapi/linux/bpf.h
> +++ b/tools/include/uapi/linux/bpf.h
> @@ -414,6 +414,9 @@ enum {
>
> /* Enable memory-mapping BPF map */
> BPF_F_MMAPABLE = (1U << 10),
> +
> +/* Share perf_event among processes */
> + BPF_F_PRESERVE_ELEMS = (1U << 11),
> };
>
> /* Flags for BPF_PROG_QUERY. */
>
next prev parent reply other threads:[~2020-09-30 14:49 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-29 21:56 [PATCH v2 bpf-next 0/2] introduce BPF_F_PRESERVE_ELEMS Song Liu
2020-09-29 21:56 ` [PATCH v2 bpf-next 1/2] bpf: introduce BPF_F_PRESERVE_ELEMS for perf event array Song Liu
2020-09-30 14:49 ` Daniel Borkmann [this message]
2020-09-30 15:04 ` Song Liu
2020-09-29 21:56 ` [PATCH v2 bpf-next 2/2] selftests/bpf: add tests for BPF_F_PRESERVE_ELEMS Song Liu
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