linux-kernel - RE: [PATCH bpf-next v5 1/2] docs/bpf: Add table to describe LRU properties

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Message-ID: <644540052bcaa_19af020828@john.notmuch>
Date:   Sun, 23 Apr 2023 07:26:13 -0700
From:   John Fastabend <john.fastabend@...il.com>
To:     Joe Stringer <joe@...valent.com>, bpf@...r.kernel.org
Cc:     linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org,
        ast@...nel.org, corbet@....net, martin.lau@...ux.dev,
        bagasdotme@...il.com, maxtram95@...il.com, john.fastabend@...il.com
Subject: RE: [PATCH bpf-next v5 1/2] docs/bpf: Add table to describe LRU
 properties

Joe Stringer wrote:
> Depending on the map type and flags for LRU, different properties are
> global or percpu. Add a table to describe these.
> 
> Signed-off-by: Joe Stringer <joe@...valent.com>
> ---
> v5: Use bold rather than verbatim for column header
> v4: Initial posting
> ---
>  Documentation/bpf/map_hash.rst | 11 ++++++++++-
>  1 file changed, 10 insertions(+), 1 deletion(-)
> 
> diff --git a/Documentation/bpf/map_hash.rst b/Documentation/bpf/map_hash.rst
> index 8669426264c6..1314dfc5e7e1 100644
> --- a/Documentation/bpf/map_hash.rst
> +++ b/Documentation/bpf/map_hash.rst
> @@ -29,7 +29,16 @@ will automatically evict the least recently used entries when the hash
>  table reaches capacity. An LRU hash maintains an internal LRU list that
>  is used to select elements for eviction. This internal LRU list is
>  shared across CPUs but it is possible to request a per CPU LRU list with
> -the ``BPF_F_NO_COMMON_LRU`` flag when calling ``bpf_map_create``.
> +the ``BPF_F_NO_COMMON_LRU`` flag when calling ``bpf_map_create``.  The
> +following table outlines the properties of LRU maps depending on the a
> +map type and the flags used to create the map.
> +
> +======================== ========================= ================================
> +Flag                     ``BPF_MAP_TYPE_LRU_HASH`` ``BPF_MAP_TYPE_LRU_PERCPU_HASH``
> +======================== ========================= ================================
> +**BPF_F_NO_COMMON_LRU**  Per-CPU LRU, global map   Per-CPU LRU, per-cpu map
> +**!BPF_F_NO_COMMON_LRU** Global LRU, global map    Global LRU, per-cpu map
> +======================== ========================= ================================
>  
>  Usage
>  =====
> -- 
> 2.34.1
> 

Acked-by: John Fastabend <john.fastabend@...il.com>