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

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Message-Id: <20230422172054.3355436-1-joe@isovalent.com>
Date:   Sat, 22 Apr 2023 10:20:53 -0700
From:   Joe Stringer <joe@...valent.com>
To:     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: [PATCH bpf-next v5 1/2] docs/bpf: Add table to describe LRU properties

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