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@isovalent.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20230422172054.3355436-1-joe@isovalent.com
This commit is contained in:
Joe Stringer 2023-04-22 10:20:53 -07:00 committed by Daniel Borkmann
parent b3e8701dd1
commit af0335d292
1 changed files with 10 additions and 1 deletions

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@ -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
=====