Commit af0335d2 authored by Joe Stringer's avatar Joe Stringer Committed by Daniel Borkmann
Browse files

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: default avatarJoe Stringer <joe@isovalent.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Acked-by: default avatarJohn Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20230422172054.3355436-1-joe@isovalent.com
parent b3e8701d

Documentation/bpf/map_hash.rst

+10 −1
Original line number Diff line number Diff line
@@ -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

=====