diff options
| author | Yohei Kojima <y-koj@outlook.jp> | 2023-04-24 10:22:45 +0100 |
|---|---|---|
| committer | Alex Bennée <alex.bennee@linaro.org> | 2023-04-27 14:58:29 +0100 |
| commit | 4f513984edba8bf7e615ad08d54987e47d94a0be (patch) | |
| tree | adc23a8c2f5b8fd08f9fa303fc351ca1210d8e39 | |
| parent | d044b7c33a564e50e0a6b156d71b3262f1faf0a7 (diff) | |
qemu-options.hx: Update descriptions of memory options for NUMA node
This commit adds the following description:
1. `memdev` option is recommended over `mem` option (see [1,2])
2. users must specify memory for all NUMA nodes (see [2])
This commit also separates descriptions for `mem` and `memdev` into two
paragraphs. The old doc describes legacy `mem` option first, and it was
a bit confusing.
Related documentation:
[1] https://wiki.qemu.org/ChangeLog/5.1#Incompatible_changes
[2] https://www.qemu.org/docs/master/about/removed-features.html
Signed-off-by: Yohei Kojima <y-koj@outlook.jp>
Message-Id: <TYZPR06MB5418D6B0175A49E8E76988439D8E9@TYZPR06MB5418.apcprd06.prod.outlook.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
[AJB: fix documentation in commit message]
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20230424092249.58552-15-alex.bennee@linaro.org>
| -rw-r--r-- | qemu-options.hx | 25 |
1 files changed, 16 insertions, 9 deletions
diff --git a/qemu-options.hx b/qemu-options.hx index baa0589733..b5efa648ba 100644 --- a/qemu-options.hx +++ b/qemu-options.hx @@ -405,15 +405,22 @@ SRST -numa node,nodeid=0 -numa node,nodeid=1 \ -numa cpu,node-id=0,socket-id=0 -numa cpu,node-id=1,socket-id=1 - Legacy '\ ``mem``\ ' assigns a given RAM amount to a node (not supported - for 5.1 and newer machine types). '\ ``memdev``\ ' assigns RAM from - a given memory backend device to a node. If '\ ``mem``\ ' and - '\ ``memdev``\ ' are omitted in all nodes, RAM is split equally between them. - - - '\ ``mem``\ ' and '\ ``memdev``\ ' are mutually exclusive. - Furthermore, if one node uses '\ ``memdev``\ ', all of them have to - use it. + '\ ``memdev``\ ' option assigns RAM from a given memory backend + device to a node. It is recommended to use '\ ``memdev``\ ' option + over legacy '\ ``mem``\ ' option. This is because '\ ``memdev``\ ' + option provides better performance and more control over the + backend's RAM (e.g. '\ ``prealloc``\ ' parameter of + '\ ``-memory-backend-ram``\ ' allows memory preallocation). + + For compatibility reasons, legacy '\ ``mem``\ ' option is + supported in 5.0 and older machine types. Note that '\ ``mem``\ ' + and '\ ``memdev``\ ' are mutually exclusive. If one node uses + '\ ``memdev``\ ', the rest nodes have to use '\ ``memdev``\ ' + option, and vice versa. + + Users must specify memory for all NUMA nodes by '\ ``memdev``\ ' + (or legacy '\ ``mem``\ ' if available). In QEMU 5.2, the support + for '\ ``-numa node``\ ' without memory specified was removed. '\ ``initiator``\ ' is an additional option that points to an initiator NUMA node that has best performance (the lowest latency or |