Re: [PATCH] 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 documantations: [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(a)outlook.jp&gt; --- qemu-options.hx | 25 ++++++++++++++++--------- 1 file changed, 16 insertions(+), 9 deletions(-) diff --git a/qemu-options.hx b/qemu-options.hx index 59bdf67a2c..174f0d0c2d 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