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This patch updates an outdated description in qemu-options.hx . The patch reflects the changes in qemu behavior already described in another documentation, and it also changes paragraph structure for further readability. The original patch is: https://patchew.org/QEMU/tyzpr06mb5418d6b0175a49e8e76988439d...@tyzpr06mb5418.apcprd06.prod.outlook.com/ On 2023/03/30 19:09, Yohei Kojima wrote: > 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-...@outlook.jp> > --- > 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
