On 4/27/20 8:33 PM, Andrew Morton wrote:
On Mon, 27 Apr 2020 20:04:29 +0200 Vlastimil Babka <vbabka@xxxxxxx> wrote:
...
+ sysctl.*= [KNL]
+ Set a sysctl parameter, right before loading the init
+ process, as if the value was written to the respective
+ /proc/sys/... file. Both '.' and '/' are recognized as
+ separators. Unrecognized parameters and invalid values
+ are reported in the kernel log. Sysctls registered
+ later by a loaded module cannot be set this way.
+ Example: sysctl.vm.swappiness=40
Why support "."? I think only supporting "/" is perfectly adequate and
simplifies documentation. It aligns the command-line syntax with the
rest of the sysctl documentation. I'm not seeing the need to provide
two ways of doing the same thing?
AFAIK the "." is traditional, and "/" is a newer artefact of moving from the
binary syscall form to procfs based form. So by "command-line syntax" you mean
echo and cat, not sysctl tool? Because "man sysctl" says:
variable
The name of a key to read from. An example is kernel.ostype. The '/'
separator is also accepted in place of a '.'.
So I'm not strongly against supporting only / but I expect most people are used
to the . and it will take them two attempts to pass the sysctl boot parameter
correctly if they don't use it regularly - first trying . form, wonder why it
doesn't work, then read the doc and realize it's not supported?
Vlastimil
