On 9/25/2018 1:26 PM, Dave Hansen wrote:
On 09/25/2018 01:20 PM, Alexander Duyck wrote:
> + vm_debug[=options] [KNL] Available with CONFIG_DEBUG_VM=y.
> + May slow down system boot speed, especially when
> + enabled on systems with a large amount of memory.
> + All options are enabled by default, and this
> + interface is meant to allow for selectively
> + enabling or disabling specific virtual memory
> + debugging features.
> + Available options are:
> + P Enable page structure init time poisoning
> + - Disable all of the above options
Can we have vm_debug=off for turning things off, please? That seems to
be pretty standard.
No. The simple reason for that is that you had requested this work like
the slub_debug. If we are going to do that then each individual letter
represents a feature. That is why the "-" represents off. We cannot have
letters represent flags, and letters put together into words. For
example slub_debug=OFF would turn on sanity checks and turn off
debugging for caches that would have causes higher minimum slab orders.
Either I can do this as a single parameter that supports on/off
semantics, or I can support it as a slub_debug type parameter that does
flags based on the input options. I would rather not muddy things by
trying to do both.
Also, we need to document the defaults. I think the default is
debug options are enabled", but it would be nice to document that.
In the description I call out "All options are enabled by default, and
this interface is meant to allow for selectively enabling or disabling".