On 9/26/2018 8:41 AM, Dave Hansen wrote:
On 09/26/2018 08:24 AM, Alexander Duyck wrote:
With no options it works just like slub_debug and enables all
available options. So in our case it is a NOP since we wanted the
debugging enabled by default.
Yeah, but slub_debug is different.
First, nobody uses the slub_debug=- option because *that* is only used
when you have SLUB_DEBUG=y *and* CONFIG_SLUB_DEBUG_ON=y, which not even
Fedora does.
slub_debug is *primarily* for *adding* debug features. For this, we
need to turn them off.
It sounds like following slub_debug was a bad idea, especially following
its semantics too closely when it doesn't make sense.
I actually like the idea of using slub_debug style semantics. It makes
sense when you start thinking about future features being added. Then we
might actually have scenarios where vm_debug=P will make sense, but for
right now it is probably not going to be used. Basically this all makes
room for future expansion. It is just ugly to read right now while we
only have one feature controlled by this bit.
