On 09/12/2018 07:49 AM, Alexander Duyck wrote: >>> + page_init_poison= [KNL] Boot-time parameter changing the >>> + state of poisoning of page structures during early >>> + boot. Used to verify page metadata is not accessed >>> + prior to initialization. Available with >>> + CONFIG_DEBUG_VM=y. >>> + off: turn off poisoning >>> + on: turn on poisoning (default) >>> + >> what about the following wording or something along those lines >> >> Boot-time parameter to control struct page poisoning which is a >> debugging feature to catch unitialized struct page access. This option >> is available only for CONFIG_DEBUG_VM=y and it affects boot time >> (especially on large systems). If there are no poisoning bugs reported >> on the particular system and workload it should be safe to disable it to >> speed up the boot time. > That works for me. I will update it for the next release. FWIW, I rather liked Dan's idea of wrapping this under vm_debug=<something>. We've got a zoo of boot options and it's really hard to _remember_ what does what. For this case, we're creating one that's only available under a specific debug option and I think it makes total sense to name the boot option accordingly. For now, I think it makes total sense to do vm_debug=all/off. If, in the future, we get more options, we can do things like slab does and do vm_debug=P (for Page poison) for this feature specifically. vm_debug = [KNL] Available with CONFIG_DEBUG_VM=y. May slow down boot speed, especially on larger- memory systems when enabled. off: turn off all runtime VM debug features all: turn on all debug features (default)
