This allows the guarded heap to be used in a much more targeted way,
if it's suspected specific object_caches have problems.
Enabled by default for KDEBUG. The new safemode/kernel option is
"guarded_heap_for_object_caches". This accepts a comma-separated
list of quoted strings, optionally with * at beginning and/or end
(but not middle.) Examples:
mbufs* # matches caches starting with "mbufs"
*jumbo9* # matches caches containing "jumbo9"
"*jumbo9 chunks","mbufs*" # matches caches ending with "jumbo9 chunks"
# or starting with "mbufs"
This should help with diagnosing #19973, among others, without needing
to compile custom versions of drivers or anything like that.
Unfortunately it is not possible to use this mechanism to selectively
replace parts of the slab malloc. The slab malloc free() relies on
the MemoryManager to figure out what cache an object belongs to, which
doesn't work if objects of some size classes aren't known to the
MemoryManager at all.
Augustin Cavalier
7240f3762f