VM_PAGE_RESERVE_USER
#define VM_MEMORY_RESERVE_USER (VM_PAGE_RESERVE_USER * B_PAGE_SIZE)
static const size_t kNotePagesLimit = VM_PAGE_RESERVE_USER * 4;
static const size_t kWarnPagesLimit = VM_PAGE_RESERVE_USER;
sFreePagesTarget = VM_PAGE_RESERVE_USER
VM_PAGE_RESERVE_USER, // user