FreeBSD/amd64-current virtual kernel

Back when machines had 128MB RAM, kernel customization was important.  Today, most standalone machines have so much RAM that customizing the kernel is pointless — until you virtualize, that is.  If you can assign a virtual machine 128MB of RAM again, reducing kernel size again becomes useful. I have a lot of single-purpose virtual machines with puny memory allocations.

The following kernel config works for amd64 virtual machines, running on VMWare ESXi and on Linux KVM booting diskless.  (It also supports iSCSI, as part of my boot-cluster-from-iSCSI master plan, but most of you won’t need that.)

cpu             HAMMER
ident           VM-ISCSI
makeoptions     DEBUG=-g                # Build kernel with gdb(1) debug symbols
options         SCHED_ULE               # ULE scheduler
options         PREEMPTION              # Enable kernel thread preemption
options         INET                    # InterNETworking
options         INET6                   # IPv6 communications protocols
options         SCTP                    # Stream Control Transmission Protocol
options         FFS                     # Berkeley Fast Filesystem
options         SOFTUPDATES             # Enable FFS soft updates support
options         UFS_ACL                 # Support for access control lists
options         UFS_DIRHASH             # Improve performance on big directories
options         UFS_GJOURNAL            # Enable gjournal-based UFS journaling
options         MD_ROOT                 # MD is a potential root device
options         NFSCLIENT               # Network Filesystem Client
options         NFSSERVER               # Network Filesystem Server
options         NFSLOCKD                # Network Lock Manager
options         NFS_ROOT                # NFS usable as /, requires NFSCLIENT
options         PROCFS                  # Process filesystem (requires PSEUDOFS)
options         PSEUDOFS                # Pseudo-filesystem framework
options         GEOM_PART_GPT           # GUID Partition Tables.
options         GEOM_LABEL              # Provides labelization
options         COMPAT_FREEBSD32        # Compatible with i386 binaries
options         SCSI_DELAY=5000         # Delay (in ms) before probing SCSI
options         KTRACE                  # ktrace(1) support
options         STACK                   # stack(9) support
options         SYSVSHM                 # SYSV-style shared memory
options         SYSVMSG                 # SYSV-style message queues
options         SYSVSEM                 # SYSV-style semaphores
options         P1003_1B_SEMAPHORES     # POSIX-style semaphores
options         _KPOSIX_PRIORITY_SCHEDULING # POSIX P1003_1B real-time extensions
options         PRINTF_BUFR_SIZE=128    # Prevent printf output being interspersed.
options         KBD_INSTALL_CDEV        # install a CDEV entry in /dev
options         HWPMC_HOOKS             # Necessary kernel hooks for hwpmc(4)
options         AUDIT                   # Security event auditing
options         MAC                     # TrustedBSD MAC Framework
options         FLOWTABLE               # per-cpu routing cache
options         INCLUDE_CONFIG_FILE     # Include this file in kernel
options         KDB                     # Enable kernel debugger support.
options         DDB                     # Support DDB.
options         GDB                     # Support remote GDB.
options         DEADLKRES               # Enable the deadlock resolver
options         INVARIANTS              # Enable calls of extra sanity checking
options         INVARIANT_SUPPORT       # Extra sanity checks of internal structures, required by INVARIANTS
options         WITNESS                 # Enable checks to detect deadlocks and cycles
options         WITNESS_SKIPSPIN        # Don't run witness on spinlocks for speed
options         SMP                     # Symmetric MultiProcessor Kernel
device          cpufreq
device          acpi
device          pci
device          fdc
device          ata
device          atadisk         # ATA disk drives
device          atapicd         # ATAPI CDROM drives
options         ATA_STATIC_ID   # Static device numbering
device          mpt             # LSI-Logic MPT-Fusion
device          scbus           # SCSI bus (required for SCSI)
device          da              # Direct Access (disks)
device          pass            # Passthrough device (direct SCSI access)
device          ses             # SCSI Environmental Services (and SAF-TE)
device          atkbdc          # AT keyboard controller
device          atkbd           # AT keyboard
device          psm             # PS/2 mouse
device          kbdmux          # keyboard multiplexer
device          vga             # VGA video card driver
device          sc
device          agp             # support several AGP chipsets
device          uart            # Generic UART driver
device          ppc
device          ppbus           # Parallel port bus (required)
device          lpt             # Printer
device          em              # Intel PRO/1000 Gigabit Ethernet Family
device          miibus          # MII bus support
device          re              # RealTek 8139C+/8169/8169S/8110S
device          loop            # Network loopback
device          random          # Entropy device
device          ether           # Ethernet support
device          vlan            # 802.1Q VLAN support
device          tun             # Packet tunnel.
device          pty             # BSD-style compatibility pseudo ttys
device          md              # Memory "disks"
device          gif             # IPv6 and IPv4 tunneling
device          faith           # IPv6-to-IPv4 relaying (translation)
device          bpf             # Berkeley packet filter
options         USB_DEBUG       # enable debug msgs
device          uhci            # UHCI PCI->USB interface
device          ohci            # OHCI PCI->USB interface
device          ehci            # EHCI PCI->USB interface (USB 2.0)
device          usb             # USB Bus (required)
device          uhid            # "Human Interface Devices"
device          ukbd            # Keyboard
device          umass           # Disks/Mass storage - Requires scbus and da
device          iscsi_initiator
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