Query about "Function call interrupts" entry in /proc/interrupts file

Hi all,

In the /proc/interrupts file, there is one entry called the Function
call interrupts.
Can anyone please explain to me how this interrupt is generated or
what it does?
Thanks!

$ cat /proc/interrupts

CPU0 CPU1
0: 7555 0 IO-APIC-edge timer
1: 2 0 IO-APIC-edge i8042
4: 2 0 IO-APIC-edge
6: 5 0 IO-APIC-edge floppy
7: 0 0 IO-APIC-edge parport0
8: 1 0 IO-APIC-edge rtc0
9: 0 0 IO-APIC-fasteoi acpi
12: 4 0 IO-APIC-edge i8042
14: 5184503 0 IO-APIC-edge ata_piix
15: 0 0 IO-APIC-edge ata_piix
16: 10030496 0 IO-APIC-fasteoi ohci1394, HDA Intel
17: 33961000 0 IO-APIC-fasteoi eth0
18: 0 0 IO-APIC-fasteoi uhci_hcd:usb4
21: 2710967 0 IO-APIC-fasteoi ehci_hcd:usb1, uhci_hcd:usb2
22: 0 0 IO-APIC-fasteoi uhci_hcd:usb3
23: 0 0 IO-APIC-fasteoi uhci_hcd:usb5
2299: 2594538 0 PCI-MSI-edge ahci
NMI: 0 0 Non-maskable interrupts
LOC: 175008553 173744798 Local timer interrupts
RES: 1503295 3085980 Rescheduling interrupts
CAL: 1361 2486 Function call interrupts
TLB: 546223 608398 TLB shootdowns
SPU: 0 0 Spurious interrupts
ERR: 0
MIS: 0