I read that Bottom halves are called only at the end of slow interrupts not after fast interrupts. Timer tick is a fast interrupt(SA_INTERRUPT - set). Then how is TIMER_BH called ? Please clarify. Thanks in advance, Nirranjan.K - Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ IRC Channel: irc.openprojects.net / #kernelnewbies Web Page: http://www.kernelnewbies.org/