Re: using fast interrupts with em(4)

From: M. Warner Losh (imp_at_bsdimp.com)
Date: 09/30/05

  • Next message: M. Warner Losh: "Re: serial login to SBC" 
    Date: Fri, 30 Sep 2005 10:31:18 -0600 (MDT)
To: kerndev@yahoo.com

    In message: <20050930010434.67727.qmail@web35003.mail.mud.yahoo.com>
                Kernel Dev <kerndev@yahoo.com> writes:
    : Hello All. For a project, I am looking into making the em(4) driver use fast interrupts. Has someone done this or are there other driver references that could help me in this?
    :
    : I understand that the main problems are:
    :
    : 1. Sharing of interrupts.
    : 2. Blocking (memory and mutexes).
    :
    : Are there any other issues I might have missed?

    You can share fast interrupts, but it isn't a good idea...

    You can't block in a fast interrupt. You must use spin locks. You
    cannot call anything that will sleep in a fast interrupt. Ideally,
    you'd not modify anything that isn't covered by your own spin locks,
    leaving that for a taskqueue or similar queueing strategy.

    Warner
    _______________________________________________
    freebsd-hackers@freebsd.org mailing list
    http://lists.freebsd.org/mailman/listinfo/freebsd-hackers
    To unsubscribe, send any mail to "freebsd-hackers-unsubscribe@freebsd.org"

  • Next message: M. Warner Losh: "Re: serial login to SBC"