Date: Fri, 30 Sep 2005 10:31:18 -0600 (MDT) From: "M. Warner Losh" <imp@bsdimp.com> To: kerndev@yahoo.com Cc: hackers@freebsd.org Subject: Re: using fast interrupts with em(4) Message-ID: <20050930.103118.121221639.imp@bsdimp.com> In-Reply-To: <20050930010434.67727.qmail@web35003.mail.mud.yahoo.com> References: <20050930010434.67727.qmail@web35003.mail.mud.yahoo.com>
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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
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