Skip site navigation (1)Skip section navigation (2)
Date:      Fri, 04 Dec 1998 12:40:06 -0800
From:      David Greenman <dg@root.com>
To:        Archie Cobbs <archie@whistle.com>
Cc:        freebsd-hackers@FreeBSD.ORG
Subject:   Re: Help with clist_alloc_cblocks() 
Message-ID:  <199812042040.MAA08017@root.com>
In-Reply-To: Your message of "Fri, 04 Dec 1998 12:28:57 PST." <199812042028.MAA06497@bubba.whistle.com> 

next in thread | previous in thread | raw e-mail | index | archive | help
>I'm trying to write a line discipline, roughly similar to the PPP
>line discipline. My question is, what are the correct parameters to
>give to clist_alloc_cblocks()?
>
>  /*
>   * Pre-allocate cblocks to the an appropriate amount.
>   */
>
>    ttyflush(tp, FREAD | FWRITE);
>    clist_alloc_cblocks(&tp->t_canq, 0, 0);
>    clist_alloc_cblocks(&tp->t_rawq, 0, 0); 	/* XXX probably wrong! */
>    clist_alloc_cblocks(&tp->t_outq, MLEN + NGT_HIWATER, MLEN + NGT_HIWATER);
>
>I'm not sure how to determine what the correct values to call
>clist_alloc_cblocks() should be. The values I'm using now cause a
>bunch of "interrupt-level buffer overflows" reported from the sio
>driver. It looks like I can simply increase the values for tp->t_rawq
>but I'd like to understand exactly what they mean first.

   A lack of cblocks should not cause interrupt-level buffer overflows.

-DG

David Greenman
Co-founder/Principal Architect, The FreeBSD Project

To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe freebsd-hackers" in the body of the message



Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?199812042040.MAA08017>