Messages in this thread | | | Date | Mon, 15 Jul 2002 14:55:21 +0530 | From | Dipankar Sarma <> | Subject | Re: [RFC] BH removal text |
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On Sun, Jul 14, 2002 at 03:17:30AM -0700, William Lee Irwin III wrote: > On Sun, Jul 14, 2002 at 10:22:19AM +0530, Dipankar Sarma wrote: > > Even if you replace timemr_bh() with a tasklet, you still need > > to take the global_bh_lock to ensure that timers don't race with > > single-threaded BH processing in drivers. I wrote this patch [included] > > to get rid of timer_bh in Ingo's smptimers, but it acquires > > global_bh_lock as well as net_bh_lock, the latter to ensure > > that some older protocol code that expected serialization of > > NET_BH and timers work correctly (see deliver_to_old_ones()). > > They need to be cleaned up too. > > This is great stuff. I'll definitely try it out in an hour or two. I'd > be interested in helping with the cleanup of the things assuming the BH > things still exist but might need a wee bit of hand-holding to get > through it. I'll go around flagging people down who might be able to > help me with it as I go.
I did a quick and dirty search on packet_type.data == NULL protocols. Here is a list -
802/psnap.c appletalk/ddp.c ax25/af_ax25.c core/ext8022.c econet/af_econet.c irda/irsyms.c x25/af_x25.c
These need to be made safe for a non-BH based timer. I guess the current code assumes serialization between timer and BH context code due to the use of now-defunct NET_BH.
> > I actually suspect tty-related things are a likely culprit as > significant use of the serial console occurs.
It should also be possible to make minimal non-smptimers bhless_timer patch - just in case smptimers isn't going in any time soon. It will run a timer tasklet off of do_timer(). The tasklet handler still has to grab global_bh_lock and the likes to keep the tty and other drivers that expect serialization BH and timers or use __global_cli, happy. Will such a patch be useful ?
Thanks -- Dipankar Sarma <dipankar@in.ibm.com> http://lse.sourceforge.net Linux Technology Center, IBM Software Lab, Bangalore, India. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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