Date: Tue, 5 Feb 2013 14:08:15 -0500 From: Randall Stewart <rrs@lakerest.net> To: Randall Stewart <rrs@lakerest.net> Cc: freebsd-net@freebsd.org, Robert Watson <rwatson@freebsd.org>, Jack Vogel <jfvogel@gmail.com>, John Baldwin <jhb@freebsd.org>, Kip Macy <kmacy@freebsd.org> Subject: Re: Driver patch to look at... Message-ID: <00075DDD-73A1-4CA4-9574-036D43B071D9@lakerest.net> In-Reply-To: <990BD290-643B-4BC7-8D64-6D4CE987025A@lakerest.net> References: <D3AA078A-CD19-4228-A019-BE9C985895E2@lakerest.net> <201302051213.51401.jhb@freebsd.org> <0D421326-9A80-4E21-A18E-E717F5C02164@lakerest.net> <201302051352.52741.jhb@freebsd.org> <990BD290-643B-4BC7-8D64-6D4CE987025A@lakerest.net>
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Hmm wait, I could probably do the compare to whats in the ring buffer ;-D R On Feb 5, 2013, at 2:04 PM, Randall Stewart wrote: > Hmm >=20 > That would trade off a stack pointer + a compare > vs always doing the move. >=20 > Thats fine until I have to add the _mc() version, then the put > back would be an atomic, and most of the time the return from > this is probably not changed=85 >=20 > I really would prefer not to since the compare and maybe store vs > the always store.. though the same now, would be far more expensive > in the _mc version.. if we do a _mc version of course ;-) >=20 > But I am willing to do whatever .. since this really needs to be = fixed. >=20 > R > On Feb 5, 2013, at 1:52 PM, John Baldwin wrote: >=20 >> On Tuesday, February 05, 2013 12:44:01 pm Randall Stewart wrote: >>> Actually, no it is used. >>>=20 >>> If you look in if_var.h int he drbr_putback() function, it does >>> a buf_ring_swap when the old mbuf pointer does not equal the >>> new mbuf pointer. This *does* happen, I crashed at least once >>> yesterday when the igb driver did something to free the original >>> mbuf and return a new mbuf with the data (prepend or some such). >>>=20 >>> I also have found several issues that I have fixed this morning.. = its been >>> crash city on my test beds.. >>>=20 >>> Here is the latest patch with all fixes and suggested changes from = emaste=20 >> (thanks Ed) >>=20 >> Actually, one more suggestion then (since you have to keep putback). = It >> would be nice to not have to require 'snext' in all the callers. How >> about replace buf_ring_swap() with a buf_ring_putback_sc() that = accepts the >> mbuf and just stores it at the head unconditionally and have = drbr_putback() >> use that? >>=20 >> --=20 >> John Baldwin >> _______________________________________________ >> freebsd-net@freebsd.org mailing list >> http://lists.freebsd.org/mailman/listinfo/freebsd-net >> To unsubscribe, send any mail to = "freebsd-net-unsubscribe@freebsd.org" >>=20 >=20 > ------------------------------ > Randall Stewart > 803-317-4952 (cell) >=20 > _______________________________________________ > freebsd-net@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-net > To unsubscribe, send any mail to "freebsd-net-unsubscribe@freebsd.org" >=20 ------------------------------ Randall Stewart 803-317-4952 (cell)
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