Date: Tue, 5 Feb 2013 14:04:12 -0500 From: Randall Stewart <rrs@lakerest.net> To: John Baldwin <jhb@freebsd.org> Cc: freebsd-net@freebsd.org, Robert Watson <rwatson@freebsd.org>, Jack Vogel <jfvogel@gmail.com>, Kip Macy <kmacy@freebsd.org> Subject: Re: Driver patch to look at... Message-ID: <990BD290-643B-4BC7-8D64-6D4CE987025A@lakerest.net> In-Reply-To: <201302051352.52741.jhb@freebsd.org> 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>
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Hmm That would trade off a stack pointer + a compare vs always doing the move. 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 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 ;-) But I am willing to do whatever .. since this really needs to be fixed. R On Feb 5, 2013, at 1:52 PM, John Baldwin wrote: > 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 ------------------------------ Randall Stewart 803-317-4952 (cell)
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