Date: Sat, 17 Nov 2001 08:40:06 -0800 (PST) From: John Baldwin <jhb@FreeBSD.org> To: Terry Lambert <tlambert2@mindspring.com> Cc: freebsd-arch@FreeBSD.ORG, Peter Wemm <peter@wemm.org>, Matthew Dillon <dillon@apollo.backplane.com> Subject: Re: Need review - patch for socket locking and ref counting Message-ID: <XFMail.011117084006.jhb@FreeBSD.org> In-Reply-To: <3BF6652F.FC50C99A@mindspring.com>
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On 17-Nov-01 Terry Lambert wrote: > Matthew Dillon wrote: >> >> I've thought about it a bit and I've come to the conclusion that >> we should *not* have multiple mutex pools. > > It's pretty obvious even under casual thought that the deadlock > avoidance can't work correctly in theis scenario, so you MUST > limit yourself to last acquisition. Err, witness doesn't do deadlock avoidance, and it just checks lock orders. However, the problem is that the order of a larger lock (reader writer lock) is being compared with those of its components. Obviously one is going to acquire the lock used to implement a reader/writer lock both while holding and not holding the reader/writer lock. Witness cannot efficiently handle this, so instead we disable witness checks on the component locks. > By the same token, it does not make sense to permit recursion on > such mutexes. Err, we don't on most mutexes. -- John Baldwin <jhb@FreeBSD.org> <>< http://www.FreeBSD.org/~jhb/ "Power Users Use the Power to Serve!" - http://www.FreeBSD.org/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message
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