Date: Thu, 28 Mar 2002 14:37:21 -0800 From: Kirk McKusick <mckusick@beastie.mckusick.com> To: Terry Lambert <tlambert2@mindspring.com> Cc: "Brian F. Feldman" <green@FreeBSD.ORG>, arch@FreeBSD.ORG Subject: Re: vnode::v_op bugfix / PERFORCE change 8574 for review (fwd) Message-ID: <200203282237.g2SMbLD99685@beastie.mckusick.com> In-Reply-To: Your message of "Thu, 28 Mar 2002 14:05:22 PST." <3CA393A2.FB67CC2B@mindspring.com>
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I concur with your suggestion below that the new patch is a better approach. Your ideal solution below sounds reasonable though I have not thought it through completely. Kirk McKusick =-=-=-=-= Date: Thu, 28 Mar 2002 14:05:22 -0800 From: Terry Lambert <tlambert2@mindspring.com> To: Kirk McKusick <mckusick@beastie.mckusick.com> CC: "Brian F. Feldman" <green@FreeBSD.ORG>, arch@FreeBSD.ORG Subject: Re: vnode::v_op bugfix / PERFORCE change 8574 for review (fwd) Kirk McKusick wrote: > I believe your proposed fix is both necessary and correct. It should be noted that this code is the same as Alexander Kabaev's original proposed patch. Alexander's new patch, which I also suggested, is to overallocate the vector area, and then update it in place. I think that Alexander's new patch is a better workaround for the problem, both because (as he points out) the pointer fix fails when the VFS becomes preemptible, and because of the extra dereference overhead. I'm not terrifically happy about either one of them, but at least there is a much lower impact in refactoring the VOP lists (the new patch) rather than reallocating them, and since both operations are exceedingly rare (add/remove a new VOP), if one has to go in, I would prefer that it be Alexander's new one. Ideally, we would back out the default_vfs.c changes, add a "next" pointer field into the VOP list, link the list forward in order of adjacency at startup, and add new VOPs by linking them onto the end the the chain. Then none of this hackery would be necessary. -- Terry To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message
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