Date: Sun, 14 Jul 2002 03:20:04 -0700 (PDT) From: Don Lewis <dl-freebsd@catspoiler.org> To: phk@critter.freebsd.dk Cc: arch@FreeBSD.ORG Subject: Re: wiring the sysctl output buffer Message-ID: <200207141020.g6EAK4wr020922@gw.catspoiler.org> In-Reply-To: <56792.1026640649@critter.freebsd.dk>
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On 14 Jul, Poul-Henning Kamp wrote: > In message <200207140954.g6E9sBwr020599@gw.catspoiler.org>, Don Lewis writes: >>On 14 Jul, Poul-Henning Kamp wrote: >>> It used to be that sysctl unconditionally wired the output buffer, >>> but that gave rise to a host of other problems. >> >>Anything specific that I should be aware of? > > No, just bad deadlocks and such. > > You may also want to restrict the amount of buffer you pin > if I hand the kernel a 2G buffer for a 4 byte sysctl integer > you wouldn't want to pin it all. Yeah, that could be bad, but the SYSCTL_OUT() in the current API pins the whole user supplied buffer on the first call. My new entry point does the same thing, but allows the caller to do this potentially blocking operation earlier. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message
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