Date: Fri, 12 Jul 2002 14:09:32 -0400 (EDT) From: John Baldwin <jhb@FreeBSD.org> To: Mike Makonnen <makonnen@pacbell.net> Cc: freebsd-smp@FreeBSD.ORG, Alfred Perlstein <bright@mu.org> Subject: Re: Getting resource limits out from under Giant Message-ID: <XFMail.20020712140932.jhb@FreeBSD.org> In-Reply-To: <20020712020633.6a66f187.makonnen@pacbell.net>
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On 12-Jul-2002 Mike Makonnen wrote: > On Fri, 12 Jul 2002 01:16:32 -0700 > Alfred Perlstein <bright@mu.org> wrote: > >> >> Cool! Are you sure that no one can come in and mess with some other >> process's p->p_limit structure? If so you may need to protect >> it via the proc lock. >> > > Hmm... looks like I missed one. The vm system touches it. Other than > that, > it looks like all other references are just reading from it. > > In the case where there's a chance I might switch plimits structures > I do a proc lock in addition to locking the limits structure. Otherwise, > if all I'm doing is changing the value of one of the limits I only lock > the > limits structure itself. Is that not enough? You need to ensure you have a stable reference to the limits structure. If you are dereferencing p_limit you need to use the proc lock to protect reading that pointer. The lock also ensure the value is up to date. -- 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-smp" in the body of the message
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