Date: Wed, 5 Oct 2016 16:14:12 +0300 From: Konstantin Belousov <kostikbel@gmail.com> To: Lewis Donzis <lew@perftech.com> Cc: Jilles Tjoelker <jilles@stack.nl>, deischen@freebsd.org, freebsd-arch@freebsd.org Subject: Re: mq on kqueue broken after upgrade to FreeBSD 11 Message-ID: <20161005131412.GF38409@kib.kiev.ua> In-Reply-To: <95CA96C0-A0F2-46B6-8BEA-E1A923FEC91D@perftech.com> References: <20160930184418.1047afc2@kan> <20161001092515.GW38409@kib.kiev.ua> <20161001201655.GA91457@stack.nl> <20161001210722.GC38409@kib.kiev.ua> <20161001231524.GB91457@stack.nl> <20161002114613.GE38409@kib.kiev.ua> <20161002132242.GA2628@stack.nl> <7A72D37B-6C57-41FE-893F-592235A19D9D@perftech.com> <20161002163708.GG38409@kib.kiev.ua> <95CA96C0-A0F2-46B6-8BEA-E1A923FEC91D@perftech.com>
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On Mon, Oct 03, 2016 at 07:27:54AM -0500, Lewis Donzis wrote: > That's a very good point, I hadn't considered those other functions, > and it???s clear that an fd is allocated and stored in the mqd_t. > But using close() instead of mq_close() wouldn't delete the sigevent > or free the memory that was allocated by mq_open(). In other words, > I don't understand why you'd ever want/need to use close() on the > underlying fd. I really have troubles giving any useful interpretation to your question. OS provides the kernel service which backs the posix message queue implementation in userspace, as a file descriptor. To release resources designated by the file descriptor, it must be closed, as in, close(2) must be called. Librt does this in mq_close(3). Why should I need to show a case of using close(2) on kernel mq descriptor (perhaps besides librt) ? And how this changes or augments the fact that kmq is file descriptor ?
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