Date: Tue, 6 Jul 2004 17:17:32 +1000 From: Tim Robbins <tjr@freebsd.org> To: ngl <ngl@ur.ru> Cc: freebsd-stable@freebsd.org Subject: Re: Shared/exclusive (rw) locks Message-ID: <20040706071732.GA64106@cat.robbins.dropbear.id.au> In-Reply-To: <0e6601c46324$d335afe0$8501a8c0@spirit> References: <0e0401c46312$089eea10$8501a8c0@spirit> <20040706050055.GA63647@cat.robbins.dropbear.id.au> <0e3d01c46316$df50c7a0$8501a8c0@spirit> <20040706054134.GB63647@cat.robbins.dropbear.id.au> <0e6601c46324$d335afe0$8501a8c0@spirit>
next in thread | previous in thread | raw e-mail | index | archive | help
On Tue, Jul 06, 2004 at 12:45:27PM +0600, ngl wrote: > That means, freebsd stable has no spin rwlocks ? Right. Reader-writer spinlocks would not be very useful in FreeBSD 4; because only one thread can be running in the kernel at once, the only opportunity you'd have to share reader locks would be if you slept while holding a spinlock, which is a bad idea (and not permitted by FreeBSD 5 or Linux). If you want -rwlocks, you'll have to use lockmgr() (which is a sleep lock). Tim
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20040706071732.GA64106>