Date: Mon, 07 Jan 2013 22:26:52 -0800 From: Richard Sharpe <rsharpe@richardsharpe.com> To: Daniel Eischen <deischen@freebsd.org> Cc: freebsd-hackers@freebsd.org Subject: Re: Is it possible to block pending queued RealTime signals (AIO originating)? Message-ID: <1357626412.6752.24.camel@localhost.localdomain> In-Reply-To: <Pine.GSO.4.64.1301072215400.14726@sea.ntplx.net> References: <1357608470.6752.22.camel@localhost.localdomain> <Pine.GSO.4.64.1301072215400.14726@sea.ntplx.net>
next in thread | previous in thread | raw e-mail | index | archive | help
On Mon, 2013-01-07 at 22:24 -0500, Daniel Eischen wrote: > On Mon, 7 Jan 2013, Richard Sharpe wrote: > > > Hi folks, > > > > I am running into a problem with AIO in Samba 3.6.x under FreeBSD 8.0 > > and I want to check if the assumptions made by the original coder are > > correct. > > > > Essentially, the code queues a number of AIO requests (up to 100) and > > specifies an RT signal to be sent upon completion with siginfo_t. > > > > These are placed into an array. > > > > The code assumes that when handling one of these signals, if it has > > already received N such siginfo_t structures, it can BLOCK further > > instances of the signal while these structures are drained by the main > > code in Samba. > > > > However, my debugging suggests that if a bunch of signals have already > > been queued, you cannot block those undelivered but already queued > > signals. > > > > I am certain that they are all being delivered to the main thread and > > that they keep coming despite the code trying to stop them at 64 (they > > get all the way up to the 100 that were queued.) > > > > Can someone confirm whether I have this correct or not? > > If true, could they not use sigwaitinfo() from a separate > thread instead and just bypass having to use a signal > handler altogether? That thread can either call sigwaitinfo() > when it is ready to receive more signals, or block on a > semaphore/CV/whatever while events are being processed. So, I guess that what I want is something that will continue to work for both Linux and FreeBSD with minimal code divergence ... I guess I need to write a simpler program to check what the deal is.
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?1357626412.6752.24.camel>