Date: Tue, 08 Jan 2013 10:46:34 +0800 From: David Xu <davidxu@freebsd.org> To: freebsd-hackers@freebsd.org Subject: Re: Is it possible to block pending queued RealTime signals (AIO originating)? Message-ID: <50EB888A.2030802@freebsd.org> In-Reply-To: <1357608470.6752.22.camel@localhost.localdomain> References: <1357608470.6752.22.camel@localhost.localdomain>
next in thread | previous in thread | raw e-mail | index | archive | help
On 2013/01/08 09:27, 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? > I am curious that how the code BLOCKs the signal in its signal handler ? AFAIK, after signal handler returned, original signal mask is restored, and re-enables the signal delivering, unless you change it in ucontext.uc_sigmask. Regards, David Xu
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?50EB888A.2030802>