From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pavel Machek Subject: Re: [ofa-general] Re: [GIT PULL] please pull ummunotify Date: Mon, 28 Sep 2009 22:49:23 +0200 Message-ID: <20090928204923.GA1960@elf.ucw.cz> References: <20090915113434.GF1328@ucw.cz> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Roland Dreier Cc: linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, general-ZwoEplunGu1OwGhvXhtEPSCwEArCW2h5@public.gmane.org, akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org, torvalds-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org List-Id: linux-rdma@vger.kernel.org On Tue 2009-09-15 07:57:56, Roland Dreier wrote: > > > I don't remember seeing discussion of this on lkml. Yes it is in > > -next... > > eg http://lkml.org/lkml/2009/7/31/197 and followups, or search for v2 > and earlier patches. Well... it seems little overspecialized. Just modifying libc to provide hooks you want looks like better solution. > > Basically it allows app to 'trace itself'? ...with interesting mmap() > > interface, exporting int to userspace, hoping it behaves atomically...? > > Yes, it allows app to trace what the kernel does to memory mappings. I > don't believe there's any real issue to atomicity of mmap'ed memory, > since userspace really just tests whether read value is == to old read > value or not. That still needs memory barriers etc.. to ensure reliable operation, no? Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html