From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Hellstrom Date: Mon, 03 Jan 2011 14:14:23 +0000 Subject: Re: SPARC32 SMP IRQ15 question Message-Id: <4D21E6C7.8070207@gaisler.com> List-Id: References: <4D0A2102.8030100@gaisler.com> In-Reply-To: <4D0A2102.8030100@gaisler.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: sparclinux@vger.kernel.org David Miller wrote: >From: Daniel Hellstrom >Date: Wed, 22 Dec 2010 14:23:27 +0100 > > > >>I will try to create a patch for the atomic layer for SMP LEON systems >>since they have the CASA instruction. >> >> > >But see my other posting, you still have to fix the irq15 problem. > >Merely switching to CASA doesn't mean you don't still have a problem >because spin_lock_irqsave() and other similar pieces of code expect >they will not be interrupted by smp_call_function() calls. > > I totally agree, I brought up the atomic layer as an example because it could be triggered easiest. The atomic layer can be modified for LEON to gain some performance improvements I guess, I made a dirty patch for testing it seemed to work but then it freezes in the memory zone lock instead. I will continue my investigations later, first I want to clean up my single-CPU patches and submit them to the list. Daniel