From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andi Kleen Date: Wed, 28 Jan 2004 21:09:21 +0000 Subject: Re: [RFC/PATCH, 2/4] readX_check() performance evaluation Message-Id: <20040128220921.7ba0bb78.ak@suse.de> List-Id: References: <00a301c3e541$c13a6350$2987110a@lsd.css.fujitsu.com> <20040128182003.GL11844@parcelfarce.linux.theplanet.co.uk> <20040128204049.627e6312.ak@suse.de> <20040128211554.0cc890fb.ak@suse.de> In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Linus Torvalds Cc: willy@debian.org, ishii.hironobu@jp.fujitsu.com, linux-kernel@vger.kernel.org, linux-ia64@vger.kernel.org On Wed, 28 Jan 2004 12:28:56 -0800 (PST) Linus Torvalds wrote: > > Alternatively, if you get a lot of information at MCE time (CPU that did > the access + some device data), just queue up the information in a per-CPU > queue. You don't have to worry about overflow - you can just drop if if That assumes that the access happened with preempt off ? That's fine if it's guaranteed that the MCE still happened inside readl/writel. But if it's delayed longer for some reason there is no guarantee that you can find back to the CPU that caused the fault. Putting it into the pci_dev and using RCU would be probably better. -Andi