From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ecfrec.frec.bull.fr (ecfrec.frec.bull.fr [129.183.4.8]) by ozlabs.org (Postfix) with ESMTP id D5839DDE17 for ; Wed, 3 Sep 2008 23:41:15 +1000 (EST) Date: Wed, 3 Sep 2008 15:41:05 +0200 From: Sebastien Dugue To: benh@kernel.crashing.org Subject: Re: [PATCH 2/2] powerpc - Make the irq reverse mapping radix tree lockless Message-ID: <20080903154105.7dff49db@bull.net> In-Reply-To: <1219209781.21386.25.camel@pasglop> References: <1218029429-21114-1-git-send-email-sebastien.dugue@bull.net> <1218029429-21114-3-git-send-email-sebastien.dugue@bull.net> <1219209781.21386.25.camel@pasglop> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Cc: dwalker@mvista.com, tinytim@us.ibm.com, linux-rt-users@vger.kernel.org, linux-kernel@vger.kernel.org, rostedt@goodmis.org, jean-pierre.dion@bull.net, michael@ellerman.id.au, linuxppc-dev@ozlabs.org, paulus@samba.org, gilles.carry@ext.bull.net, tglx@linutronix.de List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Wed, 20 Aug 2008 15:23:01 +1000 Benjamin Herrenschmidt wrote: > BTW. It would be good to try to turn the GFP_ATOMIC into GFP_KERNEL, That would be nice indeed > maybe using a semaphore instead of a lock to protect insertion vs. > initialisation. a semaphore? are you meaning a mutex? If not, I fail to understand what you're implying. > The old scheme was fine because if the atomic allocation > failed, it could fallback to the linear search and try again on the next > interrupt. Not anymore. Right, that's the problem with this new scheme and I'm still trying to find a way to handle memory allocation failures be it for GFP_ATOMIC or GFP_KERNEL. I could not think of anything simple so far and I'm open for suggestions. Thanks, Sebastien.