From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chris Wilson Subject: Re: [PATCH 00/26] [RFCish] GEN7 dynamic page tables Date: Thu, 20 Mar 2014 12:17:18 +0000 Message-ID: <20140320121718.GD4463@nuc-i3427.alporthouse.com> References: <1395121738-29126-1-git-send-email-benjamin.widawsky@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from fireflyinternet.com (mail.fireflyinternet.com [87.106.93.118]) by gabe.freedesktop.org (Postfix) with ESMTP id 197E36E046 for ; Thu, 20 Mar 2014 05:17:21 -0700 (PDT) Content-Disposition: inline In-Reply-To: <1395121738-29126-1-git-send-email-benjamin.widawsky@intel.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" To: Ben Widawsky Cc: Intel GFX List-Id: intel-gfx@lists.freedesktop.org On Mon, Mar 17, 2014 at 10:48:32PM -0700, Ben Widawsky wrote: > Okay, so what does this do? > The patch series /dynamicizes/ page table allocation and teardown for > GEN7. It also starts to introduce GEN8, but the tricky stuff is still > not done. Up until now, all our page tables are pre-allocated when the > address space is created. That's actually okay for current GENs since we > don't use many address spaces, and the page tables occupy only 2MB each. > However, on GEN8 we can use a deeper page table, and to preallocate such > an address space would be very costly. This work was done for GEN7 first > because this is the most well tested with full PPGTT, and stable > platforms are readily available. > > In this patch series, I've demonstrated how we will manage tracking used > page tables (bitmaps), and broken things out into much more discrete > functions. I'm hoping I'll get feedback on the way I've implemented > things (primarily if it seems fundamentally flawed in any way). The real > goal was to prove out the dynamic allocation so we can begin to enable > GEN8 in the same way. I'll emphasize now that I put in a lot of effort > limit risk with each patch, and this does result in some excess churn. I like it. -Chris -- Chris Wilson, Intel Open Source Technology Centre