From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chris Wilson Subject: Re: [PATCH 15/26] drm/i915: Create page table allocators Date: Tue, 18 Mar 2014 09:14:09 +0000 Message-ID: <20140318091409.GF18530@nuc-i3427.alporthouse.com> References: <1395121738-29126-1-git-send-email-benjamin.widawsky@intel.com> <1395121738-29126-16-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 1A0802BE26 for ; Tue, 18 Mar 2014 02:14:12 -0700 (PDT) Content-Disposition: inline In-Reply-To: <1395121738-29126-16-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 10:48:47PM -0700, Ben Widawsky wrote: > As we move toward dynamic page table allocation, it becomes much easier > to manage our data structures if break do things less coarsely by > breaking up all of our actions into individual tasks. This makes the > code easier to write, read, and verify. > > Aside from the dissection of the allocation functions, the patch > statically allocates the page table structures without a page directory. > This remains the same for all platforms, > > The patch itself should not have much functional difference. The primary > noticeable difference is the fact that page tables are no longer > allocated, but rather statically declared as part of the page directory. > This has non-zero overhead, but things gain non-trivial complexity as a > result. We increase overhead for increased complexity. What's the selling point of this patch then? Otherwise, patch does as you say. -Chris -- Chris Wilson, Intel Open Source Technology Centre