1. Computers
  2. Display Drivers
  3. Graphics Cards
  4. Memory
  5. Motherboards
  6. Processors
  7. Software
  8. Storage
  9. Operating Systems


Facebook RSS Twitter Twitter Google Plus


Phoronix Test Suite

OpenBenchmarking.org

Concerns Come Over Linaro's Memory Manager Plans

Hardware

Published on 21 April 2011 07:52 AM EDT
Written by Michael Larabel in Hardware
2 Comments

On Monday there was the Phoronix news item about Linaro aiming to unify Linux memory management; in particular it's for embedded ARM platforms and making the existing Linux video memory managers more compatible with that of the SoC designs and drivers. They want the memory manager to be able to share memory buffers across different devices and processes, which is something somewhat sought after already by Linux graphics developers for GEM/TTM, but this may end up leading to a new memory management fork.

On Monday, the Linaro group brought up the issue on the DRI development list, among other lists, but it didn't spark any noteworthy exchanges. Yesterday though it was brought up on the Wayland Display Server mailing list where a vocal discussion ensued. It's this thread.

Tiago Vignatti began by asking whether any of Linaro's kernel memory management work would be pushed upstream or whether this is a fork of the community. Linaro though plans to push the work back upstream into the mainline kernel tree.

Others also chimed in. E.g. "Not again, due! Does DRI has some mentally wrong that cann't be fixed other than re-create? Forking is not always the best thing. A is suck, I can write batter one that does exactly the same as A, but more clean code. So I go ahead and write new B. Because B is new, so I have to fix fix fix fix bugs. Long time after, B fixed all bugs and function the same as A, and, the code is now as buggy as A's."

Tom Cooksey mentions that since GEM/TTM don't current allow sharing of buffers between drivers and don't allow physically contiguous memory allocations, Linaro may end up with "a good chance TTM will be ripped out, stuck into its own driver (with its own device node /dev/ttm) and extended to meet everyone's requirements."

But, for example, upstream TTM actually wants the support for sharing of buffers between drivers since it would be needed for some multi-card configurations, etc. TTM reworking is also needed for being able to handle OpenCL on its stack, etc.

The PathScale engineers and their hired hands had also forked the PSCNV driver for the memory management reasons, among others, to adapt it to better handle such work. PathScale's prinicipal concerns boiled down to no memory security/protection, under TTM's current model the buffer objects can be moved at any time, and TTM being hard to port to other operating systems.

Linaro's Jesse Barker had the following to say on the matter: "No one wants to reinvent the wheel unless it's absolutely necessary (and it typically isn't), but SoC vendors and software partners are encountering problems that they haven't been able to solve with the current upstream mechanisms. Initially, we're primarily concerned with making sure we're asking the right questions and identifying the right people to ask and answer them. Everything will be done publicly and in the mainline. No forking, no revolution, just problem solving. If it turns out that someone else has beaten us to it, that's great."

About The Author
Michael Larabel is the principal author of Phoronix.com and founded the web-site in 2004 with a focus on enriching the Linux hardware experience and being the largest web-site devoted to Linux hardware reviews, particularly for products relevant to Linux gamers and enthusiasts but also commonly reviewing servers/workstations and embedded Linux devices. Michael has written more than 10,000 articles covering the state of Linux hardware support, Linux performance, graphics hardware drivers, and other topics. Michael is also the lead developer of the Phoronix Test Suite, Phoromatic, and OpenBenchmarking.org automated testing software. He can be followed via and or contacted via .
Latest Linux Hardware Reviews
  1. Scythe Mugen MAX
  2. Intel Core i7 5960X Haswell-E On Linux
  3. Intel 80GB 530 Series M.2 SSD On Linux
  4. With A New Motherboard, The Core i7 5960X Haswell-E Lights Up
Latest Linux Articles
  1. RadeonSI Gallium3D vs. Catalyst At 4K UHD On Linux
  2. MSAA RadeonSI Gallium3D Performance Preview
  3. Intel Core i7 5960X CPU Core Scaling Under Linux
  4. AMD RadeonSI Gallium3D Performance For 4K Linux Gaming
Latest Linux News
  1. Valve Begins Publicly Tracking AMD Catalyst Linux Issues
  2. Digia Qt Spinoff Is Called "The Qt Company"
  3. GNOME 3.14 Makes More Progress In Running Natively On Wayland
  4. Minix 3.3 Released With Cortex-A8 ARM Support, NetBSD Userland Compatibility
  5. More Intel DRM Changes Queued For Linux 3.18, Including Old i830M Fixes
  6. New Code Starts Lining Up For X.Org Server 1.17
  7. Rust Developers Planning For The Rust 1.0 Language
  8. RPM 4.12 Brings New Switches, New Rpm2Archive Utility
  9. Nouveau For Linux 3.18 Gains DP Audio, More Re-Clocking
  10. SUSE Gets Bought Out Again
Latest Forum Discussions
  1. New Group Calls For Boycotting Systemd
  2. support for first generation UVD blocks (RV6xx, RS780, RS880 and RV790)
  3. Nvidia joins the ranks of Apple and Microsoft
  4. Updated and Optimized Ubuntu Free Graphics Drivers
  5. Hd 6850
  6. nv and xorg.conf under Debian PPC
  7. X.Org Is Looking For Some Female Help
  8. FSF Issues Their Rebuttal To Apple's New iPhone, Watch & Apple Pay