Linux Kernel, Linux Foundation and Graphics


-
The final step for huge-page swapping
For many years, Linux system administrators have gone out of their way to avoid swapping. The advent of nonvolatile memory is changing the equation, though, and swapping is starting to look interesting again — if it can perform well enough. That is not the case in current kernels, but a longstanding project to allow the swapping of transparent huge pages promises to improve that situation considerably. That work is reaching its final stage and might just enter the mainline soon.
The use of huge pages can improve the performance of the system significantly, so the kernel works hard to make them available. The transparent huge pages mechanism collects application data into huge pages behind the scenes, and the memory-management subsystem as a whole works hard to ensure that appropriately sized pages are available. When it comes time to swap out a process's pages, though, all of that work is discarded, and a huge page is split back into hundreds of normal pages to be written out. When swapping was slow and generally avoided, that didn't matter much, but it is a bigger problem if one wants to swap to a fast device and maintain performance.
-
Revisiting the MAP_SHARED_VALIDATE hack
One of the the most commonly repeated mistakes in system-call design is a failure to check for unknown flags wherever flags are accepted. If there is ever a point where callers can get away with setting unknown flags, then adding new flags becomes a hazardous act. In the case of mmap(), though, developers found a clever way around this problem. A recent discussion has briefly called that approach into question, though, and raised the issue of what constitutes a kernel regression. No changes are forthcoming as a result, but the discussion does provide an opportunity to look at both the specific hack and how the kernel community decides whether a change is a regression or not.
Back in 2017, several developers were trying to figure out a way to safely allow direct user-space access to files stored on nonvolatile memory devices. The hardware allows this memory to be addressed directly by the processor, but any changes could go astray if the filesystem were to move blocks around at the same time. The solution that arose was a new mmap() flag called MAP_SYNC. When a file is mapped with this flag set (and the file is stored on a nonvolatile memory device), the kernel will take extra care to ensure that access to the mapping and filesystem-level changes will not conflict with each other. As far as applications are concerned, using this flag solves the problem.
-
Take Our Survey on Open Source Programs
Please take eight minutes to complete this survey. The results will be shared publicly on The New Stack, and The Linux Foundation’s GitHub page.
-
Mesa 18.1.4 release candidate
Mesa 18.1.4 is planned for release this Friday, July 13th, at or around 10 AM PDT.
-
Mesa 18.1.4 Being Prepared With Intel Fixes & A Couple For Radeon
Another routine Mesa 18.1. point release is being prepared while waiting for the August debut of the Mesa 18.2 feature update.
Dylan Baker, the Mesa 18.1 release manager and his first stab at the task, has announced the Mesa 18.1.4 release candidate today. In its current form, Mesa 18.1.4 is comprised of just over two dozen patches.
-
Pre-AMDGPU xf86-video-ati X.Org Driver Sees A Round Of Improvements
It's rare in recent years to have anything to report on xf86-video-ati, the X.Org driver for the display/2D experience for pre-GCN Radeon graphics cards. But this week has been a large batch of fixes and improvements for those using this DDX driver with pre-HD7000 series hardware.
Longtime Radeon Linux driver developer Michel Dänzer has landed a number of commits already this week of various fixes/cleanups, some of which were inspired by the xf86-video-amdgpu DDX driver that is used for current-generation hardware with the AMDGPU kernel driver (unless using xf86-video-modesetting...).
-
- Login or register to post comments
Printer-friendly version
- 1492 reads
PDF version
More in Tux Machines
- Highlights
- Front Page
- Latest Headlines
- Archive
- Recent comments
- All-Time Popular Stories
- Hot Topics
- New Members
- February 2019 (796)
- January 2019 (1149)
- December 2018 (996)
- November 2018 (989)
- October 2018 (942)
- September 2018 (948)
- August 2018 (1020)
- July 2018 (950)
- June 2018 (918)
- May 2018 (932)
- April 2018 (884)
- March 2018 (929)
- February 2018 (781)
- January 2018 (893)
- December 2017 (769)
- November 2017 (870)
- October 2017 (841)
- September 2017 (888)
- August 2017 (889)
- July 2017 (930)
- June 2017 (876)
- May 2017 (704)
- April 2017 (947)
- March 2017 (991)
- February 2017 (871)
- January 2017 (977)
- December 2016 (944)
- November 2016 (929)
- October 2016 (988)
- September 2016 (1064)
Recent comments
31 min 14 sec ago
1 hour 15 min ago
2 hours 10 min ago
8 hours 3 min ago
8 hours 7 min ago
8 hours 8 min ago
8 hours 11 min ago
21 hours 56 min ago
22 hours 18 min ago
1 day 5 hours ago