After two months of development Linus Torvalds introduced The kernel release Linux 5.13 . Among the most notable changes: EROFS file system, initial support for Apple M1 chips, CGRUP controller “MISC”, termination of support / dev / kmem, support for new GPU Intel and AMD, the ability to directly call the kernel functions from BPF programs, randomization of the kernel stack for Each system call, the ability to build in CFI with CFI protection (Control Flow Integrity), LandLock LSM module for additional processes restrictions, virtual audio device based on Virtio, Multi-Shot mode in IO_URING.
The new version is taken 17189 fixes from 2150 developers (the largest in history), the size of the patch is 60 MB (changes affected 12996 files, added 794705 lines of code, removed 399590 lines). About 47% of all changes presented in 5.13 are associated with device drivers, about 14% of the changes have
Attitude to the update code specific to hardware architectures, 13%
associated with a network stack, 5% – with file systems and 4% with internal
core subsystems.
- Disk subsystem, enter / output and file systems
- Added Support File System Erofs (Enhanced Read-Only File System) proposed by Huawei for use on read-only sections. The new FS supports data storage in a compressed form and compared to EXT4 demonstrates similar performance when performing sequential read operations, but once overtakes EXT4 with random access to the data. For example, with compression level 4 and testing on a server with a hard disk of FS EROFS overtook EXT4 in random read operations more than six times, and when using an Android smartphone with Flash almost three times. As in other Read-Only FS, the EROFS structure is significantly simplified by discarding when implementing some metadata areas, such as bitmap cards.
- For the SMB3 file system, the mounting option “Rasize” is implemented, with which you can determine the size of the proactive reading window (READAHAD) to increase the performance of some types of load.
- in FS EXT4 is provided to overwrite directory items when you delete files. Ext4 is also allowed simultaneous use of the operation mode without records of symbols and encryption register.
- in FS EXFAT Added support for the Fitrim IOCTL command (Discard), to inform the drive about unused in FS blocks.
- In FS XFS Added the ability to seize the place from the last distribution group in the FS, which was the first link in implementing the function reduction function of existing sections with FS XFS.
- Added new system call quotactl_path, which differs from the quotactl by which allows you to control quotas not through a special device file, but through the direction of the path to the mounting point of the FS.