[apparmor] [PATCH v2 0/2] apparmor: switch from zlib to zstd

[Jon Tourville]

This changes the algorithm used by apparmor to compress profile data             
from zlib to zstd, using the new zstd API introduced in 5.16.                    
                                                                                 
Zstd provides a larger range of compression levels than zlib and                 
significantly better performance at the default level (for a relatively          
small increase in compressed size).                                              
                                                                                 
At the default compression levels, zstd's execution time was 16% that            
of zlib with a size of 111%. At maximum compression levels, zstd's               
execution time was 187% that of zlib with a size of 88%. This gives              
users options for either improving performance or decreasing memory              
usage over zlib.                                                                 
                                                                                 
Performance testing was done in the kernel against the default set of            
profiles loaded by a fresh install of Ubuntu 22.04 desktop.                      
                                                                                 
v2: Patch review changes                                                         
    - Reallocate output buffer to the compressed size                            
    - Add sysfs files to expose min/max values for                               
      raw_data_compression_level                                                 

Jon Tourville (2):
  apparmor: use zstd compression for profile data
  apparmor: expose compression level limits in sysfs

 security/apparmor/Kconfig         |   4 +-
 security/apparmor/apparmorfs.c    |  89 ++++++++++++++----------
 security/apparmor/lsm.c           |  10 +--
 security/apparmor/policy_unpack.c | 109 ++++++++++++++----------------
 4 files changed, 109 insertions(+), 103 deletions(-)

-- 
2.34.1