ACK: [SRU][F:aws][PATCH v2 0/1] Set CONFIG_LOG_BUF_SHIFT=18 on all 64bit arches

[Agathe Porte]

2024-11-07 08:23 CET, Koichiro Den:
> BugLink: https://bugs.launchpad.net/bugs/2085493
> 
> SRU Justification:
> 
> [Impact]
> 
> CONFIG_LOG_BUF_SHIFT has been kept at 14 on arm64 instances. The small
> log_buf has led to sporadic test failures (see LP#2085493). Furthermore,
> since it can easily fill up before systemd-journald starts, some boot
> kernel log messages may be lost. Align the settings with master kernel
> for simplicity's sake, including other architectures.
> 
> [Fix]
> 
> Set CONFIG_LOG_BUF_SHIFT=18, which is sufficient in normal
> circumstances.
> 
> [Test Plan]
> 
> Boot testing suffices.
> I have tested with log_buf_len=256K on b:linux-aws-5.4 and confirmed that the
> sporadic failures observed in LP#2085493 disappeared.
> 
> [Where problems could occur]
> 
> Raising the size of the log_buf will increase kernel memory usage
> which cannot be reclaimed. On arm64 instance types, the size will
> increase from 16 KB to 256 KB. Users who want to keep it at 16 KB
> might need to explicitly set log_buf_len= kernel parameter.
> 
> [Notes]
> 
> v2:
>   - fix BugLink in commit message + fix subject
> 
> 
> Koichiro Den (1):
>   UBUNTU: [Config] aws: CONFIG_LOG_BUF_SHIFT=18 on all 64bit arches
> 
>  debian.aws/config/annotations | 1 -
>  1 file changed, 1 deletion(-)

Acked-by: Agathe Porte <agathe.porte at canonical.com>