Conversation
sima@chaos.social

🐧sima🐧

great architecting today, much success, I fixed a release blocking perf regression by

... reading the docs 🤯

team already did all the debugging and triaging and root-causing, but apparently reading the docs to figure out what prctl we need to set needs the big guns 😱

2
0
1
vbabka

Reply to @sima@chaos.social
@sima please tell me it wasn't PR_SET_THP_DISABLE
2
1
4
jani@fosstodon.org

Jani Nikula

Reply to @sima@chaos.social

@sima That's gotta be cheating.

0
0
1
jarkko

Jarkko Sakkinen

Reply to @vbabka
@vbabka @sima good to be aware of this +1
0
0
1
sima@chaos.social

🐧sima🐧

Reply to @vbabka

@vbabka perf regression was with a very clever hack for buffer sharing in drm across processes. but they already had a new one using pidfd_getfd as an actually cleaner design, which needs PR_SET_TRACER to work with ptrace_scope = 1

apparently no one knew this prctl exists, and they tried to ship with a "pls add CAP_SYS_PTRACE" in the release notes

0
0
1
About social.kernel.org

Terms of service

  1. Please do not use this service in violation of the Linux Kernel Code of Conduct. Doing so will result in your account suspension with the referral of the matter to the CoC committee.

  2. "Repeating"/"boosting" someone else's status on this platform will be treated as endorsement and will fall under rule #1.

  3. You are encouraged to use this platform to promote your work on the Linux Kernel, but there is no restriction on permitted topics (with the exception of anything covered by #1 above).

  4. There is no requirement to post in English, but it should be considered the primary language of communication on this platform.

Privacy notice

The admins of this service have access to all posted statuses. They aren't looking, but if it's something they shouldn't know about, then you should not post it on this platform.

Please see the Linux Foundation Privacy Policy, which applies to this platform as well.

Getting your own account

If you would like an account on this instance, please check that the following applies to you:

  • You are listed in MAINTAINERS or CREDITS

  • OR: You have a kernel.org account or email address

  • OR: You have a long and established history of involvement with the Linux Kernel

If the above is true and you agree with the Terms of Service and Privacy Notice listed above, please use these instructions to request an account: