Ignore forked but not exec'd child processes#1302
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This commit introduces code into the procfs Sampler such that discovered children that are not exec'd yet are not polled. We have found that in rare cases this causes a double-count of the parent's memory, although it's not accumulated as such by Linux itself. Signed-off-by: Brian L. Troutwine <brian.troutwine@datadoghq.com>
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Signed-off-by: Brian L. Troutwine <brian.troutwine@datadoghq.com>
Signed-off-by: Brian L. Troutwine <brian.troutwine@datadoghq.com>
scottopell
approved these changes
Mar 27, 2025
lading/src/observer/linux/procfs.rs
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| // This is a new process. We initialize its | ||
| // process info and then determine by | ||
| // examination of the exe/cmdline if the process | ||
| // is not exec'd -- meaning we will not poll it |
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| // is not exec'd -- meaning we will not poll it | |
| // is fork'd but not exec'd -- meaning we will not poll it |
lading/src/observer/linux/procfs.rs
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| let parent_info = match initialize_process_info(parent_pid).await { | ||
| Ok(Some(info)) => info, | ||
| Ok(None) => { | ||
| warn!("Could not initialize parent process info"); |
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I was going back and forth on whether this is fatal or not, and I agree that this is fine to return Ok, if we return an Err, then the observer server will crash and this will never retry, which is not the behavior we want. This is a retry-able error.
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To your point, this is an error and not a warning.
Technically lading recovers but an error has happened that results in unexpected results.
preinlein
approved these changes
Mar 27, 2025
This was referenced Mar 27, 2025
Signed-off-by: Brian L. Troutwine <brian.troutwine@datadoghq.com>
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What does this PR do?
This commit introduces code into the procfs Sampler such that discovered
children that are not exec'd yet are not polled. We have found that in
rare cases this causes a double-count of the parent's memory, although it's
not accumulated as such by Linux itself.