6 ms·

There are more details in https://lwn.net/Articles/864184/ https://lwn.net/Articles/864184/. I already forgot why it's necessary, but I know the article explain

• marcodiego 5y ago
  For the record: "The killed process is, itself, responsible for cleaning up and freeing its resources, a task that is carried out in kernel context. If, however, the killed process finds itself blocked in an uninterruptible sleep, that cleanup work could be delayed indefinitely. There are other factors that can slow down the freeing of memory, including how busy the relevant CPU is and whether that CPU is running in a slow, low-power state."