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In man page of ps under Process State Codes, the I flag (capital i) is not mentioned but ps aux shows the I flag in some processes as shown by the image below.

enter image description here

What does the I flag mean?

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    Please, DO NOT post pictures of text. Copying it out of terminal would have been much easier for both of us. – NieDzejkob Dec 23 '17 at 10:53
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It means “idle”. This state was introduced very recently, in September 2017 (version 4.14 of the Linux kernel). It is used for kernel threads which use the TASK_IDLE state when idling, instead of TASK_INTERRUPTIBLE; in previous versions of the kernel, such threads were reported as TASK_UNINTERRUPTIBLE which was confusing.

ps reports this without needing any change itself, because it reports the state directly from /proc.

  • What is the difference between those two states? – Thorbjørn Ravn Andersen Dec 22 '17 at 19:08
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    See this commit: uninterruptible tasks contribute to the load average, so idle kernel threads idled in interruptible state, but that caused some issues, so a new “no load” state was introduced, along with a helper “idle” state. The idle state was made reportable in the later patch linked in the answer. So basically “idle” is “uninterruptible” but doesn’t contribute to the load average. – Stephen Kitt Dec 22 '17 at 20:12

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