The following reply was made to PR kern/31430; it has been noted by GNATS.
From: YAMAMOTO Takashi <yamt@xxxxxxxxxxxxxxxxx>
Cc: christos@xxxxxxxxxx, gnats-bugs@xxxxxxxxxx,
Subject: Re: kern/31430: ptyfs isn't getting mtime right
Date: Thu, 13 Oct 2005 01:00:50 +0900
> The patch below is a result of a discussion off-line with Christos.
> The granularity of the mtime doesn't need to be down to the nanosecond
> - using the kernel "time" variable (which is updated on each
> hardclock call) saves a potentially relatively expensive call to
> microtime/nanotime for each write, and is more than accurate enough to
> track pty idle times.
it isn't good to mix "time" and nanotime
because it can make timestamps go backward sometimes.