Memory leak in Apache?

["Arnab Ganguly" <aganguly01@xxxxxxxxx>]

Hi All,
I was referring to http://httpd.apache.org/docs/2.0/misc/perf-tuning.html and the below paragraph is a snippet from the given url
I am not clear about the which memory leaks it is referring.I have highlighted that part.

Related to process creation is process death induced by the
    MaxRequestsPerChild
    setting. By default this is 0,
    which means that there is no limit to the number of requests
    handled per child. If your configuration currently has this set
    to some very low number, such as 30, you may want to bump this
    up significantly. If you are running SunOS or an old version of
    Solaris, limit this to 10000 or so because of memory leaks.

Can somebody explain me the above memory leaks?Is it fixed in the 
Apache2.2 onwards release, also in case of Linux OS do we need to follow the same procedure as that of SunOS for the param MaxRequestPerChild.

Thanks in advance.
-A