getpagesize() to size_t. For some reason getpagesize() is defined to
return int, and several of the page counts we get come back from the
kernel as int32_t; in LP64 without the cast the byte count will be
computed in a 32-bit value and for large processes will overflow and
become negative... and then remain negative when divided by 1024 to
convert to kilobytes.
Fixes a problem I hit the other day where I saw negative RSS, which
turns out also to be PR 40642.
Note: other logic in here will break down when we first get >2TB
processes... and int32 page counts will break on >8TB processes. But
hopefully we won't see any of that for a few years yet.
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