Questions about /proc/stat

M. Edward (
Thu, 28 Mar 2002 09:18:07 -0800 (PST)

I have some questions about the "page" and "swap" entries in /proc/stat.
Here is the relevant code from 2.4.12

292 len += sprintf(page + len,
293 "page %u %u\n"
294 "swap %u %u\n"
295 "intr %u",
296 kstat.pgpgin >> 1,
297 kstat.pgpgout >> 1,
298 kstat.pswpin,
299 kstat.pswpout,
300 sum
301 );

1. Why are kstat.pgpgin and kstat.pgpgout shifted right / halved?

2. Are the "page" and "swap" numbers mutually exclusive? That is, if a
page is brought in from swap and counted in kstat.pswpin, is it also
counted in kstat.pgpgin? I found the places in the code where the counts
are incremented, but I couldn't tell if the swapin routine calls the
block driver or not.

M. Edward Borasky

Actually, for their size, elephants don't smell all that bad.

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