schwarze@ pointed out that systat(1) refers to a non-documented
function: uvm_swap_get(). I doubt referencing a UVM function is
something appropriate. Diff below tries to explain in word what the
counter is: the number of swap page that have been read from disk.
It is not only incremented in the page fault handler, so I used the
word 'moved'.
Comments, oks?
Index: usr.bin/systat/systat.1
===================================================================
RCS file: /cvs/src/usr.bin/systat/systat.1,v
retrieving revision 1.114
diff -u -p -r1.114 systat.1
--- usr.bin/systat/systat.1 16 Jan 2020 16:46:47 -0000 1.114
+++ usr.bin/systat/systat.1 22 Apr 2020 21:16:00 -0000
@@ -715,7 +715,7 @@ swap pages in use
.It swpgonly
in use swap pages not in RAM
.It nswget
-fault called uvm_swap_get()
+swap pages moved from disk to RAM
.It nanon
total anon's
.Pp
Index: sys/uvm/uvmexp.h
===================================================================
RCS file: /cvs/src/sys/uvm/uvmexp.h,v
retrieving revision 1.4
diff -u -p -r1.4 uvmexp.h
--- sys/uvm/uvmexp.h 6 Nov 2018 07:49:38 -0000 1.4
+++ sys/uvm/uvmexp.h 22 Apr 2020 21:15:37 -0000
@@ -78,7 +78,7 @@ struct uvmexp {
int swpages; /* number of PAGE_SIZE'ed swap pages */
int swpginuse; /* number of swap pages in use */
int swpgonly; /* number of swap pages in use, not also in RAM */
- int nswget; /* number of times fault calls uvm_swap_get() */
+ int nswget; /* number of swap pages moved from disk to RAM */
int nanon; /* XXX number total of anon's in system */
int unused05; /* formerly nanonneeded */
int unused06; /* formerly nfreeanon */
