vmem: add metrics start with "pgscan_" in Kernel Linux

Some Linux Kernel versions have metrics start with "pgscan_"
in /proc/vmstat, for instance:
```
cat /proc/vmstat | grep pgscan
pgscan_kswapd 0
pgscan_direct 0
pgscan_direct_throttle 0
```

Signed-off-by: tiozhang <zyhtheonly@yeah.net>
Signed-off-by: luffysong <zsfz_one@163.com>
Co-authored-by: luffysong <zsfz_one@163.com>

diff --git a/src/vmem.c b/src/vmem.c
index a4112bbbad1d1d3f3a09eeede81b45cbea85b46b..64b78dda41c228d45ace257792558ac0479d11c7 100644 (file)
--- a/src/vmem.c
+++ b/src/vmem.c
@@ -211,6 +211,10 @@ static int vmem_read(void) {
       char *inst = key + strlen("pgsteal_");
       value_t value = {.derive = counter};
       submit_one(inst, "vmpage_action", "steal", value);
+    } else if (strncmp("pgscan_", key, strlen("pgscan_")) == 0) {
+      char *inst = key + strlen("pgscan_");
+      value_t value = {.derive = counter};
+      submit_one(inst, "vmpage_action", "scan", value);
     } else if (strncmp("pgscan_kswapd_", key, strlen("pgscan_kswapd_")) == 0) {
       char *inst = key + strlen("pgscan_kswapd_");
       value_t value = {.derive = counter};