prevent the read ahead of /proc/slabinfo in ss

Signed-off-by: Bryton Lee <brytonlee01@gmail.com>

diff --git a/misc/ss.c b/misc/ss.c
index a5c482f65edcbf4cc764d09793dbf57ecf762a90..2678033fc344c7d65ffb62703d80029ab3f76edd 100644 (file)
--- a/misc/ss.c
+++ b/misc/ss.c
@@ -618,7 +618,7 @@ struct slabstat
        int skbs;
 };
 
-struct slabstat slabstat;
+static struct slabstat slabstat;
 
 static const char *slabstat_ids[] =
 {
@@ -634,6 +634,10 @@ static int get_slabstat(struct slabstat *s)
        char buf[256];
        FILE *fp;
        int cnt;
+       static int slabstat_valid;
+
+       if (slabstat_valid)
+               return 0;
 
        memset(s, 0, sizeof(*s));
 
@@ -657,6 +661,8 @@ static int get_slabstat(struct slabstat *s)
                        break;
        }
 
+       slabstat_valid = 1;
+
        fclose(fp);
        return 0;
 }
@@ -2297,6 +2303,8 @@ static int tcp_show(struct filter *f, int socktype)
         * it is able to give us some memory for snapshot.
         */
        if (1) {
+               get_slabstat(&slabstat);
+
                int guess = slabstat.socks+slabstat.tcp_syns;
                if (f->states&(1<<SS_TIME_WAIT))
                        guess += slabstat.tcp_tws;
@@ -3234,6 +3242,8 @@ static int print_summary(void)
        if (get_snmp_int("Tcp:", "CurrEstab", &sn.tcp_estab) < 0)
                perror("ss: get_snmpstat");
 
+       get_slabstat(&slabstat);
+
        printf("Total: %d (kernel %d)\n", s.socks, slabstat.socks);
 
        printf("TCP:   %d (estab %d, closed %d, orphaned %d, synrecv %d, timewait %d/%d), ports %d\n",
@@ -3587,8 +3597,6 @@ int main(int argc, char *argv[])
        argc -= optind;
        argv += optind;
 
-       get_slabstat(&slabstat);
-
        if (do_summary) {
                print_summary();
                if (do_default && argc == 0)