diff --git a/Macros.h b/Macros.h
index 6b064abb6..4d870afe9 100644
--- a/Macros.h
+++ b/Macros.h
@@ -33,6 +33,10 @@ in the source distribution for its full text.
 #define SPACESHIP_NUMBER(a, b)         (((a) > (b)) - ((a) < (b)))
 #endif
 
+#ifndef SPACESHIP_NUMBER_NA
+#define SPACESHIP_NUMBER_NA(a, b, na)  (((a) == (na)) ? (((b) == (na)) ? 0 : -1) : (((b) == (na)) ? 1 : SPACESHIP_NUMBER(a, b)))
+#endif
+
 #ifndef SPACESHIP_NULLSTR
 #define SPACESHIP_NULLSTR(a, b)        strcmp((a) ? (a) : "", (b) ? (b) : "")
 #endif
diff --git a/linux/LinuxProcess.c b/linux/LinuxProcess.c
index 930ef1ff9..9b79e68ca 100644
--- a/linux/LinuxProcess.c
+++ b/linux/LinuxProcess.c
@@ -113,6 +113,10 @@ Process* LinuxProcess_new(const Machine* host) {
    LinuxProcess* this = xCalloc(1, sizeof(LinuxProcess));
    Object_setClass(this, Class(LinuxProcess));
    Process_init(&this->super, host);
+   this->m_pss   = ULLONG_MAX;
+   this->m_swap  = ULLONG_MAX;
+   this->m_psswp = ULLONG_MAX;
+   this->m_epss  = ULLONG_MAX;
    return (Process*)this;
 }
 
@@ -379,13 +383,13 @@ static int LinuxProcess_compareByKey(const Process* v1, const Process* v2, Proce
    case M_PRIV:
       return SPACESHIP_NUMBER(p1->m_priv, p2->m_priv);
    case M_PSS:
-      return SPACESHIP_NUMBER(p1->m_pss, p2->m_pss);
+      return SPACESHIP_NUMBER_NA(p1->m_pss, p2->m_pss, ULLONG_MAX);
    case M_SWAP:
-      return SPACESHIP_NUMBER(p1->m_swap, p2->m_swap);
+      return SPACESHIP_NUMBER_NA(p1->m_swap, p2->m_swap, ULLONG_MAX);
    case M_PSSWP:
-      return SPACESHIP_NUMBER(p1->m_psswp, p2->m_psswp);
+      return SPACESHIP_NUMBER_NA(p1->m_psswp, p2->m_psswp, ULLONG_MAX);
    case M_EPSS:
-      return SPACESHIP_NUMBER(p1->m_epss, p2->m_epss);
+      return SPACESHIP_NUMBER_NA(p1->m_epss, p2->m_epss, ULLONG_MAX);
    case UTIME:
       return SPACESHIP_NUMBER(p1->utime, p2->utime);
    case CUTIME:
diff --git a/linux/LinuxProcess.h b/linux/LinuxProcess.h
index 0a25bc70b..c533edfa4 100644
--- a/linux/LinuxProcess.h
+++ b/linux/LinuxProcess.h
@@ -41,10 +41,10 @@ typedef struct LinuxProcess_ {
    unsigned long long int cstime;
    long m_share;
    long m_priv;
-   long m_pss;
-   long m_swap;
-   long m_psswp;
-   long m_epss;
+   unsigned long long m_pss;
+   unsigned long long m_swap;
+   unsigned long long m_psswp;
+   unsigned long long m_epss;
    long m_trs;
    long m_drs;
    long m_lrs;
diff --git a/linux/LinuxProcessTable.c b/linux/LinuxProcessTable.c
index fc43baac3..95fb17d24 100644
--- a/linux/LinuxProcessTable.c
+++ b/linux/LinuxProcessTable.c
@@ -878,8 +878,13 @@ static bool LinuxProcessTable_readSmapsFile(LinuxProcess* process, openat_arg_t
    //http://elixir.free-electrons.com/linux/v4.10/source/fs/proc/task_mmu.c#L719
    //kernel will return data in chunks of size PAGE_SIZE or less.
    FILE* fp = fopenat(procFd, haveSmapsRollup ? "smaps_rollup" : "smaps", "r");
-   if (!fp)
+   if (!fp) {
+      process->m_pss   = ULLONG_MAX;
+      process->m_swap  = ULLONG_MAX;
+      process->m_psswp = ULLONG_MAX;
+      process->m_epss  = ULLONG_MAX;
       return false;
+   }
 
    process->m_pss   = 0;
    process->m_swap  = 0;
@@ -891,6 +896,10 @@ static bool LinuxProcessTable_readSmapsFile(LinuxProcess* process, openat_arg_t
       if (!strchr(buffer, '\n')) {
          // Partial line, skip to end of this line
          if (!skipEndOfLine(fp)) {
+            process->m_pss   = ULLONG_MAX;
+            process->m_swap  = ULLONG_MAX;
+            process->m_psswp = ULLONG_MAX;
+            process->m_epss  = ULLONG_MAX;
             fclose(fp);
             return false;
          }
@@ -898,14 +907,23 @@ static bool LinuxProcessTable_readSmapsFile(LinuxProcess* process, openat_arg_t
       }
 
       if (String_startsWith(buffer, "Pss:")) {
-         process->m_pss += strtol(buffer + 4, NULL, 10);
+         process->m_pss += strtoull(buffer + 4, NULL, 10);
       } else if (String_startsWith(buffer, "Swap:")) {
-         process->m_swap += strtol(buffer + 5, NULL, 10);
+         process->m_swap += strtoull(buffer + 5, NULL, 10);
       } else if (String_startsWith(buffer, "SwapPss:")) {
-         process->m_psswp += strtol(buffer + 8, NULL, 10);
+         process->m_psswp += strtoull(buffer + 8, NULL, 10);
       }
    }
 
+   if (ferror(fp)) {
+      process->m_pss   = ULLONG_MAX;
+      process->m_swap  = ULLONG_MAX;
+      process->m_psswp = ULLONG_MAX;
+      process->m_epss  = ULLONG_MAX;
+      fclose(fp);
+      return false;
+   }
+
    process->m_epss = process->m_pss + process->m_psswp;
 
    fclose(fp);
diff --git a/pcp/PCPProcess.c b/pcp/PCPProcess.c
index ae4a3e0dc..ef2170022 100644
--- a/pcp/PCPProcess.c
+++ b/pcp/PCPProcess.c
@@ -11,6 +11,7 @@ in the source distribution for its full text.
 
 #include "pcp/PCPProcess.h"
 
+#include <limits.h>
 #include <math.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -97,6 +98,9 @@ Process* PCPProcess_new(const Machine* host) {
    PCPProcess* this = xCalloc(1, sizeof(PCPProcess));
    Object_setClass(this, Class(PCPProcess));
    Process_init(&this->super, host);
+   this->m_pss   = ULLONG_MAX;
+   this->m_swap  = ULLONG_MAX;
+   this->m_psswp = ULLONG_MAX;
    return (Process*)this;
 }
 
@@ -229,11 +233,11 @@ static int PCPProcess_compareByKey(const Process* v1, const Process* v2, Process
    case M_PRIV:
       return SPACESHIP_NUMBER(p1->m_priv, p2->m_priv);
    case M_PSS:
-      return SPACESHIP_NUMBER(p1->m_pss, p2->m_pss);
+      return SPACESHIP_NUMBER_NA(p1->m_pss, p2->m_pss, ULLONG_MAX);
    case M_SWAP:
-      return SPACESHIP_NUMBER(p1->m_swap, p2->m_swap);
+      return SPACESHIP_NUMBER_NA(p1->m_swap, p2->m_swap, ULLONG_MAX);
    case M_PSSWP:
-      return SPACESHIP_NUMBER(p1->m_psswp, p2->m_psswp);
+      return SPACESHIP_NUMBER_NA(p1->m_psswp, p2->m_psswp, ULLONG_MAX);
    case UTIME:
       return SPACESHIP_NUMBER(p1->utime, p2->utime);
    case CUTIME:
diff --git a/pcp/PCPProcess.h b/pcp/PCPProcess.h
index e95375714..2baafdd8b 100644
--- a/pcp/PCPProcess.h
+++ b/pcp/PCPProcess.h
@@ -37,9 +37,9 @@ typedef struct PCPProcess_ {
    unsigned long long int cstime;
    long m_share;
    long m_priv;
-   long m_pss;
-   long m_swap;
-   long m_psswp;
+   unsigned long long m_pss;
+   unsigned long long m_swap;
+   unsigned long long m_psswp;
    long m_trs;
    long m_drs;
    long m_lrs;
diff --git a/pcp/PCPProcessTable.c b/pcp/PCPProcessTable.c
index c227dca08..08432163a 100644
--- a/pcp/PCPProcessTable.c
+++ b/pcp/PCPProcessTable.c
@@ -212,9 +212,9 @@ static void PCPProcessTable_updateMemory(PCPProcess* pp, int pid, int offset) {
 }
 
 static void PCPProcessTable_updateSmaps(PCPProcess* pp, pid_t pid, int offset) {
-   pp->m_pss = Metric_instance_u64(PCP_PROC_SMAPS_PSS, pid, offset, 0);
-   pp->m_swap = Metric_instance_u64(PCP_PROC_SMAPS_SWAP, pid, offset, 0);
-   pp->m_psswp = Metric_instance_u64(PCP_PROC_SMAPS_SWAPPSS, pid, offset, 0);
+   pp->m_pss = Metric_instance_u64(PCP_PROC_SMAPS_PSS, pid, offset, ULLONG_MAX);
+   pp->m_swap = Metric_instance_u64(PCP_PROC_SMAPS_SWAP, pid, offset, ULLONG_MAX);
+   pp->m_psswp = Metric_instance_u64(PCP_PROC_SMAPS_SWAPPSS, pid, offset, ULLONG_MAX);
 }
 
 static void PCPProcessTable_readOomData(PCPProcess* pp, int pid, int offset) {