Linux: Add PSS (proportional set size), Swap and SwapPSS calculation

Original code was written by *Craig M. Brandenburg* for htop 1.0.2
Many performance improvements by GitHub user *linvinus*, ported to htop 2.0.2

linux/LinuxProcess.c

@@ -24,6 +24,7 @@ in the source distribution for its full text.
 #define PROCESS_FLAG_LINUX_VSERVER  0x0400
 #define PROCESS_FLAG_LINUX_CGROUP   0x0800
 #define PROCESS_FLAG_LINUX_OOM      0x1000
+#define PROCESS_FLAG_LINUX_SMAPS    0x2000
 
 typedef enum UnsupportedProcessFields {
    FLAGS = 9,
@@ -87,7 +88,10 @@ typedef enum LinuxProcessFields {
    PERCENT_IO_DELAY = 117,
    PERCENT_SWAP_DELAY = 118,
    #endif
-   LAST_PROCESSFIELD = 119,
+   M_PSS = 119,
+   M_SWAP = 120,
+   M_PSSWP = 121,
+   LAST_PROCESSFIELD = 122,
 } LinuxProcessField;
 
 #include "IOPriority.h"
@@ -103,6 +107,9 @@ typedef struct LinuxProcess_ {
    unsigned long long int cutime;
    unsigned long long int cstime;
    long m_share;
+   long m_pss;
+   long m_swap;
+   long m_psswp;
    long m_trs;
    long m_drs;
    long m_lrs;
@@ -239,6 +246,9 @@ ProcessFieldData Process_fields[] = {
    [PERCENT_IO_DELAY] = { .name = "PERCENT_IO_DELAY", .title = "IOD% ", .description = "Block I/O delay %", .flags = 0, },
    [PERCENT_SWAP_DELAY] = { .name = "PERCENT_SWAP_DELAY", .title = "SWAPD% ", .description = "Swapin delay %", .flags = 0, },
 #endif
+   [M_PSS] = { .name = "M_PSS", .title = "  PSS ", .description = "proportional set size, same as M_RESIDENT but each page is divided by the number of processes sharing it.", .flags = PROCESS_FLAG_LINUX_SMAPS, },
+   [M_SWAP] = { .name = "M_SWAP", .title = " SWAP ", .description = "Size of the process's swapped pages", .flags = PROCESS_FLAG_LINUX_SMAPS, },
+   [M_PSSWP] = { .name = "M_PSSWP", .title = " PSSWP ", .description = "shows proportional swap share of this mapping, Unlike \"Swap\", this does not take into account swapped out page of underlying shmem objects.", .flags = PROCESS_FLAG_LINUX_SMAPS, },
    [LAST_PROCESSFIELD] = { .name = "*** report bug! ***", .title = NULL, .description = NULL, .flags = 0, },
 };
 
@@ -344,6 +354,9 @@ void LinuxProcess_writeField(Process* this, RichString* str, ProcessField field)
    case M_LRS: Process_humanNumber(str, lp->m_lrs * PAGE_SIZE_KB, coloring); return;
    case M_TRS: Process_humanNumber(str, lp->m_trs * PAGE_SIZE_KB, coloring); return;
    case M_SHARE: Process_humanNumber(str, lp->m_share * PAGE_SIZE_KB, coloring); return;
+   case M_PSS: Process_humanNumber(str, lp->m_pss, coloring); return;
+   case M_SWAP: Process_humanNumber(str, lp->m_swap, coloring); return;
+   case M_PSSWP: Process_humanNumber(str, lp->m_psswp, coloring); return;
    case UTIME: Process_printTime(str, lp->utime); return;
    case STIME: Process_printTime(str, lp->stime); return;
    case CUTIME: Process_printTime(str, lp->cutime); return;
@@ -435,6 +448,12 @@ long LinuxProcess_compare(const void* v1, const void* v2) {
       return (p2->m_trs - p1->m_trs);
    case M_SHARE:
       return (p2->m_share - p1->m_share);
+   case M_PSS:
+      return (p2->m_pss - p1->m_pss);
+   case M_SWAP:
+      return (p2->m_swap - p1->m_swap);
+   case M_PSSWP:
+      return (p2->m_psswp - p1->m_psswp);
    case UTIME:  diff = p2->utime - p1->utime; goto test_diff;
    case CUTIME: diff = p2->cutime - p1->cutime; goto test_diff;
    case STIME:  diff = p2->stime - p1->stime; goto test_diff;

linux/LinuxProcess.h

@@ -15,6 +15,7 @@ in the source distribution for its full text.
 #define PROCESS_FLAG_LINUX_VSERVER  0x0400
 #define PROCESS_FLAG_LINUX_CGROUP   0x0800
 #define PROCESS_FLAG_LINUX_OOM      0x1000
+#define PROCESS_FLAG_LINUX_SMAPS    0x2000
 
 typedef enum UnsupportedProcessFields {
    FLAGS = 9,
@@ -78,7 +79,10 @@ typedef enum LinuxProcessFields {
    PERCENT_IO_DELAY = 117,
    PERCENT_SWAP_DELAY = 118,
    #endif
-   LAST_PROCESSFIELD = 119,
+   M_PSS = 119,
+   M_SWAP = 120,
+   M_PSSWP = 121,
+   LAST_PROCESSFIELD = 122,
 } LinuxProcessField;
 
 #include "IOPriority.h"
@@ -94,6 +98,9 @@ typedef struct LinuxProcess_ {
    unsigned long long int cutime;
    unsigned long long int cstime;
    long m_share;
+   long m_pss;
+   long m_swap;
+   long m_psswp;
    long m_trs;
    long m_drs;
    long m_lrs;

linux/LinuxProcessList.c

@@ -486,6 +486,58 @@ static bool LinuxProcessList_readStatmFile(LinuxProcess* process, const char* di
    return (errno == 0);
 }
 
+static bool LinuxProcessList_readSmapsFile(LinuxProcess* process, const char* dirname, const char* name) {
+   //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.
+
+   char buffer[PAGE_SIZE];// 4k
+   char *start,*end;
+   ssize_t nread=0;
+   int tmp=0;
+   snprintf(buffer, MAX_NAME, "%s/%s/smaps", dirname, name);
+   int fd = open(buffer, O_RDONLY);
+   if (fd == -1)
+      return false;
+
+   process->m_pss   = 0;
+   process->m_swap  = 0;
+   process->m_psswp = 0;
+
+   while ( ( nread =  read(fd,buffer, sizeof(buffer)) ) > 0 ){
+        start = (char *)&buffer;
+        end   = start + nread;
+        do{//parse 4k block
+
+            if( (tmp = (end - start)) > 0 &&
+                (start = memmem(start,tmp,"\nPss:",5)) != NULL )
+            {
+              process->m_pss += strtol(start+5, &start, 10);
+              start += 3;//now we must be at the end of line "Pss:                   0 kB"
+            }else
+              break; //read next 4k block
+
+            if( (tmp = (end - start)) > 0 &&
+                (start = memmem(start,tmp,"\nSwap:",6)) != NULL )
+            {
+              process->m_swap += strtol(start+6, &start, 10);
+              start += 3;
+            }else
+              break;
+
+            if( (tmp = (end - start)) > 0 &&
+                (start = memmem(start,tmp,"\nSwapPss:",9)) != NULL )
+            {
+              process->m_psswp += strtol(start+9, &start, 10);
+              start += 3;
+            }else
+              break;
+
+        }while(1);
+   }//while read
+   close(fd);
+   return true;
+}
+
 #ifdef HAVE_OPENVZ
 
 static void LinuxProcessList_readOpenVZData(LinuxProcess* process, const char* dirname, const char* name) {
@@ -815,6 +867,21 @@ static bool LinuxProcessList_recurseProcTree(LinuxProcessList* this, const char*
       if (! LinuxProcessList_readStatmFile(lp, dirname, name))
          goto errorReadingProcess;
 
+      if ((settings->flags & PROCESS_FLAG_LINUX_SMAPS) && !Process_isKernelThread(proc)){
+         if (!parent){
+            // Read smaps file of each process only every second pass to improve performance
+            static int smaps_flag = 0;
+            if ((pid & 1) == smaps_flag){
+               LinuxProcessList_readSmapsFile(lp, dirname, name);
+            }
+            if (pid == 1) {
+               smaps_flag = !smaps_flag;
+            }
+        } else {
+            lp->m_pss = ((LinuxProcess*)parent)->m_pss;
+        }
+      }
+
       proc->show = ! ((hideKernelThreads && Process_isKernelThread(proc)) || (hideUserlandThreads && Process_isUserlandThread(proc)));
 
       char command[MAX_NAME+1];