Linux: overhaul memory partition

Use similar calculation than procps.
Show AvailableMemory in text mode.
Use total minus available memory instead of manually computed used-
memory as fraction part in bar mode (if available).

MemoryMeter.c

@@ -7,6 +7,8 @@ in the source distribution for its full text.
 
 #include "MemoryMeter.h"
 
+#include <math.h>
+
 #include "CRT.h"
 #include "Object.h"
 #include "Platform.h"
@@ -21,9 +23,15 @@ static const int MemoryMeter_attributes[] = {
 
 static void MemoryMeter_updateValues(Meter* this, char* buffer, size_t size) {
    int written;
+
+   /* available memory is not supported on all platforms */
+   this->values[3] = NAN;
    Platform_setMemoryValues(this);
 
-   written = Meter_humanUnit(buffer, this->values[0], size);
+   /* Do not print available memory in bar mode */
+   this->curItems = 3;
+
+   written = Meter_humanUnit(buffer, isnan(this->values[3]) ? this->values[0] : this->total - this->values[3], size);
    METER_BUFFER_CHECK(buffer, size, written);
 
    METER_BUFFER_APPEND_CHR(buffer, size, '/');
@@ -34,18 +42,29 @@ static void MemoryMeter_updateValues(Meter* this, char* buffer, size_t size) {
 static void MemoryMeter_display(const Object* cast, RichString* out) {
    char buffer[50];
    const Meter* this = (const Meter*)cast;
+
    RichString_writeAscii(out, CRT_colors[METER_TEXT], ":");
    Meter_humanUnit(buffer, this->total, sizeof(buffer));
    RichString_appendAscii(out, CRT_colors[METER_VALUE], buffer);
+
    Meter_humanUnit(buffer, this->values[0], sizeof(buffer));
    RichString_appendAscii(out, CRT_colors[METER_TEXT], " used:");
    RichString_appendAscii(out, CRT_colors[MEMORY_USED], buffer);
+
    Meter_humanUnit(buffer, this->values[1], sizeof(buffer));
    RichString_appendAscii(out, CRT_colors[METER_TEXT], " buffers:");
    RichString_appendAscii(out, CRT_colors[MEMORY_BUFFERS_TEXT], buffer);
+
    Meter_humanUnit(buffer, this->values[2], sizeof(buffer));
    RichString_appendAscii(out, CRT_colors[METER_TEXT], " cache:");
    RichString_appendAscii(out, CRT_colors[MEMORY_CACHE], buffer);
+
+   /* available memory is not supported on all platforms */
+   if (!isnan(this->values[3])) {
+      Meter_humanUnit(buffer, this->values[3], sizeof(buffer));
+      RichString_appendAscii(out, CRT_colors[METER_TEXT], " available:");
+      RichString_appendAscii(out, CRT_colors[METER_VALUE], buffer);
+   }
 }
 
 const MeterClass MemoryMeter_class = {
@@ -56,7 +75,7 @@ const MeterClass MemoryMeter_class = {
    },
    .updateValues = MemoryMeter_updateValues,
    .defaultMode = BAR_METERMODE,
-   .maxItems = 3,
+   .maxItems = 4,
    .total = 100.0,
    .attributes = MemoryMeter_attributes,
    .name = "Memory",

ProcessList.h

@@ -34,6 +34,9 @@ in the source distribution for its full text.
 #define MAX_READ 2048
 #endif
 
+typedef unsigned long long int memory_t;
+#define MEMORY_MAX ULLONG_MAX
+
 typedef struct ProcessList_ {
    const Settings* settings;
 
@@ -61,14 +64,15 @@ typedef struct ProcessList_ {
    int userlandThreads;
    int kernelThreads;
 
-   unsigned long long int totalMem;
+   memory_t totalMem;
-   unsigned long long int usedMem;
+   memory_t usedMem;
-   unsigned long long int buffersMem;
+   memory_t buffersMem;
-   unsigned long long int cachedMem;
+   memory_t cachedMem;
+   memory_t availableMem;
 
-   unsigned long long int totalSwap;
+   memory_t totalSwap;
-   unsigned long long int usedSwap;
+   memory_t usedSwap;
-   unsigned long long int cachedSwap;
+   memory_t cachedSwap;
 
    int cpuCount;
 

linux/HugePageMeter.c

@@ -35,7 +35,7 @@ static void HugePageMeter_updateValues(Meter* this, char* buffer, size_t size) {
    assert(ARRAYSIZE(HugePageMeter_labels) == HTOP_HUGEPAGE_COUNT);
 
    int written;
-   unsigned long long int usedTotal = 0;
+   memory_t usedTotal = 0;
    unsigned nextUsed = 0;
 
    const LinuxProcessList* lpl = (const LinuxProcessList*) this->pl;
@@ -47,8 +47,8 @@ static void HugePageMeter_updateValues(Meter* this, char* buffer, size_t size) {
       HugePageMeter_active_labels[i] = NULL;
    }
    for (unsigned i = 0; i < HTOP_HUGEPAGE_COUNT; i++) {
-      unsigned long long int value = lpl->usedHugePageMem[i];
+      memory_t value = lpl->usedHugePageMem[i];
-      if (value != ULLONG_MAX) {
+      if (value != MEMORY_MAX) {
          this->values[nextUsed] = value;
          usedTotal += value;
          HugePageMeter_active_labels[nextUsed] = HugePageMeter_labels[i];

linux/LinuxProcessList.c

@@ -1525,64 +1525,82 @@ errorReadingProcess:
 }
 
 static inline void LinuxProcessList_scanMemoryInfo(ProcessList* this) {
-   unsigned long long int freeMem = 0;
+   memory_t availableMem = 0;
-   unsigned long long int swapFree = 0;
+   memory_t freeMem = 0;
-   unsigned long long int shmem = 0;
+   memory_t totalMem = 0;
-   unsigned long long int sreclaimable = 0;
+   memory_t buffersMem = 0;
+   memory_t cachedMem = 0;
+   memory_t swapTotalMem = 0;
+   memory_t swapCacheMem = 0;
+   memory_t swapFreeMem = 0;
+   memory_t sreclaimableMem = 0;
 
    FILE* file = fopen(PROCMEMINFOFILE, "r");
-   if (file == NULL) {
+   if (!file)
       CRT_fatalError("Cannot open " PROCMEMINFOFILE);
-   }
-   char buffer[128];
-   while (fgets(buffer, 128, file)) {
 
-      #define tryRead(label, variable)                                         \
+   char buffer[128];
-         if (String_startsWith(buffer, label)) {                               \
+   while (fgets(buffer, sizeof(buffer), file)) {
-            sscanf(buffer + strlen(label), " %32llu kB", variable);            \
+
-            break;                                                             \
+      #define tryRead(label, variable)                                       \
+         if (String_startsWith(buffer, label)) {                             \
+            memory_t parsed_;                                                \
+            if (sscanf(buffer + strlen(label), "%llu kB", &parsed_) == 1) {  \
+               variable = parsed_;                                           \
+            }                                                                \
+            break;                                                           \
          }
 
       switch (buffer[0]) {
       case 'M':
-         tryRead("MemTotal:", &this->totalMem);
+         tryRead("MemAvailable:", availableMem);
-         tryRead("MemFree:", &freeMem);
+         tryRead("MemFree:", freeMem);
+         tryRead("MemTotal:", totalMem);
          break;
       case 'B':
-         tryRead("Buffers:", &this->buffersMem);
+         tryRead("Buffers:", buffersMem);
          break;
       case 'C':
-         tryRead("Cached:", &this->cachedMem);
+         tryRead("Cached:", cachedMem);
          break;
       case 'S':
          switch (buffer[1]) {
          case 'w':
-            tryRead("SwapTotal:", &this->totalSwap);
+            tryRead("SwapTotal:", swapTotalMem);
-            tryRead("SwapCached:", &this->cachedSwap);
+            tryRead("SwapCached:", swapCacheMem);
-            tryRead("SwapFree:", &swapFree);
+            tryRead("SwapFree:", swapFreeMem);
-            break;
-         case 'h':
-            tryRead("Shmem:", &shmem);
             break;
          case 'R':
-            tryRead("SReclaimable:", &sreclaimable);
+            tryRead("SReclaimable:", sreclaimableMem);
             break;
          }
          break;
       }
+
       #undef tryRead
    }
 
-   this->usedMem = this->totalMem - freeMem;
-   this->cachedMem = this->cachedMem + sreclaimable - shmem;
-   this->usedSwap = this->totalSwap - swapFree - this->cachedSwap;
    fclose(file);
+
+   /*
+    * Compute memory partition like procps(free)
+    *  https://gitlab.com/procps-ng/procps/-/blob/master/proc/sysinfo.c
+    */
+   this->totalMem = totalMem;
+   this->cachedMem = cachedMem + sreclaimableMem;
+   const memory_t usedDiff = freeMem + cachedMem + sreclaimableMem + buffersMem;
+   this->usedMem = (totalMem >= usedDiff) ? totalMem - usedDiff : totalMem - freeMem;
+   this->buffersMem = buffersMem;
+   this->availableMem = availableMem != 0 ? MINIMUM(availableMem, totalMem) : freeMem;
+   this->totalSwap = swapTotalMem;
+   this->usedSwap = swapTotalMem - swapFreeMem - swapCacheMem;
+   this->cachedSwap = swapCacheMem;
 }
 
 static void LinuxProcessList_scanHugePages(LinuxProcessList* this) {
    this->totalHugePageMem = 0;
    for (unsigned i = 0; i < HTOP_HUGEPAGE_COUNT; i++) {
-      this->usedHugePageMem[i] = ULLONG_MAX;
+      this->usedHugePageMem[i] = MEMORY_MAX;
    }
 
    DIR* dir = opendir("/sys/kernel/mm/hugepages");
@@ -1614,7 +1632,7 @@ static void LinuxProcessList_scanHugePages(LinuxProcessList* this) {
       if (r <= 0)
          continue;
 
-      unsigned long long int total = strtoull(content, NULL, 10);
+      memory_t total = strtoull(content, NULL, 10);
       if (total == 0)
          continue;
 
@@ -1623,7 +1641,7 @@ static void LinuxProcessList_scanHugePages(LinuxProcessList* this) {
       if (r <= 0)
          continue;
 
-      unsigned long long int free = strtoull(content, NULL, 10);
+      memory_t free = strtoull(content, NULL, 10);
 
       int shift = ffsl(hugePageSize) - 1 - (HTOP_HUGEPAGE_BASE_SHIFT - 10);
       assert(shift >= 0 && shift < HTOP_HUGEPAGE_COUNT);
@@ -1636,9 +1654,9 @@ static void LinuxProcessList_scanHugePages(LinuxProcessList* this) {
 }
 
 static inline void LinuxProcessList_scanZramInfo(LinuxProcessList* this) {
-   unsigned long long int totalZram = 0;
+   memory_t totalZram = 0;
-   unsigned long long int usedZramComp = 0;
+   memory_t usedZramComp = 0;
-   unsigned long long int usedZramOrig = 0;
+   memory_t usedZramOrig = 0;
 
    char mm_stat[34];
    char disksize[34];
@@ -1659,9 +1677,9 @@ static inline void LinuxProcessList_scanZramInfo(LinuxProcessList* this) {
          }
          break;
       }
-      unsigned long long int size = 0;
+      memory_t size = 0;
-      unsigned long long int orig_data_size = 0;
+      memory_t orig_data_size = 0;
-      unsigned long long int compr_data_size = 0;
+      memory_t compr_data_size = 0;
 
       if (!fscanf(disksize_file, "%llu\n", &size) ||
           !fscanf(mm_stat_file, "    %llu       %llu", &orig_data_size, &compr_data_size)) {
@@ -1684,9 +1702,9 @@ static inline void LinuxProcessList_scanZramInfo(LinuxProcessList* this) {
 }
 
 static inline void LinuxProcessList_scanZfsArcstats(LinuxProcessList* lpl) {
-   unsigned long long int dbufSize = 0;
+   memory_t dbufSize = 0;
-   unsigned long long int dnodeSize = 0;
+   memory_t dnodeSize = 0;
-   unsigned long long int bonusSize = 0;
+   memory_t bonusSize = 0;
 
    FILE* file = fopen(PROCARCSTATSFILE, "r");
    if (file == NULL) {

linux/LinuxProcessList.h

@@ -74,8 +74,10 @@ typedef struct LinuxProcessList_ {
    int netlink_family;
    #endif
 
-   unsigned long long int totalHugePageMem;
+   memory_t totalHugePageMem;
-   unsigned long long int usedHugePageMem[HTOP_HUGEPAGE_COUNT];
+   memory_t usedHugePageMem[HTOP_HUGEPAGE_COUNT];
+
+   memory_t availableMem;
 
    ZfsArcStats zfs;
    ZramStats zram;

linux/Platform.c

@@ -283,14 +283,11 @@ void Platform_setMemoryValues(Meter* this) {
    const ProcessList* pl = this->pl;
    const LinuxProcessList* lpl = (const LinuxProcessList*) pl;
 
-   long int usedMem = pl->usedMem;
+   this->total     = pl->totalMem;
-   long int buffersMem = pl->buffersMem;
+   this->values[0] = pl->usedMem;
-   long int cachedMem = pl->cachedMem;
+   this->values[1] = pl->buffersMem;
-   usedMem -= buffersMem + cachedMem + lpl->totalHugePageMem;
+   this->values[2] = pl->cachedMem;
-   this->total = pl->totalMem - lpl->totalHugePageMem;
+   this->values[3] = pl->availableMem;
-   this->values[0] = usedMem;
-   this->values[1] = buffersMem;
-   this->values[2] = cachedMem;
 
    if (lpl->zfs.enabled != 0) {
       this->values[0] -= lpl->zfs.size;

linux/ZramStats.h

@@ -2,9 +2,9 @@
 #define HEADER_ZramStats
 
 typedef struct ZramStats_ {
-   unsigned long long int totalZram;
+   memory_t totalZram;
-   unsigned long long int usedZramComp;
+   memory_t usedZramComp;
-   unsigned long long int usedZramOrig;
+   memory_t usedZramOrig;
 } ZramStats;
 
 #endif