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fix(agent): prevent memory/swap uint64 underflow causing unrealistic usage spikes #1978

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fix(agent): prevent memory/swap uint64 underflow causing unrealistic usage spikes #1978

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16 changes: 11 additions & 5 deletions agent/system.go
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Original file line number Diff line number Diff line change
Expand Up @@ -168,15 +168,21 @@ func (a *Agent) getSystemStats(cacheTimeMs uint16) system.Stats {
}

// memory
if v, err := mem.VirtualMemory(); err == nil {
// skip anomalous readings caused by transient /proc/meminfo inconsistencies (uint64 underflow in gopsutil)
if v, err := mem.VirtualMemory(); err == nil && v.Used <= v.Total {
// swap
systemStats.Swap = utils.BytesToGigabytes(v.SwapTotal)
systemStats.SwapUsed = utils.BytesToGigabytes(v.SwapTotal - v.SwapFree - v.SwapCached)
if v.SwapTotal >= v.SwapFree+v.SwapCached {
systemStats.SwapUsed = utils.BytesToGigabytes(v.SwapTotal - v.SwapFree - v.SwapCached)
}
// cache + buffers value for default mem calculation
// note: gopsutil automatically adds SReclaimable to v.Cached
cacheBuff := v.Cached + v.Buffers - v.Shared
if cacheBuff <= 0 {
cacheBuff = max(v.Total-v.Free-v.Used, 0)
var cacheBuff uint64
if v.Cached+v.Buffers > v.Shared {
cacheBuff = v.Cached + v.Buffers - v.Shared
}
if cacheBuff == 0 && v.Total > v.Free+v.Used {
cacheBuff = v.Total - v.Free - v.Used
}
// htop memory calculation overrides (likely outdated as of mid 2025)
if a.memCalc == "htop" {
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