[Bug]: system.ram counts static hugepages as "used" memory, causing false alerts on KVM hypervisors with most of the RAM in HPs

Bug description

On KVM/QEMU hypervisors with pre-allocated hugepages, system.ram reports hugepages as "used" memory. This makes the ram_in_use health alert effectively useless, as it always shows near-critical utilization even when the system is under no memory pressure.

This is analogous to the ZFS ARC issue that was fixed in #12843 / #12847 -- specialized memory that is pre-allocated but not indicative of real memory pressure is counted as "used."

Example from a 1 TB hypervisor running RHEL 9.6 EUS with Netdata v2.10.3:

grep -E 'MemTotal|MemFree|MemAvailable|Huge' /proc/meminfo

MemTotal: 1055902584 kB
MemFree: 23681988 kB
MemAvailable: 37933000 kB
HugePages_Total: 458752
HugePages_Free: 384000
HugePages_Rsvd: 0
HugePages_Surp: 0
Hugepagesize: 2048 kB
Hugetlb: 939524096 kB
Total RAM: ~1 TB

Hugepages reserved: 896 GB (85% of total), pre-allocated for KVM guests
Hugepages actually in use by VMs: ~146 GB (only 74,752 of 458,752 pages occupied)
Hugepages idle: ~750 GB
MemAvailable: ~37 GB
Netdata system.ram reports "used": ~95%+

The ram_in_use alert formula $used * 100 / ($used + $cached + $free + $buffers) does not account for hugepages, so it fires at the default 90% threshold even though the system has hundreds of GB of idle hugepages.

Expected behavior

system.ram should expose hugepages as a separate dimension (similar to how ZFS ARC was handled in #12847), so that:

The chart visually distinguishes hugepage memory from genuinely used memory.
The ram_in_use alert can exclude hugepages from its calculation, or a used_ram_to_ignore variable can be set to subtract Hugetlb from /proc/meminfo.

Steps to reproduce

Installa netdata from rpm (official repos) and check the RAM usage

Installation method

manual setup of official DEB/RPM packages

System info

[raistlin@daltigoth ~]$ uname -a; grep -HvE "^#|URL" /etc/*release
Linux daltigoth 5.14.0-570.123.1.el9_6.x86_64 #1 SMP PREEMPT_DYNAMIC Fri Jun 19 03:08:16 EDT 2026 x86_64 x86_64 x86_64 GNU/Linux
/etc/os-release:NAME="Red Hat Enterprise Linux"
/etc/os-release:VERSION="9.6 (Plow)"
/etc/os-release:ID="rhel"
/etc/os-release:ID_LIKE="fedora"
/etc/os-release:VERSION_ID="9.6"
/etc/os-release:PLATFORM_ID="platform:el9"
/etc/os-release:PRETTY_NAME="Red Hat Enterprise Linux 9.6 (Plow)"
/etc/os-release:ANSI_COLOR="0;31"
/etc/os-release:LOGO="fedora-logo-icon"
/etc/os-release:CPE_NAME="cpe:/o:redhat:enterprise_linux:9::baseos"
/etc/os-release:
/etc/os-release:REDHAT_BUGZILLA_PRODUCT="Red Hat Enterprise Linux 9"
/etc/os-release:REDHAT_BUGZILLA_PRODUCT_VERSION=9.6
/etc/os-release:REDHAT_SUPPORT_PRODUCT="Red Hat Enterprise Linux"
/etc/os-release:REDHAT_SUPPORT_PRODUCT_VERSION="9.6"
/etc/redhat-release:Red Hat Enterprise Linux release 9.6 (Plow)
/etc/system-release:Red Hat Enterprise Linux release 9.6 (Plow)

Netdata build info

/etc/system-release:Red Hat Enterprise Linux release 9.6 (Plow)
[raistlin@daltigoth ~]$ netdata -W buildinfo
time=2026-06-25T11:05:26.020+02:00 comm=netdata source=daemon level=info errno="13, Permission denied" tid=3248826  msg="CONFIG: cannot open file '/etc/netdata/stream.conf'. Using internal defaults."
time=2026-06-25T11:05:26.020+02:00 comm=netdata source=daemon level=notice tid=3248826  msg="CONFIG: cannot load user config '/etc/netdata/stream.conf'. Will try stock config."
time=2026-06-25T11:05:26.021+02:00 comm=netdata source=collector level=error errno="13, Permission denied" tid=3248826  msg="Runtime directory '/tmp/netdata' is not writable, falling back to '/tmp'"
time=2026-06-25T11:05:26.023+02:00 comm=netdata source=daemon level=error errno="13, Permission denied" tid=3248826  msg="SYSTEM INFO: System info script /usr/libexec/netdata/plugins.d/system-info.sh not found or not readable."
Packaging:
    Netdata Version ____________________________________________ : v2.10.3
    Installation Type __________________________________________ : binpkg-rpm
    Package Architecture _______________________________________ : x86_64
    Package Distro _____________________________________________ :  
    Configure Options __________________________________________ : cmake -DCMAKE_BUILD_TYPE=RelWithDebInfo -DCMAKE_C_STANDARD=11 -DCMAKE_CXX_STANDARD=17 -DBUILD_SHARED_LIBS=OFF -DCMAKE_C_FLAGS='-O2 -flto=auto -ffat-lto-objects -fexceptions -g -grecord-gcc-switches -pipe -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -fstack-protector-strong -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1  -m64 -march=x86-64-v2 -mtune=generic -fasynchronous-unwind-tables -fstack-clash-protection -fcf-protection -fexceptions -ffunction-sections -fdata-sections -Wno-builtin-macro-redefined -fno-omit-frame-pointer -funwind-tables -fasynchronous-unwind-tables' -DCMAKE_CXX_FLAGS='-O2 -flto=auto -ffat-lto-objects -fexceptions -g -grecord-gcc-switches -pipe -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -fstack-protector-strong -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1  -m64 -march=x86-64-v2 -mtune=generic -fasynchronous-unwind-tables -fstack-clash-protection -fcf-protection -O2 -flto=auto -ffat-lto-objects -fexceptions -g -grecord-gcc-switches -pipe -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -fstack-protector-strong -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1  -m64 -march=x86-64-v2 -mtune=generic -fasynchronous-unwind-tables -fstack-clash-protection -fcf-protection -fexceptions -ffunction-sections -fdata-sections -Wno-builtin-macro-redefined -fno-omit-frame-pointer -funwind-tables -fasynchronous-unwind-tables' -DCMAKE_COMPILE_DEFINITIONS='_GNU_SOURCE' -DCMAKE_EXE_LINKER_FLAGS='-Wl,-z,relro -Wl,--as-needed  -Wl,-z,now -specs=/usr/lib/rpm/redhat/redhat-hardened-ld -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -fexceptions -ffunction-sections -fdata-sections -Wno-builtin-macro-redefined -rdynamic' -DCMAKE_SHARED_LINKER_FLAGS='-Wl,-z,relro -Wl,--as-needed  -Wl,-z,now -specs=/usr/lib/rpm/redhat/redhat-hardened-ld -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1'
Default Directories:
    User Configurations ________________________________________ : /etc/netdata
    Stock Configurations _______________________________________ : /usr/lib/netdata/conf.d
    Ephemeral Databases (metrics data, metadata) _______________ : /var/cache/netdata
    Permanent Databases ________________________________________ : /var/lib/netdata
    Plugins ____________________________________________________ : /usr/libexec/netdata/plugins.d
    Static Web Files ___________________________________________ : /usr/share/netdata/web
    Log Files __________________________________________________ : /var/log/netdata
    Lock Files _________________________________________________ : /var/lib/netdata/lock
    Home _______________________________________________________ : /var/lib/netdata
Operating System:
    Kernel _____________________________________________________ : 
    Kernel Version _____________________________________________ : 
    Operating System ___________________________________________ : 
    Operating System ID ________________________________________ : 
    Operating System ID Like ___________________________________ : 
    Operating System Version ___________________________________ : 
    Operating System Version ID ________________________________ : 
    Detection __________________________________________________ : 
Hardware:
    CPU Cores __________________________________________________ : 
    CPU Frequency ______________________________________________ : 
    RAM Bytes __________________________________________________ : 
    Disk Capacity ______________________________________________ : 
    CPU Architecture ___________________________________________ : 
    Virtualization Technology __________________________________ : 
    Virtualization Detection ___________________________________ : 
Container:
    Container __________________________________________________ : 
    Container Detection ________________________________________ : 
    Container Orchestrator _____________________________________ : none
    Container Operating System _________________________________ : 
    Container Operating System ID ______________________________ : 
    Container Operating System ID Like _________________________ : 
    Container Operating System Version _________________________ : 
    Container Operating System Version ID ______________________ : 
    Container Operating System Detection _______________________ : 
Features:
    Built For __________________________________________________ : Linux
    Netdata Cloud ______________________________________________ : YES
    Health (trigger alerts and send notifications) _____________ : YES
    Streaming (stream metrics to parent Netdata servers) _______ : YES
    Back-filling (of higher database tiers) ____________________ : YES
    Replication (fill the gaps of parent Netdata servers) ______ : YES
    Streaming and Replication Compression ______________________ : YES (zstd lz4 gzip)
    Contexts (index all active and archived metrics) ___________ : YES
    Tiering (multiple dbs with different metrics resolution) ___ : YES (5)
    Machine Learning ___________________________________________ : YES
    Memory Allocator ___________________________________________ : system
Database Engines:
    dbengine (compression) _____________________________________ : YES (zstd lz4)
    alloc ______________________________________________________ : YES
    ram ________________________________________________________ : YES
    none _______________________________________________________ : YES
Connectivity Capabilities:
    ACLK (Agent-Cloud Link: MQTT over WebSockets over TLS) _____ : YES
    static (Netdata internal web server) _______________________ : YES
    WebRTC (experimental) ______________________________________ : NO
    Native HTTPS (TLS Support) _________________________________ : YES
    TLS Host Verification ______________________________________ : YES
Libraries:
    LZ4 (extremely fast lossless compression algorithm) ________ : YES
    ZSTD (fast, lossless compression algorithm) ________________ : YES
    zlib (lossless data-compression library) ___________________ : YES
    Brotli (generic-purpose lossless compression algorithm) ____ : NO
    protobuf (platform-neutral data serialization protocol) ____ : YES (system)
    OpenSSL (cryptography) _____________________________________ : YES
    libdatachannel (stand-alone WebRTC data channels) __________ : NO
    JSON-C (lightweight JSON manipulation) _____________________ : YES
    libcap (Linux capabilities system operations) ______________ : NO
    libcrypto (cryptographic functions) ________________________ : YES
    libyaml (library for parsing and emitting YAML) ____________ : YES
    libmnl (library for working with netfilter) ________________ : YES
    stacktraces (library for getting stack traces) _____________ : libbacktrace (mmap, threads, data)
Plugins:
    apps (monitor processes) ___________________________________ : YES
    cgroups (monitor containers and VMs) _______________________ : YES
    cgroup-network (associate interfaces to CGROUPS) ___________ : YES
    proc (monitor Linux systems) _______________________________ : YES
    tc (monitor Linux network QoS) _____________________________ : YES
    diskspace (monitor Linux mount points) _____________________ : YES
    freebsd (monitor FreeBSD systems) __________________________ : NO
    macos (monitor MacOS systems) ______________________________ : NO
    windows (monitor Windows systems) __________________________ : NO
    statsd (collect custom application metrics) ________________ : YES
    timex (check system clock synchronization) _________________ : YES
    idlejitter (check system latency and jitter) _______________ : YES
    bash (support shell data collection jobs - charts.d) _______ : YES
    debugfs (kernel debugging metrics) _________________________ : YES
    cups (monitor printers and print jobs) _____________________ : YES
    ebpf (monitor system calls) ________________________________ : YES
    freeipmi (monitor enterprise server H/W) ___________________ : YES
    network-viewer (monitor TCP/UDP IPv4/6 sockets) ____________ : YES
    systemd-journal (monitor journal logs) _____________________ : YES
    windows-events (monitor Windows events) ____________________ : NO
    nfacct (gather netfilter accounting) _______________________ : NO
    perf (collect kernel performance events) ___________________ : YES
    slabinfo (monitor kernel object caching) ___________________ : YES
    Xen ________________________________________________________ : NO
    Xen VBD Error Tracking _____________________________________ : NO
Exporters:
    AWS Kinesis ________________________________________________ : NO
    GCP PubSub _________________________________________________ : NO
    MongoDB ____________________________________________________ : YES
    Prometheus (OpenMetrics) Exporter __________________________ : YES
    Prometheus Remote Write ____________________________________ : YES
    Graphite ___________________________________________________ : YES
    Graphite HTTP / HTTPS ______________________________________ : YES
    JSON _______________________________________________________ : YES
    JSON HTTP / HTTPS __________________________________________ : YES
    OpenTSDB ___________________________________________________ : YES
    OpenTSDB HTTP / HTTPS ______________________________________ : YES
    All Metrics API ____________________________________________ : YES
    Shell (use metrics in shell scripts) _______________________ : YES
Debug/Developer Features:
    Trace All Netdata Allocations (with charts) ________________ : NO
    Developer Mode (more runtime checks, slower) _______________ : NO
Runtime Information:
    Profile ____________________________________________________ : standalone
    Stream Parent (accept data from Children) __________________ : NO
    Stream Child (send data to a Parent) _______________________ : NO
    Total System Memory ________________________________________ : 1081244246016
    Available System Memory ____________________________________ : 39119650816
[raistlin@daltigoth ~]$

Additional info

Also, it is important to remember that there are various types of hugepages:

• hugepages can be static or transparent (anonhugepages)
• hugepages can be either 2MB or 1GB in size and a Linux system can have 4k pages, 2MB HPs and 1GB HPs at the same time and on the same system.

Start with the system.ram entry point and the ram_in_use alert, using the /proc/meminfo Hugetlb value described in the report. Compare the handling of specialized memory with the ZFS ARC changes in #12843 and #12847. Done means hugepages are visibly distinct from genuinely used memory and the alert no longer counts idle hugepages as pressure.