Linux memory tools

A toolbox to inspect Linux memory

https://github.com/tatref/linux-mem

Main tools

snap.py

/proc snapshot tool

memstats

Memory usage for groups of processes. Main target is Oracle databases

┌─────────────────┬───────┬────────────┬────────────┬────────────┬───────────┬──────────┬──────────┬─────────────┬──────────┐
│ group_name      │ procs │ mem_rss    │ mem_anon   │ mem_uss    │ swap_anon │ swap_rss │ swap_uss │ shm_mem     │ shm_swap │
├─────────────────┼───────┼────────────┼────────────┼────────────┼───────────┼──────────┼──────────┼─────────────┼──────────┤
│ Some("+ASM1")   │ 102   │ 5209.41 MB │ 4636.65 MB │ 5179.87 MB │ 0 MB      │ 0 MB     │ 0 MB     │ 3213.41 MB  │ 0 MB     │
│ None            │ 74    │ 3790.02 MB │ 3536.86 MB │ 3765.41 MB │ 0.01 MB   │ 0.01 MB  │ 0.01 MB  │ 0 MB        │ 0 MB     │
│ Some("DBB1")    │ 109   │ 2357.09 MB │ 1489.36 MB │ 2216.93 MB │ 0 MB      │ 0 MB     │ 0 MB     │ 21479.03 MB │ 0 MB     │
│ Some("DBD1")    │ 90    │ 1614.49 MB │ 1101.75 MB │ 1470.30 MB │ 0 MB      │ 0 MB     │ 0 MB     │ 4299.16 MB  │ 0 MB     │
└─────────────────┴───────┴────────────┴────────────┴────────────┴───────────┴──────────┴──────────┴─────────────┴──────────┘

kpageflags

Live visual map of physical memory with client/server modes

Usage

Local usage

sudo ./target/release/kpageflags-viewer

Server usage

sudo ./target/release/kpageflags-viewer server 192.168.0.1:10000

Client usage

./target/release/kpageflags-viewer client 192.168.0.1:10000

Building

Cross compiling to Windows (client only)

cargo install cross  # requires podman/docker
cross b --release --target x86_64-pc-windows-gnu --bin kpageflags-viewer

processes2png

Visual map of processes memory

For details, see my blog post

Effect of memory compaction:

Small tools

procinfo

Memory map details for single process. List virtual memory, physical pages, physical flags...

Information is grabbed from /proc/<pid>/smaps, /proc/<pid>/pagemap, /proc/kpageflags

Usage: procinfo <pid...>

# procinfo 12345
0x00007ff437847000-0x00007ff437849000 MMPermissions(NONE | READ | WRITE | PRIVATE) 0 Anonymous
PFN=0x0000159f83 MemoryPageFlags(SOFT_DIRTY | PRESENT | 0x159f83) / Some(PhysicalPageFlags(UPTODATE | LRU | MMAP | ANON | SWAPBACKED))
PFN=0x000010a5cb MemoryPageFlags(SOFT_DIRTY | PRESENT | 0x10a5cb) / Some(PhysicalPageFlags(UPTODATE | LRU | MMAP | ANON | SWAPBACKED))
stats: VSZ=8 kiB, RSS=8 kiB, SWAP=0 kiB
0x00007ff43784d000-0x00007ff437854000 MMPermissions(NONE | READ | SHARED) 160259 Path("/usr/lib64/gconv/gconv-modules.cache")
PFN=0x0000109d63 MemoryPageFlags(SOFT_DIRTY | FILE | PRESENT | 0x109d63) / Some(PhysicalPageFlags(REFERENCED | UPTODATE | LRU | ACTIVE | MMAP))
PFN=0x0000109d5b MemoryPageFlags(SOFT_DIRTY | FILE | PRESENT | 0x109d5b) / Some(PhysicalPageFlags(REFERENCED | UPTODATE | LRU | ACTIVE | MMAP))

shmat

Attach shared memory segments to current process

shmem

Shared memory tool

connections

Establish lots of connections to Oracle database

find_instances

Find Oracle database instances, connect to DB and run some request. Env variables (SID, lib...) and user are found automatically.