4

To see some memory info I can watch it in top of through cat /proc/meminfo.
In /proc/meminfo I can see the swap usage of the whole system like this:

SwapCached:            4 kB
SwapTotal:      33460220 kB
SwapFree:       33460216 kB

But there can be I situation when almost all the swap is used (i.e. there is a too small piece of SwapFree). How can I figure out, which process(es) are eating this swap?

UPD: there is a too small piece of SwapFree basically means that there is some process(processes) which ate a lot of memory and didn't use it for a long time. I need to find such processes.

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5
  • @Peregrino69 If something gets swapped it means that it eats a lot of memory and is not under use. I.e. these memory pages are rarely used
    – NK-cell
    Commented Sep 20, 2021 at 16:02
  • @Peregrino69 Nope. The question is what processes are eating swap. I need to find all the processes that ate memory a lot and didn't use it for long time, so they were swapped. If process is eating memory eagerly and uses it quite often - I'm not interested in that.
    – NK-cell
    Commented Sep 20, 2021 at 16:32
  • @Peregrino69 why not as answer?
    – NK-cell
    Commented Sep 20, 2021 at 17:36
  • @Peregrino69 press 'p' to add swap to display when I go to SWAP: ` SWAP = Swapped Size (KiB)` and press p nothing happens..
    – NK-cell
    Commented Sep 20, 2021 at 17:42
  • 1
    Now that works, at least to the point of displaying swap - can't vouch further as my swap utilization is zero. Thanks for kicking my butt :-) I'm dropping a comment on the thread I quoted.
    – Peregrino69
    Commented Sep 20, 2021 at 17:58

3 Answers 3

Reset to default
9
  1. Run top
  2. Press f to select displayed fields
  3. Navigate down to SWAP using arrow keys
  4. Hit Space - SWAP will become preceded by asterisk *
  5. Press right arrow key - this will allow you to move SWAP to a convenient place in the listing, for example between %MEM and TIME+
  6. Press q to return to top view

Step 5 isn't necessary, just convenience - without it SWAP will be showing up as the last entry of the list, after COMMAND.

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3
  • Thanks! But how can I see, which processes ate more swap? Should I sort?
    – NK-cell
    Commented Sep 21, 2021 at 10:24
  • "without it SWAP will be showing up as the last entry of the list, after COMMAND" - nope, it will not show after COMMAND column in my case.
    – NK-cell
    Commented Sep 21, 2021 at 10:25
  • The testing comes from my system (BunsenLabs / Debian 10) which runs a version of top, I can't be certain whether your system has the same version, so can't confirm whether step 5 is needed there. By default top in my system sorts on CPU utilization, so you need to use either option -o when launching it, or choose the column used for sorting with command s in the field view (f).
    – Peregrino69
    Commented Sep 21, 2021 at 10:34
2

You can use smem command line tool.

smem manpages:

Memory can be reported by process, by user, by mapping,
or systemwide. Both text mode and graphical output are available.

smem memory reporting tool

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2
  • I'm unfamiliar with this tool, but the webpage doesn't mention swap. Judging by the output it only shows RAM or combined RAM or swap, which isn't useful in this case.
    – Peregrino69
    Commented Sep 20, 2021 at 17:55
  • Unfortunately this tool is not a regular utility in Linux. So it most likely that there is no such tool in random server/machine. It is not always possible to download anything from anywhere
    – NK-cell
    Commented Sep 21, 2021 at 10:27
1

A tool for monitoring memory and swap usage is smemstat, what can show top-like output with

smemstat -mT
( "Swap reports memory that is swapped out to disk." man smemstat )

in terminal, sorted for highest memory usage on top.

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2
  • Thanks. Is there a way to sort processes by swap?
    – NK-cell
    Commented Oct 10, 2021 at 9:15
  • [1] smemstat -m | sort -n -k 2 or reverse smemstat -m | sort -nr -k 2 should sort for amount of swap used, [2] customizing a script superuser.com/a/355710/981508 for more diverse tasks
    – beyondtime
    Commented Oct 10, 2021 at 13:06

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