> Source: [sk176764](https://support.checkpoint.com/results/sk/sk176764)

# sk176764 - High memory utilization on a Security Gateway after configuring a very high value for the kernel parameter 'fwmultik_input_queue_len'

| Property | Value |
|----------|-------|
| Solution ID | sk176764 |
| Date Created | 2021-12-06 |
| Last Modified | 2025-05-27 |
| Technical Level | Advanced |
| Products | Security Gateway |
| Versions | R82.10, R82, R81.20, R81.10 (EOS), R81 (EOS) |
| OS | Gaia |

## Symptoms

- * The "`ps aux`" command on the Security Gateway shows higher than usual memory utilization by all CoreXL Firewall instances (the "`fwk`" processes).

* The "`fw ctl pstat`" command on the Security Gateway shows higher than usual memory utilization in the "`Kernel memory (kmem) statistics`" section.

* Rebooting the Security Gateway does not resolve the memory utilization issue.

* The higher than usual memory utilization does not depend on the number of concurrent connections through the Security Gateway.

## Cause

A higher than usual value is configured for the kernel parameter "`fwmultik_input_queue_len`" on the Security Gateway / Cluster Members.

This kernel parameter controls the size of the CoreXL input queue (see [sk61143](https://support.checkpoint.com/results/sk/sk61143)). The greater the value, the more memory CoreXL Firewall instances consume to hold the incoming packets.

Example:  
Show / Hide this section  
Environment: VSX Gateway with 10 Virtual Systems. Version: R80.40 Take 126. Configured memory: 24 GB.

**Scenario 1 (normal memory usage) - The value of "`fwmultik_input_queue_len`" is 2048**
> Output of "`ps auxw --sort -rss | grep -E "PID|fwk"`":
>
> ```
> USER        PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
> admin     18538  2.9  3.7 2096492 943860 ?      S<Ll Dec05  26:30 fwk
> admin     27595  1.2  1.6 1565016 412408 ?      S<Ll Dec05  11:10 fwk
> admin     99072  1.2  1.6 1565004 412264 ?      S<Ll Dec05  11:24 fwk
> admin     97651  1.2  1.6 1565004 412232 ?      S<Ll Dec05  11:14 fwk
> ```
>
> Output of "`free -h`":
>
> ```
>               total        used        free      shared  buff/cache   available
> Mem:            24G        4.7G         17G         54M        2.1G         18G
> Swap:          8.0G          0B        8.0G
> ```
>
> Output of "`fw ctl pstat`":
>
> ```
> Virtual System Capacity Summary:
>   Physical memory used:  16% (3532 MB out of 21140 MB) - below watermark
>   Kernel   memory used:   4% (857 MB out of 21140 MB) - below watermark
>   Virtual  memory used:   8% (2047 MB out of 24374 MB) - below watermark
>      Used: 879 MB by FW, 1152 MB by zeco
>   Concurrent Connections: 0% (5 out of 14900) - below watermark
>   Aggressive Aging is enabled, not active
> ```

**Scenario 2 (excessive memory usage) - The value of "fwmultik_input_queue_len" is 409600**
> Output of "`ps auxw --sort -rss | grep -E "PID|fwk"`":
>
> ```
> USER        PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
> admin     18609 19.3 33.6 9766476 8577020 ?     S<Ll 14:35   0:37 fwk
> admin     30137  2.3 16.1 5301496 4105264 ?     S<Ll 14:36   0:03 fwk
> admin     30160  2.9  5.5 2622260 1426236 ?     S<Ll 14:36   0:04 fwk
> admin     30121  2.4  5.5 2622248 1426224 ?     S<Ll 14:36   0:03 fwk
> admin     30136  3.6  5.5 2622244 1426220 ?     S<Ll 14:36   0:05 fwk
> admin     30173  3.5  5.5 2622244 1426220 ?     S<Ll 14:36   0:05 fwk
> admin     30175  3.0  5.5 2617032 1420996 ?     S<Ll 14:36   0:04 fwk
> ```
>
> Output of "`free -h`":
>
> ```
>              total        used        free      shared  buff/cache   available
> Mem:           24G         22G        1.2G         23M        1.1G        1.4G
> Swap:         8.0G        3.1M        8.0G
> ```
>
> Output of "`fw ctl pstat`":
>
> ```
> Virtual System Capacity Summary:
>   Physical memory used:  99% (21107 MB out of 21140 MB) - below watermark
>   Kernel   memory used:  91% (19442 MB out of 21140 MB) - above watermark
>   Virtual  memory used:  39% (9537 MB out of 24374 MB) - below watermark
>      Used: 8369 MB by FW, 1152 MB by zeco
>   Concurrent Connections: 0% (3 out of 14900) - below watermark
>   Aggressive Aging is enabled, active
> ```

## Solution

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