Re: mbuf cluster leak?

[mlelstv%serpens.de@localhost (Michael van Elst)]

mpumford%mudcovered.org.uk@localhost (Mike Pumford) writes:

>However the system is running just fine and happily forwarding traffic 
>and has been for the last 160 days. Also fur the duration of the time 
>I've been writing this e-mail that number has remained totally constant 
>even though I've been interacting with it over SSH.

There is only pressure on the pool caches when the system runs out
of memory. Then the pool caches will be invalidated, and all
unused items will be returned to the pools. If that frees
pool pages, these will be returned to the VM system.

E.g.:

Name        Size Requests Fail Releases Pgreq Pgrel Npage Hiwat Minpg Maxpg Idle
mclpl       2048       45    0        0    27     0    27    27     0 129204   4

[ ... Fetching a program that just allocates all memory and running it. ... ]

Name        Size Requests Fail Releases Pgreq Pgrel Npage Hiwat Minpg Maxpg Idle
mclpl       2048       50    0       45    27     4    23    27     0 129204  20


The interesting part is why the cache needed 27 pages (at 2 items
per page, you'd need 23) and why the remaining 50-45 items still
need 23 pages (worst case should be 5 pages for 5 items).