Bug 257318 - uma consumes memory when reattaching device
Summary: uma consumes memory when reattaching device
Status: New
Alias: None
Product: Base System
Classification: Unclassified
Component: kern (show other bugs)
Version: 13.0-STABLE
Hardware: Any Any
: --- Affects Some People
Assignee: freebsd-bugs (Nobody)
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2021-07-21 19:25 UTC by jcaplan
Modified: 2021-07-21 19:25 UTC (History)
0 users

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Description jcaplan 2021-07-21 19:25:30 UTC
Overview
--------

After patching in fixes for all identified leaks, detaching and re-attaching the same device consistently results in kmem allocation.

currently open leaks:
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=256714
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=257218

Steps to Reproduce:
-------------------

#!/bin/bash

for i in {1..1000}; do
        echo $i
        devctl detach pci0:3:0:0
        devctl attach pci0:3:0:0
        sysctl vm.uma_kmem_total
done

Expected Result
---------------

Perhaps after some initial warming stage, detaching and re-attaching the same device should not increase the amount of memory consumed by uma.

Actual Result
-------------

Even after many thousands of iterations, uma_kmem_total continues to increase

Build Date & Hardware
---------------------
FreeBSD freebsd 13.0-RELEASE FreeBSD 13.0-RELEASE #7 releng/13.0-n244733-ea31abc261f-dirty: Wed Jul 21 14:53:10 UTC 2021

Additional Information
----------------------

Seem to keep hitting keg_alloc_slab from cache_alloc_retry