linux-kernel - Re: [PATCH v4] kmemleak: survive in a low-memory situation

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Date:   Thu, 28 Mar 2019 11:41:40 -0400
From:   Qian Cai <cai@....pw>
To:     Catalin Marinas <catalin.marinas@....com>
Cc:     Michal Hocko <mhocko@...nel.org>, akpm@...ux-foundation.org,
        cl@...ux.com, willy@...radead.org, penberg@...nel.org,
        rientjes@...gle.com, iamjoonsoo.kim@....com, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4] kmemleak: survive in a low-memory situation

On Thu, 2019-03-28 at 15:05 +0000, Catalin Marinas wrote:
> > It takes 2 runs of LTP oom01 tests to disable kmemleak.
> 
> What configuration are you using (number of CPUs, RAM)? I tried this on
> an arm64 guest under kvm with 4 CPUs and 512MB of RAM, together with
> fault injection on kmemleak_object cache and running oom01 several times
> without any failures.

Apparently, the CPUs are so fast and the disk is so slow (swapping). It ends up
taking a long time for OOM to kick in.

# lscpu
Architecture:        x86_64
CPU op-mode(s):      32-bit, 64-bit
Byte Order:          Little Endian
CPU(s):              48
On-line CPU(s) list: 0-47
Thread(s) per core:  2
Core(s) per socket:  12
Socket(s):           2
NUMA node(s):        2
Vendor ID:           GenuineIntel
CPU family:          6
Model:               85
Model name:          Intel(R) Xeon(R) Gold 6126T CPU @ 2.60GHz
Stepping:            4
CPU MHz:             3300.002
BogoMIPS:            5200.00
Virtualization:      VT-x
L1d cache:           32K
L1i cache:           32K
L2 cache:            1024K
L3 cache:            19712K
NUMA node0 CPU(s):   0-11,24-35
NUMA node1 CPU(s):   12-23,36-47

# free -m
              total        used        free      shared  buff/cache   available
Mem:         166206       31737      134063          33         406      133584
Swap:          4095           0        4095

# lspci | grep -i sata
00:11.5 SATA controller: Intel Corporation C620 Series Chipset Family SSATA
Controller [AHCI mode] (rev 08)
00:17.0 SATA controller: Intel Corporation C620 Series Chipset Family SATA
Controller [AHCI mode] (rev 08)