Re: [PATCH v4 00/17] khwasan: kernel hardware assisted address sanitizer

[Evgenii Stepanov]

Looking at a live Android device under load, slab (according to
/proc/meminfo) + kernel stack take 8-10% available RAM (~350MB).
Kasan's overhead of 2x - 3x on top of it is not insignificant.

On Fri, Jun 29, 2018 at 7:41 PM, Andrew Morton
<akpm@xxxxxxxxxxxxxxxxxxxx> wrote:
> On Fri, 29 Jun 2018 14:45:08 +0200 Andrey Konovalov <andreyknvl@xxxxxxxxxx> wrote:
>
>> >> What kind of memory consumption testing would you like to see?
>> >
>> > Well, 100kb or so is a teeny amount on virtually any machine.  I'm
>> > assuming the savings are (much) more significant once the machine gets
>> > loaded up and doing work?
>>
>> So with clean kernel after boot we get 40 kb memory usage. With KASAN
>> it is ~120 kb, which is 200% overhead. With KHWASAN it's 50 kb, which
>> is 25% overhead. This should approximately scale to any amounts of
>> used slab memory. For example with 100 mb memory usage we would get
>> +200 mb for KASAN and +25 mb with KHWASAN. (And KASAN also requires
>> quarantine for better use-after-free detection). I can explicitly
>> mention the overhead in %s in the changelog.
>>
>> If you think it makes sense, I can also make separate measurements
>> with some workload. What kind of workload should I use?
>
> Whatever workload people were running when they encountered problems
> with KASAN memory consumption ;)
>
> I dunno, something simple.  `find / > /dev/null'?
>