On Mon, 2 Jul 2018 12:16:42 -0700 Evgenii Stepanov <eugenis@xxxxxxxxxx> wrote: > 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'? > > > > 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. > (top-posting repaired. Please don't) For a debugging, not-for-production-use feature, that overhead sounds quite acceptable to me. What problems is it known to cause?
