On Fri, Jun 29, 2018 at 3:01 PM, Mark Rutland <mark.rutland@xxxxxxx> wrote: > On Fri, Jun 29, 2018 at 02:45:08PM +0200, Andrey Konovalov wrote: >> 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. > > Could you elaborate on where that SLAB overhead comes from? > > IIUC that's not for the shadow itself (since it's allocated up-front and > not accounted to SLAB), and that doesn't take into account the > quarantine, so what's eating that space? Redzones. KHWASAN doesn't need them since the next slab object is marked with a different tag (with a high probability) and acts as a redzone. -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
