From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-f71.google.com (mail-pg0-f71.google.com [74.125.83.71]) by kanga.kvack.org (Postfix) with ESMTP id 0C0036B02FD for ; Wed, 7 Jun 2017 22:43:13 -0400 (EDT) Received: by mail-pg0-f71.google.com with SMTP id u8so11013137pgo.11 for ; Wed, 07 Jun 2017 19:43:13 -0700 (PDT) Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65]) by mx.google.com with SMTPS id 10sor1833732pfh.8.2017.06.07.19.43.12 for (Google Transport Security); Wed, 07 Jun 2017 19:43:12 -0700 (PDT) Date: Thu, 8 Jun 2017 11:43:05 +0900 From: Joonsoo Kim Subject: Re: [PATCH v1 00/11] mm/kasan: support per-page shadow memory to reduce memory consumption Message-ID: <20170608024303.GC27998@js1304-desktop> References: <20170524074539.GA9697@js1304-desktop> <20170525004104.GA21336@js1304-desktop> <3a7664a9-e360-ab68-610a-1b697a4b00b5@virtuozzo.com> <20170531055047.GA21606@js1304-desktop> <80f2f6f7-0a37-53dc-843e-1adbed4377fa@virtuozzo.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <80f2f6f7-0a37-53dc-843e-1adbed4377fa@virtuozzo.com> Sender: owner-linux-mm@kvack.org List-ID: To: Andrey Ryabinin Cc: Dmitry Vyukov , Andrew Morton , Alexander Potapenko , kasan-dev , "linux-mm@kvack.org" , LKML , Thomas Gleixner , Ingo Molnar , "H . Peter Anvin" , kernel-team@lge.com On Wed, May 31, 2017 at 07:31:53PM +0300, Andrey Ryabinin wrote: > On 05/31/2017 08:50 AM, Joonsoo Kim wrote: > >>> But the main win as I see it is that that's basically complete support > >>> for 32-bit arches. People do ask about arm32 support: > >>> https://groups.google.com/d/msg/kasan-dev/Sk6BsSPMRRc/Gqh4oD_wAAAJ > >>> https://groups.google.com/d/msg/kasan-dev/B22vOFp-QWg/EVJPbrsgAgAJ > >>> and probably mips32 is relevant as well. > >> > >> I don't see how above is relevant for 32-bit arches. Current design > >> is perfectly fine for 32-bit arches. I did some POC arm32 port couple years > >> ago - https://github.com/aryabinin/linux/commits/kasan/arm_v0_1 > >> It has some ugly hacks and non-critical bugs. AFAIR it also super-slow because I (mistakenly) > >> made shadow memory uncached. But otherwise it works. > > > > Could you explain that where is the code to map shadow memory uncached? > > I don't find anything related to it. > > > > I didn't set set any cache policy (L_PTE_MT_*) on shadow mapping (see set_pte_at() calls ) > which means it's L_PTE_MT_UNCACHED Thanks for pointing it out. I did some quick tests and found that it's not super(?) slow on my QEMU. Maybe, it would be different with real machine. Thanks. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org