Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932426AbcCKN6L (ORCPT ); Fri, 11 Mar 2016 08:58:11 -0500 Received: from mail-lb0-f182.google.com ([209.85.217.182]:36076 "EHLO mail-lb0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932170AbcCKN6A convert rfc822-to-8bit (ORCPT ); Fri, 11 Mar 2016 08:58:00 -0500 MIME-Version: 1.0 In-Reply-To: References: <14d02da417b3941fd871566e16a164ca4d4ccabc.1457519440.git.glider@google.com> Date: Fri, 11 Mar 2016 16:57:58 +0300 Message-ID: Subject: Re: [PATCH v5 2/7] mm, kasan: SLAB support From: Andrey Ryabinin To: Alexander Potapenko Cc: Andrey Konovalov , Christoph Lameter , Dmitry Vyukov , Andrew Morton , Steven Rostedt , Joonsoo Kim , JoonSoo Kim , Kostya Serebryany , kasan-dev , LKML , "linux-mm@kvack.org" Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1670 Lines: 58 2016-03-11 16:05 GMT+03:00 Alexander Potapenko : > On Fri, Mar 11, 2016 at 12:47 PM, Andrey Ryabinin > wrote: >> 2016-03-09 14:05 GMT+03:00 Alexander Potapenko : >> >>> +struct kasan_track { >>> + u64 cpu : 6; /* for NR_CPUS = 64 */ >> >> What about NR_CPUS > 64 ? > After a discussion with Dmitry we've decided to drop |cpu| and |when| > at all, as they do not actually help debugging. > This way we'll make kasan_track only 8 bytes (4 bytes for PID, 4 bytes > for stack handle). > Then the meta structures will be smaller and have nice alignment: > Sounds good. > struct kasan_track { > u32 pid; > depot_stack_handle_t stack; > }; > > struct kasan_alloc_meta { > struct kasan_track track; > u32 state : 2; /* enum kasan_state */ > u32 alloc_size : 30; > u32 reserved; /* we can use it to store an additional stack > handle, e.g. for debugging RCU */ > }; > > struct kasan_free_meta { > /* This field is used while the object is in the quarantine. > * Otherwise it might be used for the allocator freelist. > */ > void **quarantine_link; > struct kasan_track track; > }; > > >>> + u64 pid : 16; /* 65536 processes */ >>> + u64 when : 42; /* ~140 years */ >>> +}; >>> + > > > > -- > Alexander Potapenko > Software Engineer > > Google Germany GmbH > Erika-Mann-Straße, 33 > 80636 München > > Geschäftsführer: Matthew Scott Sucherman, Paul Terence Manicle > Registergericht und -nummer: Hamburg, HRB 86891 > Sitz der Gesellschaft: Hamburg