From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f53.google.com (mail-wm0-f53.google.com [74.125.82.53]) by kanga.kvack.org (Postfix) with ESMTP id B08E06B0256 for ; Fri, 11 Mar 2016 08:05:46 -0500 (EST) Received: by mail-wm0-f53.google.com with SMTP id l68so16842780wml.1 for ; Fri, 11 Mar 2016 05:05:46 -0800 (PST) Received: from mail-wm0-x22c.google.com (mail-wm0-x22c.google.com. [2a00:1450:400c:c09::22c]) by mx.google.com with ESMTPS id cu9si10956868wjc.53.2016.03.11.05.05.45 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 11 Mar 2016 05:05:45 -0800 (PST) Received: by mail-wm0-x22c.google.com with SMTP id p65so17272122wmp.1 for ; Fri, 11 Mar 2016 05:05:45 -0800 (PST) MIME-Version: 1.0 In-Reply-To: References: <14d02da417b3941fd871566e16a164ca4d4ccabc.1457519440.git.glider@google.com> Date: Fri, 11 Mar 2016 14:05:45 +0100 Message-ID: Subject: Re: [PATCH v5 2/7] mm, kasan: SLAB support From: Alexander Potapenko Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Sender: owner-linux-mm@kvack.org List-ID: To: Andrey Ryabinin Cc: Andrey Konovalov , Christoph Lameter , Dmitry Vyukov , Andrew Morton , Steven Rostedt , Joonsoo Kim , JoonSoo Kim , Kostya Serebryany , kasan-dev , LKML , "linux-mm@kvack.org" 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 =3D 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: 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 */ >> +}; >> + --=20 Alexander Potapenko Software Engineer Google Germany GmbH Erika-Mann-Stra=C3=9Fe, 33 80636 M=C3=BCnchen Gesch=C3=A4ftsf=C3=BChrer: Matthew Scott Sucherman, Paul Terence Manicle Registergericht und -nummer: Hamburg, HRB 86891 Sitz der Gesellschaft: Hamburg -- 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