linux-ext4 - Re: SLAB_TYPESAFE_BY_RCU without constructors (was Re: [PATCH v4 13/17] khwasan: add hooks implementation)

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CACT4Y+akncPCAZ2pUX3xEpUPELQAei1XzYByB8Dohfz-Ve0k5w@mail.gmail.com>
Date:   Wed, 1 Aug 2018 18:47:26 +0200
From:   Dmitry Vyukov <dvyukov@...gle.com>
To:     Eric Dumazet <eric.dumazet@...il.com>
Cc:     Christopher Lameter <cl@...ux.com>,
        Eric Dumazet <edumazet@...gle.com>,
        Andrey Ryabinin <aryabinin@...tuozzo.com>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        "Theodore Ts'o" <tytso@....edu>, Jan Kara <jack@...e.com>,
        linux-ext4@...r.kernel.org,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Pablo Neira Ayuso <pablo@...filter.org>,
        Jozsef Kadlecsik <kadlec@...ckhole.kfki.hu>,
        Florian Westphal <fw@...len.de>,
        David Miller <davem@...emloft.net>,
        NetFilter <netfilter-devel@...r.kernel.org>,
        coreteam@...filter.org, netdev <netdev@...r.kernel.org>,
        Gerrit Renker <gerrit@....abdn.ac.uk>, dccp@...r.kernel.org,
        Jani Nikula <jani.nikula@...ux.intel.com>,
        Joonas Lahtinen <joonas.lahtinen@...ux.intel.com>,
        Rodrigo Vivi <rodrigo.vivi@...el.com>,
        David Airlie <airlied@...ux.ie>,
        intel-gfx <intel-gfx@...ts.freedesktop.org>,
        DRI <dri-devel@...ts.freedesktop.org>,
        Alexey Kuznetsov <kuznet@....inr.ac.ru>,
        Hideaki YOSHIFUJI <yoshfuji@...ux-ipv6.org>,
        Ursula Braun <ubraun@...ux.ibm.com>,
        linux-s390 <linux-s390@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        linux-mm <linux-mm@...ck.org>,
        Andrey Konovalov <andreyknvl@...gle.com>
Subject: Re: SLAB_TYPESAFE_BY_RCU without constructors (was Re: [PATCH v4
 13/17] khwasan: add hooks implementation)

On Wed, Aug 1, 2018 at 6:25 PM, Eric Dumazet <eric.dumazet@...il.com> wrote:
> On 08/01/2018 09:22 AM, Christopher Lameter wrote:
>> On Wed, 1 Aug 2018, Eric Dumazet wrote:
>>
>>> The idea of having a ctor() would only be a win if all the fields that
>>> can be initialized in the ctor are contiguous and fill an integral
>>> number of cache lines.
>>
>> Ok. Its reducing code size and makes the object status more consistent.
>> Isn't that enough?
>>
>
> Prove it ;)
>
> I yet have to seen actual numbers.

Proving with numbers is required for a claimed performance improvement
at the cost of code degradation/increase. For a win-win change there
is really nothing to prove.