linux-kernel - Re: [patch 2/3] MAP_NOZERO

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]

Date:	Wed, 27 Jun 2007 11:13:52 -0700 (PDT)
From:	Davide Libenzi <davidel@...ilserver.org>
To:	Hugh Dickins <hugh@...itas.com>
cc:	Ulrich Drepper <drepper@...il.com>, blaisorblade@...oo.it,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [patch 2/3] MAP_NOZERO - implement sys_brk2()

On Wed, 27 Jun 2007, Hugh Dickins wrote:

> In honesty, I should add that I dislike and distrust Davide's
> MAP_NOZERO very much indeed!  Would much rather leave my cpus
> spending a little time in clear_page().  A uid in struct page
> (though I'm sure we could find somewhere to tuck it away) -
> the horror, the horror!  But I've so far failed to find a killer
> argument against it, and am hoping for someone else to do so.

Little time? Please, do not trust me. Start oprofile and run a kernel 
build. Look, I'm not even talking about som micro benchmark explicitly 
built to exploit the thing. A kernel build.
You will find clear_page to be the *1st* kernel entry after cc1 and as.
That is bad for two reasons. The time it spends in there, and the cache it 
blows.



- Davide


-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/