From: Andrew Morton <akpm@linux-foundation•org>
To: Yuri Tikhonov <yur@emcraft•com>
Cc: wd@denx•de, dzu@denx•de, linux-kernel@vger•kernel.org,
miltonm@bga•com, linuxppc-dev@ozlabs•org,
viro@zeniv•linux.org.uk, Geert.Uytterhoeven@sonycom•com,
yanok@emcraft•com
Subject: Re: Re[2]: [PATCH][v2] fork_init: fix division by zero
Date: Thu, 11 Dec 2008 14:26:11 -0800 [thread overview]
Message-ID: <20081211142611.1790a62a.akpm@linux-foundation.org> (raw)
In-Reply-To: <483237973.20081212012232@emcraft.com>
On Fri, 12 Dec 2008 01:22:32 +0300
Yuri Tikhonov <yur@emcraft•com> wrote:
> > so how about avoiding the nasty ifdefs and doing
>
> I'm OK with the approach below, but, leading resulting to the same,
> this involves some overhead to the code where there was no this
> overhead before this patch: e.g. your implementation is finally boils
> down to ~5 times more processor instructions than there were before,
> plus operations with stack for the 'm' variable.
>
> On the other hand, my approach with nasty (I agree) ifdefs doesn't
> lead to overheads to the code which does not need this: i.e. the most
> common situation of small PAGE_SIZEs. Big PAGE_SIZE is the exception,
> so I believe that the more common cases should not suffer because of
> this.
yes, but...
> > --- a/kernel/fork.c~fork_init-fix-division-by-zero
> > +++ a/kernel/fork.c
> > @@ -69,6 +69,7 @@
> > #include <asm/mmu_context.h>
> > #include <asm/cacheflush.h>
> > #include <asm/tlbflush.h>
> > +#include <asm/div64.h>
> >
> > /*
> > * Protected counters by write_lock_irq(&tasklist_lock)
> > @@ -185,10 +186,15 @@ void __init fork_init(unsigned long memp
This is __init code and it gets thrown away after bootup.
next prev parent reply other threads:[~2008-12-11 22:27 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-12-10 16:50 [PATCH][v2] fork_init: fix division by zero Yuri Tikhonov
2008-12-11 20:16 ` Andrew Morton
2008-12-11 20:28 ` Al Viro
2008-12-11 20:43 ` Andrew Morton
2008-12-12 2:31 ` Nick Piggin
2008-12-12 2:47 ` Andrew Morton
2008-12-12 3:36 ` Nick Piggin
2008-12-11 22:22 ` Re[2]: " Yuri Tikhonov
2008-12-11 22:26 ` Andrew Morton [this message]
2008-12-12 0:48 ` Paul Mackerras
2008-12-12 1:07 ` Andrew Morton
2008-12-18 7:47 ` Yuri Tikhonov
2008-12-18 22:45 ` Andrew Morton
2008-12-19 5:49 ` Re[2]: " Yuri Tikhonov
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20081211142611.1790a62a.akpm@linux-foundation.org \
--to=akpm@linux-foundation$(echo .)org \
--cc=Geert.Uytterhoeven@sonycom$(echo .)com \
--cc=dzu@denx$(echo .)de \
--cc=linux-kernel@vger$(echo .)kernel.org \
--cc=linuxppc-dev@ozlabs$(echo .)org \
--cc=miltonm@bga$(echo .)com \
--cc=viro@zeniv$(echo .)linux.org.uk \
--cc=wd@denx$(echo .)de \
--cc=yanok@emcraft$(echo .)com \
--cc=yur@emcraft$(echo .)com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox