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Date: Tue, 27 Mar 2007 14:40:31 -0700
From: Andrew Morton <akpm@linux-foundation.org>
To: Eric Dumazet <dada1@cosmosbay.com>
Cc: Badari Pulavarty <pbadari@gmail.com>, lkml <linux-kernel@vger.kernel.org>,
       Andi Kleen <ak@suse.de>
Subject: Re: 2.6.21-rc5-mm1
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On Tue, 27 Mar 2007 23:29:34 +0200
Eric Dumazet <dada1@cosmosbay.com> wrote:

> Andrew Morton a écrit :
> > 
> > The wheel spins around, slows then settles on.... 
> > time-smp-friendly-alignment-of-struct-clocksource.patch!
> > 
> > Presumably because the ____cacheline_aligned made vsyscall_gtod_data_t get
> > too big.  Or something.
> 
> Very strange, since here I have plenty of available room (256 bytes) :
> 
> ffffffffff600000 T vgettimeofday
> ffffffffff60004e t vsysc2
> ffffffffff600140 t vread_hpet
> ffffffffff600150 t vread_tsc
> ffffffffff600180 D __vsyscall_gtod_data
> ffffffffff600280 D __vgetcpu_mode
> ffffffffff6002c0 D __jiffies
> <lot of space (256 bytes)>
> ffffffffff600400 T vtime
> ffffffffff600413 t vsysc1
> ffffffffff600800 T vgetcpu
> ffffffffff600c00 T venosys_1
> 
> It must depends on the compiler, and/or CONFIG_XXX options...

Badari's config triggered it for me.

> Anyway, I think we can safely move __vgetcpu_mode & __jiffies to the 1024 
> bytes area dedicated to vgetcpu() implementation. This saves 128 bytes from 
> vsyscall_0 area.
> 
> Could we add this patch instead of dropping 
> time-smp-friendly-alignment-of-struct-clocksource.patch ?

When you tell me it works OK with Badari's config ;)