From: Segher Boessenkool <segher@kernel.crashing.org>
To: michael@ellerman.id.au
Cc: Olof Johansson <olof@lixom.net>,
linuxppc-dev@ozlabs.org, paulus@samba.org, anton@samba.org
Subject: Re: [PATCH] powerpc: save trap number in bad_stack
Date: Fri, 20 Apr 2007 10:51:06 +0200 [thread overview]
Message-ID: <a3519d3b3474ab6530e6e1092e3d60d0@kernel.crashing.org> (raw)
In-Reply-To: <1177035524.6890.7.camel@concordia.ozlabs.ibm.com>
>>> + u64 trap_save; /* Used when bad stack is encountered */
>>
>> Can you put it elsewhere in the PACA (around less frequently used
>> bits) ? This is a pretty hot area of the PACA...
>
> It's only set in the bad_stack case though.
>
> You should put it after cpu_start, there's a bit hole there, and
> trap_save is readonly during normal operation, so it shouldn't be a
> performance hit.
That's not a performance hit compared to the current
state of the code, sure; but that "hot slot" could
be used for a hotter variable, instead.
Segher
next prev parent reply other threads:[~2007-04-20 8:51 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-04-16 6:23 [PATCH] powerpc: save trap number in bad_stack Olof Johansson
2007-04-19 23:17 ` Benjamin Herrenschmidt
2007-04-20 2:18 ` Michael Ellerman
2007-04-20 8:51 ` Segher Boessenkool [this message]
2007-04-22 23:34 ` Olof Johansson
2007-04-22 23:38 ` [PATCH] [v2] " Olof Johansson
2007-04-23 9:29 ` Gabriel Paubert
2007-04-23 11:49 ` Olof Johansson
2007-04-23 12:19 ` [PATCH] [v3] " Olof Johansson
2007-04-23 15:11 ` [PATCH] [v4] " Olof Johansson
2007-04-23 15:34 ` Stephen Rothwell
2007-04-23 13:22 ` [PATCH] [v2] " Stephen Rothwell
2007-04-23 13:33 ` Michael Ellerman
2007-04-23 13:39 ` David Gibson
2007-04-23 13:54 ` Olof Johansson
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