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From: Keith Owens <kaos@sgi.com>
To: linux-ia64@vger.kernel.org
Subject: Re: [patch 1/6] align kenrel rbs on 128 byte
Date: Tue, 31 Jan 2006 08:57:12 +0000	[thread overview]
Message-ID: <6389.1138697832@kao2.melbourne.sgi.com> (raw)
In-Reply-To: <200601310848.k0V8mbg11087@unix-os.sc.intel.com>

"Chen, Kenneth W" (on Tue, 31 Jan 2006 00:48:28 -0800) wrote:
>The bottom of kernel rbs stack is the memory used to spill user
>dirty stack register partition when entering the kernel.  This
>space is heavily used on every kernel entry and exit. It deserve
>having its own dedicated cache line and not to share with tail
>end of thread_info which is not used heavily.
>
>Align the bottom of kernel rbs stack to 128 byte boundary.
>
>Signed-off-by: Ken Chen <kenneth.w.chen@intel.com>
>
>
>--- ./include/asm-ia64/ptrace.h.orig	2006-01-19 16:45:49.695591377 -0800
>+++ ./include/asm-ia64/ptrace.h	2006-01-20 02:24:05.985205410 -0800
>@@ -75,7 +75,7 @@
> # define KERNEL_STACK_SIZE_ORDER		0
> #endif
> 
>-#define IA64_RBS_OFFSET			((IA64_TASK_SIZE + IA64_THREAD_INFO_SIZE + 15) & ~15)
>+#define IA64_RBS_OFFSET			((IA64_TASK_SIZE + IA64_THREAD_INFO_SIZE + 127) & ~127)
> #define IA64_STK_OFFSET			((1 << KERNEL_STACK_SIZE_ORDER)*PAGE_SIZE)
> 
> #define KERNEL_STACK_SIZE		IA64_STK_OFFSET

The cache lines are not guaranteed to be 128 byte aligned, they were 64
on bigsur.  Change 127 to (L1_CACHE_BYTES - 1).


  reply	other threads:[~2006-01-31  8:57 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-01-31  8:48 [patch 1/6] align kenrel rbs on 128 byte Chen, Kenneth W
2006-01-31  8:57 ` Keith Owens [this message]
2006-01-31  9:42 ` Chen, Kenneth W
2006-01-31 10:15 ` Andreas Schwab
2006-01-31 11:00 ` Jes Sorensen
2006-01-31 15:26 ` Russ Anderson
2006-01-31 16:25 ` Chen, Kenneth W
2006-01-31 19:58 ` Richard Harke
2006-01-31 19:59 ` Chen, Kenneth W
2006-01-31 20:16 ` Richard Harke

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