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From: Jeremy Fitzhardinge <jeremy@goop.org>
To: Rusty Russell <rusty@rustcorp.com.au>
Cc: Ingo Molnar <mingo@elte.hu>,
	lkml - Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Zachary Amsden <zach@vmware.com>,
	Jeremy Fitzhardinge <jeremy@xensource.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Andi Kleen <ak@suse.de>
Subject: Re: [PATCH 8/8] Convert PDA into the percpu section
Date: Tue, 06 Mar 2007 16:35:06 -0800	[thread overview]
Message-ID: <45EE08BA.6080309@goop.org> (raw)
In-Reply-To: <1173226350.4644.54.camel@localhost.localdomain>

Rusty Russell wrote:
> 	If we used __thread, then gcc could do this optimization for us when it
> knows an rvalue is needed, however:
>
> 1) gcc wants to use %gs, not %fs, which is measurably slower for the
> kernel,
> 2) gcc wants to use huge offsets to store the address of the per-cpu
> space, and this breaks Xen (and current lguest, but new lguest no longer
> uses segments for protection)
>   

Well, if we go to the effort of teaching gcc how to use %fs, we can
probably convince it to generate positive offset TLS relocs too.

    J

  reply	other threads:[~2007-03-07  0:35 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-03-06 12:39 [PATCH 0/8] x86 boot, pda and gdt cleanups Rusty Russell
2007-03-06 12:53 ` [PATCH 1/8] Remove cpu_gdt_table: use boot_gdt_table until migration to per-cpu Rusty Russell
2007-03-06 12:54   ` [PATCH 2/8] Remove NR_CPUS from asm-generic/percpu.h Rusty Russell
2007-03-06 12:55     ` [PATCH 3/8] Use per-cpu variables for GDT, PDA Rusty Russell
2007-03-06 12:57       ` [PATCH 4/8] Cleanup setup_pda Rusty Russell
2007-03-06 12:58         ` [PATCH 5/8] Cleanup GDT access Rusty Russell
2007-03-06 13:00           ` [PATCH 6/8] Allow per-cpu variables to be page-aligned Rusty Russell
2007-03-06 13:01             ` [PATCH 7/8] Page-align the GDT Rusty Russell
2007-03-06 13:03               ` [PATCH 8/8] Convert PDA into the percpu section Rusty Russell
2007-03-06 13:10                 ` Ingo Molnar
2007-03-07  0:12                   ` Rusty Russell
2007-03-07  0:35                     ` Jeremy Fitzhardinge [this message]
2007-03-06 18:28                 ` Jeremy Fitzhardinge
2007-03-06 19:34                 ` Andi Kleen
2007-03-06 18:37                   ` Jeremy Fitzhardinge
2007-03-07  0:33                   ` Rusty Russell
2007-03-07 11:55                     ` Rusty Russell
2007-03-13 17:15                 ` Jeremy Fitzhardinge
2007-03-14  2:27                   ` Rusty Russell
2007-03-06 13:15             ` [PATCH 6/8] Allow per-cpu variables to be page-aligned Ingo Molnar
2007-03-07  0:16               ` Rusty Russell
2007-03-07  0:44                 ` H. Peter Anvin
2007-03-06 18:17             ` Jeremy Fitzhardinge
2007-03-07  0:29               ` Rusty Russell
2007-03-06 18:16           ` [PATCH 5/8] Cleanup GDT access Jeremy Fitzhardinge
2007-03-06 18:14       ` [PATCH 3/8] Use per-cpu variables for GDT, PDA Jeremy Fitzhardinge
2007-03-06 13:21     ` [PATCH 2/8] Remove NR_CPUS from asm-generic/percpu.h Ingo Molnar
2007-03-06 13:20   ` [PATCH 1/8] Remove cpu_gdt_table: use boot_gdt_table until migration to per-cpu Ingo Molnar
2007-03-06 13:26     ` Ingo Molnar
2007-03-07  0:22     ` Rusty Russell
2007-03-13 20:48 ` [PATCH 0/8] x86 boot, pda and gdt cleanups Jeremy Fitzhardinge
2007-03-14  2:25   ` Rusty Russell
2007-03-14  4:39     ` Jeremy Fitzhardinge
2007-03-14  6:54       ` Rusty Russell
2007-03-14 23:55   ` Rusty Russell
2007-03-15  1:57     ` Jeremy Fitzhardinge

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