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Re: FOR REVIEW: New x86-64 vsyscall vgetcpu()
- From: Zoltan Menyhart <Zoltan dot Menyhart at bull dot net>
- To: Andi Kleen <ak at suse dot de>
- Cc: Jes Sorensen <jes at sgi dot com>, Tony Luck <tony dot luck at intel dot com>, discuss at x86-64 dot org, linux-kernel at vger dot kernel dot org, libc-alpha at sourceware dot org, vojtech at suse dot cz, linux-ia64 at vger dot kernel dot org
- Date: Fri, 16 Jun 2006 17:31:12 +0200
- Subject: Re: FOR REVIEW: New x86-64 vsyscall vgetcpu()
- References: <email@example.com> <44929CE6.firstname.lastname@example.org> <4492A5E4.email@example.com> <firstname.lastname@example.org>
Andi Kleen wrote:
That is not how user space TLS works. It usually has a base a register.
Can you please give me a real life (simplified) example?
This means it cannot be cache colored (because you would need a static
offset) and you couldn't share task_structs on a page.
I do not see the problem. Can you explain please?
E.g. the scheduler pulls a task instead of the current one. The CPU
will see "current->thread_info.cpu"-s of all the tasks at the same
Also you would make task_struct part of the userland ABI which
seems like a very very bad idea to me. It means we couldn't change
We can make some wrapper, e.g.:
"vgetcpu()" would also be added to the ABI which we couldn't change