Re: [PATCH 13/14] x86/ticketlock: add slowpath logic

From: Jeremy Fitzhardinge
Date: Wed Nov 17 2010 - 04:08:19 EST


On 11/17/2010 12:56 AM, Jeremy Fitzhardinge wrote:
> On 11/17/2010 12:52 AM, Jeremy Fitzhardinge wrote:
>> But, yes, %z0 sounds interesting. Is it documented anywhere? I think
>> I've tried to use it in the past and run into gcc bugs.
> This one: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39590
>
> Should be OK in this case because there's no 64-bit values to be seen...
Hm, it fails when __ticket_t is 16 bits:

/home/jeremy/git/linux/arch/x86/include/asm/spinlock.h: Assembler messages:
/home/jeremy/git/linux/arch/x86/include/asm/spinlock.h:73: Error: suffix
or operands invalid for `or'

lock; ors $1, 2(%rbx) #,


So I don't think that's going to work out...

J
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