Re: kernel: ldt allocation failed

From: Denis Vlasenko (vda@port.imtp.ilyichevsk.odessa.ua)
Date: Wed Feb 06 2002 - 13:02:25 EST


On 6 February 2002 11:19, Andi Kleen wrote:
> Denis Vlasenko <vda@port.imtp.ilyichevsk.odessa.ua> writes:
> > I am ignorant on the subject, but why LDT is used in Linux at all?
> > LDT register can be set to 0, this can speed up task switch time and save
> > some memory used for LDT.
>
> glibc thread local data uses an LDT for the segment register.
>
> glibc 2.3 seems to plan to use segment register based thread local data for
> even non threaded programs, so it would be a good idea to optimize LDT
> allocation a bit (= not allocate 64K of vmalloc space every time
> sys_modify_ldt is called - there is only 8MB of it)

What do they use on arches without LDT or equivalent?

--
vda
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