asid.c File Reference

ASID management. More...

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Functions
	SPINLOCK_INITIALIZE (asidlock)
asid_t	asid_get (void)
void	asid_put (asid_t asid)
Variables
static count_t	asids_allocated = 0

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Detailed Description

Modern processor architectures optimize TLB utilization by using ASIDs (a.k.a. memory contexts on sparc64 and region identifiers on ia64). These ASIDs help to associate each TLB item with an address space, thus making finer-grained TLB invalidation possible.

Unfortunatelly, there are usually less ASIDs available than there can be unique as_t structures (i.e. address spaces recognized by the kernel).

When system runs short of ASIDs, it will attempt to steal ASID from an address space that has not been active for a while.

This code depends on the fact that ASIDS_ALLOCABLE is greater than number of supported CPUs (i.e. the amount of concurently active address spaces).

Architectures that don't have hardware support for address spaces do not compile with this file.

Definition in file asid.c.

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