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Commit b478458a authored by Jan Beulich's avatar Jan Beulich Committed by Thomas Gleixner
Browse files

x86: avoid re-loading LDT in unrelated address spaces 



Performance optimization.

Signed-off-by: default avatarJan Beulich <jbeulich@novell.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent 78b58e54

arch/x86/kernel/ldt.c

+3 −3
Original line number Original line Diff line number Diff line
@@ -20,9 +20,9 @@ 
#include <asm/mmu_context.h>

#include <asm/mmu_context.h>





#ifdef CONFIG_SMP

#ifdef CONFIG_SMP

static void flush_ldt(void *null)

static void flush_ldt(void *current_mm)

{

{

	if (current->active_mm)

	if (current->active_mm == current_mm)

		load_LDT(&current->active_mm->context);

		load_LDT(&current->active_mm->context);

}

}

#endif

#endif
@@ -68,7 +68,7 @@ static int alloc_ldt(mm_context_t *pc, int mincount, int reload) 
		load_LDT(pc);

		load_LDT(pc);

		mask = cpumask_of_cpu(smp_processor_id());

		mask = cpumask_of_cpu(smp_processor_id());

		if (!cpus_equal(current->mm->cpu_vm_mask, mask))

		if (!cpus_equal(current->mm->cpu_vm_mask, mask))

			smp_call_function(flush_ldt, NULL, 1, 1);

			smp_call_function(flush_ldt, current->mm, 1, 1);

		preempt_enable();

		preempt_enable();

#else

#else

		load_LDT(pc);

		load_LDT(pc);