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Commit 25969354 authored by Ralf Baechle's avatar Ralf Baechle
Browse files

[MIPS] Avoid interprocessor function calls. 



On the 34K where multiple virtual processors are implemented in a single
core and share a single TLB, interprocessor function calls are not needed
to flush a cache, so avoid them.

Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
parent f1aaee53

arch/mips/kernel/smp.c

+30 −5
Original line number Diff line number Diff line
@@ -318,6 +318,32 @@ static void flush_tlb_mm_ipi(void *mm) 
	local_flush_tlb_mm((struct mm_struct *)mm);

}



/*

 * Special Variant of smp_call_function for use by TLB functions:

 *

 *  o No return value

 *  o collapses to normal function call on UP kernels

 *  o collapses to normal function call on systems with a single shared

 *    primary cache.

 *  o CONFIG_MIPS_MT_SMTC currently implies there is only one physical core.

 */

static inline void smp_on_other_tlbs(void (*func) (void *info), void *info)

{

#ifndef CONFIG_MIPS_MT_SMTC

	smp_call_function(func, info, 1, 1);

#endif

}



static inline void smp_on_each_tlb(void (*func) (void *info), void *info)

{

	preempt_disable();



	smp_on_other_tlbs(func, info);

	func(info);



	preempt_enable();

}



/*

 * The following tlb flush calls are invoked when old translations are

 * being torn down, or pte attributes are changing. For single threaded
@@ -336,7 +362,7 @@ void flush_tlb_mm(struct mm_struct *mm) 
	preempt_disable();



	if ((atomic_read(&mm->mm_users) != 1) || (current->mm != mm)) {

		smp_call_function(flush_tlb_mm_ipi, (void *)mm, 1, 1);

		smp_on_other_tlbs(flush_tlb_mm_ipi, (void *)mm);

	} else {

		int i;

		for (i = 0; i < num_online_cpus(); i++)
@@ -372,7 +398,7 @@ void flush_tlb_range(struct vm_area_struct *vma, unsigned long start, unsigned l 
		fd.vma = vma;

		fd.addr1 = start;

		fd.addr2 = end;

		smp_call_function(flush_tlb_range_ipi, (void *)&fd, 1, 1);

		smp_on_other_tlbs(flush_tlb_range_ipi, (void *)&fd);

	} else {

		int i;

		for (i = 0; i < num_online_cpus(); i++)
@@ -414,7 +440,7 @@ void flush_tlb_page(struct vm_area_struct *vma, unsigned long page) 


		fd.vma = vma;

		fd.addr1 = page;

		smp_call_function(flush_tlb_page_ipi, (void *)&fd, 1, 1);

		smp_on_other_tlbs(flush_tlb_page_ipi, (void *)&fd);

	} else {

		int i;

		for (i = 0; i < num_online_cpus(); i++)
@@ -434,8 +460,7 @@ static void flush_tlb_one_ipi(void *info) 


void flush_tlb_one(unsigned long vaddr)

{

	smp_call_function(flush_tlb_one_ipi, (void *) vaddr, 1, 1);

	local_flush_tlb_one(vaddr);

	smp_on_each_tlb(flush_tlb_one_ipi, (void *) vaddr);

}



static DEFINE_PER_CPU(struct cpu, cpu_devices);