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Commit ca6c99c0 authored by Andy Lutomirski's avatar Andy Lutomirski Committed by Ingo Molnar
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x86/mm: Reimplement flush_tlb_page() using flush_tlb_mm_range() 



flush_tlb_page() was very similar to flush_tlb_mm_range() except that
it had a couple of issues:

 - It was missing an smp_mb() in the case where
   current->active_mm != mm.  (This is a longstanding bug reported by Nadav Amit)

 - It was missing tracepoints and vm counter updates.

The only reason that I can see for keeping it at as a separate
function is that it could avoid a few branches that
flush_tlb_mm_range() needs to decide to flush just one page.  This
hardly seems worthwhile.  If we decide we want to get rid of those
branches again, a better way would be to introduce an
__flush_tlb_mm_range() helper and make both flush_tlb_page() and
flush_tlb_mm_range() use it.

Signed-off-by: default avatarAndy Lutomirski <luto@kernel.org>
Acked-by: default avatarKees Cook <keescook@chromium.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Borislav Petkov <bpetkov@suse.de>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Nadav Amit <namit@vmware.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/3cc3847cf888d8907577569b8bac3f01992ef8f9.1495492063.git.luto@kernel.org


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 56fff1bb

arch/x86/include/asm/tlbflush.h

+5 −1
Original line number Diff line number Diff line
@@ -307,11 +307,15 @@ static inline void flush_tlb_kernel_range(unsigned long start, 
		flush_tlb_mm_range(vma->vm_mm, start, end, vma->vm_flags)



extern void flush_tlb_all(void);

extern void flush_tlb_page(struct vm_area_struct *, unsigned long);

extern void flush_tlb_mm_range(struct mm_struct *mm, unsigned long start,

				unsigned long end, unsigned long vmflag);

extern void flush_tlb_kernel_range(unsigned long start, unsigned long end);



static inline void flush_tlb_page(struct vm_area_struct *vma, unsigned long a)

{

	flush_tlb_mm_range(vma->vm_mm, a, a + PAGE_SIZE, VM_NONE);

}



void native_flush_tlb_others(const struct cpumask *cpumask,

				struct mm_struct *mm,

				unsigned long start, unsigned long end);

arch/x86/mm/tlb.c

+0 −27
Original line number Diff line number Diff line
@@ -354,33 +354,6 @@ void flush_tlb_mm_range(struct mm_struct *mm, unsigned long start, 
	preempt_enable();

}



void flush_tlb_page(struct vm_area_struct *vma, unsigned long start)

{

	struct mm_struct *mm = vma->vm_mm;



	preempt_disable();



	if (current->active_mm == mm) {

		if (current->mm) {

			/*

			 * Implicit full barrier (INVLPG) that synchronizes

			 * with switch_mm.

			 */

			__flush_tlb_one(start);

		} else {

			leave_mm(smp_processor_id());



			/* Synchronize with switch_mm. */

			smp_mb();

		}

	}



	if (cpumask_any_but(mm_cpumask(mm), smp_processor_id()) < nr_cpu_ids)

		flush_tlb_others(mm_cpumask(mm), mm, start, start + PAGE_SIZE);



	preempt_enable();

}



static void do_flush_tlb_all(void *info)

{

	count_vm_tlb_event(NR_TLB_REMOTE_FLUSH_RECEIVED);