commit 016c4d92cd16f569c6485ae62b076c1a4b779536
author Rik van Riel <riel@surriel.com> Tue Sep 25 23:58:42 2018 -0400
committer Peter Zijlstra <peterz@infradead.org> Tue Oct 09 16:51:12 2018 +0200
tree b734bacfc71fe52ac281da272536d5156ec8a252
parent 7d49b28a80b830c3ca876d33bedc58d62a78e16f

x86/mm/tlb: Add freed_tables argument to flush_tlb_mm_range

Add an argument to flush_tlb_mm_range to indicate whether page tables
are about to be freed after this TLB flush. This allows for an
optimization of flush_tlb_mm_range to skip CPUs in lazy TLB mode.

No functional changes.

Cc: npiggin@gmail.com
Cc: mingo@kernel.org
Cc: will.deacon@arm.com
Cc: songliubraving@fb.com
Cc: kernel-team@fb.com
Cc: luto@kernel.org
Cc: hpa@zytor.com
Signed-off-by: Rik van Riel <riel@surriel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20180926035844.1420-6-riel@surriel.com

arch/x86/include/asm/tlb.h

diff --git a/arch/x86/include/asm/tlb.h b/arch/x86/include/asm/tlb.h
index afbe7d1..404b8b1d 100644
--- a/arch/x86/include/asm/tlb.h
+++ b/arch/x86/include/asm/tlb.h
@@ -20,7 +20,7 @@
 		end = tlb->end;
 	}
 
-	flush_tlb_mm_range(tlb->mm, start, end, stride_shift);
+	flush_tlb_mm_range(tlb->mm, start, end, stride_shift, tlb->freed_tables);
 }
 
 /*

arch/x86/include/asm/tlbflush.h

diff --git a/arch/x86/include/asm/tlbflush.h b/arch/x86/include/asm/tlbflush.h
index d6c0cd9..1dea986 100644
--- a/arch/x86/include/asm/tlbflush.h
+++ b/arch/x86/include/asm/tlbflush.h
@@ -536,22 +536,24 @@
 
 #define local_flush_tlb() __flush_tlb()
 
-#define flush_tlb_mm(mm)	flush_tlb_mm_range(mm, 0UL, TLB_FLUSH_ALL, 0UL)
+#define flush_tlb_mm(mm)						\
+		flush_tlb_mm_range(mm, 0UL, TLB_FLUSH_ALL, 0UL, true)
 
 #define flush_tlb_range(vma, start, end)				\
 	flush_tlb_mm_range((vma)->vm_mm, start, end,			\
 			   ((vma)->vm_flags & VM_HUGETLB)		\
 				? huge_page_shift(hstate_vma(vma))	\
-				: PAGE_SHIFT)
+				: PAGE_SHIFT, false)
 
 extern void flush_tlb_all(void);
 extern void flush_tlb_mm_range(struct mm_struct *mm, unsigned long start,
-				unsigned long end, unsigned int stride_shift);
+				unsigned long end, unsigned int stride_shift,
+				bool freed_tables);
 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, PAGE_SHIFT);
+	flush_tlb_mm_range(vma->vm_mm, a, a + PAGE_SIZE, PAGE_SHIFT, false);
 }
 
 void native_flush_tlb_others(const struct cpumask *cpumask,

arch/x86/kernel/ldt.c

diff --git a/arch/x86/kernel/ldt.c b/arch/x86/kernel/ldt.c
index 7fdb241..ab18e08 100644
--- a/arch/x86/kernel/ldt.c
+++ b/arch/x86/kernel/ldt.c
@@ -273,7 +273,7 @@
 	map_ldt_struct_to_user(mm);
 
 	va = (unsigned long)ldt_slot_va(slot);
-	flush_tlb_mm_range(mm, va, va + LDT_SLOT_STRIDE, PAGE_SHIFT);
+	flush_tlb_mm_range(mm, va, va + LDT_SLOT_STRIDE, PAGE_SHIFT, false);
 
 	ldt->slot = slot;
 	return 0;

arch/x86/kernel/vm86_32.c

diff --git a/arch/x86/kernel/vm86_32.c b/arch/x86/kernel/vm86_32.c
index 52fed70..c2fd397 100644
--- a/arch/x86/kernel/vm86_32.c
+++ b/arch/x86/kernel/vm86_32.c
@@ -199,7 +199,7 @@
 	pte_unmap_unlock(pte, ptl);
 out:
 	up_write(&mm->mmap_sem);
-	flush_tlb_mm_range(mm, 0xA0000, 0xA0000 + 32*PAGE_SIZE, PAGE_SHIFT);
+	flush_tlb_mm_range(mm, 0xA0000, 0xA0000 + 32*PAGE_SIZE, PAGE_SHIFT, false);
 }
 
 

arch/x86/mm/tlb.c

diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c
index 9fb30d2..14bf39f 100644
--- a/arch/x86/mm/tlb.c
+++ b/arch/x86/mm/tlb.c
@@ -609,7 +609,8 @@
 static unsigned long tlb_single_page_flush_ceiling __read_mostly = 33;
 
 void flush_tlb_mm_range(struct mm_struct *mm, unsigned long start,
-				unsigned long end, unsigned int stride_shift)
+				unsigned long end, unsigned int stride_shift,
+				bool freed_tables)
 {
 	int cpu;