[tip:x86/mm] x86/mm/tlb: Add freed_tables argument to flush_tlb_mm_range

From: tip-bot for Rik van Riel
Date: Tue Oct 09 2018 - 11:00:47 EST


Commit-ID: 016c4d92cd16f569c6485ae62b076c1a4b779536
Gitweb: https://git.kernel.org/tip/016c4d92cd16f569c6485ae62b076c1a4b779536
Author: Rik van Riel <riel@xxxxxxxxxxx>
AuthorDate: Tue, 25 Sep 2018 23:58:42 -0400
Committer: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
CommitDate: Tue, 9 Oct 2018 16:51:12 +0200

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@xxxxxxxxx
Cc: mingo@xxxxxxxxxx
Cc: will.deacon@xxxxxxx
Cc: songliubraving@xxxxxx
Cc: kernel-team@xxxxxx
Cc: luto@xxxxxxxxxx
Cc: hpa@xxxxxxxxx
Signed-off-by: Rik van Riel <riel@xxxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/20180926035844.1420-6-riel@xxxxxxxxxxx
---
arch/x86/include/asm/tlb.h | 2 +-
arch/x86/include/asm/tlbflush.h | 10 ++++++----
arch/x86/kernel/ldt.c | 2 +-
arch/x86/kernel/vm86_32.c | 2 +-
arch/x86/mm/tlb.c | 3 ++-
5 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/arch/x86/include/asm/tlb.h b/arch/x86/include/asm/tlb.h
index afbe7d1e68cf..404b8b1d44f5 100644
--- a/arch/x86/include/asm/tlb.h
+++ b/arch/x86/include/asm/tlb.h
@@ -20,7 +20,7 @@ static inline void tlb_flush(struct mmu_gather *tlb)
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);
}

/*
diff --git a/arch/x86/include/asm/tlbflush.h b/arch/x86/include/asm/tlbflush.h
index d6c0cd9e9591..1dea9860ce5b 100644
--- a/arch/x86/include/asm/tlbflush.h
+++ b/arch/x86/include/asm/tlbflush.h
@@ -536,22 +536,24 @@ struct flush_tlb_info {

#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,
diff --git a/arch/x86/kernel/ldt.c b/arch/x86/kernel/ldt.c
index 7fdb2414ca65..ab18e0884dc6 100644
--- a/arch/x86/kernel/ldt.c
+++ b/arch/x86/kernel/ldt.c
@@ -273,7 +273,7 @@ map_ldt_struct(struct mm_struct *mm, struct ldt_struct *ldt, int slot)
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;
diff --git a/arch/x86/kernel/vm86_32.c b/arch/x86/kernel/vm86_32.c
index 52fed70f671e..c2fd39752da8 100644
--- a/arch/x86/kernel/vm86_32.c
+++ b/arch/x86/kernel/vm86_32.c
@@ -199,7 +199,7 @@ static void mark_screen_rdonly(struct mm_struct *mm)
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);
}


diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c
index 9fb30d27854b..14bf39fc0447 100644
--- a/arch/x86/mm/tlb.c
+++ b/arch/x86/mm/tlb.c
@@ -609,7 +609,8 @@ void native_flush_tlb_others(const struct cpumask *cpumask,
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;