linux-kernel - [RFC][PATCH 03/11] x86/mm: Page size aware flush_tlb_mm

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Date:   Thu, 13 Sep 2018 11:21:13 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     will.deacon@....com, aneesh.kumar@...ux.vnet.ibm.com,
        akpm@...ux-foundation.org, npiggin@...il.com
Cc:     linux-arch@...r.kernel.org, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org, peterz@...radead.org,
        linux@...linux.org.uk, heiko.carstens@...ibm.com,
        Dave Hansen <dave.hansen@...ux.intel.com>
Subject: [RFC][PATCH 03/11] x86/mm: Page size aware flush_tlb_mm_range()

Use the new tlb_get_unmap_shift() to determine the stride of the
INVLPG loop.

Cc: Will Deacon <will.deacon@....com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@...ux.vnet.ibm.com>
Cc: Andrew Morton <akpm@...ux-foundation.org>
Cc: Nick Piggin <npiggin@...il.com>
Cc: Dave Hansen <dave.hansen@...ux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
---
 arch/x86/include/asm/tlb.h      |   21 ++++++++++++++-------
 arch/x86/include/asm/tlbflush.h |   10 ++++++----
 arch/x86/mm/tlb.c               |   10 +++++-----
 3 files changed, 25 insertions(+), 16 deletions(-)

--- a/arch/x86/include/asm/tlb.h
+++ b/arch/x86/include/asm/tlb.h
@@ -6,16 +6,23 @@
 #define tlb_end_vma(tlb, vma) do { } while (0)
 #define __tlb_remove_tlb_entry(tlb, ptep, address) do { } while (0)
 
-#define tlb_flush(tlb)							\
-{									\
-	if (!tlb->fullmm && !tlb->need_flush_all) 			\
-		flush_tlb_mm_range(tlb->mm, tlb->start, tlb->end, 0UL);	\
-	else								\
-		flush_tlb_mm_range(tlb->mm, 0UL, TLB_FLUSH_ALL, 0UL);	\
-}
+static inline void tlb_flush(struct mmu_gather *tlb);
 
 #include <asm-generic/tlb.h>
 
+static inline void tlb_flush(struct mmu_gather *tlb)
+{
+	unsigned long start = 0UL, end = TLB_FLUSH_ALL;
+	unsigned int invl_shift = tlb_get_unmap_shift(tlb);
+
+	if (!tlb->fullmm && !tlb->need_flush_all) {
+		start = tlb->start;
+		end = tlb->end;
+	}
+
+	flush_tlb_mm_range(tlb->mm, start, end, invl_shift);
+}
+
 /*
  * While x86 architecture in general requires an IPI to perform TLB
  * shootdown, enablement code for several hypervisors overrides
--- a/arch/x86/include/asm/tlbflush.h
+++ b/arch/x86/include/asm/tlbflush.h
@@ -507,23 +507,25 @@ struct flush_tlb_info {
 	unsigned long		start;
 	unsigned long		end;
 	u64			new_tlb_gen;
+	unsigned int		invl_shift;
 };
 
 #define local_flush_tlb() __flush_tlb()
 
 #define flush_tlb_mm(mm)	flush_tlb_mm_range(mm, 0UL, TLB_FLUSH_ALL, 0UL)
 
-#define flush_tlb_range(vma, start, end)	\
-		flush_tlb_mm_range(vma->vm_mm, start, end, vma->vm_flags)
+#define flush_tlb_range(vma, start, end)			\
+		flush_tlb_mm_range((vma)->vm_mm, start, end,	\
+				(vma)->vm_flags & VM_HUGETLB ? PMD_SHIFT : PAGE_SHIFT)
 
 extern void flush_tlb_all(void);
 extern void flush_tlb_mm_range(struct mm_struct *mm, unsigned long start,
-				unsigned long end, unsigned long vmflag);
+				unsigned long end, unsigned int invl_shift);
 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);
+	flush_tlb_mm_range(vma->vm_mm, a, a + PAGE_SIZE, PAGE_SHIFT);
 }
 
 void native_flush_tlb_others(const struct cpumask *cpumask,
--- a/arch/x86/mm/tlb.c
+++ b/arch/x86/mm/tlb.c
@@ -522,12 +522,12 @@ static void flush_tlb_func_common(const
 	    f->new_tlb_gen == mm_tlb_gen) {
 		/* Partial flush */
 		unsigned long addr;
-		unsigned long nr_pages = (f->end - f->start) >> PAGE_SHIFT;
+		unsigned long nr_pages = (f->end - f->start) >> f->invl_shift;
 
 		addr = f->start;
 		while (addr < f->end) {
 			__flush_tlb_one_user(addr);
-			addr += PAGE_SIZE;
+			addr += 1UL << f->invl_shift;
 		}
 		if (local)
 			count_vm_tlb_events(NR_TLB_LOCAL_FLUSH_ONE, nr_pages);
@@ -616,12 +616,13 @@ void native_flush_tlb_others(const struc
 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 long vmflag)
+				unsigned long end, unsigned int invl_shift)
 {
 	int cpu;
 
 	struct flush_tlb_info info __aligned(SMP_CACHE_BYTES) = {
 		.mm = mm,
+		.invl_shift = invl_shift,
 	};
 
 	cpu = get_cpu();
@@ -631,8 +632,7 @@ void flush_tlb_mm_range(struct mm_struct
 
 	/* Should we flush just the requested range? */
 	if ((end != TLB_FLUSH_ALL) &&
-	    !(vmflag & VM_HUGETLB) &&
-	    ((end - start) >> PAGE_SHIFT) <= tlb_single_page_flush_ceiling) {
+	    ((end - start) >> invl_shift) <= tlb_single_page_flush_ceiling) {
 		info.start = start;
 		info.end = end;
 	} else {