[PATCH v6 4/7] mm: refactoring TLB gathering API

Nadav Amit
2017-08-02T07:34:31Z

From: Minchan Kim <minchan@kernel.org>

This patch is a preparatory patch for solving race problems caused by
TLB batch. For that, we will increase/decrease TLB flush pending count
of mm_struct whenever tlb_[gather|finish]_mmu is called.

Before making it simple, this patch separates architecture specific
part and rename it to arch_tlb_[gather|finish]_mmu and generic part
just calls it.

It shouldn't change any behavior.

Cc: Ingo Molnar <mingo@redhat.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: linux-arch@vger.kernel.org
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Nadav Amit <namit@vmware.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
---
arch/arm/include/asm/tlb.h | 6 ++++--
arch/ia64/include/asm/tlb.h | 6 ++++--
arch/s390/include/asm/tlb.h | 12 ++++++------
arch/sh/include/asm/tlb.h | 6 ++++--
arch/um/include/asm/tlb.h | 8 +++++---
include/asm-generic/tlb.h | 7 ++++---
include/linux/mm_types.h | 6 ++++++
mm/memory.c | 28 +++++++++++++++++++++-------
8 files changed, 54 insertions(+), 25 deletions(-)

diff --git a/arch/arm/include/asm/tlb.h b/arch/arm/include/asm/tlb.h
index 3f2eb76243e3..7f5b2a2d3861 100644
--- a/arch/arm/include/asm/tlb.h
+++ b/arch/arm/include/asm/tlb.h
@@ -148,7 +148,8 @@ static inline void tlb_flush_mmu(struct mmu_gather *tlb)
}

static inline void
-tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm, unsigned long start, unsigned long end)
+arch_tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm,
+ unsigned long start, unsigned long end)
{
tlb->mm = mm;
tlb->fullmm = !(start | (end+1));
@@ -166,7 +167,8 @@ tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm, unsigned long start
}

static inline void
-tlb_finish_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long end)
+arch_tlb_finish_mmu(struct mmu_gather *tlb,
+ unsigned long start, unsigned long end)
{
tlb_flush_mmu(tlb);

diff --git a/arch/ia64/include/asm/tlb.h b/arch/ia64/include/asm/tlb.h
index fced197b9626..93cadc04ac62 100644
--- a/arch/ia64/include/asm/tlb.h
+++ b/arch/ia64/include/asm/tlb.h
@@ -168,7 +168,8 @@ static inline void __tlb_alloc_page(struct mmu_gather *tlb)

static inline void
-tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm, unsigned long start, unsigned long end)
+arch_tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm,
+ unsigned long start, unsigned long end)
{
tlb->mm = mm;
tlb->max = ARRAY_SIZE(tlb->local);
@@ -185,7 +186,8 @@ tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm, unsigned long start
* collected.
*/
static inline void
-tlb_finish_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long end)
+arch_tlb_finish_mmu(struct mmu_gather *tlb,
+ unsigned long start, unsigned long end)
{
/*
* Note: tlb->nr may be 0 at this point, so we can't rely on tlb->start_addr and
diff --git a/arch/s390/include/asm/tlb.h b/arch/s390/include/asm/tlb.h
index 853b2a3d8dee..0e59ef57e234 100644
--- a/arch/s390/include/asm/tlb.h
+++ b/arch/s390/include/asm/tlb.h
@@ -47,10 +47,9 @@ struct mmu_table_batch {
extern void tlb_table_flush(struct mmu_gather *tlb);
extern void tlb_remove_table(struct mmu_gather *tlb, void *table);

-static inline void tlb_gather_mmu(struct mmu_gather *tlb,
- struct mm_struct *mm,
- unsigned long start,
- unsigned long end)
+static inline void
+arch_tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm,
+ unsigned long start, unsigned long end)
{
tlb->mm = mm;
tlb->start = start;
@@ -76,8 +75,9 @@ static inline void tlb_flush_mmu(struct mmu_gather *tlb)
tlb_flush_mmu_free(tlb);
}

-static inline void tlb_finish_mmu(struct mmu_gather *tlb,
- unsigned long start, unsigned long end)
+static inline void
+arch_tlb_finish_mmu(struct mmu_gather *tlb,
+ unsigned long start, unsigned long end)
{
tlb_flush_mmu(tlb);
}
diff --git a/arch/sh/include/asm/tlb.h b/arch/sh/include/asm/tlb.h
index 46e0d635e36f..89786560dbd4 100644
--- a/arch/sh/include/asm/tlb.h
+++ b/arch/sh/include/asm/tlb.h
@@ -36,7 +36,8 @@ static inline void init_tlb_gather(struct mmu_gather *tlb)
}

static inline void
-tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm, unsigned long start, unsigned long end)
+arch_tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm,
+ unsigned long start, unsigned long end)
{
tlb->mm = mm;
tlb->start = start;
@@ -47,7 +48,8 @@ tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm, unsigned long start
}

static inline void
-tlb_finish_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long end)
+arch_tlb_finish_mmu(struct mmu_gather *tlb,
+ unsigned long start, unsigned long end)
{
if (tlb->fullmm)
flush_tlb_mm(tlb->mm);
diff --git a/arch/um/include/asm/tlb.h b/arch/um/include/asm/tlb.h
index 600a2e9bfee2..2a901eca7145 100644
--- a/arch/um/include/asm/tlb.h
+++ b/arch/um/include/asm/tlb.h
@@ -45,7 +45,8 @@ static inline void init_tlb_gather(struct mmu_gather *tlb)
}

static inline void
-tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm, unsigned long start, unsigned long end)
+arch_tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm,
+ unsigned long start, unsigned long end)
{
tlb->mm = mm;
tlb->start = start;
@@ -80,12 +81,13 @@ tlb_flush_mmu(struct mmu_gather *tlb)
tlb_flush_mmu_free(tlb);
}

-/* tlb_finish_mmu
+/* arch_tlb_finish_mmu
* Called at the end of the shootdown operation to free up any resources
* that were required.
*/
static inline void
-tlb_finish_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long end)
+arch_tlb_finish_mmu(struct mmu_gather *tlb,
+ unsigned long start, unsigned long end)
{
tlb_flush_mmu(tlb);

diff --git a/include/asm-generic/tlb.h b/include/asm-generic/tlb.h
index 8afa4335e5b2..8f71521e7a44 100644
--- a/include/asm-generic/tlb.h
+++ b/include/asm-generic/tlb.h
@@ -112,10 +112,11 @@ struct mmu_gather {

#define HAVE_GENERIC_MMU_GATHER

-void tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm, unsigned long start, unsigned long end);
+void arch_tlb_gather_mmu(struct mmu_gather *tlb,
+ struct mm_struct *mm, unsigned long start, unsigned long end);
void tlb_flush_mmu(struct mmu_gather *tlb);
-void tlb_finish_mmu(struct mmu_gather *tlb, unsigned long start,
- unsigned long end);
+void arch_tlb_finish_mmu(struct mmu_gather *tlb,
+ unsigned long start, unsigned long end);
extern bool __tlb_remove_page_size(struct mmu_gather *tlb, struct page *page,
int page_size);

diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 2956513619a7..248f4ed1f3e1 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -518,6 +518,12 @@ static inline cpumask_t *mm_cpumask(struct mm_struct *mm)
return mm->cpu_vm_mask_var;
}

+struct mmu_gather;
+extern void tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm,
+ unsigned long start, unsigned long end);
+extern void tlb_finish_mmu(struct mmu_gather *tlb,
+ unsigned long start, unsigned long end);
+
#if defined(CONFIG_NUMA_BALANCING) || defined(CONFIG_COMPACTION)
/*
* Memory barriers to keep this state in sync are graciously provided by
diff --git a/mm/memory.c b/mm/memory.c
index bb11c474857e..7848b5030be0 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -215,12 +215,8 @@ static bool tlb_next_batch(struct mmu_gather *tlb)
return true;
}

-/* tlb_gather_mmu
- * Called to initialize an (on-stack) mmu_gather structure for page-table
- * tear-down from @mm. The @fullmm argument is used when @mm is without
- * users and we're going to destroy the full address space (exit/execve).
- */
-void tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm, unsigned long start, unsigned long end)
+void arch_tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm,
+ unsigned long start, unsigned long end)
{
tlb->mm = mm;

@@ -275,7 +271,8 @@ void tlb_flush_mmu(struct mmu_gather *tlb)
* Called at the end of the shootdown operation to free up any resources
* that were required.
*/
-void tlb_finish_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long end)
+void arch_tlb_finish_mmu(struct mmu_gather *tlb,
+ unsigned long start, unsigned long end)
{
struct mmu_gather_batch *batch, *next;

@@ -398,6 +395,23 @@ void tlb_remove_table(struct mmu_gather *tlb, void *table)

#endif /* CONFIG_HAVE_RCU_TABLE_FREE */

+/* tlb_gather_mmu
+ * Called to initialize an (on-stack) mmu_gather structure for page-table
+ * tear-down from @mm. The @fullmm argument is used when @mm is without
+ * users and we're going to destroy the full address space (exit/execve).
+ */
+void tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm,
+ unsigned long start, unsigned long end)
+{
+ arch_tlb_gather_mmu(tlb, mm, start, end);
+}
+
+void tlb_finish_mmu(struct mmu_gather *tlb,
+ unsigned long start, unsigned long end)
+{
+ arch_tlb_finish_mmu(tlb, start, end);
+}
+
/*
* Note: this doesn't free the actual pages themselves. That
* has been handled earlier when unmapping all the memory regions.
--
2.11.0