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Subject[PATCH v10 6/9] mm/mmu_gather: enable tlb flush range in generic mmu_gather
Date
This patch enabled the tlb flush range support in generic mmu layer.

Most of arch has self tlb flush range support, like ARM/IA64 etc.
X86 arch has no this support in hardware yet. But another instruction
'invlpg' can implement this function in some degree. So, enable this
feather in generic layer for x86 now. and maybe useful for other archs
in further.

Generic mmu_gather struct is protected by micro
HAVE_GENERIC_MMU_GATHER. Other archs that has flush range supported
own self mmu_gather struct. So, now this change is safe for them.

In future we may unify this struct and related functions on multiple
archs.

Thanks for Peter Zijlstra time and time reminder for multiple
architecture code safe!

Signed-off-by: Alex Shi <alex.shi@intel.com>
---
include/asm-generic/tlb.h | 2 ++
mm/memory.c | 9 +++++++++
2 files changed, 11 insertions(+), 0 deletions(-)
diff --git a/include/asm-generic/tlb.h b/include/asm-generic/tlb.h
index 75e888b..ed6642a 100644
--- a/include/asm-generic/tlb.h
+++ b/include/asm-generic/tlb.h
@@ -86,6 +86,8 @@ struct mmu_gather {
#ifdef CONFIG_HAVE_RCU_TABLE_FREE
struct mmu_table_batch *batch;
#endif
+ unsigned long start;
+ unsigned long end;
unsigned int need_flush : 1, /* Did free PTEs */
fast_mode : 1; /* No batching */

diff --git a/mm/memory.c b/mm/memory.c
index 2466d12..91f6945 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -206,6 +206,8 @@ void tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm, bool fullmm)
tlb->mm = mm;

tlb->fullmm = fullmm;
+ tlb->start = -1UL;
+ tlb->end = 0;
tlb->need_flush = 0;
tlb->fast_mode = (num_possible_cpus() == 1);
tlb->local.next = NULL;
@@ -248,6 +250,8 @@ void tlb_finish_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long e
{
struct mmu_gather_batch *batch, *next;

+ tlb->start = start;
+ tlb->end = end;
tlb_flush_mmu(tlb);

/* keep the page table cache within bounds */
@@ -1204,6 +1208,11 @@ again:
*/
if (force_flush) {
force_flush = 0;
+
+#ifdef HAVE_GENERIC_MMU_GATHER
+ tlb->start = addr;
+ tlb->end = end;
+#endif
tlb_flush_mmu(tlb);
if (addr != end)
goto again;
--
1.7.5.4


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