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authorWill Deacon <will.deacon@arm.com>2014-10-29 10:03:09 +0000
committerWill Deacon <will.deacon@arm.com>2014-11-17 10:12:42 +0000
commitfb7332a9fedfd62b1ba6530c86f39f0fa38afd49 (patch)
tree5e77bd4944da750634c4438df64257cdeaa58888 /include/asm-generic
parent63648dd20fa0780ab6c1e923b5c276d257422cb3 (diff)
downloadlinux-fb7332a9fedfd62b1ba6530c86f39f0fa38afd49.tar.bz2
mmu_gather: move minimal range calculations into generic code
On architectures with hardware broadcasting of TLB invalidation messages , it makes sense to reduce the range of the mmu_gather structure when unmapping page ranges based on the dirty address information passed to tlb_remove_tlb_entry. arm64 already does this by directly manipulating the start/end fields of the gather structure, but this confuses the generic code which does not expect these fields to change and can end up calculating invalid, negative ranges when forcing a flush in zap_pte_range. This patch moves the minimal range calculation out of the arm64 code and into the generic implementation, simplifying zap_pte_range in the process (which no longer needs to care about start/end, since they will point to the appropriate ranges already). With the range being tracked by core code, the need_flush flag is dropped in favour of checking that the end of the range has actually been set. Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Russell King - ARM Linux <linux@arm.linux.org.uk> Cc: Michal Simek <monstr@monstr.eu> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Will Deacon <will.deacon@arm.com>
Diffstat (limited to 'include/asm-generic')
-rw-r--r--include/asm-generic/tlb.h57
1 files changed, 47 insertions, 10 deletions
diff --git a/include/asm-generic/tlb.h b/include/asm-generic/tlb.h
index 5672d7ea1fa0..08848050922e 100644
--- a/include/asm-generic/tlb.h
+++ b/include/asm-generic/tlb.h
@@ -96,10 +96,9 @@ struct mmu_gather {
#endif
unsigned long start;
unsigned long end;
- unsigned int need_flush : 1, /* Did free PTEs */
/* we are in the middle of an operation to clear
* a full mm and can make some optimizations */
- fullmm : 1,
+ unsigned int fullmm : 1,
/* we have performed an operation which
* requires a complete flush of the tlb */
need_flush_all : 1;
@@ -128,16 +127,54 @@ static inline void tlb_remove_page(struct mmu_gather *tlb, struct page *page)
tlb_flush_mmu(tlb);
}
+static inline void __tlb_adjust_range(struct mmu_gather *tlb,
+ unsigned long address)
+{
+ tlb->start = min(tlb->start, address);
+ tlb->end = max(tlb->end, address + PAGE_SIZE);
+}
+
+static inline void __tlb_reset_range(struct mmu_gather *tlb)
+{
+ tlb->start = TASK_SIZE;
+ tlb->end = 0;
+}
+
+/*
+ * In the case of tlb vma handling, we can optimise these away in the
+ * case where we're doing a full MM flush. When we're doing a munmap,
+ * the vmas are adjusted to only cover the region to be torn down.
+ */
+#ifndef tlb_start_vma
+#define tlb_start_vma(tlb, vma) do { } while (0)
+#endif
+
+#define __tlb_end_vma(tlb, vma) \
+ do { \
+ if (!tlb->fullmm && tlb->end) { \
+ tlb_flush(tlb); \
+ __tlb_reset_range(tlb); \
+ } \
+ } while (0)
+
+#ifndef tlb_end_vma
+#define tlb_end_vma __tlb_end_vma
+#endif
+
+#ifndef __tlb_remove_tlb_entry
+#define __tlb_remove_tlb_entry(tlb, ptep, address) do { } while (0)
+#endif
+
/**
* tlb_remove_tlb_entry - remember a pte unmapping for later tlb invalidation.
*
- * Record the fact that pte's were really umapped in ->need_flush, so we can
- * later optimise away the tlb invalidate. This helps when userspace is
- * unmapping already-unmapped pages, which happens quite a lot.
+ * Record the fact that pte's were really unmapped by updating the range,
+ * so we can later optimise away the tlb invalidate. This helps when
+ * userspace is unmapping already-unmapped pages, which happens quite a lot.
*/
#define tlb_remove_tlb_entry(tlb, ptep, address) \
do { \
- tlb->need_flush = 1; \
+ __tlb_adjust_range(tlb, address); \
__tlb_remove_tlb_entry(tlb, ptep, address); \
} while (0)
@@ -151,27 +188,27 @@ static inline void tlb_remove_page(struct mmu_gather *tlb, struct page *page)
#define tlb_remove_pmd_tlb_entry(tlb, pmdp, address) \
do { \
- tlb->need_flush = 1; \
+ __tlb_adjust_range(tlb, address); \
__tlb_remove_pmd_tlb_entry(tlb, pmdp, address); \
} while (0)
#define pte_free_tlb(tlb, ptep, address) \
do { \
- tlb->need_flush = 1; \
+ __tlb_adjust_range(tlb, address); \
__pte_free_tlb(tlb, ptep, address); \
} while (0)
#ifndef __ARCH_HAS_4LEVEL_HACK
#define pud_free_tlb(tlb, pudp, address) \
do { \
- tlb->need_flush = 1; \
+ __tlb_adjust_range(tlb, address); \
__pud_free_tlb(tlb, pudp, address); \
} while (0)
#endif
#define pmd_free_tlb(tlb, pmdp, address) \
do { \
- tlb->need_flush = 1; \
+ __tlb_adjust_range(tlb, address); \
__pmd_free_tlb(tlb, pmdp, address); \
} while (0)