From: Will Deacon will.deacon@arm.com
commit a6d60245d6d9b1caf66b0d94419988c4836980af upstream
It is common for architectures with hugepage support to require only a single TLB invalidation operation per hugepage during unmap(), rather than iterating through the mapping at a PAGE_SIZE increment. Currently, however, the level in the page table where the unmap() operation occurs is not stored in the mmu_gather structure, therefore forcing architectures to issue additional TLB invalidation operations or to give up and over-invalidate by e.g. invalidating the entire TLB.
Ideally, we could add an interval rbtree to the mmu_gather structure, which would allow us to associate the correct mapping granule with the various sub-mappings within the range being invalidated. However, this is costly in terms of book-keeping and memory management, so instead we approximate by keeping track of the page table levels that are cleared and provide a means to query the smallest granule required for invalidation.
Signed-off-by: Will Deacon will.deacon@arm.com Cc: stable@vger.kernel.org # 4.19 Signed-off-by: Santosh Sivaraj santosh@fossix.org [santosh: prerequisite for upcoming tlbflush backports] Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- include/asm-generic/tlb.h | 58 +++++++++++++++++++++++++++++++++++++++------- mm/memory.c | 4 ++- 2 files changed, 53 insertions(+), 9 deletions(-)
--- a/include/asm-generic/tlb.h +++ b/include/asm-generic/tlb.h @@ -114,6 +114,14 @@ struct mmu_gather { */ unsigned int freed_tables : 1;
+ /* + * at which levels have we cleared entries? + */ + unsigned int cleared_ptes : 1; + unsigned int cleared_pmds : 1; + unsigned int cleared_puds : 1; + unsigned int cleared_p4ds : 1; + struct mmu_gather_batch *active; struct mmu_gather_batch local; struct page *__pages[MMU_GATHER_BUNDLE]; @@ -148,6 +156,10 @@ static inline void __tlb_reset_range(str tlb->end = 0; } tlb->freed_tables = 0; + tlb->cleared_ptes = 0; + tlb->cleared_pmds = 0; + tlb->cleared_puds = 0; + tlb->cleared_p4ds = 0; }
static inline void tlb_flush_mmu_tlbonly(struct mmu_gather *tlb) @@ -197,6 +209,25 @@ static inline void tlb_remove_check_page } #endif
+static inline unsigned long tlb_get_unmap_shift(struct mmu_gather *tlb) +{ + if (tlb->cleared_ptes) + return PAGE_SHIFT; + if (tlb->cleared_pmds) + return PMD_SHIFT; + if (tlb->cleared_puds) + return PUD_SHIFT; + if (tlb->cleared_p4ds) + return P4D_SHIFT; + + return PAGE_SHIFT; +} + +static inline unsigned long tlb_get_unmap_size(struct mmu_gather *tlb) +{ + return 1UL << tlb_get_unmap_shift(tlb); +} + /* * 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, @@ -230,13 +261,19 @@ static inline void tlb_remove_check_page #define tlb_remove_tlb_entry(tlb, ptep, address) \ do { \ __tlb_adjust_range(tlb, address, PAGE_SIZE); \ + tlb->cleared_ptes = 1; \ __tlb_remove_tlb_entry(tlb, ptep, address); \ } while (0)
-#define tlb_remove_huge_tlb_entry(h, tlb, ptep, address) \ - do { \ - __tlb_adjust_range(tlb, address, huge_page_size(h)); \ - __tlb_remove_tlb_entry(tlb, ptep, address); \ +#define tlb_remove_huge_tlb_entry(h, tlb, ptep, address) \ + do { \ + unsigned long _sz = huge_page_size(h); \ + __tlb_adjust_range(tlb, address, _sz); \ + if (_sz == PMD_SIZE) \ + tlb->cleared_pmds = 1; \ + else if (_sz == PUD_SIZE) \ + tlb->cleared_puds = 1; \ + __tlb_remove_tlb_entry(tlb, ptep, address); \ } while (0)
/** @@ -250,6 +287,7 @@ static inline void tlb_remove_check_page #define tlb_remove_pmd_tlb_entry(tlb, pmdp, address) \ do { \ __tlb_adjust_range(tlb, address, HPAGE_PMD_SIZE); \ + tlb->cleared_pmds = 1; \ __tlb_remove_pmd_tlb_entry(tlb, pmdp, address); \ } while (0)
@@ -264,6 +302,7 @@ static inline void tlb_remove_check_page #define tlb_remove_pud_tlb_entry(tlb, pudp, address) \ do { \ __tlb_adjust_range(tlb, address, HPAGE_PUD_SIZE); \ + tlb->cleared_puds = 1; \ __tlb_remove_pud_tlb_entry(tlb, pudp, address); \ } while (0)
@@ -289,7 +328,8 @@ static inline void tlb_remove_check_page #define pte_free_tlb(tlb, ptep, address) \ do { \ __tlb_adjust_range(tlb, address, PAGE_SIZE); \ - tlb->freed_tables = 1; \ + tlb->freed_tables = 1; \ + tlb->cleared_pmds = 1; \ __pte_free_tlb(tlb, ptep, address); \ } while (0) #endif @@ -298,7 +338,8 @@ static inline void tlb_remove_check_page #define pmd_free_tlb(tlb, pmdp, address) \ do { \ __tlb_adjust_range(tlb, address, PAGE_SIZE); \ - tlb->freed_tables = 1; \ + tlb->freed_tables = 1; \ + tlb->cleared_puds = 1; \ __pmd_free_tlb(tlb, pmdp, address); \ } while (0) #endif @@ -308,7 +349,8 @@ static inline void tlb_remove_check_page #define pud_free_tlb(tlb, pudp, address) \ do { \ __tlb_adjust_range(tlb, address, PAGE_SIZE); \ - tlb->freed_tables = 1; \ + tlb->freed_tables = 1; \ + tlb->cleared_p4ds = 1; \ __pud_free_tlb(tlb, pudp, address); \ } while (0) #endif @@ -319,7 +361,7 @@ static inline void tlb_remove_check_page #define p4d_free_tlb(tlb, pudp, address) \ do { \ __tlb_adjust_range(tlb, address, PAGE_SIZE); \ - tlb->freed_tables = 1; \ + tlb->freed_tables = 1; \ __p4d_free_tlb(tlb, pudp, address); \ } while (0) #endif --- a/mm/memory.c +++ b/mm/memory.c @@ -279,8 +279,10 @@ void arch_tlb_finish_mmu(struct mmu_gath { struct mmu_gather_batch *batch, *next;
- if (force) + if (force) { + __tlb_reset_range(tlb); __tlb_adjust_range(tlb, start, end - start); + }
tlb_flush_mmu(tlb);