From 1cf35d47712dd5dc4d62c6ce984f04ac6eab0408 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Fri, 25 Apr 2014 16:05:40 -0700 Subject: mm: split 'tlb_flush_mmu()' into tlb flushing and memory freeing parts The mmu-gather operation 'tlb_flush_mmu()' has done two things: the actual tlb flush operation, and the batched freeing of the pages that the TLB entries pointed at. This splits the operation into separate phases, so that the forced batched flushing done by zap_pte_range() can now do the actual TLB flush while still holding the page table lock, but delay the batched freeing of all the pages to after the lock has been dropped. This in turn allows us to avoid a race condition between set_page_dirty() (as called by zap_pte_range() when it finds a dirty shared memory pte) and page_mkclean(): because we now flush all the dirty page data from the TLB's while holding the pte lock, page_mkclean() will be held up walking the (recently cleaned) page tables until after the TLB entries have been flushed from all CPU's. Reported-by: Benjamin Herrenschmidt Tested-by: Dave Hansen Acked-by: Hugh Dickins Cc: Peter Zijlstra Cc: Russell King - ARM Linux Cc: Tony Luck Signed-off-by: Linus Torvalds --- arch/ia64/include/asm/tlb.h | 42 ++++++++++++++++++++++++++++++++---------- 1 file changed, 32 insertions(+), 10 deletions(-) (limited to 'arch/ia64/include/asm') diff --git a/arch/ia64/include/asm/tlb.h b/arch/ia64/include/asm/tlb.h index bc5efc7..39d64e0 100644 --- a/arch/ia64/include/asm/tlb.h +++ b/arch/ia64/include/asm/tlb.h @@ -91,18 +91,9 @@ extern struct ia64_tr_entry *ia64_idtrs[NR_CPUS]; #define RR_RID_MASK 0x00000000ffffff00L #define RR_TO_RID(val) ((val >> 8) & 0xffffff) -/* - * Flush the TLB for address range START to END and, if not in fast mode, release the - * freed pages that where gathered up to this point. - */ static inline void -ia64_tlb_flush_mmu (struct mmu_gather *tlb, unsigned long start, unsigned long end) +ia64_tlb_flush_mmu_tlbonly(struct mmu_gather *tlb, unsigned long start, unsigned long end) { - unsigned long i; - unsigned int nr; - - if (!tlb->need_flush) - return; tlb->need_flush = 0; if (tlb->fullmm) { @@ -135,6 +126,14 @@ ia64_tlb_flush_mmu (struct mmu_gather *tlb, unsigned long start, unsigned long e flush_tlb_range(&vma, ia64_thash(start), ia64_thash(end)); } +} + +static inline void +ia64_tlb_flush_mmu_free(struct mmu_gather *tlb) +{ + unsigned long i; + unsigned int nr; + /* lastly, release the freed pages */ nr = tlb->nr; @@ -144,6 +143,19 @@ ia64_tlb_flush_mmu (struct mmu_gather *tlb, unsigned long start, unsigned long e free_page_and_swap_cache(tlb->pages[i]); } +/* + * Flush the TLB for address range START to END and, if not in fast mode, release the + * freed pages that where gathered up to this point. + */ +static inline void +ia64_tlb_flush_mmu (struct mmu_gather *tlb, unsigned long start, unsigned long end) +{ + if (!tlb->need_flush) + return; + ia64_tlb_flush_mmu_tlbonly(tlb, start, end); + ia64_tlb_flush_mmu_free(tlb); +} + static inline void __tlb_alloc_page(struct mmu_gather *tlb) { unsigned long addr = __get_free_pages(GFP_NOWAIT | __GFP_NOWARN, 0); @@ -206,6 +218,16 @@ static inline int __tlb_remove_page(struct mmu_gather *tlb, struct page *page) return tlb->max - tlb->nr; } +static inline void tlb_flush_mmu_tlbonly(struct mmu_gather *tlb) +{ + ia64_tlb_flush_mmu_tlbonly(tlb, tlb->start_addr, tlb->end_addr); +} + +static inline void tlb_flush_mmu_free(struct mmu_gather *tlb) +{ + ia64_tlb_flush_mmu_free(tlb); +} + static inline void tlb_flush_mmu(struct mmu_gather *tlb) { ia64_tlb_flush_mmu(tlb, tlb->start_addr, tlb->end_addr); -- cgit v1.1