0b4e273fb8
Customize the hooks in tlb.h to optimize TLB flushing some more. Add start and end fields to tlb_gather_mmu, which are used to limit the address space range scanned when a region is unmapped. The interfaces which just free page tables, without actually changing mappings, don't need to cause a TLB flush. Signed-off-by: Jeff Dike <jdike@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
126 lines
3.1 KiB
C
126 lines
3.1 KiB
C
#ifndef __UM_TLB_H
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#define __UM_TLB_H
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#include <linux/swap.h>
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#include <asm/percpu.h>
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#include <asm/pgalloc.h>
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#include <asm/tlbflush.h>
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#define tlb_start_vma(tlb, vma) do { } while (0)
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#define tlb_end_vma(tlb, vma) do { } while (0)
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#define tlb_flush(tlb) flush_tlb_mm((tlb)->mm)
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/* struct mmu_gather is an opaque type used by the mm code for passing around
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* any data needed by arch specific code for tlb_remove_page.
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*/
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struct mmu_gather {
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struct mm_struct *mm;
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unsigned int need_flush; /* Really unmapped some ptes? */
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unsigned long start;
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unsigned long end;
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unsigned int fullmm; /* non-zero means full mm flush */
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};
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/* Users of the generic TLB shootdown code must declare this storage space. */
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DECLARE_PER_CPU(struct mmu_gather, mmu_gathers);
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static inline void __tlb_remove_tlb_entry(struct mmu_gather *tlb, pte_t *ptep,
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unsigned long address)
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{
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if (tlb->start > address)
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tlb->start = address;
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if (tlb->end < address + PAGE_SIZE)
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tlb->end = address + PAGE_SIZE;
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}
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static inline void init_tlb_gather(struct mmu_gather *tlb)
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{
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tlb->need_flush = 0;
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tlb->start = TASK_SIZE;
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tlb->end = 0;
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if (tlb->fullmm) {
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tlb->start = 0;
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tlb->end = TASK_SIZE;
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}
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}
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/* tlb_gather_mmu
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* Return a pointer to an initialized struct mmu_gather.
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*/
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static inline struct mmu_gather *
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tlb_gather_mmu(struct mm_struct *mm, unsigned int full_mm_flush)
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{
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struct mmu_gather *tlb = &get_cpu_var(mmu_gathers);
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tlb->mm = mm;
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tlb->fullmm = full_mm_flush;
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init_tlb_gather(tlb);
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return tlb;
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}
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extern void flush_tlb_mm_range(struct mm_struct *mm, unsigned long start,
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unsigned long end);
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static inline void
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tlb_flush_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long end)
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{
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if (!tlb->need_flush)
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return;
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flush_tlb_mm_range(tlb->mm, tlb->start, tlb->end);
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init_tlb_gather(tlb);
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}
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/* tlb_finish_mmu
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* Called at the end of the shootdown operation to free up any resources
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* that were required.
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*/
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static inline void
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tlb_finish_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long end)
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{
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tlb_flush_mmu(tlb, start, end);
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/* keep the page table cache within bounds */
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check_pgt_cache();
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put_cpu_var(mmu_gathers);
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}
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/* tlb_remove_page
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* Must perform the equivalent to __free_pte(pte_get_and_clear(ptep)),
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* while handling the additional races in SMP caused by other CPUs
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* caching valid mappings in their TLBs.
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*/
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static inline void tlb_remove_page(struct mmu_gather *tlb, struct page *page)
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{
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tlb->need_flush = 1;
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free_page_and_swap_cache(page);
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return;
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}
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/**
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* tlb_remove_tlb_entry - remember a pte unmapping for later tlb invalidation.
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*
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* Record the fact that pte's were really umapped in ->need_flush, so we can
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* later optimise away the tlb invalidate. This helps when userspace is
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* unmapping already-unmapped pages, which happens quite a lot.
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*/
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#define tlb_remove_tlb_entry(tlb, ptep, address) \
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do { \
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tlb->need_flush = 1; \
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__tlb_remove_tlb_entry(tlb, ptep, address); \
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} while (0)
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#define pte_free_tlb(tlb, ptep) __pte_free_tlb(tlb, ptep)
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#define pud_free_tlb(tlb, pudp) __pud_free_tlb(tlb, pudp)
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#define pmd_free_tlb(tlb, pmdp) __pmd_free_tlb(tlb, pmdp)
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#define tlb_migrate_finish(mm) do {} while (0)
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#endif
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