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thp: add tlb_remove_pmd_tlb_entry

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We have tlb_remove_tlb_entry to indicate a pte tlb flush entry should be
flushed, but not a corresponding API for pmd entry.  This isn't a
problem so far because THP is only for x86 currently and tlb_flush()
under x86 will flush entire TLB.  But this is confusion and could be
missed if thp is ported to other arch.

Also convert tlb->need_flush = 1 to a VM_BUG_ON(!tlb->need_flush) in
__tlb_remove_page() as suggested by Andrea Arcangeli.  The
__tlb_remove_page() function is supposed to be called after
tlb_remove_xxx_tlb_entry() and we can catch any misuse.

Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Reviewed-by: Andrea Arcangeli <aarcange@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Johannes Weiner <jweiner@redhat.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Shaohua Li 2012-01-12 17:19:16 -08:00 committed by Linus Torvalds
parent e5591307f0
commit f21760b15d
4 changed files with 19 additions and 4 deletions
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14
include/asm-generic/tlb.h
View file

@ -139,6 +139,20 @@ static inline void tlb_remove_page(struct mmu_gather *tlb, struct page *page)
__tlb_remove_tlb_entry(tlb, ptep, address); \
} while (0)
/**
* tlb_remove_pmd_tlb_entry - remember a pmd mapping for later tlb invalidation
* This is a nop so far, because only x86 needs it.
*/
#ifndef __tlb_remove_pmd_tlb_entry
#define __tlb_remove_pmd_tlb_entry(tlb, pmdp, address) do {} while (0)
#endif
#define tlb_remove_pmd_tlb_entry(tlb, pmdp, address) \
do { \
tlb->need_flush = 1; \
__tlb_remove_pmd_tlb_entry(tlb, pmdp, address); \
} while (0)
#define pte_free_tlb(tlb, ptep, address) \
do { \
tlb->need_flush = 1; \

2
include/linux/huge_mm.h
View file

@ -18,7 +18,7 @@ extern struct page *follow_trans_huge_pmd(struct mm_struct *mm,
unsigned int flags);
extern int zap_huge_pmd(struct mmu_gather *tlb,
struct vm_area_struct *vma,
pmd_t *pmd);
pmd_t *pmd, unsigned long addr);
extern int mincore_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
unsigned long addr, unsigned long end,
unsigned char *vec);

3
mm/huge_memory.c
View file

@ -1026,7 +1026,7 @@ out:
}
int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
pmd_t *pmd)
pmd_t *pmd, unsigned long addr)
{
int ret = 0;
@ -1042,6 +1042,7 @@ int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
pgtable = get_pmd_huge_pte(tlb->mm);
page = pmd_page(*pmd);
pmd_clear(pmd);
tlb_remove_pmd_tlb_entry(tlb, pmd, addr);
page_remove_rmap(page);
VM_BUG_ON(page_mapcount(page) < 0);
add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR);

4
mm/memory.c
View file

@ -293,7 +293,7 @@ int __tlb_remove_page(struct mmu_gather *tlb, struct page *page)
{
struct mmu_gather_batch *batch;
tlb->need_flush = 1;
VM_BUG_ON(!tlb->need_flush);
if (tlb_fast_mode(tlb)) {
free_page_and_swap_cache(page);
@ -1231,7 +1231,7 @@ static inline unsigned long zap_pmd_range(struct mmu_gather *tlb,
if (next-addr != HPAGE_PMD_SIZE) {
VM_BUG_ON(!rwsem_is_locked(&tlb->mm->mmap_sem));
split_huge_page_pmd(vma->vm_mm, pmd);
} else if (zap_huge_pmd(tlb, vma, pmd))
} else if (zap_huge_pmd(tlb, vma, pmd, addr))
continue;
/* fall through */
}