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Commit f21760b1 authored by Shaohua Li's avatar Shaohua Li Committed by Linus Torvalds
Browse files

thp: add tlb_remove_pmd_tlb_entry 



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: default avatarShaohua Li <shaohua.li@intel.com>
Reviewed-by: default avatarAndrea 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: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent e5591307

include/asm-generic/tlb.h

+14 −0
Original line number Diff line number Diff line
@@ -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;				\

include/linux/huge_mm.h

+1 −1
Original line number Diff line number Diff line
@@ -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);

mm/huge_memory.c

+2 −1
Original line number Diff line number Diff line
@@ -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);

mm/memory.c

+2 −2
Original line number Diff line number Diff line
@@ -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 */

		}