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mm/khugepaged: unify collapse pmd clear, flush and free

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Unify the code that flushes, clears pmd entry, and frees the PTE table
level into a new function collapse_and_free_pmd().

This cleanup is useful as in the next patch we will add another call to
this function to iterate through PTE prior to freeing the level for page
table check.

Link: https://lkml.kernel.org/r/20220131203249.2832273-4-pasha.tatashin@soleen.com
Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Slaby <jirislaby@kernel.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Paul Turner <pjt@google.com>
Cc: Wei Xu <weixugc@google.com>
Cc: Will Deacon <will@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Pasha Tatashin 2022-02-03 20:49:20 -08:00 committed by Linus Torvalds
parent 64d8b9e145
commit e59a47b8a4
1 changed files with 18 additions and 16 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

34
mm/khugepaged.c
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@ -1416,6 +1416,19 @@ static int khugepaged_add_pte_mapped_thp(struct mm_struct *mm,
return 0;
}
static void collapse_and_free_pmd(struct mm_struct *mm, struct vm_area_struct *vma,
unsigned long addr, pmd_t *pmdp)
{
spinlock_t *ptl;
pmd_t pmd;
ptl = pmd_lock(vma->vm_mm, pmdp);
pmd = pmdp_collapse_flush(vma, addr, pmdp);
spin_unlock(ptl);
mm_dec_nr_ptes(mm);
pte_free(mm, pmd_pgtable(pmd));
}
/**
* collapse_pte_mapped_thp - Try to collapse a pte-mapped THP for mm at
* address haddr.
@ -1433,7 +1446,7 @@ void collapse_pte_mapped_thp(struct mm_struct *mm, unsigned long addr)
struct vm_area_struct *vma = find_vma(mm, haddr);
struct page *hpage;
pte_t *start_pte, *pte;
pmd_t *pmd, _pmd;
pmd_t *pmd;
spinlock_t *ptl;
int count = 0;
int i;
@ -1509,12 +1522,7 @@ void collapse_pte_mapped_thp(struct mm_struct *mm, unsigned long addr)
}
/* step 4: collapse pmd */
ptl = pmd_lock(vma->vm_mm, pmd);
_pmd = pmdp_collapse_flush(vma, haddr, pmd);
spin_unlock(ptl);
mm_dec_nr_ptes(mm);
pte_free(mm, pmd_pgtable(_pmd));
collapse_and_free_pmd(mm, vma, haddr, pmd);
drop_hpage:
unlock_page(hpage);
put_page(hpage);
@ -1552,7 +1560,7 @@ static void retract_page_tables(struct address_space *mapping, pgoff_t pgoff)
struct vm_area_struct *vma;
struct mm_struct *mm;
unsigned long addr;
pmd_t *pmd, _pmd;
pmd_t *pmd;
i_mmap_lock_write(mapping);
vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, pgoff) {
@ -1591,14 +1599,8 @@ static void retract_page_tables(struct address_space *mapping, pgoff_t pgoff)
* reverse order. Trylock is a way to avoid deadlock.
*/
if (mmap_write_trylock(mm)) {
if (!khugepaged_test_exit(mm)) {
spinlock_t *ptl = pmd_lock(mm, pmd);
/* assume page table is clear */
_pmd = pmdp_collapse_flush(vma, addr, pmd);
spin_unlock(ptl);
mm_dec_nr_ptes(mm);
pte_free(mm, pmd_pgtable(_pmd));
}
if (!khugepaged_test_exit(mm))
collapse_and_free_pmd(mm, vma, addr, pmd);
mmap_write_unlock(mm);
} else {
/* Try again later */