2022-05-10 08:59:12

by Anshuman Khandual

Subject: [PATCH] arm64/hugetlb: Drop TLB flush from get_clear_flush()

This drops now redundant TLB flush in get_clear_flush() which is no longer
required after recent commit 697a1d44af8b ("tlb: hugetlb: Add more sizes to
tlb_remove_huge_tlb_entry"). It also renames this function i.e dropping off
'_flush' and replacing it with '__contig' as appropriate.

Cc: Catalin Marinas <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Mike Kravetz <[email protected]>
Cc: [email protected]
Cc: [email protected]
Signed-off-by: Anshuman Khandual <[email protected]>
---
This applies on v5.18-rc6

arch/arm64/mm/hugetlbpage.c | 16 +++++-----------
1 file changed, 5 insertions(+), 11 deletions(-)

diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c
index cbace1c9e137..749435b01a89 100644
--- a/arch/arm64/mm/hugetlbpage.c
+++ b/arch/arm64/mm/hugetlbpage.c
@@ -166,15 +166,14 @@ static inline int num_contig_ptes(unsigned long size, size_t *pgsize)
*
* This helper performs the break step.
*/
-static pte_t get_clear_flush(struct mm_struct *mm,
+static pte_t get_clear_contig(struct mm_struct *mm,
unsigned long addr,
pte_t *ptep,
unsigned long pgsize,
unsigned long ncontig)
{
pte_t orig_pte = huge_ptep_get(ptep);
- bool valid = pte_valid(orig_pte);
- unsigned long i, saddr = addr;
+ unsigned long i;

for (i = 0; i < ncontig; i++, addr += pgsize, ptep++) {
pte_t pte = ptep_get_and_clear(mm, addr, ptep);
@@ -190,11 +189,6 @@ static pte_t get_clear_flush(struct mm_struct *mm,
if (pte_young(pte))
orig_pte = pte_mkyoung(orig_pte);
}
-
- if (valid) {
- struct vm_area_struct vma = TLB_FLUSH_VMA(mm, 0);
- flush_tlb_range(&vma, saddr, addr);
- }
return orig_pte;
}

@@ -392,7 +386,7 @@ pte_t huge_ptep_get_and_clear(struct mm_struct *mm,

ncontig = find_num_contig(mm, addr, ptep, &pgsize);

- return get_clear_flush(mm, addr, ptep, pgsize, ncontig);
+ return get_clear_contig(mm, addr, ptep, pgsize, ncontig);
}

/*
@@ -443,7 +437,7 @@ int huge_ptep_set_access_flags(struct vm_area_struct *vma,
if (!__cont_access_flags_changed(ptep, pte, ncontig))
return 0;

- orig_pte = get_clear_flush(vma->vm_mm, addr, ptep, pgsize, ncontig);
+ orig_pte = get_clear_contig(vma->vm_mm, addr, ptep, pgsize, ncontig);

/* Make sure we don't lose the dirty or young state */
if (pte_dirty(orig_pte))
@@ -476,7 +470,7 @@ void huge_ptep_set_wrprotect(struct mm_struct *mm,
ncontig = find_num_contig(mm, addr, ptep, &pgsize);
dpfn = pgsize >> PAGE_SHIFT;

- pte = get_clear_flush(mm, addr, ptep, pgsize, ncontig);
+ pte = get_clear_contig(mm, addr, ptep, pgsize, ncontig);
pte = pte_wrprotect(pte);

hugeprot = pte_pgprot(pte);
--
2.20.1

2022-05-11 21:39:11

by Catalin Marinas

Subject: Re: [PATCH] arm64/hugetlb: Drop TLB flush from get_clear_flush()

On Tue, 10 May 2022 10:09:30 +0530, Anshuman Khandual wrote:
> This drops now redundant TLB flush in get_clear_flush() which is no longer
> required after recent commit 697a1d44af8b ("tlb: hugetlb: Add more sizes to
> tlb_remove_huge_tlb_entry"). It also renames this function i.e dropping off
> '_flush' and replacing it with '__contig' as appropriate.
>
>

Applied to arm64 (for-next/misc), thanks!

[1/1] arm64/hugetlb: Drop TLB flush from get_clear_flush()
https://git.kernel.org/arm64/c/fb396bb459c1

--
Catalin