Re: [PATCH v2 3/3] hugetlb: Convert hugetlb_wp() to use struct vm_fault

Vishal Moola
2024-04-08T17:47:18Z

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On Sun, Apr 07, 2024 at 05:12:42PM +0800, Muchun Song wrote:
>
>
> On 2024/4/2 04:26, Vishal Moola (Oracle) wrote:
> > hugetlb_wp() can use the struct vm_fault passed in from hugetlb_fault().
> > This alleviates the stack by consolidating 5 variables into a single
> > struct.
> >
> > Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
> > ---
> > mm/hugetlb.c | 61 ++++++++++++++++++++++++++--------------------------
> > 1 file changed, 30 insertions(+), 31 deletions(-)
> >
> > diff --git a/mm/hugetlb.c b/mm/hugetlb.c
> > index aca2f11b4138..d4f26947173e 100644
> > --- a/mm/hugetlb.c
> > +++ b/mm/hugetlb.c
> > @@ -5918,18 +5918,16 @@ static void unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma,
> > * Keep the pte_same checks anyway to make transition from the mutex easier.
> > */
> > static vm_fault_t hugetlb_wp(struct mm_struct *mm, struct vm_area_struct *vma,
> > - unsigned long address, pte_t *ptep, unsigned int flags,
> > - struct folio *pagecache_folio, spinlock_t *ptl,
> > + struct folio *pagecache_folio,
>
> The same as comment in the previous thread.

And fold the attached patch into here as well please Andrew?

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From f4adcf13ecc15a6733af43649756e53457078221 Mon Sep 17 00:00:00 2001
From: "Vishal Moola (Oracle)" <vishal.moola@gmail.com>
Date: Mon, 8 Apr 2024 10:21:44 -0700
Subject: [PATCH 2/2] hugetlb: Simplyfy hugetlb_wp() arguments

To simplify the function arguments, as suggested by Oscar and Muchun.

Suggested-by: Muchun Song <muchun.song@linux.dev>
Suggested-by: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
---
mm/hugetlb.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 05fe610f4699..0d96a41efde8 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -5915,10 +5915,11 @@ static void unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma,
* cannot race with other handlers or page migration.
* Keep the pte_same checks anyway to make transition from the mutex easier.
*/
-static vm_fault_t hugetlb_wp(struct mm_struct *mm, struct vm_area_struct *vma,
- struct folio *pagecache_folio,
+static vm_fault_t hugetlb_wp(struct folio *pagecache_folio,
struct vm_fault *vmf)
{
+ struct vm_area_struct *vma = vmf->vma;
+ struct mm_struct *mm = vma->vm_mm;
const bool unshare = vmf->flags & FAULT_FLAG_UNSHARE;
pte_t pte = huge_ptep_get(vmf->pte);
struct hstate *h = hstate_vma(vma);
@@ -6364,7 +6365,7 @@ static vm_fault_t hugetlb_no_page(struct address_space *mapping,
hugetlb_count_add(pages_per_huge_page(h), mm);
if ((vmf->flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
/* Optimization, do the COW without a second fault */
- ret = hugetlb_wp(mm, vma, folio, vmf);
+ ret = hugetlb_wp(folio, vmf);
}

spin_unlock(vmf->ptl);
@@ -6577,7 +6578,7 @@ vm_fault_t hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,

if (flags & (FAULT_FLAG_WRITE|FAULT_FLAG_UNSHARE)) {
if (!huge_pte_write(vmf.orig_pte)) {
- ret = hugetlb_wp(mm, vma, pagecache_folio, &vmf);
+ ret = hugetlb_wp(pagecache_folio, &vmf);
goto out_put_page;
} else if (likely(flags & FAULT_FLAG_WRITE)) {
vmf.orig_pte = huge_pte_mkdirty(vmf.orig_pte);
--
2.43.0