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Message-ID: <0cc0e4d1af6722b3b0d121647089659bd8060087.1724441678.git.lorenzo.stoakes@oracle.com>
Date: Fri, 23 Aug 2024 21:07:00 +0100
From: Lorenzo Stoakes <lorenzo.stoakes@...cle.com>
To: linux-mm@...ck.org, linux-kernel@...r.kernel.org,
Andrew Morton <akpm@...ux-foundation.org>
Cc: "Liam R . Howlett" <Liam.Howlett@...cle.com>,
Vlastimil Babka <vbabka@...e.cz>
Subject: [PATCH v2 05/10] mm: abstract vma_expand() to use vma_merge_struct
The purpose of the vmg is to thread merge state through functions and avoid
egregious parameter lists. We expand this to vma_expand(), which is used
for a number of merge cases.
Accordingly, adjust its callers, mmap_region() and relocate_vma_down(), to
use a vmg.
An added purpose of this change is the ability in a future commit to
perform all new VMA range merging using vma_expand().
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@...cle.com>
---
mm/mmap.c | 16 +++++++++-------
mm/vma.c | 39 +++++++++++++++++----------------------
mm/vma.h | 5 +----
tools/testing/vma/vma.c | 3 +--
4 files changed, 28 insertions(+), 35 deletions(-)
diff --git a/mm/mmap.c b/mm/mmap.c
index c72f50feb98a..0d242c9b1f4c 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1371,7 +1371,6 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
struct ma_state mas_detach;
struct maple_tree mt_detach;
unsigned long end = addr + len;
- unsigned long merge_start = addr, merge_end = end;
bool writable_file_mapping = false;
int error = -ENOMEM;
VMA_ITERATOR(vmi, mm, addr);
@@ -1424,8 +1423,8 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
/* Attempt to expand an old mapping */
/* Check next */
if (next && next->vm_start == end && can_vma_merge_before(&vmg)) {
- merge_end = next->vm_end;
- vma = next;
+ vmg.end = next->vm_end;
+ vma = vmg.vma = next;
vmg.pgoff = next->vm_pgoff - pglen;
/*
* We set this here so if we will merge with the previous VMA in
@@ -1438,15 +1437,15 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
/* Check prev */
if (prev && prev->vm_end == addr && can_vma_merge_after(&vmg)) {
- merge_start = prev->vm_start;
- vma = prev;
+ vmg.start = prev->vm_start;
+ vma = vmg.vma = prev;
vmg.pgoff = prev->vm_pgoff;
vma_prev(&vmi); /* Equivalent to going to the previous range */
}
if (vma) {
/* Actually expand, if possible */
- if (!vma_expand(&vmi, vma, merge_start, merge_end, vmg.pgoff, next)) {
+ if (!vma_expand(&vmg)) {
khugepaged_enter_vma(vma, vm_flags);
goto expanded;
}
@@ -2319,6 +2318,7 @@ int relocate_vma_down(struct vm_area_struct *vma, unsigned long shift)
unsigned long new_start = old_start - shift;
unsigned long new_end = old_end - shift;
VMA_ITERATOR(vmi, mm, new_start);
+ VMG_STATE(vmg, mm, &vmi, new_start, old_end, 0, vma->vm_pgoff);
struct vm_area_struct *next;
struct mmu_gather tlb;
@@ -2335,7 +2335,8 @@ int relocate_vma_down(struct vm_area_struct *vma, unsigned long shift)
/*
* cover the whole range: [new_start, old_end)
*/
- if (vma_expand(&vmi, vma, new_start, old_end, vma->vm_pgoff, NULL))
+ vmg.vma = vma;
+ if (vma_expand(&vmg))
return -ENOMEM;
/*
@@ -2368,6 +2369,7 @@ int relocate_vma_down(struct vm_area_struct *vma, unsigned long shift)
tlb_finish_mmu(&tlb);
vma_prev(&vmi);
+
/* Shrink the vma to just the new range */
return vma_shrink(&vmi, vma, new_start, new_end, vma->vm_pgoff);
}
diff --git a/mm/vma.c b/mm/vma.c
index b1ec412fac7f..4867ae722a9a 100644
--- a/mm/vma.c
+++ b/mm/vma.c
@@ -467,30 +467,25 @@ void validate_mm(struct mm_struct *mm)
/*
* vma_expand - Expand an existing VMA
*
- * @vmi: The vma iterator
- * @vma: The vma to expand
- * @start: The start of the vma
- * @end: The exclusive end of the vma
- * @pgoff: The page offset of vma
- * @next: The current of next vma.
+ * @vmg: Describes a VMA expansion operation.
*
- * Expand @vma to @start and @end. Can expand off the start and end. Will
- * expand over @next if it's different from @vma and @end == @next->vm_end.
- * Checking if the @vma can expand and merge with @next needs to be handled by
- * the caller.
+ * Expand @vma to vmg->start and vmg->end. Can expand off the start and end.
+ * Will expand over vmg->next if it's different from vmg->vma and vmg->end ==
+ * vmg->next->vm_end. Checking if the vmg->vma can expand and merge with
+ * vmg->next needs to be handled by the caller.
*
* Returns: 0 on success
*/
-int vma_expand(struct vma_iterator *vmi, struct vm_area_struct *vma,
- unsigned long start, unsigned long end, pgoff_t pgoff,
- struct vm_area_struct *next)
+int vma_expand(struct vma_merge_struct *vmg)
{
struct vm_area_struct *anon_dup = NULL;
bool remove_next = false;
+ struct vm_area_struct *vma = vmg->vma;
+ struct vm_area_struct *next = vmg->next;
struct vma_prepare vp;
vma_start_write(vma);
- if (next && (vma != next) && (end == next->vm_end)) {
+ if (next && (vma != next) && (vmg->end == next->vm_end)) {
int ret;
remove_next = true;
@@ -503,21 +498,21 @@ int vma_expand(struct vma_iterator *vmi, struct vm_area_struct *vma,
init_multi_vma_prep(&vp, vma, NULL, remove_next ? next : NULL, NULL);
/* Not merging but overwriting any part of next is not handled. */
VM_WARN_ON(next && !vp.remove &&
- next != vma && end > next->vm_start);
+ next != vma && vmg->end > next->vm_start);
/* Only handles expanding */
- VM_WARN_ON(vma->vm_start < start || vma->vm_end > end);
+ VM_WARN_ON(vma->vm_start < vmg->start || vma->vm_end > vmg->end);
/* Note: vma iterator must be pointing to 'start' */
- vma_iter_config(vmi, start, end);
- if (vma_iter_prealloc(vmi, vma))
+ vma_iter_config(vmg->vmi, vmg->start, vmg->end);
+ if (vma_iter_prealloc(vmg->vmi, vma))
goto nomem;
vma_prepare(&vp);
- vma_adjust_trans_huge(vma, start, end, 0);
- vma_set_range(vma, start, end, pgoff);
- vma_iter_store(vmi, vma);
+ vma_adjust_trans_huge(vma, vmg->start, vmg->end, 0);
+ vma_set_range(vma, vmg->start, vmg->end, vmg->pgoff);
+ vma_iter_store(vmg->vmi, vma);
- vma_complete(&vp, vmi, vma->vm_mm);
+ vma_complete(&vp, vmg->vmi, vma->vm_mm);
return 0;
nomem:
diff --git a/mm/vma.h b/mm/vma.h
index 9060a1a1edfa..8f01fbc20fe7 100644
--- a/mm/vma.h
+++ b/mm/vma.h
@@ -128,10 +128,7 @@ void init_vma_prep(struct vma_prepare *vp,
void vma_complete(struct vma_prepare *vp,
struct vma_iterator *vmi, struct mm_struct *mm);
-int vma_expand(struct vma_iterator *vmi, struct vm_area_struct *vma,
- unsigned long start, unsigned long end, pgoff_t pgoff,
- struct vm_area_struct *next);
-
+int vma_expand(struct vma_merge_struct *vmg);
int vma_shrink(struct vma_iterator *vmi, struct vm_area_struct *vma,
unsigned long start, unsigned long end, pgoff_t pgoff);
diff --git a/tools/testing/vma/vma.c b/tools/testing/vma/vma.c
index b12f72979478..cce1ba78c57f 100644
--- a/tools/testing/vma/vma.c
+++ b/tools/testing/vma/vma.c
@@ -121,8 +121,7 @@ static struct vm_area_struct *merge_existing(struct vma_merge_struct *vmg)
*/
static int expand_existing(struct vma_merge_struct *vmg)
{
- return vma_expand(vmg->vmi, vmg->vma, vmg->start, vmg->end, vmg->pgoff,
- vmg->next);
+ return vma_expand(vmg);
}
/*
--
2.46.0
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