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mm: set up vma iterator for vma_iter_prealloc() calls
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Set the correct limits for vma_iter_prealloc() calls so that the maple
tree can be smarter about how many nodes are needed.

Link: https://lkml.kernel.org/r/20230724183157.3939892-11-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Liam R. Howlett authored and Andrew Morton committed Aug 18, 2023
1 parent f72cf24 commit b5df092
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Showing 4 changed files with 64 additions and 57 deletions.
1 change: 1 addition & 0 deletions fs/exec.c
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Original file line number Diff line number Diff line change
Expand Up @@ -701,6 +701,7 @@ static int shift_arg_pages(struct vm_area_struct *vma, unsigned long shift)
if (vma != vma_next(&vmi))
return -EFAULT;

vma_iter_prev_range(&vmi);
/*
* cover the whole range: [new_start, old_end)
*/
Expand Down
18 changes: 7 additions & 11 deletions mm/internal.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1052,23 +1052,21 @@ static inline void vma_iter_config(struct vma_iterator *vmi,
/*
* VMA Iterator functions shared between nommu and mmap
*/
static inline int vma_iter_prealloc(struct vma_iterator *vmi)
static inline int vma_iter_prealloc(struct vma_iterator *vmi,
struct vm_area_struct *vma)
{
return mas_preallocate(&vmi->mas, NULL, GFP_KERNEL);
return mas_preallocate(&vmi->mas, vma, GFP_KERNEL);
}

static inline void vma_iter_clear(struct vma_iterator *vmi,
unsigned long start, unsigned long end)
static inline void vma_iter_clear(struct vma_iterator *vmi)
{
mas_set_range(&vmi->mas, start, end - 1);
mas_store_prealloc(&vmi->mas, NULL);
}

static inline int vma_iter_clear_gfp(struct vma_iterator *vmi,
unsigned long start, unsigned long end, gfp_t gfp)
{
vmi->mas.index = start;
vmi->mas.last = end - 1;
__mas_set_range(&vmi->mas, start, end - 1);
mas_store_gfp(&vmi->mas, NULL, gfp);
if (unlikely(mas_is_err(&vmi->mas)))
return -ENOMEM;
Expand Down Expand Up @@ -1105,8 +1103,7 @@ static inline void vma_iter_store(struct vma_iterator *vmi,
((vmi->mas.index > vma->vm_start) || (vmi->mas.last < vma->vm_start)))
vma_iter_invalidate(vmi);

vmi->mas.index = vma->vm_start;
vmi->mas.last = vma->vm_end - 1;
__mas_set_range(&vmi->mas, vma->vm_start, vma->vm_end - 1);
mas_store_prealloc(&vmi->mas, vma);
}

Expand All @@ -1117,8 +1114,7 @@ static inline int vma_iter_store_gfp(struct vma_iterator *vmi,
((vmi->mas.index > vma->vm_start) || (vmi->mas.last < vma->vm_start)))
vma_iter_invalidate(vmi);

vmi->mas.index = vma->vm_start;
vmi->mas.last = vma->vm_end - 1;
__mas_set_range(&vmi->mas, vma->vm_start, vma->vm_end - 1);
mas_store_gfp(&vmi->mas, vma, gfp);
if (unlikely(mas_is_err(&vmi->mas)))
return -ENOMEM;
Expand Down
69 changes: 42 additions & 27 deletions mm/mmap.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -397,7 +397,8 @@ static int vma_link(struct mm_struct *mm, struct vm_area_struct *vma)
VMA_ITERATOR(vmi, mm, 0);
struct address_space *mapping = NULL;

if (vma_iter_prealloc(&vmi))
vma_iter_config(&vmi, vma->vm_start, vma->vm_end);
if (vma_iter_prealloc(&vmi, vma))
return -ENOMEM;

vma_iter_store(&vmi, vma);
Expand Down Expand Up @@ -649,19 +650,16 @@ int vma_expand(struct vma_iterator *vmi, struct vm_area_struct *vma,
/* Only handles expanding */
VM_WARN_ON(vma->vm_start < start || vma->vm_end > end);

if (vma_iter_prealloc(vmi))
/* Note: vma iterator must be pointing to 'start' */
vma_iter_config(vmi, start, end);
if (vma_iter_prealloc(vmi, vma))
goto nomem;

vma_prepare(&vp);
vma_adjust_trans_huge(vma, start, end, 0);
/* VMA iterator points to previous, so set to start if necessary */
if (vma_iter_addr(vmi) != start)
vma_iter_set(vmi, start);

vma->vm_start = start;
vma->vm_end = end;
vma->vm_pgoff = pgoff;
/* Note: mas must be pointing to the expanding VMA */
vma_iter_store(vmi, vma);

vma_complete(&vp, vmi, vma->vm_mm);
Expand All @@ -687,19 +685,19 @@ int vma_shrink(struct vma_iterator *vmi, struct vm_area_struct *vma,

WARN_ON((vma->vm_start != start) && (vma->vm_end != end));

if (vma_iter_prealloc(vmi))
if (vma->vm_start < start)
vma_iter_config(vmi, vma->vm_start, start);
else
vma_iter_config(vmi, end, vma->vm_end);

if (vma_iter_prealloc(vmi, NULL))
return -ENOMEM;

init_vma_prep(&vp, vma);
vma_prepare(&vp);
vma_adjust_trans_huge(vma, start, end, 0);

if (vma->vm_start < start)
vma_iter_clear(vmi, vma->vm_start, start);

if (vma->vm_end > end)
vma_iter_clear(vmi, end, vma->vm_end);

vma_iter_clear(vmi);
vma->vm_start = start;
vma->vm_end = end;
vma->vm_pgoff = pgoff;
Expand Down Expand Up @@ -973,7 +971,17 @@ struct vm_area_struct *vma_merge(struct vma_iterator *vmi, struct mm_struct *mm,
if (err)
return NULL;

if (vma_iter_prealloc(vmi))
if (vma_start < vma->vm_start || vma_end > vma->vm_end)
vma_expanded = true;

if (vma_expanded) {
vma_iter_config(vmi, vma_start, vma_end);
} else {
vma_iter_config(vmi, adjust->vm_start + adj_start,
adjust->vm_end);
}

if (vma_iter_prealloc(vmi, vma))
return NULL;

init_multi_vma_prep(&vp, vma, adjust, remove, remove2);
Expand All @@ -982,8 +990,6 @@ struct vm_area_struct *vma_merge(struct vma_iterator *vmi, struct mm_struct *mm,

vma_prepare(&vp);
vma_adjust_trans_huge(vma, vma_start, vma_end, adj_start);
if (vma_start < vma->vm_start || vma_end > vma->vm_end)
vma_expanded = true;

vma->vm_start = vma_start;
vma->vm_end = vma_end;
Expand Down Expand Up @@ -1923,7 +1929,7 @@ static int expand_upwards(struct vm_area_struct *vma, unsigned long address)
struct vm_area_struct *next;
unsigned long gap_addr;
int error = 0;
MA_STATE(mas, &mm->mm_mt, 0, 0);
MA_STATE(mas, &mm->mm_mt, vma->vm_start, address);

if (!(vma->vm_flags & VM_GROWSUP))
return -EFAULT;
Expand All @@ -1948,6 +1954,10 @@ static int expand_upwards(struct vm_area_struct *vma, unsigned long address)
/* Check that both stack segments have the same anon_vma? */
}

if (next)
mas_prev_range(&mas, address);

__mas_set_range(&mas, vma->vm_start, address - 1);
if (mas_preallocate(&mas, vma, GFP_KERNEL))
return -ENOMEM;

Expand Down Expand Up @@ -1993,7 +2003,6 @@ static int expand_upwards(struct vm_area_struct *vma, unsigned long address)
anon_vma_interval_tree_pre_update_vma(vma);
vma->vm_end = address;
/* Overwrite old entry in mtree. */
mas_set_range(&mas, vma->vm_start, address - 1);
mas_store_prealloc(&mas, vma);
anon_vma_interval_tree_post_update_vma(vma);
spin_unlock(&mm->page_table_lock);
Expand Down Expand Up @@ -2038,6 +2047,10 @@ int expand_downwards(struct vm_area_struct *vma, unsigned long address)
return -ENOMEM;
}

if (prev)
mas_next_range(&mas, vma->vm_start);

__mas_set_range(&mas, address, vma->vm_end - 1);
if (mas_preallocate(&mas, vma, GFP_KERNEL))
return -ENOMEM;

Expand Down Expand Up @@ -2084,7 +2097,6 @@ int expand_downwards(struct vm_area_struct *vma, unsigned long address)
vma->vm_start = address;
vma->vm_pgoff -= grow;
/* Overwrite old entry in mtree. */
mas_set_range(&mas, address, vma->vm_end - 1);
mas_store_prealloc(&mas, vma);
anon_vma_interval_tree_post_update_vma(vma);
spin_unlock(&mm->page_table_lock);
Expand Down Expand Up @@ -2325,17 +2337,18 @@ int __split_vma(struct vma_iterator *vmi, struct vm_area_struct *vma,
if (!new)
return -ENOMEM;

err = -ENOMEM;
if (vma_iter_prealloc(vmi))
goto out_free_vma;

if (new_below) {
new->vm_end = addr;
} else {
new->vm_start = addr;
new->vm_pgoff += ((addr - vma->vm_start) >> PAGE_SHIFT);
}

err = -ENOMEM;
vma_iter_config(vmi, new->vm_start, new->vm_end);
if (vma_iter_prealloc(vmi, new))
goto out_free_vma;

err = vma_dup_policy(vma, new);
if (err)
goto out_free_vmi;
Expand Down Expand Up @@ -2693,7 +2706,6 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
vma_iter_next_range(&vmi);
}


/* Actually expand, if possible */
if (vma &&
!vma_expand(&vmi, vma, merge_start, merge_end, vm_pgoff, next)) {
Expand Down Expand Up @@ -2790,7 +2802,7 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
goto close_and_free_vma;

error = -ENOMEM;
if (vma_iter_prealloc(&vmi))
if (vma_iter_prealloc(&vmi, vma))
goto close_and_free_vma;

/* Lock the VMA since it is modified after insertion into VMA tree */
Expand Down Expand Up @@ -3053,7 +3065,8 @@ static int do_brk_flags(struct vma_iterator *vmi, struct vm_area_struct *vma,
if (vma && vma->vm_end == addr && !vma_policy(vma) &&
can_vma_merge_after(vma, flags, NULL, NULL,
addr >> PAGE_SHIFT, NULL_VM_UFFD_CTX, NULL)) {
if (vma_iter_prealloc(vmi))
vma_iter_config(vmi, vma->vm_start, addr + len);
if (vma_iter_prealloc(vmi, vma))
goto unacct_fail;

init_vma_prep(&vp, vma);
Expand All @@ -3068,6 +3081,8 @@ static int do_brk_flags(struct vma_iterator *vmi, struct vm_area_struct *vma,
goto out;
}

if (vma)
vma_iter_next_range(vmi);
/* create a vma struct for an anonymous mapping */
vma = vm_area_alloc(mm);
if (!vma)
Expand Down
33 changes: 14 additions & 19 deletions mm/nommu.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -583,15 +583,16 @@ static int delete_vma_from_mm(struct vm_area_struct *vma)
{
VMA_ITERATOR(vmi, vma->vm_mm, vma->vm_start);

if (vma_iter_prealloc(&vmi)) {
vma_iter_config(&vmi, vma->vm_start, vma->vm_end);
if (vma_iter_prealloc(&vmi, vma)) {
pr_warn("Allocation of vma tree for process %d failed\n",
current->pid);
return -ENOMEM;
}
cleanup_vma_from_mm(vma);

/* remove from the MM's tree and list */
vma_iter_clear(&vmi, vma->vm_start, vma->vm_end);
vma_iter_clear(&vmi);
return 0;
}
/*
Expand Down Expand Up @@ -1054,9 +1055,6 @@ unsigned long do_mmap(struct file *file,
if (!vma)
goto error_getting_vma;

if (vma_iter_prealloc(&vmi))
goto error_vma_iter_prealloc;

region->vm_usage = 1;
region->vm_flags = vm_flags;
region->vm_pgoff = pgoff;
Expand Down Expand Up @@ -1198,6 +1196,10 @@ unsigned long do_mmap(struct file *file,

share:
BUG_ON(!vma->vm_region);
vma_iter_config(&vmi, vma->vm_start, vma->vm_end);
if (vma_iter_prealloc(&vmi, vma))
goto error_just_free;

setup_vma_to_mm(vma, current->mm);
current->mm->map_count++;
/* add the VMA to the tree */
Expand Down Expand Up @@ -1244,14 +1246,6 @@ unsigned long do_mmap(struct file *file,
len, current->pid);
show_mem();
return -ENOMEM;

error_vma_iter_prealloc:
kmem_cache_free(vm_region_jar, region);
vm_area_free(vma);
pr_warn("Allocation of vma tree for process %d failed\n", current->pid);
show_mem();
return -ENOMEM;

}

unsigned long ksys_mmap_pgoff(unsigned long addr, unsigned long len,
Expand Down Expand Up @@ -1336,12 +1330,6 @@ int split_vma(struct vma_iterator *vmi, struct vm_area_struct *vma,
if (!new)
goto err_vma_dup;

if (vma_iter_prealloc(vmi)) {
pr_warn("Allocation of vma tree for process %d failed\n",
current->pid);
goto err_vmi_preallocate;
}

/* most fields are the same, copy all, and then fixup */
*region = *vma->vm_region;
new->vm_region = region;
Expand All @@ -1355,6 +1343,13 @@ int split_vma(struct vma_iterator *vmi, struct vm_area_struct *vma,
region->vm_pgoff = new->vm_pgoff += npages;
}

vma_iter_config(vmi, new->vm_start, new->vm_end);
if (vma_iter_prealloc(vmi, vma)) {
pr_warn("Allocation of vma tree for process %d failed\n",
current->pid);
goto err_vmi_preallocate;
}

if (new->vm_ops && new->vm_ops->open)
new->vm_ops->open(new);

Expand Down

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