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Message-ID: <e6a1d727-b65e-4ffd-8ce7-00ea12316553@lucifer.local>
Date: Fri, 30 Aug 2024 14:28:55 +0100
From: Lorenzo Stoakes <lorenzo.stoakes@...cle.com>
To: "Liam R. Howlett" <Liam.Howlett@...cle.com>, linux-mm@...ck.org,
linux-kernel@...r.kernel.org,
Andrew Morton <akpm@...ux-foundation.org>,
Vlastimil Babka <vbabka@...e.cz>
Subject: Re: [PATCH v2 03/10] mm: introduce vma_merge_struct and abstract
vma_merge(),vma_modify()
On Wed, Aug 28, 2024 at 03:35:06PM GMT, Liam R. Howlett wrote:
> * Lorenzo Stoakes <lorenzo.stoakes@...cle.com> [240823 16:07]:
> > Rather than passing around huge numbers of parameters to numerous helper
> > functions, abstract them into a single struct that we thread through the
> > operation, the vma_merge_struct ('vmg').
> >
> > Adjust vma_merge() and vma_modify() to accept this parameter, as well as
> > predicate functions can_vma_merge_before(), can_vma_merge_after(), and the
> > vma_modify_...() helper functions.
> >
> > Also introduce VMG_STATE() and VMG_VMA_STATE() helper macros to allow for
> > easy vmg declaration.
> >
> > We additionally remove the requirement that vma_merge() is passed a VMA
> > object representing the candidate new VMA. Previously it used this to
> > obtain the mm_struct, file and anon_vma properties of the proposed range (a
> > rather confusing state of affairs), which are now provided by the vmg
> > directly.
> >
> > We also remove the pgoff calculation previously performed vma_modify(), and
> > instead calculate this in VMG_VMA_STATE() via the vma_pgoff_offset()
> > helper.
> >
> > Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@...cle.com>
>
> Some small things..
All addressed except one thing, see below...
>
> Reviewed-by: Liam R. Howlett <Liam.Howlett@...cle.com>
Thanks!
>
> > ---
> > mm/mmap.c | 77 ++++++++-------
> > mm/vma.c | 209 ++++++++++++++++++++++++----------------
> > mm/vma.h | 128 ++++++++++++++----------
> > tools/testing/vma/vma.c | 43 +--------
> > 4 files changed, 249 insertions(+), 208 deletions(-)
> >
> > diff --git a/mm/mmap.c b/mm/mmap.c
> > index e495b0381265..4066c0444495 100644
> > --- a/mm/mmap.c
> > +++ b/mm/mmap.c
> > @@ -1373,9 +1373,11 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
> > unsigned long end = addr + len;
> > unsigned long merge_start = addr, merge_end = end;
> > bool writable_file_mapping = false;
> > - pgoff_t vm_pgoff;
> > int error = -ENOMEM;
> > VMA_ITERATOR(vmi, mm, addr);
> > + VMG_STATE(vmg, mm, &vmi, addr, end, vm_flags, pgoff);
> > +
> > + vmg.file = file;
> >
>
> Extra whitespace here.
>
> > /* Find the first overlapping VMA */
> > vma = vma_find(&vmi, end);
> > @@ -1388,12 +1390,12 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
> > if (vms_gather_munmap_vmas(&vms, &mas_detach))
> > return -ENOMEM;
> >
> > - next = vms.next;
> > - prev = vms.prev;
> > + next = vmg.next = vms.next;
> > + prev = vmg.prev = vms.prev;
> > vma = NULL;
> > } else {
> > - next = vma_next(&vmi);
> > - prev = vma_prev(&vmi);
> > + next = vmg.next = vma_next(&vmi);
> > + prev = vmg.prev = vma_prev(&vmi);
> > if (prev)
> > vma_iter_next_range(&vmi);
> > }
> > @@ -1413,6 +1415,7 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
> >
> > vms.nr_accounted = 0;
> > vm_flags |= VM_ACCOUNT;
> > + vmg.flags = vm_flags;
> > }
> >
> > if (vm_flags & VM_SPECIAL)
> > @@ -1421,28 +1424,31 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
> > /* Attempt to expand an old mapping */
> > /* Check next */
> > if (next && next->vm_start == end && !vma_policy(next) &&
> > - can_vma_merge_before(next, vm_flags, NULL, file, pgoff+pglen,
> > - NULL_VM_UFFD_CTX, NULL)) {
> > + can_vma_merge_before(&vmg)) {
> > merge_end = next->vm_end;
> > vma = next;
> > - vm_pgoff = next->vm_pgoff - pglen;
> > + vmg.pgoff = next->vm_pgoff - pglen;
> > + /*
> > + * We set this here so if we will merge with the previous VMA in
> > + * the code below, can_vma_merge_after() ensures anon_vma
> > + * compatibility between prev and next.
> > + */
> > + vmg.anon_vma = vma->anon_vma;
> > + vmg.uffd_ctx = vma->vm_userfaultfd_ctx;
> > }
> >
> > /* Check prev */
> > if (prev && prev->vm_end == addr && !vma_policy(prev) &&
> > - (vma ? can_vma_merge_after(prev, vm_flags, vma->anon_vma, file,
> > - pgoff, vma->vm_userfaultfd_ctx, NULL) :
> > - can_vma_merge_after(prev, vm_flags, NULL, file, pgoff,
> > - NULL_VM_UFFD_CTX, NULL))) {
> > + can_vma_merge_after(&vmg)) {
> > merge_start = prev->vm_start;
> > vma = prev;
> > - vm_pgoff = prev->vm_pgoff;
> > + 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, vm_pgoff, next)) {
> > + if (!vma_expand(&vmi, vma, merge_start, merge_end, vmg.pgoff, next)) {
> > khugepaged_enter_vma(vma, vm_flags);
> > goto expanded;
> > }
> > @@ -1772,26 +1778,29 @@ static int do_brk_flags(struct vma_iterator *vmi, struct vm_area_struct *vma,
> > * Expand the existing vma if possible; Note that singular lists do not
> > * occur after forking, so the expand will only happen on new VMAs.
> > */
> > - 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)) {
> > - vma_iter_config(vmi, vma->vm_start, addr + len);
> > - if (vma_iter_prealloc(vmi, vma))
> > - goto unacct_fail;
> > -
> > - vma_start_write(vma);
> > -
> > - init_vma_prep(&vp, vma);
> > - vma_prepare(&vp);
> > - vma_adjust_trans_huge(vma, vma->vm_start, addr + len, 0);
> > - vma->vm_end = addr + len;
> > - vm_flags_set(vma, VM_SOFTDIRTY);
> > - vma_iter_store(vmi, vma);
> > -
> > - vma_complete(&vp, vmi, mm);
> > - validate_mm(mm);
> > - khugepaged_enter_vma(vma, flags);
> > - goto out;
> > + if (vma && vma->vm_end == addr && !vma_policy(vma)) {
> > + VMG_STATE(vmg, mm, vmi, addr, addr + len, flags, PHYS_PFN(addr));
> > +
> > + vmg.prev = vma;
> > + if (can_vma_merge_after(&vmg)) {
> > + vma_iter_config(vmi, vma->vm_start, addr + len);
> > + if (vma_iter_prealloc(vmi, vma))
> > + goto unacct_fail;
> > +
> > + vma_start_write(vma);
> > +
> > + init_vma_prep(&vp, vma);
> > + vma_prepare(&vp);
> > + vma_adjust_trans_huge(vma, vma->vm_start, addr + len, 0);
> > + vma->vm_end = addr + len;
> > + vm_flags_set(vma, VM_SOFTDIRTY);
> > + vma_iter_store(vmi, vma);
> > +
> > + vma_complete(&vp, vmi, mm);
> > + validate_mm(mm);
> > + khugepaged_enter_vma(vma, flags);
> > + goto out;
> > + }
> > }
> >
> > if (vma)
> > diff --git a/mm/vma.c b/mm/vma.c
> > index e5a5e418c7cb..74c627ff0313 100644
> > --- a/mm/vma.c
> > +++ b/mm/vma.c
> > @@ -7,16 +7,18 @@
> > #include "vma_internal.h"
> > #include "vma.h"
> >
> > -/*
> > - * If the vma has a ->close operation then the driver probably needs to release
> > - * per-vma resources, so we don't attempt to merge those if the caller indicates
> > - * the current vma may be removed as part of the merge.
> > - */
> > -static inline bool is_mergeable_vma(struct vm_area_struct *vma,
> > - struct file *file, unsigned long vm_flags,
> > - struct vm_userfaultfd_ctx vm_userfaultfd_ctx,
> > - struct anon_vma_name *anon_name, bool may_remove_vma)
> > +static inline bool is_mergeable_vma(struct vma_merge_struct *vmg, bool merge_next)
> > {
> > + struct vm_area_struct *vma = merge_next ? vmg->next : vmg->prev;
> > + /*
> > + * If the vma has a ->close operation then the driver probably needs to
> > + * release per-vma resources, so we don't attempt to merge those if the
> > + * caller indicates the current vma may be removed as part of the merge,
> > + * which is the case if we are attempting to merge the next VMA into
> > + * this one.
> > + */
> > + bool may_remove_vma = merge_next;
> > +
> > /*
> > * VM_SOFTDIRTY should not prevent from VMA merging, if we
> > * match the flags but dirty bit -- the caller should mark
> > @@ -25,15 +27,15 @@ static inline bool is_mergeable_vma(struct vm_area_struct *vma,
> > * the kernel to generate new VMAs when old one could be
> > * extended instead.
> > */
> > - if ((vma->vm_flags ^ vm_flags) & ~VM_SOFTDIRTY)
> > + if ((vma->vm_flags ^ vmg->flags) & ~VM_SOFTDIRTY)
> > return false;
> > - if (vma->vm_file != file)
> > + if (vma->vm_file != vmg->file)
> > return false;
> > if (may_remove_vma && vma->vm_ops && vma->vm_ops->close)
> > return false;
> > - if (!is_mergeable_vm_userfaultfd_ctx(vma, vm_userfaultfd_ctx))
> > + if (!is_mergeable_vm_userfaultfd_ctx(vma, vmg->uffd_ctx))
> > return false;
> > - if (!anon_vma_name_eq(anon_vma_name(vma), anon_name))
> > + if (!anon_vma_name_eq(anon_vma_name(vma), vmg->anon_name))
> > return false;
> > return true;
> > }
> > @@ -94,16 +96,16 @@ static void init_multi_vma_prep(struct vma_prepare *vp,
> > * We assume the vma may be removed as part of the merge.
> > */
> > bool
> > -can_vma_merge_before(struct vm_area_struct *vma, unsigned long vm_flags,
> > - struct anon_vma *anon_vma, struct file *file,
> > - pgoff_t vm_pgoff, struct vm_userfaultfd_ctx vm_userfaultfd_ctx,
> > - struct anon_vma_name *anon_name)
> > +can_vma_merge_before(struct vma_merge_struct *vmg)
> > {
> > - if (is_mergeable_vma(vma, file, vm_flags, vm_userfaultfd_ctx, anon_name, true) &&
> > - is_mergeable_anon_vma(anon_vma, vma->anon_vma, vma)) {
> > - if (vma->vm_pgoff == vm_pgoff)
> > + pgoff_t pglen = PHYS_PFN(vmg->end - vmg->start);
> > +
> > + if (is_mergeable_vma(vmg, true) &&
> > + is_mergeable_anon_vma(vmg->anon_vma, vmg->next->anon_vma, vmg->next)) {
> > + if (vmg->next->vm_pgoff == vmg->pgoff + pglen)
> > return true;
> > }
> > +
> > return false;
> > }
> >
> > @@ -116,18 +118,11 @@ can_vma_merge_before(struct vm_area_struct *vma, unsigned long vm_flags,
> > *
> > * We assume that vma is not removed as part of the merge.
> > */
> > -bool
> > -can_vma_merge_after(struct vm_area_struct *vma, unsigned long vm_flags,
> > - struct anon_vma *anon_vma, struct file *file,
> > - pgoff_t vm_pgoff, struct vm_userfaultfd_ctx vm_userfaultfd_ctx,
> > - struct anon_vma_name *anon_name)
> > +bool can_vma_merge_after(struct vma_merge_struct *vmg)
> > {
> > - if (is_mergeable_vma(vma, file, vm_flags, vm_userfaultfd_ctx, anon_name, false) &&
> > - is_mergeable_anon_vma(anon_vma, vma->anon_vma, vma)) {
> > - pgoff_t vm_pglen;
> > -
> > - vm_pglen = vma_pages(vma);
> > - if (vma->vm_pgoff + vm_pglen == vm_pgoff)
> > + if (is_mergeable_vma(vmg, false) &&
>
> I started putting /* merge_next = */ false, so that it's easier to read.
> Not a whole lot of arguments, but it is still useful to remember what is
> passed.
>
> > + is_mergeable_anon_vma(vmg->anon_vma, vmg->prev->anon_vma, vmg->prev)) {
> > + if (vmg->prev->vm_pgoff + vma_pages(vmg->prev) == vmg->pgoff)
> > return true;
> > }
> > return false;
> > @@ -1022,16 +1017,10 @@ int do_vmi_munmap(struct vma_iterator *vmi, struct mm_struct *mm,
> > * **** is not represented - it will be merged and the vma containing the
> > * area is returned, or the function will return NULL
> > */
> > -static struct vm_area_struct
> > -*vma_merge(struct vma_iterator *vmi, struct vm_area_struct *prev,
> > - struct vm_area_struct *src, unsigned long addr, unsigned long end,
> > - unsigned long vm_flags, pgoff_t pgoff, struct mempolicy *policy,
> > - struct vm_userfaultfd_ctx vm_userfaultfd_ctx,
> > - struct anon_vma_name *anon_name)
> > +static struct vm_area_struct *vma_merge(struct vma_merge_struct *vmg)
> > {
> > - struct mm_struct *mm = src->vm_mm;
> > - struct anon_vma *anon_vma = src->anon_vma;
> > - struct file *file = src->vm_file;
> > + struct mm_struct *mm = vmg->mm;
> > + struct vm_area_struct *prev = vmg->prev;
> > struct vm_area_struct *curr, *next, *res;
> > struct vm_area_struct *vma, *adjust, *remove, *remove2;
> > struct vm_area_struct *anon_dup = NULL;
> > @@ -1041,16 +1030,18 @@ static struct vm_area_struct
> > bool merge_prev = false;
> > bool merge_next = false;
> > bool vma_expanded = false;
> > + unsigned long addr = vmg->start;
> > + unsigned long end = vmg->end;
> > unsigned long vma_start = addr;
> > unsigned long vma_end = end;
> > - pgoff_t pglen = (end - addr) >> PAGE_SHIFT;
> > + pgoff_t pglen = PHYS_PFN(end - addr);
> > long adj_start = 0;
> >
> > /*
> > * We later require that vma->vm_flags == vm_flags,
> > * so this tests vma->vm_flags & VM_SPECIAL, too.
> > */
> > - if (vm_flags & VM_SPECIAL)
> > + if (vmg->flags & VM_SPECIAL)
> > return NULL;
> >
> > /* Does the input range span an existing VMA? (cases 5 - 8) */
> > @@ -1058,27 +1049,26 @@ static struct vm_area_struct
> >
> > if (!curr || /* cases 1 - 4 */
> > end == curr->vm_end) /* cases 6 - 8, adjacent VMA */
> > - next = vma_lookup(mm, end);
> > + next = vmg->next = vma_lookup(mm, end);
> > else
> > - next = NULL; /* case 5 */
> > + next = vmg->next = NULL; /* case 5 */
> >
> > if (prev) {
> > vma_start = prev->vm_start;
> > vma_pgoff = prev->vm_pgoff;
> >
> > /* Can we merge the predecessor? */
> > - if (addr == prev->vm_end && mpol_equal(vma_policy(prev), policy)
> > - && can_vma_merge_after(prev, vm_flags, anon_vma, file,
> > - pgoff, vm_userfaultfd_ctx, anon_name)) {
> > + if (addr == prev->vm_end && mpol_equal(vma_policy(prev), vmg->policy)
> > + && can_vma_merge_after(vmg)) {
> > +
> > merge_prev = true;
> > - vma_prev(vmi);
> > + vma_prev(vmg->vmi);
> > }
> > }
> >
> > /* Can we merge the successor? */
> > - if (next && mpol_equal(policy, vma_policy(next)) &&
> > - can_vma_merge_before(next, vm_flags, anon_vma, file, pgoff+pglen,
> > - vm_userfaultfd_ctx, anon_name)) {
> > + if (next && mpol_equal(vmg->policy, vma_policy(next)) &&
> > + can_vma_merge_before(vmg)) {
> > merge_next = true;
> > }
> >
> > @@ -1129,7 +1119,7 @@ static struct vm_area_struct
> > remove = curr;
> > } else { /* case 5 */
> > adjust = curr;
> > - adj_start = (end - curr->vm_start);
> > + adj_start = end - curr->vm_start;
>
> unnecessary change, if you respin.. but it's temporary.
>
> > }
> > if (!err)
> > err = dup_anon_vma(prev, curr, &anon_dup);
> > @@ -1169,13 +1159,13 @@ static struct vm_area_struct
> > vma_expanded = true;
> >
> > if (vma_expanded) {
> > - vma_iter_config(vmi, vma_start, vma_end);
> > + vma_iter_config(vmg->vmi, vma_start, vma_end);
> > } else {
> > - vma_iter_config(vmi, adjust->vm_start + adj_start,
> > + vma_iter_config(vmg->vmi, adjust->vm_start + adj_start,
> > adjust->vm_end);
> > }
> >
> > - if (vma_iter_prealloc(vmi, vma))
> > + if (vma_iter_prealloc(vmg->vmi, vma))
> > goto prealloc_fail;
> >
> > init_multi_vma_prep(&vp, vma, adjust, remove, remove2);
> > @@ -1187,20 +1177,20 @@ static struct vm_area_struct
> > vma_set_range(vma, vma_start, vma_end, vma_pgoff);
> >
> > if (vma_expanded)
> > - vma_iter_store(vmi, vma);
> > + vma_iter_store(vmg->vmi, vma);
> >
> > if (adj_start) {
> > adjust->vm_start += adj_start;
> > adjust->vm_pgoff += adj_start >> PAGE_SHIFT;
> > if (adj_start < 0) {
> > WARN_ON(vma_expanded);
> > - vma_iter_store(vmi, next);
> > + vma_iter_store(vmg->vmi, next);
> > }
> > }
> >
> > - vma_complete(&vp, vmi, mm);
> > + vma_complete(&vp, vmg->vmi, mm);
> > validate_mm(mm);
> > - khugepaged_enter_vma(res, vm_flags);
> > + khugepaged_enter_vma(res, vmg->flags);
> > return res;
> >
> > prealloc_fail:
> > @@ -1208,8 +1198,8 @@ static struct vm_area_struct
> > unlink_anon_vmas(anon_dup);
> >
> > anon_vma_fail:
> > - vma_iter_set(vmi, addr);
> > - vma_iter_load(vmi);
> > + vma_iter_set(vmg->vmi, addr);
> > + vma_iter_load(vmg->vmi);
> > return NULL;
> > }
> >
> > @@ -1226,32 +1216,27 @@ static struct vm_area_struct
> > * The function returns either the merged VMA, the original VMA if a split was
> > * required instead, or an error if the split failed.
> > */
> > -struct vm_area_struct *vma_modify(struct vma_iterator *vmi,
> > - struct vm_area_struct *prev,
> > - struct vm_area_struct *vma,
> > - unsigned long start, unsigned long end,
> > - unsigned long vm_flags,
> > - struct mempolicy *policy,
> > - struct vm_userfaultfd_ctx uffd_ctx,
> > - struct anon_vma_name *anon_name)
> > +static struct vm_area_struct *vma_modify(struct vma_merge_struct *vmg)
> > {
> > - pgoff_t pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT);
> > + struct vm_area_struct *vma = vmg->vma;
> > struct vm_area_struct *merged;
> >
> > - merged = vma_merge(vmi, prev, vma, start, end, vm_flags,
> > - pgoff, policy, uffd_ctx, anon_name);
> > + /* First, try to merge. */
> > + merged = vma_merge(vmg);
> > if (merged)
> > return merged;
> >
> > - if (vma->vm_start < start) {
> > - int err = split_vma(vmi, vma, start, 1);
> > + /* Split any preceding portion of the VMA. */
> > + if (vma->vm_start < vmg->start) {
> > + int err = split_vma(vmg->vmi, vma, vmg->start, 1);
> >
> > if (err)
> > return ERR_PTR(err);
> > }
> >
> > - if (vma->vm_end > end) {
> > - int err = split_vma(vmi, vma, end, 0);
> > + /* Split any trailing portion of the VMA. */
> > + if (vma->vm_end > vmg->end) {
> > + int err = split_vma(vmg->vmi, vma, vmg->end, 0);
> >
> > if (err)
> > return ERR_PTR(err);
> > @@ -1260,6 +1245,65 @@ struct vm_area_struct *vma_modify(struct vma_iterator *vmi,
> > return vma;
> > }
> >
> > +struct vm_area_struct *vma_modify_flags(
> > + struct vma_iterator *vmi, struct vm_area_struct *prev,
> > + struct vm_area_struct *vma, unsigned long start, unsigned long end,
> > + unsigned long new_flags)
> > +{
> > + VMG_VMA_STATE(vmg, vmi, prev, vma, start, end);
> > +
> > + vmg.flags = new_flags;
> > +
> > + return vma_modify(&vmg);
> > +}
> > +
> > +struct vm_area_struct
> > +*vma_modify_flags_name(struct vma_iterator *vmi,
> > + struct vm_area_struct *prev,
> > + struct vm_area_struct *vma,
> > + unsigned long start,
> > + unsigned long end,
> > + unsigned long new_flags,
> > + struct anon_vma_name *new_name)
> > +{
> > + VMG_VMA_STATE(vmg, vmi, prev, vma, start, end);
> > +
> > + vmg.flags = new_flags;
> > + vmg.anon_name = new_name;
> > +
> > + return vma_modify(&vmg);
> > +}
> > +
> > +struct vm_area_struct
> > +*vma_modify_policy(struct vma_iterator *vmi,
> > + struct vm_area_struct *prev,
> > + struct vm_area_struct *vma,
> > + unsigned long start, unsigned long end,
> > + struct mempolicy *new_pol)
> > +{
> > + VMG_VMA_STATE(vmg, vmi, prev, vma, start, end);
> > +
> > + vmg.policy = new_pol;
> > +
> > + return vma_modify(&vmg);
> > +}
> > +
> > +struct vm_area_struct
> > +*vma_modify_flags_uffd(struct vma_iterator *vmi,
> > + struct vm_area_struct *prev,
> > + struct vm_area_struct *vma,
> > + unsigned long start, unsigned long end,
> > + unsigned long new_flags,
> > + struct vm_userfaultfd_ctx new_ctx)
> > +{
> > + VMG_VMA_STATE(vmg, vmi, prev, vma, start, end);
> > +
> > + vmg.flags = new_flags;
> > + vmg.uffd_ctx = new_ctx;
> > +
> > + return vma_modify(&vmg);
> > +}
> > +
> > /*
> > * Attempt to merge a newly mapped VMA with those adjacent to it. The caller
> > * must ensure that [start, end) does not overlap any existing VMA.
> > @@ -1269,8 +1313,11 @@ struct vm_area_struct
> > struct vm_area_struct *vma, unsigned long start,
> > unsigned long end, pgoff_t pgoff)
> > {
> > - return vma_merge(vmi, prev, vma, start, end, vma->vm_flags, pgoff,
> > - vma_policy(vma), vma->vm_userfaultfd_ctx, anon_vma_name(vma));
> > + VMG_VMA_STATE(vmg, vmi, prev, vma, start, end);
> > +
> > + vmg.pgoff = pgoff;
> > +
> > + return vma_merge(&vmg);
> > }
> >
> > /*
> > @@ -1281,12 +1328,10 @@ struct vm_area_struct *vma_merge_extend(struct vma_iterator *vmi,
> > struct vm_area_struct *vma,
> > unsigned long delta)
> > {
> > - pgoff_t pgoff = vma->vm_pgoff + vma_pages(vma);
> > + VMG_VMA_STATE(vmg, vmi, vma, vma, vma->vm_end, vma->vm_end + delta);
> >
> > /* vma is specified as prev, so case 1 or 2 will apply. */
> > - return vma_merge(vmi, vma, vma, vma->vm_end, vma->vm_end + delta,
> > - vma->vm_flags, pgoff, vma_policy(vma),
> > - vma->vm_userfaultfd_ctx, anon_vma_name(vma));
> > + return vma_merge(&vmg);
> > }
>
> Many of these are small and can be static inline, some (all?) in the
> header.
I don't like exposing the raw underlying merge function, so this is on
purpose. No indication of perf hit.
>
> >
> > void unlink_file_vma_batch_init(struct unlink_vma_file_batch *vb)
> > diff --git a/mm/vma.h b/mm/vma.h
> > index c774642697a0..9060a1a1edfa 100644
> > --- a/mm/vma.h
> > +++ b/mm/vma.h
> > @@ -52,6 +52,59 @@ struct vma_munmap_struct {
> > unsigned long data_vm;
> > };
> >
> > +/* Represents a VMA merge operation. */
> > +struct vma_merge_struct {
> > + struct mm_struct *mm;
> > + struct vma_iterator *vmi;
> > + pgoff_t pgoff;
> > + struct vm_area_struct *prev;
> > + struct vm_area_struct *next; /* Modified by vma_merge(). */
> > + struct vm_area_struct *vma; /* Either a new VMA or the one being modified. */
> > + unsigned long start;
> > + unsigned long end;
> > + unsigned long flags;
> > + struct file *file;
> > + struct anon_vma *anon_vma;
> > + struct mempolicy *policy;
> > + struct vm_userfaultfd_ctx uffd_ctx;
> > + struct anon_vma_name *anon_name;
> > +};
> > +
> > +/* Assumes addr >= vma->vm_start. */
> > +static inline pgoff_t vma_pgoff_offset(struct vm_area_struct *vma,
> > + unsigned long addr)
> > +{
> > + return vma->vm_pgoff + PHYS_PFN(addr - vma->vm_start);
> > +}
> > +
> > +#define VMG_STATE(name, mm_, vmi_, start_, end_, flags_, pgoff_) \
> > + struct vma_merge_struct name = { \
> > + .mm = mm_, \
> > + .vmi = vmi_, \
> > + .start = start_, \
> > + .end = end_, \
> > + .flags = flags_, \
> > + .pgoff = pgoff_, \
> > + }
> > +
> > +#define VMG_VMA_STATE(name, vmi_, prev_, vma_, start_, end_) \
> > + struct vma_merge_struct name = { \
> > + .mm = vma_->vm_mm, \
> > + .vmi = vmi_, \
> > + .prev = prev_, \
> > + .next = NULL, \
> > + .vma = vma_, \
> > + .start = start_, \
> > + .end = end_, \
> > + .flags = vma_->vm_flags, \
> > + .pgoff = vma_pgoff_offset(vma_, start_), \
> > + .file = vma_->vm_file, \
> > + .anon_vma = vma_->anon_vma, \
> > + .policy = vma_policy(vma_), \
> > + .uffd_ctx = vma_->vm_userfaultfd_ctx, \
> > + .anon_name = anon_vma_name(vma_), \
> > + }
> > +
> > #ifdef CONFIG_DEBUG_VM_MAPLE_TREE
> > void validate_mm(struct mm_struct *mm);
> > #else
> > @@ -208,80 +261,53 @@ void remove_vma(struct vm_area_struct *vma, bool unreachable, bool closed);
> > void unmap_region(struct ma_state *mas, struct vm_area_struct *vma,
> > struct vm_area_struct *prev, struct vm_area_struct *next);
> >
> > -/* Required by mmap_region(). */
> > -bool
> > -can_vma_merge_before(struct vm_area_struct *vma, unsigned long vm_flags,
> > - struct anon_vma *anon_vma, struct file *file,
> > - pgoff_t vm_pgoff, struct vm_userfaultfd_ctx vm_userfaultfd_ctx,
> > - struct anon_vma_name *anon_name);
> > -
> > -/* Required by mmap_region() and do_brk_flags(). */
> > -bool
> > -can_vma_merge_after(struct vm_area_struct *vma, unsigned long vm_flags,
> > - struct anon_vma *anon_vma, struct file *file,
> > - pgoff_t vm_pgoff, struct vm_userfaultfd_ctx vm_userfaultfd_ctx,
> > - struct anon_vma_name *anon_name);
> > -
> > -struct vm_area_struct *vma_modify(struct vma_iterator *vmi,
> > - struct vm_area_struct *prev,
> > - struct vm_area_struct *vma,
> > - unsigned long start, unsigned long end,
> > - unsigned long vm_flags,
> > - struct mempolicy *policy,
> > - struct vm_userfaultfd_ctx uffd_ctx,
> > - struct anon_vma_name *anon_name);
> > +/*
> > + * Can we merge the VMA described by vmg into the following VMA vmg->next?
> > + *
> > + * Required by mmap_region().
> > + */
> > +bool can_vma_merge_before(struct vma_merge_struct *vmg);
> > +
> > +/*
> > + * Can we merge the VMA described by vmg into the preceding VMA vmg->prev?
> > + *
> > + * Required by mmap_region() and do_brk_flags().
> > + */
> > +bool can_vma_merge_after(struct vma_merge_struct *vmg);
> >
> > /* We are about to modify the VMA's flags. */
> > -static inline struct vm_area_struct
> > -*vma_modify_flags(struct vma_iterator *vmi,
> > - struct vm_area_struct *prev,
> > - struct vm_area_struct *vma,
> > - unsigned long start, unsigned long end,
> > - unsigned long new_flags)
> > -{
> > - return vma_modify(vmi, prev, vma, start, end, new_flags,
> > - vma_policy(vma), vma->vm_userfaultfd_ctx,
> > - anon_vma_name(vma));
> > -}
> > +struct vm_area_struct *vma_modify_flags(struct vma_iterator *vmi,
> > + struct vm_area_struct *prev,
> > + struct vm_area_struct *vma,
> > + unsigned long start, unsigned long end,
> > + unsigned long new_flags);
>
> Does this get better with two tab indent?
>
> >
> > /* We are about to modify the VMA's flags and/or anon_name. */
> > -static inline struct vm_area_struct
> > +struct vm_area_struct
> > *vma_modify_flags_name(struct vma_iterator *vmi,
> > struct vm_area_struct *prev,
> > struct vm_area_struct *vma,
> > unsigned long start,
> > unsigned long end,
> > unsigned long new_flags,
> > - struct anon_vma_name *new_name)
> > -{
> > - return vma_modify(vmi, prev, vma, start, end, new_flags,
> > - vma_policy(vma), vma->vm_userfaultfd_ctx, new_name);
> > -}
> > + struct anon_vma_name *new_name);
> >
> > /* We are about to modify the VMA's memory policy. */
> > -static inline struct vm_area_struct
> > +struct vm_area_struct
> > *vma_modify_policy(struct vma_iterator *vmi,
> > struct vm_area_struct *prev,
> > struct vm_area_struct *vma,
> > unsigned long start, unsigned long end,
> > - struct mempolicy *new_pol)
> > -{
> > - return vma_modify(vmi, prev, vma, start, end, vma->vm_flags,
> > - new_pol, vma->vm_userfaultfd_ctx, anon_vma_name(vma));
> > -}
> > + struct mempolicy *new_pol);
> >
> > /* We are about to modify the VMA's flags and/or uffd context. */
> > -static inline struct vm_area_struct
> > +struct vm_area_struct
> > *vma_modify_flags_uffd(struct vma_iterator *vmi,
> > struct vm_area_struct *prev,
> > struct vm_area_struct *vma,
> > unsigned long start, unsigned long end,
> > unsigned long new_flags,
> > - struct vm_userfaultfd_ctx new_ctx)
> > -{
> > - return vma_modify(vmi, prev, vma, start, end, new_flags,
> > - vma_policy(vma), new_ctx, anon_vma_name(vma));
> > -}
> > + struct vm_userfaultfd_ctx new_ctx);
> >
> > struct vm_area_struct
> > *vma_merge_new_vma(struct vma_iterator *vmi, struct vm_area_struct *prev,
> > diff --git a/tools/testing/vma/vma.c b/tools/testing/vma/vma.c
> > index 9b272633ca9e..b12f72979478 100644
> > --- a/tools/testing/vma/vma.c
> > +++ b/tools/testing/vma/vma.c
> > @@ -22,26 +22,6 @@ static bool fail_prealloc;
> > */
> > #include "../../../mm/vma.c"
> >
> > -/*
> > - * Temporarily forward-ported from a future in which vmg's are used for merging.
>
> the future is soon.
>
> > - */
> > -struct vma_merge_struct {
> > - struct mm_struct *mm;
> > - struct vma_iterator *vmi;
> > - pgoff_t pgoff;
> > - struct vm_area_struct *prev;
> > - struct vm_area_struct *next; /* Modified by vma_merge(). */
> > - struct vm_area_struct *vma; /* Either a new VMA or the one being modified. */
> > - unsigned long start;
> > - unsigned long end;
> > - unsigned long flags;
> > - struct file *file;
> > - struct anon_vma *anon_vma;
> > - struct mempolicy *policy;
> > - struct vm_userfaultfd_ctx uffd_ctx;
> > - struct anon_vma_name *anon_name;
> > -};
> > -
> > const struct vm_operations_struct vma_dummy_vm_ops;
> > static struct anon_vma dummy_anon_vma;
> >
> > @@ -115,14 +95,6 @@ static struct vm_area_struct *alloc_and_link_vma(struct mm_struct *mm,
> > /* Helper function which provides a wrapper around a merge new VMA operation. */
> > static struct vm_area_struct *merge_new(struct vma_merge_struct *vmg)
> > {
> > - /* vma_merge() needs a VMA to determine mm, anon_vma, and file. */
> > - struct vm_area_struct dummy = {
> > - .vm_mm = vmg->mm,
> > - .vm_flags = vmg->flags,
> > - .anon_vma = vmg->anon_vma,
> > - .vm_file = vmg->file,
> > - };
> > -
> > /*
> > * For convenience, get prev and next VMAs. Which the new VMA operation
> > * requires.
> > @@ -131,8 +103,7 @@ static struct vm_area_struct *merge_new(struct vma_merge_struct *vmg)
> > vmg->prev = vma_prev(vmg->vmi);
> >
> > vma_iter_set(vmg->vmi, vmg->start);
> > - return vma_merge_new_vma(vmg->vmi, vmg->prev, &dummy, vmg->start,
> > - vmg->end, vmg->pgoff);
> > + return vma_merge(vmg);
> > }
> >
> > /*
> > @@ -141,17 +112,7 @@ static struct vm_area_struct *merge_new(struct vma_merge_struct *vmg)
> > */
> > static struct vm_area_struct *merge_existing(struct vma_merge_struct *vmg)
> > {
> > - /* vma_merge() needs a VMA to determine mm, anon_vma, and file. */
> > - struct vm_area_struct dummy = {
> > - .vm_mm = vmg->mm,
> > - .vm_flags = vmg->flags,
> > - .anon_vma = vmg->anon_vma,
> > - .vm_file = vmg->file,
> > - };
> > -
> > - return vma_merge(vmg->vmi, vmg->prev, &dummy, vmg->start, vmg->end,
> > - vmg->flags, vmg->pgoff, vmg->policy, vmg->uffd_ctx,
> > - vmg->anon_name);
> > + return vma_merge(vmg);
> > }
> >
> > /*
> > --
> > 2.46.0
> >
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