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Message-ID: <CAJuCfpGD3EC_chwHWBETSJ9x7DR6umX6kFZES0sWyphtVNeNRw@mail.gmail.com>
Date: Fri, 28 May 2021 18:26:26 -0700
From: Suren Baghdasaryan <surenb@...gle.com>
To: Liam Howlett <liam.howlett@...cle.com>
Cc: "maple-tree@...ts.infradead.org" <maple-tree@...ts.infradead.org>,
"linux-mm@...ck.org" <linux-mm@...ck.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
Andrew Morton <akpm@...ux-foundation.org>,
Song Liu <songliubraving@...com>,
Davidlohr Bueso <dave@...olabs.net>,
"Paul E . McKenney" <paulmck@...nel.org>,
Matthew Wilcox <willy@...radead.org>,
Laurent Dufour <ldufour@...ux.ibm.com>,
David Rientjes <rientjes@...gle.com>,
Axel Rasmussen <axelrasmussen@...gle.com>,
Vlastimil Babka <vbabka@...e.cz>,
Rik van Riel <riel@...riel.com>,
Peter Zijlstra <peterz@...radead.org>,
Michel Lespinasse <walken.cr@...il.com>
Subject: Re: [PATCH 33/94] mm: Remove rb tree.
On Wed, Apr 28, 2021 at 8:36 AM Liam Howlett <liam.howlett@...cle.com> wrote:
>
> Remove the RB tree and start using the maple tree for vm_area_struct
> tracking.
>
> Drop validate_mm() calls in expand_upwards() and expand_downwards() as
> the lock is not held.
>
> Signed-off-by: Liam R. Howlett <Liam.Howlett@...cle.com>
> ---
> arch/x86/kernel/tboot.c | 1 -
> drivers/firmware/efi/efi.c | 1 -
> fs/proc/task_nommu.c | 55 ++--
> include/linux/mm.h | 4 +-
> include/linux/mm_types.h | 26 +-
> kernel/fork.c | 8 -
> mm/init-mm.c | 2 -
> mm/mmap.c | 525 ++++++++-----------------------------
> mm/nommu.c | 96 +++----
> mm/util.c | 8 +
> 10 files changed, 185 insertions(+), 541 deletions(-)
>
> diff --git a/arch/x86/kernel/tboot.c b/arch/x86/kernel/tboot.c
> index 6f978f722dff..121f28bb2209 100644
> --- a/arch/x86/kernel/tboot.c
> +++ b/arch/x86/kernel/tboot.c
> @@ -97,7 +97,6 @@ void __init tboot_probe(void)
>
> static pgd_t *tboot_pg_dir;
> static struct mm_struct tboot_mm = {
> - .mm_rb = RB_ROOT,
> .mm_mt = MTREE_INIT(mm_mt, MAPLE_ALLOC_RANGE),
> .pgd = swapper_pg_dir,
> .mm_users = ATOMIC_INIT(2),
> diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
> index 271ae8c7bb07..8aaeaa824576 100644
> --- a/drivers/firmware/efi/efi.c
> +++ b/drivers/firmware/efi/efi.c
> @@ -54,7 +54,6 @@ static unsigned long __initdata mem_reserve = EFI_INVALID_TABLE_ADDR;
> static unsigned long __initdata rt_prop = EFI_INVALID_TABLE_ADDR;
>
> struct mm_struct efi_mm = {
> - .mm_rb = RB_ROOT,
> .mm_mt = MTREE_INIT(mm_mt, MAPLE_ALLOC_RANGE),
> .mm_users = ATOMIC_INIT(2),
> .mm_count = ATOMIC_INIT(1),
> diff --git a/fs/proc/task_nommu.c b/fs/proc/task_nommu.c
> index a6d21fc0033c..8691a1216d1c 100644
> --- a/fs/proc/task_nommu.c
> +++ b/fs/proc/task_nommu.c
> @@ -22,15 +22,13 @@ void task_mem(struct seq_file *m, struct mm_struct *mm)
> {
> struct vm_area_struct *vma;
> struct vm_region *region;
> - struct rb_node *p;
> unsigned long bytes = 0, sbytes = 0, slack = 0, size;
> -
> - mmap_read_lock(mm);
> - for (p = rb_first(&mm->mm_rb); p; p = rb_next(p)) {
> - vma = rb_entry(p, struct vm_area_struct, vm_rb);
> + MA_STATE(mas, &mm->mm_mt, 0, 0);
>
> + mmap_read_lock(mm);
> + rcu_read_lock();
> + mas_for_each(&mas, vma, ULONG_MAX) {
> bytes += kobjsize(vma);
> -
> region = vma->vm_region;
> if (region) {
> size = kobjsize(region);
> @@ -53,7 +51,7 @@ void task_mem(struct seq_file *m, struct mm_struct *mm)
> sbytes += kobjsize(mm);
> else
> bytes += kobjsize(mm);
> -
> +
> if (current->fs && current->fs->users > 1)
> sbytes += kobjsize(current->fs);
> else
> @@ -77,20 +75,21 @@ void task_mem(struct seq_file *m, struct mm_struct *mm)
> "Shared:\t%8lu bytes\n",
> bytes, slack, sbytes);
>
> + rcu_read_unlock();
> mmap_read_unlock(mm);
> }
>
> unsigned long task_vsize(struct mm_struct *mm)
> {
> struct vm_area_struct *vma;
> - struct rb_node *p;
> unsigned long vsize = 0;
> + MA_STATE(mas, &mm->mm_mt, 0, 0);
>
> mmap_read_lock(mm);
> - for (p = rb_first(&mm->mm_rb); p; p = rb_next(p)) {
> - vma = rb_entry(p, struct vm_area_struct, vm_rb);
> + rcu_read_lock();
> + mas_for_each(&mas, vma, ULONG_MAX)
> vsize += vma->vm_end - vma->vm_start;
> - }
> + rcu_read_unlock();
> mmap_read_unlock(mm);
> return vsize;
> }
> @@ -101,12 +100,12 @@ unsigned long task_statm(struct mm_struct *mm,
> {
> struct vm_area_struct *vma;
> struct vm_region *region;
> - struct rb_node *p;
> unsigned long size = kobjsize(mm);
> + MA_STATE(mas, &mm->mm_mt, 0, 0);
>
> mmap_read_lock(mm);
> - for (p = rb_first(&mm->mm_rb); p; p = rb_next(p)) {
> - vma = rb_entry(p, struct vm_area_struct, vm_rb);
> + rcu_read_lock();
> + mas_for_each(&mas, vma, ULONG_MAX) {
> size += kobjsize(vma);
> region = vma->vm_region;
> if (region) {
> @@ -119,6 +118,7 @@ unsigned long task_statm(struct mm_struct *mm,
> >> PAGE_SHIFT;
> *data = (PAGE_ALIGN(mm->start_stack) - (mm->start_data & PAGE_MASK))
> >> PAGE_SHIFT;
> + rcu_read_unlock();
> mmap_read_unlock(mm);
> size >>= PAGE_SHIFT;
> size += *text + *data;
> @@ -190,17 +190,20 @@ static int nommu_vma_show(struct seq_file *m, struct vm_area_struct *vma)
> */
> static int show_map(struct seq_file *m, void *_p)
> {
> - struct rb_node *p = _p;
> -
> - return nommu_vma_show(m, rb_entry(p, struct vm_area_struct, vm_rb));
> + return nommu_vma_show(m, _p);
> }
>
> static void *m_start(struct seq_file *m, loff_t *pos)
> {
> struct proc_maps_private *priv = m->private;
> struct mm_struct *mm;
> - struct rb_node *p;
> - loff_t n = *pos;
> + struct vm_area_struct *vma;
> + unsigned long addr = *pos;
> + MA_STATE(mas, &priv->mm->mm_mt, addr, addr);
> +
> + /* See m_next(). Zero at the start or after lseek. */
> + if (addr == -1UL)
> + return NULL;
>
> /* pin the task and mm whilst we play with them */
> priv->task = get_proc_task(priv->inode);
> @@ -216,14 +219,12 @@ static void *m_start(struct seq_file *m, loff_t *pos)
> return ERR_PTR(-EINTR);
> }
>
> - /* start from the Nth VMA */
> - for (p = rb_first(&mm->mm_rb); p; p = rb_next(p))
> - if (n-- == 0)
> - return p;
> + /* start the next element from addr */
> + vma = mas_find(&mas, ULONG_MAX);
>
> mmap_read_unlock(mm);
> mmput(mm);
> - return NULL;
> + return vma;
> }
>
> static void m_stop(struct seq_file *m, void *_vml)
> @@ -242,10 +243,10 @@ static void m_stop(struct seq_file *m, void *_vml)
>
> static void *m_next(struct seq_file *m, void *_p, loff_t *pos)
> {
> - struct rb_node *p = _p;
> + struct vm_area_struct *vma = _p;
>
> - (*pos)++;
> - return p ? rb_next(p) : NULL;
> + *pos = vma->vm_end;
> + return vma->vm_next;
> }
>
> static const struct seq_operations proc_pid_maps_ops = {
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index 7f7dff6ad884..146976070fed 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -2553,8 +2553,6 @@ extern int __split_vma(struct mm_struct *, struct vm_area_struct *,
> extern int split_vma(struct mm_struct *, struct vm_area_struct *,
> unsigned long addr, int new_below);
> extern int insert_vm_struct(struct mm_struct *, struct vm_area_struct *);
> -extern void __vma_link_rb(struct mm_struct *, struct vm_area_struct *,
> - struct rb_node **, struct rb_node *);
> extern void unlink_file_vma(struct vm_area_struct *);
> extern struct vm_area_struct *copy_vma(struct vm_area_struct **,
> unsigned long addr, unsigned long len, pgoff_t pgoff,
> @@ -2699,7 +2697,7 @@ static inline struct vm_area_struct * find_vma_intersection(struct mm_struct * m
> static inline
> struct vm_area_struct *vma_lookup(struct mm_struct *mm, unsigned long addr)
> {
> - return find_vma_intersection(mm, addr, addr + 1);
> + return mtree_load(&mm->mm_mt, addr);
> }
>
> static inline unsigned long vm_start_gap(struct vm_area_struct *vma)
> diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
> index 51733fc44daf..41551bfa6ce0 100644
> --- a/include/linux/mm_types.h
> +++ b/include/linux/mm_types.h
> @@ -311,19 +311,6 @@ struct vm_area_struct {
>
> /* linked list of VM areas per task, sorted by address */
> struct vm_area_struct *vm_next, *vm_prev;
> -
> - struct rb_node vm_rb;
> -
> - /*
> - * Largest free memory gap in bytes to the left of this VMA.
> - * Either between this VMA and vma->vm_prev, or between one of the
> - * VMAs below us in the VMA rbtree and its ->vm_prev. This helps
> - * get_unmapped_area find a free area of the right size.
> - */
> - unsigned long rb_subtree_gap;
> -
> - /* Second cache line starts here. */
> -
> struct mm_struct *vm_mm; /* The address space we belong to. */
>
> /*
> @@ -333,6 +320,12 @@ struct vm_area_struct {
> pgprot_t vm_page_prot;
> unsigned long vm_flags; /* Flags, see mm.h. */
>
> + /* Information about our backing store: */
> + unsigned long vm_pgoff; /* Offset (within vm_file) in PAGE_SIZE
> + * units
> + */
> + /* Second cache line starts here. */
> + struct file *vm_file; /* File we map to (can be NULL). */
> /*
> * For areas with an address space and backing store,
> * linkage into the address_space->i_mmap interval tree.
> @@ -351,16 +344,14 @@ struct vm_area_struct {
> struct list_head anon_vma_chain; /* Serialized by mmap_lock &
> * page_table_lock */
> struct anon_vma *anon_vma; /* Serialized by page_table_lock */
> + /* Third cache line starts here. */
>
> /* Function pointers to deal with this struct. */
> const struct vm_operations_struct *vm_ops;
>
> - /* Information about our backing store: */
> - unsigned long vm_pgoff; /* Offset (within vm_file) in PAGE_SIZE
> - units */
> - struct file * vm_file; /* File we map to (can be NULL). */
> void * vm_private_data; /* was vm_pte (shared mem) */
>
> +
> #ifdef CONFIG_SWAP
> atomic_long_t swap_readahead_info;
> #endif
> @@ -389,7 +380,6 @@ struct mm_struct {
> struct {
> struct vm_area_struct *mmap; /* list of VMAs */
> struct maple_tree mm_mt;
> - struct rb_root mm_rb;
> u64 vmacache_seqnum; /* per-thread vmacache */
> #ifdef CONFIG_MMU
> unsigned long (*get_unmapped_area) (struct file *filp,
> diff --git a/kernel/fork.c b/kernel/fork.c
> index 832416ff613e..83afd3007a2b 100644
> --- a/kernel/fork.c
> +++ b/kernel/fork.c
> @@ -475,7 +475,6 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm,
> struct mm_struct *oldmm)
> {
> struct vm_area_struct *mpnt, *tmp, *prev, **pprev;
> - struct rb_node **rb_link, *rb_parent;
> int retval;
> unsigned long charge = 0;
> MA_STATE(old_mas, &oldmm->mm_mt, 0, 0);
> @@ -502,8 +501,6 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm,
> mm->exec_vm = oldmm->exec_vm;
> mm->stack_vm = oldmm->stack_vm;
>
> - rb_link = &mm->mm_rb.rb_node;
> - rb_parent = NULL;
> pprev = &mm->mmap;
> retval = ksm_fork(mm, oldmm);
> if (retval)
> @@ -597,10 +594,6 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm,
> tmp->vm_prev = prev;
> prev = tmp;
>
> - __vma_link_rb(mm, tmp, rb_link, rb_parent);
> - rb_link = &tmp->vm_rb.rb_right;
> - rb_parent = &tmp->vm_rb;
> -
> /* Link the vma into the MT */
> mas.index = tmp->vm_start;
> mas.last = tmp->vm_end - 1;
> @@ -1033,7 +1026,6 @@ static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p,
> struct user_namespace *user_ns)
> {
> mm->mmap = NULL;
> - mm->mm_rb = RB_ROOT;
> mt_init_flags(&mm->mm_mt, MAPLE_ALLOC_RANGE);
> mm->vmacache_seqnum = 0;
> atomic_set(&mm->mm_users, 1);
> diff --git a/mm/init-mm.c b/mm/init-mm.c
> index 2014d4b82294..04bbe5172b72 100644
> --- a/mm/init-mm.c
> +++ b/mm/init-mm.c
> @@ -1,6 +1,5 @@
> // SPDX-License-Identifier: GPL-2.0
> #include <linux/mm_types.h>
> -#include <linux/rbtree.h>
> #include <linux/maple_tree.h>
> #include <linux/rwsem.h>
> #include <linux/spinlock.h>
> @@ -28,7 +27,6 @@
> * and size this cpu_bitmask to NR_CPUS.
> */
> struct mm_struct init_mm = {
> - .mm_rb = RB_ROOT,
> .mm_mt = MTREE_INIT(mm_mt, MAPLE_ALLOC_RANGE),
> .pgd = swapper_pg_dir,
> .mm_users = ATOMIC_INIT(2),
> diff --git a/mm/mmap.c b/mm/mmap.c
> index 1bd43f4db28e..7747047c4cbe 100644
> --- a/mm/mmap.c
> +++ b/mm/mmap.c
> @@ -38,7 +38,6 @@
> #include <linux/audit.h>
> #include <linux/khugepaged.h>
> #include <linux/uprobes.h>
> -#include <linux/rbtree_augmented.h>
> #include <linux/notifier.h>
> #include <linux/memory.h>
> #include <linux/printk.h>
> @@ -290,93 +289,6 @@ SYSCALL_DEFINE1(brk, unsigned long, brk)
> return origbrk;
> }
>
> -static inline unsigned long vma_compute_gap(struct vm_area_struct *vma)
> -{
> - unsigned long gap, prev_end;
> -
> - /*
> - * Note: in the rare case of a VM_GROWSDOWN above a VM_GROWSUP, we
> - * allow two stack_guard_gaps between them here, and when choosing
> - * an unmapped area; whereas when expanding we only require one.
> - * That's a little inconsistent, but keeps the code here simpler.
> - */
> - gap = vm_start_gap(vma);
> - if (vma->vm_prev) {
> - prev_end = vm_end_gap(vma->vm_prev);
> - if (gap > prev_end)
> - gap -= prev_end;
> - else
> - gap = 0;
> - }
> - return gap;
> -}
> -
> -#ifdef CONFIG_DEBUG_VM_RB
> -static unsigned long vma_compute_subtree_gap(struct vm_area_struct *vma)
> -{
> - unsigned long max = vma_compute_gap(vma), subtree_gap;
> - if (vma->vm_rb.rb_left) {
> - subtree_gap = rb_entry(vma->vm_rb.rb_left,
> - struct vm_area_struct, vm_rb)->rb_subtree_gap;
> - if (subtree_gap > max)
> - max = subtree_gap;
> - }
> - if (vma->vm_rb.rb_right) {
> - subtree_gap = rb_entry(vma->vm_rb.rb_right,
> - struct vm_area_struct, vm_rb)->rb_subtree_gap;
> - if (subtree_gap > max)
> - max = subtree_gap;
> - }
> - return max;
> -}
> -
> -static int browse_rb(struct mm_struct *mm)
> -{
> - struct rb_root *root = &mm->mm_rb;
> - int i = 0, j, bug = 0;
> - struct rb_node *nd, *pn = NULL;
> - unsigned long prev = 0, pend = 0;
> -
> - for (nd = rb_first(root); nd; nd = rb_next(nd)) {
> - struct vm_area_struct *vma;
> - vma = rb_entry(nd, struct vm_area_struct, vm_rb);
> - if (vma->vm_start < prev) {
> - pr_emerg("vm_start %lx < prev %lx\n",
> - vma->vm_start, prev);
> - bug = 1;
> - }
> - if (vma->vm_start < pend) {
> - pr_emerg("vm_start %lx < pend %lx\n",
> - vma->vm_start, pend);
> - bug = 1;
> - }
> - if (vma->vm_start > vma->vm_end) {
> - pr_emerg("vm_start %lx > vm_end %lx\n",
> - vma->vm_start, vma->vm_end);
> - bug = 1;
> - }
> - spin_lock(&mm->page_table_lock);
> - if (vma->rb_subtree_gap != vma_compute_subtree_gap(vma)) {
> - pr_emerg("free gap %lx, correct %lx\n",
> - vma->rb_subtree_gap,
> - vma_compute_subtree_gap(vma));
> - bug = 1;
> - }
> - spin_unlock(&mm->page_table_lock);
> - i++;
> - pn = nd;
> - prev = vma->vm_start;
> - pend = vma->vm_end;
> - }
> - j = 0;
> - for (nd = pn; nd; nd = rb_prev(nd))
> - j++;
> - if (i != j) {
> - pr_emerg("backwards %d, forwards %d\n", j, i);
> - bug = 1;
> - }
> - return bug ? -1 : i;
> -}
> #if defined(CONFIG_DEBUG_MAPLE_TREE)
> extern void mt_validate(struct maple_tree *mt);
> extern void mt_dump(const struct maple_tree *mt);
> @@ -405,17 +317,25 @@ static void validate_mm_mt(struct mm_struct *mm)
> dump_stack();
> #ifdef CONFIG_DEBUG_VM
> dump_vma(vma_mt);
> - pr_emerg("and next in rb\n");
> + pr_emerg("and vm_next\n");
> dump_vma(vma->vm_next);
> -#endif
> +#endif // CONFIG_DEBUG_VM
> pr_emerg("mt piv: %px %lu - %lu\n", vma_mt,
> mas.index, mas.last);
> pr_emerg("mt vma: %px %lu - %lu\n", vma_mt,
> vma_mt->vm_start, vma_mt->vm_end);
> - pr_emerg("rb vma: %px %lu - %lu\n", vma,
> + if (vma->vm_prev) {
> + pr_emerg("ll prev: %px %lu - %lu\n",
> + vma->vm_prev, vma->vm_prev->vm_start,
> + vma->vm_prev->vm_end);
> + }
> + pr_emerg("ll vma: %px %lu - %lu\n", vma,
> vma->vm_start, vma->vm_end);
> - pr_emerg("rb->next = %px %lu - %lu\n", vma->vm_next,
> - vma->vm_next->vm_start, vma->vm_next->vm_end);
> + if (vma->vm_next) {
> + pr_emerg("ll next: %px %lu - %lu\n",
> + vma->vm_next, vma->vm_next->vm_start,
> + vma->vm_next->vm_end);
> + }
>
> mt_dump(mas.tree);
> if (vma_mt->vm_end != mas.last + 1) {
> @@ -441,21 +361,6 @@ static void validate_mm_mt(struct mm_struct *mm)
> rcu_read_unlock();
> mt_validate(&mm->mm_mt);
> }
> -#else
> -#define validate_mm_mt(root) do { } while (0)
> -#endif
> -static void validate_mm_rb(struct rb_root *root, struct vm_area_struct *ignore)
> -{
> - struct rb_node *nd;
> -
> - for (nd = rb_first(root); nd; nd = rb_next(nd)) {
> - struct vm_area_struct *vma;
> - vma = rb_entry(nd, struct vm_area_struct, vm_rb);
> - VM_BUG_ON_VMA(vma != ignore &&
> - vma->rb_subtree_gap != vma_compute_subtree_gap(vma),
> - vma);
> - }
> -}
>
> static void validate_mm(struct mm_struct *mm)
> {
> @@ -464,6 +369,8 @@ static void validate_mm(struct mm_struct *mm)
> unsigned long highest_address = 0;
> struct vm_area_struct *vma = mm->mmap;
>
> + validate_mm_mt(mm);
> +
> while (vma) {
> struct anon_vma *anon_vma = vma->anon_vma;
> struct anon_vma_chain *avc;
> @@ -488,80 +395,13 @@ static void validate_mm(struct mm_struct *mm)
> mm->highest_vm_end, highest_address);
> bug = 1;
> }
> - i = browse_rb(mm);
> - if (i != mm->map_count) {
> - if (i != -1)
> - pr_emerg("map_count %d rb %d\n", mm->map_count, i);
> - bug = 1;
> - }
> VM_BUG_ON_MM(bug, mm);
> }
> -#else
> -#define validate_mm_rb(root, ignore) do { } while (0)
> +
> +#else // !CONFIG_DEBUG_MAPLE_TREE
> #define validate_mm_mt(root) do { } while (0)
> #define validate_mm(mm) do { } while (0)
> -#endif
> -
> -RB_DECLARE_CALLBACKS_MAX(static, vma_gap_callbacks,
> - struct vm_area_struct, vm_rb,
> - unsigned long, rb_subtree_gap, vma_compute_gap)
> -
> -/*
> - * Update augmented rbtree rb_subtree_gap values after vma->vm_start or
> - * vma->vm_prev->vm_end values changed, without modifying the vma's position
> - * in the rbtree.
> - */
> -static void vma_gap_update(struct vm_area_struct *vma)
> -{
> - /*
> - * As it turns out, RB_DECLARE_CALLBACKS_MAX() already created
> - * a callback function that does exactly what we want.
> - */
> - vma_gap_callbacks_propagate(&vma->vm_rb, NULL);
> -}
> -
> -static inline void vma_rb_insert(struct vm_area_struct *vma,
> - struct rb_root *root)
> -{
> - /* All rb_subtree_gap values must be consistent prior to insertion */
> - validate_mm_rb(root, NULL);
> -
> - rb_insert_augmented(&vma->vm_rb, root, &vma_gap_callbacks);
> -}
> -
> -static void __vma_rb_erase(struct vm_area_struct *vma, struct rb_root *root)
> -{
> - /*
> - * Note rb_erase_augmented is a fairly large inline function,
> - * so make sure we instantiate it only once with our desired
> - * augmented rbtree callbacks.
> - */
> - rb_erase_augmented(&vma->vm_rb, root, &vma_gap_callbacks);
> -}
> -
> -static __always_inline void vma_rb_erase_ignore(struct vm_area_struct *vma,
> - struct rb_root *root,
> - struct vm_area_struct *ignore)
> -{
> - /*
> - * All rb_subtree_gap values must be consistent prior to erase,
> - * with the possible exception of
> - *
> - * a. the "next" vma being erased if next->vm_start was reduced in
> - * __vma_adjust() -> __vma_unlink()
> - * b. the vma being erased in detach_vmas_to_be_unmapped() ->
> - * vma_rb_erase()
> - */
> - validate_mm_rb(root, ignore);
> -
> - __vma_rb_erase(vma, root);
> -}
> -
> -static __always_inline void vma_rb_erase(struct vm_area_struct *vma,
> - struct rb_root *root)
> -{
> - vma_rb_erase_ignore(vma, root, vma);
> -}
> +#endif // CONFIG_DEBUG_MAPLE_TREE
>
> /*
> * vma has some anon_vma assigned, and is already inserted on that
> @@ -595,38 +435,26 @@ anon_vma_interval_tree_post_update_vma(struct vm_area_struct *vma)
> anon_vma_interval_tree_insert(avc, &avc->anon_vma->rb_root);
> }
>
> -static int find_vma_links(struct mm_struct *mm, unsigned long addr,
> - unsigned long end, struct vm_area_struct **pprev,
> - struct rb_node ***rb_link, struct rb_node **rb_parent)
> +/* Private
> + * range_has_overlap() - Check the @start - @end range for overlapping VMAs and
> + * sets up a pointer to the previous VMA
> + *
> + * @mm - the mm struct
> + * @start - the start address of the range
> + * @end - the end address of the range
> + * @pprev - the pointer to the pointer of the previous VMA
> + *
> + * Returns: True if there is an overlapping VMA, false otherwise
> + */
> +static bool range_has_overlap(struct mm_struct *mm, unsigned long start,
> + unsigned long end, struct vm_area_struct **pprev)
> {
> - struct rb_node **__rb_link, *__rb_parent, *rb_prev;
> -
> - __rb_link = &mm->mm_rb.rb_node;
> - rb_prev = __rb_parent = NULL;
> + struct vm_area_struct *existing;
>
> - while (*__rb_link) {
> - struct vm_area_struct *vma_tmp;
> -
> - __rb_parent = *__rb_link;
> - vma_tmp = rb_entry(__rb_parent, struct vm_area_struct, vm_rb);
> -
> - if (vma_tmp->vm_end > addr) {
> - /* Fail if an existing vma overlaps the area */
> - if (vma_tmp->vm_start < end)
> - return -ENOMEM;
> - __rb_link = &__rb_parent->rb_left;
> - } else {
> - rb_prev = __rb_parent;
> - __rb_link = &__rb_parent->rb_right;
> - }
> - }
> -
> - *pprev = NULL;
> - if (rb_prev)
> - *pprev = rb_entry(rb_prev, struct vm_area_struct, vm_rb);
> - *rb_link = __rb_link;
> - *rb_parent = __rb_parent;
> - return 0;
> + MA_STATE(mas, &mm->mm_mt, start, start);
> + existing = mas_find(&mas, end - 1);
> + *pprev = mas_prev(&mas, 0);
> + return existing ? true : false;
> }
>
> /*
> @@ -653,8 +481,6 @@ static inline struct vm_area_struct *vma_next(struct mm_struct *mm,
> * @start: The start of the range.
> * @len: The length of the range.
> * @pprev: pointer to the pointer that will be set to previous vm_area_struct
> - * @rb_link: the rb_node
> - * @rb_parent: the parent rb_node
> *
> * Find all the vm_area_struct that overlap from @start to
> * @end and munmap them. Set @pprev to the previous vm_area_struct.
> @@ -663,76 +489,41 @@ static inline struct vm_area_struct *vma_next(struct mm_struct *mm,
> */
> static inline int
> munmap_vma_range(struct mm_struct *mm, unsigned long start, unsigned long len,
> - struct vm_area_struct **pprev, struct rb_node ***link,
> - struct rb_node **parent, struct list_head *uf)
> + struct vm_area_struct **pprev, struct list_head *uf)
> {
> -
> - while (find_vma_links(mm, start, start + len, pprev, link, parent))
> + // Needs optimization.
> + while (range_has_overlap(mm, start, start + len, pprev))
> if (do_munmap(mm, start, len, uf))
> return -ENOMEM;
> -
> return 0;
> }
> static unsigned long count_vma_pages_range(struct mm_struct *mm,
> unsigned long addr, unsigned long end)
> {
> unsigned long nr_pages = 0;
> - unsigned long nr_mt_pages = 0;
> struct vm_area_struct *vma;
> + unsigned long vm_start, vm_end;
> + MA_STATE(mas, &mm->mm_mt, addr, addr);
>
> - /* Find first overlapping mapping */
> - vma = find_vma_intersection(mm, addr, end);
> + /* Find first overlaping mapping */
nit: I think the original comment was correct.
> + vma = mas_find(&mas, end - 1);
> if (!vma)
> return 0;
>
> - nr_pages = (min(end, vma->vm_end) -
> - max(addr, vma->vm_start)) >> PAGE_SHIFT;
> + vm_start = vma->vm_start;
> + vm_end = vma->vm_end;
> + nr_pages = (min(end, vm_end) - max(addr, vm_start)) >> PAGE_SHIFT;
>
> /* Iterate over the rest of the overlaps */
> - for (vma = vma->vm_next; vma; vma = vma->vm_next) {
> - unsigned long overlap_len;
> -
> - if (vma->vm_start > end)
> - break;
> -
> - overlap_len = min(end, vma->vm_end) - vma->vm_start;
> - nr_pages += overlap_len >> PAGE_SHIFT;
> + mas_for_each(&mas, vma, end) {
> + vm_start = vma->vm_start;
> + vm_end = vma->vm_end;
> + nr_pages += (min(end, vm_end) - vm_start) >> PAGE_SHIFT;
> }
>
> - mt_for_each(&mm->mm_mt, vma, addr, end) {
> - nr_mt_pages +=
> - (min(end, vma->vm_end) - vma->vm_start) >> PAGE_SHIFT;
> - }
> -
> - VM_BUG_ON_MM(nr_pages != nr_mt_pages, mm);
> -
> return nr_pages;
> }
>
> -void __vma_link_rb(struct mm_struct *mm, struct vm_area_struct *vma,
> - struct rb_node **rb_link, struct rb_node *rb_parent)
> -{
> - /* Update tracking information for the gap following the new vma. */
> - if (vma->vm_next)
> - vma_gap_update(vma->vm_next);
> - else
> - mm->highest_vm_end = vm_end_gap(vma);
> -
> - /*
> - * vma->vm_prev wasn't known when we followed the rbtree to find the
> - * correct insertion point for that vma. As a result, we could not
> - * update the vma vm_rb parents rb_subtree_gap values on the way down.
> - * So, we first insert the vma with a zero rb_subtree_gap value
> - * (to be consistent with what we did on the way down), and then
> - * immediately update the gap to the correct value. Finally we
> - * rebalance the rbtree after all augmented values have been set.
> - */
> - rb_link_node(&vma->vm_rb, rb_parent, rb_link);
> - vma->rb_subtree_gap = 0;
> - vma_gap_update(vma);
> - vma_rb_insert(vma, &mm->mm_rb);
> -}
> -
> static void __vma_link_file(struct vm_area_struct *vma)
> {
> struct file *file;
> @@ -780,19 +571,8 @@ static inline void vma_mt_store(struct mm_struct *mm, struct vm_area_struct *vma
> GFP_KERNEL);
> }
>
> -static void
> -__vma_link(struct mm_struct *mm, struct vm_area_struct *vma,
> - struct vm_area_struct *prev, struct rb_node **rb_link,
> - struct rb_node *rb_parent)
> -{
> - vma_mt_store(mm, vma);
> - __vma_link_list(mm, vma, prev);
> - __vma_link_rb(mm, vma, rb_link, rb_parent);
> -}
> -
> static void vma_link(struct mm_struct *mm, struct vm_area_struct *vma,
> - struct vm_area_struct *prev, struct rb_node **rb_link,
> - struct rb_node *rb_parent)
> + struct vm_area_struct *prev)
> {
> struct address_space *mapping = NULL;
>
> @@ -801,7 +581,8 @@ static void vma_link(struct mm_struct *mm, struct vm_area_struct *vma,
> i_mmap_lock_write(mapping);
> }
>
> - __vma_link(mm, vma, prev, rb_link, rb_parent);
> + vma_mt_store(mm, vma);
> + __vma_link_list(mm, vma, prev);
> __vma_link_file(vma);
>
> if (mapping)
> @@ -813,30 +594,18 @@ static void vma_link(struct mm_struct *mm, struct vm_area_struct *vma,
>
> /*
> * Helper for vma_adjust() in the split_vma insert case: insert a vma into the
> - * mm's list and rbtree. It has already been inserted into the interval tree.
> + * mm's list and the mm tree. It has already been inserted into the interval tree.
> */
> static void __insert_vm_struct(struct mm_struct *mm, struct vm_area_struct *vma)
> {
> struct vm_area_struct *prev;
> - struct rb_node **rb_link, *rb_parent;
>
> - if (find_vma_links(mm, vma->vm_start, vma->vm_end,
> - &prev, &rb_link, &rb_parent))
> - BUG();
> - __vma_link(mm, vma, prev, rb_link, rb_parent);
> + BUG_ON(range_has_overlap(mm, vma->vm_start, vma->vm_end, &prev));
> + vma_mt_store(mm, vma);
> + __vma_link_list(mm, vma, prev);
> mm->map_count++;
> }
>
> -static __always_inline void __vma_unlink(struct mm_struct *mm,
> - struct vm_area_struct *vma,
> - struct vm_area_struct *ignore)
> -{
> - vma_rb_erase_ignore(vma, &mm->mm_rb, ignore);
> - __vma_unlink_list(mm, vma);
> - /* Kill the cache */
> - vmacache_invalidate(mm);
> -}
> -
> /*
> * We cannot adjust vm_start, vm_end, vm_pgoff fields of a vma that
> * is already present in an i_mmap tree without adjusting the tree.
> @@ -854,13 +623,10 @@ int __vma_adjust(struct vm_area_struct *vma, unsigned long start,
> struct rb_root_cached *root = NULL;
> struct anon_vma *anon_vma = NULL;
> struct file *file = vma->vm_file;
> - bool start_changed = false, end_changed = false;
> + bool vma_changed = false;
> long adjust_next = 0;
> int remove_next = 0;
>
> - validate_mm(mm);
> - validate_mm_mt(mm);
> -
> if (next && !insert) {
> struct vm_area_struct *exporter = NULL, *importer = NULL;
>
> @@ -986,21 +752,23 @@ int __vma_adjust(struct vm_area_struct *vma, unsigned long start,
> }
>
> if (start != vma->vm_start) {
> - unsigned long old_start = vma->vm_start;
> + if (vma->vm_start < start)
> + vma_mt_szero(mm, vma->vm_start, start);
> + else
> + vma_changed = true;
> vma->vm_start = start;
> - if (old_start < start)
> - vma_mt_szero(mm, old_start, start);
> - start_changed = true;
> }
> if (end != vma->vm_end) {
> - unsigned long old_end = vma->vm_end;
> + if (vma->vm_end > end)
> + vma_mt_szero(mm, end, vma->vm_end);
> + else
> + vma_changed = true;
> vma->vm_end = end;
> - if (old_end > end)
> - vma_mt_szero(mm, end, old_end);
> - end_changed = true;
> + if (!next)
> + mm->highest_vm_end = vm_end_gap(vma);
> }
>
> - if (end_changed || start_changed)
> + if (vma_changed)
> vma_mt_store(mm, vma);
>
> vma->vm_pgoff = pgoff;
> @@ -1018,25 +786,9 @@ int __vma_adjust(struct vm_area_struct *vma, unsigned long start,
> }
>
> if (remove_next) {
> - /*
> - * vma_merge has merged next into vma, and needs
> - * us to remove next before dropping the locks.
> - * Since we have expanded over this vma, the maple tree will
> - * have overwritten by storing the value
> - */
> - if (remove_next != 3)
> - __vma_unlink(mm, next, next);
> - else
> - /*
> - * vma is not before next if they've been
> - * swapped.
> - *
> - * pre-swap() next->vm_start was reduced so
> - * tell validate_mm_rb to ignore pre-swap()
> - * "next" (which is stored in post-swap()
> - * "vma").
> - */
> - __vma_unlink(mm, next, vma);
> + __vma_unlink_list(mm, next);
> + /* Kill the cache */
> + vmacache_invalidate(mm);
> if (file)
> __remove_shared_vm_struct(next, file, mapping);
> } else if (insert) {
> @@ -1046,15 +798,6 @@ int __vma_adjust(struct vm_area_struct *vma, unsigned long start,
> * (it may either follow vma or precede it).
> */
> __insert_vm_struct(mm, insert);
> - } else {
> - if (start_changed)
> - vma_gap_update(vma);
> - if (end_changed) {
> - if (!next)
> - mm->highest_vm_end = vm_end_gap(vma);
> - else if (!adjust_next)
> - vma_gap_update(next);
> - }
> }
>
> if (anon_vma) {
> @@ -1112,10 +855,7 @@ int __vma_adjust(struct vm_area_struct *vma, unsigned long start,
> remove_next = 1;
> end = next->vm_end;
> goto again;
> - }
> - else if (next)
> - vma_gap_update(next);
> - else {
> + } else if (!next) {
> /*
> * If remove_next == 2 we obviously can't
> * reach this path.
> @@ -1142,8 +882,6 @@ int __vma_adjust(struct vm_area_struct *vma, unsigned long start,
> uprobe_mmap(insert);
>
> validate_mm(mm);
> - validate_mm_mt(mm);
> -
> return 0;
> }
>
> @@ -1290,7 +1028,6 @@ struct vm_area_struct *vma_merge(struct mm_struct *mm,
> struct vm_area_struct *area, *next;
> int err;
>
> - validate_mm_mt(mm);
> /*
> * We later require that vma->vm_flags == vm_flags,
> * so this tests vma->vm_flags & VM_SPECIAL, too.
> @@ -1366,7 +1103,6 @@ struct vm_area_struct *vma_merge(struct mm_struct *mm,
> khugepaged_enter_vma_merge(area, vm_flags);
> return area;
> }
> - validate_mm_mt(mm);
>
> return NULL;
> }
> @@ -1536,6 +1272,7 @@ unsigned long do_mmap(struct file *file, unsigned long addr,
> vm_flags_t vm_flags;
> int pkey = 0;
>
> + validate_mm(mm);
> *populate = 0;
>
> if (!len)
> @@ -1856,10 +1593,8 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
> struct mm_struct *mm = current->mm;
> struct vm_area_struct *vma, *prev, *merge;
> int error;
> - struct rb_node **rb_link, *rb_parent;
> unsigned long charged = 0;
>
> - validate_mm_mt(mm);
> /* Check against address space limit. */
> if (!may_expand_vm(mm, vm_flags, len >> PAGE_SHIFT)) {
> unsigned long nr_pages;
> @@ -1875,8 +1610,8 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
> return -ENOMEM;
> }
>
> - /* Clear old maps, set up prev, rb_link, rb_parent, and uf */
> - if (munmap_vma_range(mm, addr, len, &prev, &rb_link, &rb_parent, uf))
> + /* Clear old maps, set up prev and uf */
> + if (munmap_vma_range(mm, addr, len, &prev, uf))
> return -ENOMEM;
> /*
> * Private writable mapping: check memory availability
> @@ -1984,7 +1719,7 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
> goto free_vma;
> }
>
> - vma_link(mm, vma, prev, rb_link, rb_parent);
> + vma_link(mm, vma, prev);
> /* Once vma denies write, undo our temporary denial count */
> if (file) {
> unmap_writable:
> @@ -2021,7 +1756,6 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
>
> vma_set_page_prot(vma);
>
> - validate_mm_mt(mm);
> return addr;
>
> unmap_and_free_vma:
> @@ -2041,7 +1775,6 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
> unacct_error:
> if (charged)
> vm_unacct_memory(charged);
> - validate_mm_mt(mm);
> return error;
> }
>
> @@ -2324,9 +2057,6 @@ find_vma_prev(struct mm_struct *mm, unsigned long addr,
>
> rcu_read_lock();
> vma = mas_find(&mas, ULONG_MAX);
> - if (!vma)
> - mas_reset(&mas);
> -
> *pprev = mas_prev(&mas, 0);
> rcu_read_unlock();
> return vma;
> @@ -2390,7 +2120,6 @@ int expand_upwards(struct vm_area_struct *vma, unsigned long address)
> unsigned long gap_addr;
> int error = 0;
>
> - validate_mm_mt(mm);
> if (!(vma->vm_flags & VM_GROWSUP))
> return -EFAULT;
>
> @@ -2437,15 +2166,13 @@ int expand_upwards(struct vm_area_struct *vma, unsigned long address)
> error = acct_stack_growth(vma, size, grow);
> if (!error) {
> /*
> - * vma_gap_update() doesn't support concurrent
> - * updates, but we only hold a shared mmap_lock
> - * lock here, so we need to protect against
> - * concurrent vma expansions.
> - * anon_vma_lock_write() doesn't help here, as
> - * we don't guarantee that all growable vmas
> - * in a mm share the same root anon vma.
> - * So, we reuse mm->page_table_lock to guard
> - * against concurrent vma expansions.
> + * We only hold a shared mmap_lock lock here, so
> + * we need to protect against concurrent vma
> + * expansions. anon_vma_lock_write() doesn't
> + * help here, as we don't guarantee that all
> + * growable vmas in a mm share the same root
> + * anon vma. So, we reuse mm->page_table_lock
> + * to guard against concurrent vma expansions.
> */
> spin_lock(&mm->page_table_lock);
> if (vma->vm_flags & VM_LOCKED)
> @@ -2453,10 +2180,9 @@ int expand_upwards(struct vm_area_struct *vma, unsigned long address)
> vm_stat_account(mm, vma->vm_flags, grow);
> anon_vma_interval_tree_pre_update_vma(vma);
> vma->vm_end = address;
> + vma_mt_store(mm, vma);
> anon_vma_interval_tree_post_update_vma(vma);
> - if (vma->vm_next)
> - vma_gap_update(vma->vm_next);
> - else
> + if (!vma->vm_next)
> mm->highest_vm_end = vm_end_gap(vma);
> spin_unlock(&mm->page_table_lock);
>
> @@ -2466,8 +2192,6 @@ int expand_upwards(struct vm_area_struct *vma, unsigned long address)
> }
> anon_vma_unlock_write(vma->anon_vma);
> khugepaged_enter_vma_merge(vma, vma->vm_flags);
> - validate_mm(mm);
> - validate_mm_mt(mm);
> return error;
> }
> #endif /* CONFIG_STACK_GROWSUP || CONFIG_IA64 */
> @@ -2475,14 +2199,12 @@ int expand_upwards(struct vm_area_struct *vma, unsigned long address)
> /*
> * vma is the first one with address < vma->vm_start. Have to extend vma.
> */
> -int expand_downwards(struct vm_area_struct *vma,
> - unsigned long address)
> +int expand_downwards(struct vm_area_struct *vma, unsigned long address)
> {
> struct mm_struct *mm = vma->vm_mm;
> struct vm_area_struct *prev;
> int error = 0;
>
> - validate_mm(mm);
> address &= PAGE_MASK;
> if (address < mmap_min_addr)
> return -EPERM;
> @@ -2519,15 +2241,13 @@ int expand_downwards(struct vm_area_struct *vma,
> error = acct_stack_growth(vma, size, grow);
> if (!error) {
> /*
> - * vma_gap_update() doesn't support concurrent
> - * updates, but we only hold a shared mmap_lock
> - * lock here, so we need to protect against
> - * concurrent vma expansions.
> - * anon_vma_lock_write() doesn't help here, as
> - * we don't guarantee that all growable vmas
> - * in a mm share the same root anon vma.
> - * So, we reuse mm->page_table_lock to guard
> - * against concurrent vma expansions.
> + * We only hold a shared mmap_lock lock here, so
> + * we need to protect against concurrent vma
> + * expansions. anon_vma_lock_write() doesn't
> + * help here, as we don't guarantee that all
> + * growable vmas in a mm share the same root
> + * anon vma. So, we reuse mm->page_table_lock
> + * to guard against concurrent vma expansions.
> */
> spin_lock(&mm->page_table_lock);
> if (vma->vm_flags & VM_LOCKED)
> @@ -2539,7 +2259,6 @@ int expand_downwards(struct vm_area_struct *vma,
> /* Overwrite old entry in mtree. */
> vma_mt_store(mm, vma);
> anon_vma_interval_tree_post_update_vma(vma);
> - vma_gap_update(vma);
> spin_unlock(&mm->page_table_lock);
>
> perf_event_mmap(vma);
> @@ -2548,7 +2267,6 @@ int expand_downwards(struct vm_area_struct *vma,
> }
> anon_vma_unlock_write(vma->anon_vma);
> khugepaged_enter_vma_merge(vma, vma->vm_flags);
> - validate_mm(mm);
> return error;
> }
>
> @@ -2681,16 +2399,14 @@ detach_vmas_to_be_unmapped(struct mm_struct *mm, struct vm_area_struct *vma,
> vma->vm_prev = NULL;
> vma_mt_szero(mm, vma->vm_start, end);
> do {
> - vma_rb_erase(vma, &mm->mm_rb);
> mm->map_count--;
> tail_vma = vma;
> vma = vma->vm_next;
> } while (vma && vma->vm_start < end);
> *insertion_point = vma;
> - if (vma) {
> + if (vma)
> vma->vm_prev = prev;
> - vma_gap_update(vma);
> - } else
> + else
> mm->highest_vm_end = prev ? vm_end_gap(prev) : 0;
> tail_vma->vm_next = NULL;
>
> @@ -2821,11 +2537,7 @@ int __do_munmap(struct mm_struct *mm, unsigned long start, size_t len,
> if (len == 0)
> return -EINVAL;
>
> - /*
> - * arch_unmap() might do unmaps itself. It must be called
> - * and finish any rbtree manipulation before this code
> - * runs and also starts to manipulate the rbtree.
> - */
> + /* arch_unmap() might do unmaps itself. */
> arch_unmap(mm, start, end);
>
> /* Find the first overlapping VMA */
> @@ -2833,7 +2545,7 @@ int __do_munmap(struct mm_struct *mm, unsigned long start, size_t len,
> if (!vma)
> return 0;
> prev = vma->vm_prev;
> - /* we have start < vma->vm_end */
> + /* we have start < vma->vm_end */
>
> /* if it doesn't overlap, we have nothing.. */
> if (vma->vm_start >= end)
> @@ -2893,7 +2605,7 @@ int __do_munmap(struct mm_struct *mm, unsigned long start, size_t len,
> if (mm->locked_vm)
> unlock_range(vma, end);
>
> - /* Detach vmas from rbtree */
> + /* Detach vmas from the MM linked list and remove from the mm tree*/
> if (!detach_vmas_to_be_unmapped(mm, vma, prev, end))
> downgrade = false;
>
> @@ -3041,11 +2753,11 @@ SYSCALL_DEFINE5(remap_file_pages, unsigned long, start, unsigned long, size,
> * anonymous maps. eventually we may be able to do some
> * brk-specific accounting here.
> */
> -static int do_brk_flags(unsigned long addr, unsigned long len, unsigned long flags, struct list_head *uf)
> +static int do_brk_flags(unsigned long addr, unsigned long len,
> + unsigned long flags, struct list_head *uf)
> {
> struct mm_struct *mm = current->mm;
> struct vm_area_struct *vma, *prev;
> - struct rb_node **rb_link, *rb_parent;
> pgoff_t pgoff = addr >> PAGE_SHIFT;
> int error;
> unsigned long mapped_addr;
> @@ -3064,8 +2776,8 @@ static int do_brk_flags(unsigned long addr, unsigned long len, unsigned long fla
> if (error)
> return error;
>
> - /* Clear old maps, set up prev, rb_link, rb_parent, and uf */
> - if (munmap_vma_range(mm, addr, len, &prev, &rb_link, &rb_parent, uf))
> + /* Clear old maps, set up prev and uf */
> + if (munmap_vma_range(mm, addr, len, &prev, uf))
> return -ENOMEM;
>
> /* Check against address space limits *after* clearing old maps... */
> @@ -3099,7 +2811,7 @@ static int do_brk_flags(unsigned long addr, unsigned long len, unsigned long fla
> vma->vm_pgoff = pgoff;
> vma->vm_flags = flags;
> vma->vm_page_prot = vm_get_page_prot(flags);
> - vma_link(mm, vma, prev, rb_link, rb_parent);
> + vma_link(mm, vma, prev);
> out:
> perf_event_mmap(vma);
> mm->total_vm += len >> PAGE_SHIFT;
> @@ -3219,26 +2931,10 @@ void exit_mmap(struct mm_struct *mm)
> int insert_vm_struct(struct mm_struct *mm, struct vm_area_struct *vma)
> {
> struct vm_area_struct *prev;
> - struct rb_node **rb_link, *rb_parent;
> - unsigned long start = vma->vm_start;
> - struct vm_area_struct *overlap = NULL;
>
> - if (find_vma_links(mm, vma->vm_start, vma->vm_end,
> - &prev, &rb_link, &rb_parent))
> + if (range_has_overlap(mm, vma->vm_start, vma->vm_end, &prev))
> return -ENOMEM;
>
> - overlap = mt_find(&mm->mm_mt, &start, vma->vm_end - 1);
> - if (overlap) {
> -
> - pr_err("Found vma ending at %lu\n", start - 1);
> - pr_err("vma : %lu => %lu-%lu\n", (unsigned long)overlap,
> - overlap->vm_start, overlap->vm_end - 1);
> -#if defined(CONFIG_DEBUG_MAPLE_TREE)
> - mt_dump(&mm->mm_mt);
> -#endif
> - BUG();
> - }
> -
> if ((vma->vm_flags & VM_ACCOUNT) &&
> security_vm_enough_memory_mm(mm, vma_pages(vma)))
> return -ENOMEM;
> @@ -3260,7 +2956,7 @@ int insert_vm_struct(struct mm_struct *mm, struct vm_area_struct *vma)
> vma->vm_pgoff = vma->vm_start >> PAGE_SHIFT;
> }
>
> - vma_link(mm, vma, prev, rb_link, rb_parent);
> + vma_link(mm, vma, prev);
> return 0;
> }
>
> @@ -3276,9 +2972,7 @@ struct vm_area_struct *copy_vma(struct vm_area_struct **vmap,
> unsigned long vma_start = vma->vm_start;
> struct mm_struct *mm = vma->vm_mm;
> struct vm_area_struct *new_vma, *prev;
> - struct rb_node **rb_link, *rb_parent;
> bool faulted_in_anon_vma = true;
> - unsigned long index = addr;
>
> validate_mm_mt(mm);
> /*
> @@ -3290,10 +2984,9 @@ struct vm_area_struct *copy_vma(struct vm_area_struct **vmap,
> faulted_in_anon_vma = false;
> }
>
> - if (find_vma_links(mm, addr, addr + len, &prev, &rb_link, &rb_parent))
> + if (range_has_overlap(mm, addr, addr + len, &prev))
> return NULL; /* should never get here */
> - if (mt_find(&mm->mm_mt, &index, addr+len - 1))
> - BUG();
> +
> new_vma = vma_merge(mm, prev, addr, addr + len, vma->vm_flags,
> vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma),
> vma->vm_userfaultfd_ctx);
> @@ -3334,7 +3027,7 @@ struct vm_area_struct *copy_vma(struct vm_area_struct **vmap,
> get_file(new_vma->vm_file);
> if (new_vma->vm_ops && new_vma->vm_ops->open)
> new_vma->vm_ops->open(new_vma);
> - vma_link(mm, new_vma, prev, rb_link, rb_parent);
> + vma_link(mm, new_vma, prev);
> *need_rmap_locks = false;
> }
> validate_mm_mt(mm);
> diff --git a/mm/nommu.c b/mm/nommu.c
> index 8848cf7cb7c1..c410f99203fb 100644
> --- a/mm/nommu.c
> +++ b/mm/nommu.c
> @@ -566,13 +566,14 @@ static void put_nommu_region(struct vm_region *region)
> */
> static void add_vma_to_mm(struct mm_struct *mm, struct vm_area_struct *vma)
> {
> - struct vm_area_struct *pvma, *prev;
> struct address_space *mapping;
> - struct rb_node **p, *parent, *rb_prev;
> + struct vm_area_struct *prev;
> + MA_STATE(mas, &mm->mm_mt, vma->vm_start, vma->vm_end);
>
> BUG_ON(!vma->vm_region);
>
> mm->map_count++;
> + printk("mm at %u\n", mm->map_count);
I think this was added while debugging and should be removed?
> vma->vm_mm = mm;
>
> /* add the VMA to the mapping */
> @@ -586,42 +587,12 @@ static void add_vma_to_mm(struct mm_struct *mm, struct vm_area_struct *vma)
> i_mmap_unlock_write(mapping);
> }
>
> + rcu_read_lock();
> + prev = mas_prev(&mas, 0);
> + rcu_read_unlock();
> + mas_reset(&mas);
> /* add the VMA to the tree */
> - parent = rb_prev = NULL;
> - p = &mm->mm_rb.rb_node;
> - while (*p) {
> - parent = *p;
> - pvma = rb_entry(parent, struct vm_area_struct, vm_rb);
> -
> - /* sort by: start addr, end addr, VMA struct addr in that order
> - * (the latter is necessary as we may get identical VMAs) */
> - if (vma->vm_start < pvma->vm_start)
> - p = &(*p)->rb_left;
> - else if (vma->vm_start > pvma->vm_start) {
> - rb_prev = parent;
> - p = &(*p)->rb_right;
> - } else if (vma->vm_end < pvma->vm_end)
> - p = &(*p)->rb_left;
> - else if (vma->vm_end > pvma->vm_end) {
> - rb_prev = parent;
> - p = &(*p)->rb_right;
> - } else if (vma < pvma)
> - p = &(*p)->rb_left;
> - else if (vma > pvma) {
> - rb_prev = parent;
> - p = &(*p)->rb_right;
> - } else
> - BUG();
> - }
> -
> - rb_link_node(&vma->vm_rb, parent, p);
> - rb_insert_color(&vma->vm_rb, &mm->mm_rb);
> -
> - /* add VMA to the VMA list also */
> - prev = NULL;
> - if (rb_prev)
> - prev = rb_entry(rb_prev, struct vm_area_struct, vm_rb);
> -
> + vma_mas_store(vma, &mas);
> __vma_link_list(mm, vma, prev);
> }
>
> @@ -634,6 +605,7 @@ static void delete_vma_from_mm(struct vm_area_struct *vma)
> struct address_space *mapping;
> struct mm_struct *mm = vma->vm_mm;
> struct task_struct *curr = current;
> + MA_STATE(mas, &vma->vm_mm->mm_mt, 0, 0);
>
> mm->map_count--;
> for (i = 0; i < VMACACHE_SIZE; i++) {
> @@ -643,7 +615,6 @@ static void delete_vma_from_mm(struct vm_area_struct *vma)
> break;
> }
> }
> -
> /* remove the VMA from the mapping */
> if (vma->vm_file) {
> mapping = vma->vm_file->f_mapping;
> @@ -656,8 +627,7 @@ static void delete_vma_from_mm(struct vm_area_struct *vma)
> }
>
> /* remove from the MM's tree and list */
> - rb_erase(&vma->vm_rb, &mm->mm_rb);
> -
> + vma_mas_remove(vma, &mas);
> __vma_unlink_list(mm, vma);
> }
>
> @@ -681,24 +651,21 @@ static void delete_vma(struct mm_struct *mm, struct vm_area_struct *vma)
> struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
> {
> struct vm_area_struct *vma;
> + MA_STATE(mas, &mm->mm_mt, addr, addr);
>
> /* check the cache first */
> vma = vmacache_find(mm, addr);
> if (likely(vma))
> return vma;
>
> - /* trawl the list (there may be multiple mappings in which addr
> - * resides) */
> - for (vma = mm->mmap; vma; vma = vma->vm_next) {
> - if (vma->vm_start > addr)
> - return NULL;
> - if (vma->vm_end > addr) {
> - vmacache_update(addr, vma);
> - return vma;
> - }
> - }
> + rcu_read_lock();
> + vma = mas_walk(&mas);
> + rcu_read_unlock();
>
> - return NULL;
> + if (vma)
> + vmacache_update(addr, vma);
> +
> + return vma;
> }
> EXPORT_SYMBOL(find_vma);
>
> @@ -730,26 +697,25 @@ static struct vm_area_struct *find_vma_exact(struct mm_struct *mm,
> {
> struct vm_area_struct *vma;
> unsigned long end = addr + len;
> + MA_STATE(mas, &mm->mm_mt, addr, addr);
>
> /* check the cache first */
> vma = vmacache_find_exact(mm, addr, end);
> if (vma)
> return vma;
>
> - /* trawl the list (there may be multiple mappings in which addr
> - * resides) */
> - for (vma = mm->mmap; vma; vma = vma->vm_next) {
> - if (vma->vm_start < addr)
> - continue;
> - if (vma->vm_start > addr)
> - return NULL;
> - if (vma->vm_end == end) {
> - vmacache_update(addr, vma);
> - return vma;
> - }
> - }
> -
> - return NULL;
> + rcu_read_lock();
> + vma = mas_walk(&mas);
> + rcu_read_unlock();
> + if (!vma)
> + return NULL;
> + if (vma->vm_start != addr)
> + return NULL;
> + if (vma->vm_end != end)
> + return NULL;
> +
> + vmacache_update(addr, vma);
> + return vma;
> }
>
> /*
> diff --git a/mm/util.c b/mm/util.c
> index 0b6dd9d81da7..35deaa0ccac5 100644
> --- a/mm/util.c
> +++ b/mm/util.c
> @@ -287,6 +287,8 @@ void __vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma,
> vma->vm_next = next;
> if (next)
> next->vm_prev = vma;
> + else
> + mm->highest_vm_end = vm_end_gap(vma);
> }
>
> void __vma_unlink_list(struct mm_struct *mm, struct vm_area_struct *vma)
> @@ -301,6 +303,12 @@ void __vma_unlink_list(struct mm_struct *mm, struct vm_area_struct *vma)
> mm->mmap = next;
> if (next)
> next->vm_prev = prev;
> + else {
> + if (prev)
> + mm->highest_vm_end = vm_end_gap(prev);
> + else
> + mm->highest_vm_end = 0;
> + }
> }
>
> /* Check if the vma is being used as a stack by this task */
> --
> 2.30.2
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