From: Liam Howlett <liam.howlett@oracle.com>
To: "maple-tree@lists.infradead.org" <maple-tree@lists.infradead.org>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Andrew Morton <akpm@linux-foundation.org>
Subject: [PATCH v6 26/71] mm/mmap: Use advanced maple tree API for mmap_region()
Date: Tue, 15 Feb 2022 14:43:11 +0000 [thread overview]
Message-ID: <20220215144241.3812052-26-Liam.Howlett@oracle.com> (raw)
In-Reply-To: <20220215144241.3812052-1-Liam.Howlett@oracle.com>
From: "Liam R. Howlett" <Liam.Howlett@Oracle.com>
Changing mmap_region() to use the maple tree state and the advanced
maple tree interface allows for a lot less tree walking.
This change removes the last caller of munmap_vma_range(), so drop this
unused function.
Add vma_expand() to expand a VMA if possible by doing the necessary
hugepage check, uprobe_munmap of files, dcache flush, modifications then
undoing the detaches, etc.
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
---
mm/mmap.c | 234 +++++++++++++++++++++++++++++++++++++++++++-----------
1 file changed, 187 insertions(+), 47 deletions(-)
diff --git a/mm/mmap.c b/mm/mmap.c
index 80ff8be0631b..8fb9a066a944 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -511,28 +511,6 @@ static inline struct vm_area_struct *__vma_next(struct mm_struct *mm,
return vma->vm_next;
}
-/*
- * munmap_vma_range() - munmap VMAs that overlap a range.
- * @mm: The mm struct
- * @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
- *
- * Find all the vm_area_struct that overlap from @start to
- * @end and munmap them. Set @pprev to the previous vm_area_struct.
- *
- * Returns: -ENOMEM on munmap failure or 0 on success.
- */
-static inline int
-munmap_vma_range(struct mm_struct *mm, unsigned long start, unsigned long len,
- struct vm_area_struct **pprev, struct list_head *uf)
-{
- 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)
{
@@ -634,6 +612,117 @@ static void __insert_vm_struct(struct mm_struct *mm, struct vm_area_struct *vma,
mm->map_count++;
}
+/*
+ * vma_expand - Expand an existing VMA
+ *
+ * @mas: The maple state
+ * @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.
+ *
+ * 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.
+ *
+ * Returns: 0 on success
+ */
+inline int vma_expand(struct ma_state *mas, struct vm_area_struct *vma,
+ unsigned long start, unsigned long end, pgoff_t pgoff,
+ struct vm_area_struct *next)
+{
+ struct mm_struct *mm = vma->vm_mm;
+ struct address_space *mapping = NULL;
+ struct rb_root_cached *root = NULL;
+ struct anon_vma *anon_vma = vma->anon_vma;
+ struct file *file = vma->vm_file;
+ bool remove_next = false;
+
+ if (next && (vma != next) && (end == next->vm_end)) {
+ remove_next = true;
+ if (next->anon_vma && !vma->anon_vma) {
+ int error;
+
+ vma->anon_vma = next->anon_vma;
+ error = anon_vma_clone(vma, next);
+ if (error)
+ return error;
+ }
+ }
+
+ /* Not merging but overwriting any part of next is not handled. */
+ VM_BUG_ON(!remove_next && next != vma && end > next->vm_start);
+ /* Only handles expanding */
+ VM_BUG_ON(vma->vm_start < start || vma->vm_end > end);
+
+ vma_adjust_trans_huge(vma, start, end, 0);
+
+ if (file) {
+ mapping = file->f_mapping;
+ root = &mapping->i_mmap;
+ uprobe_munmap(vma, vma->vm_start, vma->vm_end);
+ i_mmap_lock_write(mapping);
+ flush_dcache_mmap_lock(mapping);
+ vma_interval_tree_remove(vma, root);
+ } else if (anon_vma) {
+ anon_vma_lock_write(anon_vma);
+ anon_vma_interval_tree_pre_update_vma(vma);
+ }
+
+ vma->vm_start = start;
+ vma->vm_end = end;
+ vma->vm_pgoff = pgoff;
+ /* Note: mas must be pointing to the expanding VMA */
+ vma_mas_store(vma, mas);
+
+ if (file) {
+ vma_interval_tree_insert(vma, root);
+ flush_dcache_mmap_unlock(mapping);
+ }
+
+ /* Expanding over the next vma */
+ if (remove_next) {
+ /* Remove from mm linked list - also updates highest_vm_end */
+ __vma_unlink_list(mm, next);
+
+ /* Kill the cache */
+ vmacache_invalidate(mm);
+
+ if (file)
+ __remove_shared_vm_struct(next, file, mapping);
+
+ } else if (!next) {
+ mm->highest_vm_end = vm_end_gap(vma);
+ }
+
+ if (anon_vma) {
+ anon_vma_interval_tree_post_update_vma(vma);
+ anon_vma_unlock_write(anon_vma);
+ }
+
+ if (file) {
+ i_mmap_unlock_write(mapping);
+ uprobe_mmap(vma);
+ }
+
+ if (remove_next) {
+ if (file) {
+ uprobe_munmap(next, next->vm_start, next->vm_end);
+ fput(file);
+ }
+ if (next->anon_vma)
+ anon_vma_merge(vma, next);
+ mm->map_count--;
+ mpol_put(vma_policy(next));
+ vm_area_free(next);
+ }
+
+ validate_mm(mm);
+ return 0;
+}
+
/*
* 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.
@@ -1625,9 +1714,15 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
struct list_head *uf)
{
struct mm_struct *mm = current->mm;
- struct vm_area_struct *vma, *prev, *merge;
- int error;
+ struct vm_area_struct *vma = NULL;
+ struct vm_area_struct *prev, *next;
+ pgoff_t pglen = len >> PAGE_SHIFT;
unsigned long charged = 0;
+ unsigned long end = addr + len;
+ unsigned long merge_start = addr, merge_end = end;
+ pgoff_t vm_pgoff;
+ int error;
+ MA_STATE(mas, &mm->mm_mt, addr, end - 1);
/* Check against address space limit. */
if (!may_expand_vm(mm, vm_flags, len >> PAGE_SHIFT)) {
@@ -1637,16 +1732,17 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
* MAP_FIXED may remove pages of mappings that intersects with
* requested mapping. Account for the pages it would unmap.
*/
- nr_pages = count_vma_pages_range(mm, addr, addr + len);
+ nr_pages = count_vma_pages_range(mm, addr, end);
if (!may_expand_vm(mm, vm_flags,
(len >> PAGE_SHIFT) - nr_pages))
return -ENOMEM;
}
- /* Clear old maps, set up prev and uf */
- if (munmap_vma_range(mm, addr, len, &prev, uf))
+ /* Unmap any existing mapping in the area */
+ if (do_munmap(mm, addr, len, uf))
return -ENOMEM;
+
/*
* Private writable mapping: check memory availability
*/
@@ -1657,14 +1753,43 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
vm_flags |= VM_ACCOUNT;
}
- /*
- * Can we just expand an old mapping?
- */
- vma = vma_merge(mm, prev, addr, addr + len, vm_flags,
- NULL, file, pgoff, NULL, NULL_VM_UFFD_CTX, NULL);
- if (vma)
- goto out;
+ next = mas_next(&mas, ULONG_MAX);
+ prev = mas_prev(&mas, 0);
+ if (vm_flags & VM_SPECIAL)
+ goto cannot_expand;
+
+ /* 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)) {
+ merge_end = next->vm_end;
+ vma = next;
+ vm_pgoff = next->vm_pgoff - pglen;
+ }
+
+ /* 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))) {
+ merge_start = prev->vm_start;
+ vma = prev;
+ vm_pgoff = prev->vm_pgoff;
+ }
+
+ /* Actually expand, if possible */
+ if (vma &&
+ !vma_expand(&mas, vma, merge_start, merge_end, vm_pgoff, next)) {
+ khugepaged_enter_vma_merge(vma, vm_flags);
+ goto expanded;
+ }
+
+ mas.index = addr;
+ mas.last = end - 1;
+cannot_expand:
/*
* Determine the object being mapped and call the appropriate
* specific mapper. the address has already been validated, but
@@ -1677,7 +1802,7 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
}
vma->vm_start = addr;
- vma->vm_end = addr + len;
+ vma->vm_end = end;
vma->vm_flags = vm_flags;
vma->vm_page_prot = vm_get_page_prot(vm_flags);
vma->vm_pgoff = pgoff;
@@ -1698,28 +1823,30 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
*
* Answer: Yes, several device drivers can do it in their
* f_op->mmap method. -DaveM
- * Bug: If addr is changed, prev, rb_link, rb_parent should
- * be updated for vma_link()
*/
WARN_ON_ONCE(addr != vma->vm_start);
addr = vma->vm_start;
+ mas_reset(&mas);
/* If vm_flags changed after call_mmap(), we should try merge vma again
* as we may succeed this time.
*/
if (unlikely(vm_flags != vma->vm_flags && prev)) {
- merge = vma_merge(mm, prev, vma->vm_start, vma->vm_end, vma->vm_flags,
+ next = vma_merge(mm, prev, vma->vm_start, vma->vm_end, vma->vm_flags,
NULL, vma->vm_file, vma->vm_pgoff, NULL, NULL_VM_UFFD_CTX, NULL);
- if (merge) {
+ if (next) {
/* ->mmap() can change vma->vm_file and fput the original file. So
* fput the vma->vm_file here or we would add an extra fput for file
* and cause general protection fault ultimately.
*/
fput(vma->vm_file);
vm_area_free(vma);
- vma = merge;
- /* Update vm_flags to pick up the change. */
+ vma = prev;
+ /* Update vm_flags and possible addr to pick up the change. We don't
+ * warn here if addr changed as the vma is not linked by vma_link().
+ */
+ addr = vma->vm_start;
vm_flags = vma->vm_flags;
goto unmap_writable;
}
@@ -1743,13 +1870,28 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
goto free_vma;
}
- vma_link(mm, vma, prev);
+ if (vma->vm_file)
+ i_mmap_lock_write(vma->vm_file->f_mapping);
+
+ vma_mas_store(vma, &mas);
+ __vma_link_list(mm, vma, prev);
+ mm->map_count++;
+ if (vma->vm_file) {
+ if (vma->vm_flags & VM_SHARED)
+ mapping_allow_writable(vma->vm_file->f_mapping);
+
+ flush_dcache_mmap_lock(vma->vm_file->f_mapping);
+ vma_interval_tree_insert(vma, &vma->vm_file->f_mapping->i_mmap);
+ flush_dcache_mmap_unlock(vma->vm_file->f_mapping);
+ i_mmap_unlock_write(vma->vm_file->f_mapping);
+ }
+
/* Once vma denies write, undo our temporary denial count */
unmap_writable:
if (file && vm_flags & VM_SHARED)
mapping_unmap_writable(file->f_mapping);
file = vma->vm_file;
-out:
+expanded:
perf_event_mmap(vma);
vm_stat_account(mm, vm_flags, len >> PAGE_SHIFT);
@@ -1776,6 +1918,7 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
vma_set_page_prot(vma);
+ validate_mm(mm);
return addr;
unmap_and_free_vma:
@@ -1792,6 +1935,7 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
unacct_error:
if (charged)
vm_unacct_memory(charged);
+ validate_mm(mm);
return error;
}
@@ -2599,10 +2743,6 @@ int __do_munmap(struct mm_struct *mm, unsigned long start, size_t len,
prev = vma->vm_prev;
/* we have start < vma->vm_end */
- /* if it doesn't overlap, we have nothing.. */
- if (vma->vm_start >= end)
- return 0;
-
/*
* If we need to split any vma, do it now to save pain later.
*
--
2.34.1
next prev parent reply other threads:[~2022-02-15 14:43 UTC|newest]
Thread overview: 100+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-15 14:37 [PATCH v6 00/71] Introducing the Maple Tree Liam Howlett
2022-02-15 14:42 ` [PATCH v6 01/71] binfmt_elf: Take the mmap lock when walking the VMA list Liam Howlett
2022-02-15 14:42 ` [PATCH v6 03/71] radix tree test suite: Add pr_err define Liam Howlett
2022-02-15 14:42 ` [PATCH v6 02/71] xarray: Fix bitmap breakage Liam Howlett
2022-02-15 14:42 ` [PATCH v6 04/71] radix tree test suite: Add kmem_cache_set_non_kernel() Liam Howlett
2022-02-15 14:42 ` [PATCH v6 05/71] radix tree test suite: Add allocation counts and size to kmem_cache Liam Howlett
2022-02-15 14:42 ` [PATCH v6 06/71] radix tree test suite: Add support for slab bulk APIs Liam Howlett
2022-02-15 14:42 ` [PATCH v6 07/71] radix tree test suite: Add lockdep_is_held to header Liam Howlett
2022-02-15 14:43 ` [PATCH v6 08/71] Maple Tree: Add new data structure Liam Howlett
2022-02-16 10:11 ` Mark Hemment
2022-02-16 18:25 ` Liam Howlett
2022-02-27 1:11 ` Vasily Gorbik
2022-02-27 12:46 ` Vasily Gorbik
2022-02-28 14:36 ` Liam Howlett
2022-03-01 2:01 ` Vasily Gorbik
2022-03-01 20:39 ` Liam Howlett
2022-03-01 22:50 ` Vasily Gorbik
2022-03-01 22:56 ` Vasily Gorbik
2022-03-02 14:08 ` Liam Howlett
2022-02-15 14:43 ` [PATCH v6 09/71] lib/test_maple_tree: Add testing for maple tree Liam Howlett
2022-02-15 14:43 ` [PATCH v6 10/71] mm: Start tracking VMAs with " Liam Howlett
2022-02-15 14:43 ` [PATCH v6 11/71] mm: Add VMA iterator Liam Howlett
2022-02-16 10:50 ` Mark Hemment
2022-02-16 18:32 ` Liam Howlett
2022-02-15 14:43 ` [PATCH v6 12/71] mmap: Use the VMA iterator in count_vma_pages_range() Liam Howlett
2022-02-15 14:43 ` [PATCH v6 13/71] mm/mmap: Use the maple tree in find_vma() instead of the rbtree Liam Howlett
2022-02-15 14:43 ` [PATCH v6 15/71] mm/mmap: Use maple tree for unmapped_area{_topdown} Liam Howlett
2022-02-15 14:43 ` [PATCH v6 16/71] kernel/fork: Use maple tree for dup_mmap() during forking Liam Howlett
2022-02-15 14:43 ` [PATCH v6 14/71] mm/mmap: Use the maple tree for find_vma_prev() instead of the rbtree Liam Howlett
2022-02-15 14:43 ` [PATCH v6 18/71] proc: Remove VMA rbtree use from nommu Liam Howlett
2022-02-15 14:43 ` [PATCH v6 17/71] damon: Convert __damon_va_three_regions to use the VMA iterator Liam Howlett
2022-02-15 14:43 ` [PATCH v6 19/71] mm: Remove rb tree Liam Howlett
2022-02-15 14:43 ` [PATCH v6 20/71] mmap: Change zeroing of maple tree in __vma_adjust() Liam Howlett
2022-02-15 14:43 ` [PATCH v6 23/71] mm/khugepaged: Optimize collapse_pte_mapped_thp() by using vma_lookup() Liam Howlett
2022-02-15 14:43 ` [PATCH v6 21/71] xen: Use vma_lookup() in privcmd_ioctl_mmap() Liam Howlett
2022-02-15 14:43 ` [PATCH v6 22/71] mm: Optimize find_exact_vma() to use vma_lookup() Liam Howlett
2022-02-15 14:43 ` [PATCH v6 25/71] mm: Use maple tree operations for find_vma_intersection() Liam Howlett
2022-02-15 14:43 ` [PATCH v6 24/71] mm/mmap: Change do_brk_flags() to expand existing VMA and add do_brk_munmap() Liam Howlett
2022-02-15 14:43 ` Liam Howlett [this message]
2022-02-15 14:43 ` [PATCH v6 27/71] mm: Remove vmacache Liam Howlett
2022-02-15 14:43 ` [PATCH v6 28/71] mm: Convert vma_lookup() to use mtree_load() Liam Howlett
2022-02-15 14:43 ` [PATCH v6 29/71] mm/mmap: Move mmap_region() below do_munmap() Liam Howlett
2022-02-15 14:43 ` [PATCH v6 30/71] mm/mmap: Reorganize munmap to use maple states Liam Howlett
2022-02-15 14:43 ` [PATCH v6 31/71] mm/mmap: Change do_brk_munmap() to use do_mas_align_munmap() Liam Howlett
2022-02-15 14:43 ` [PATCH v6 32/71] arm64: Remove mmap linked list from vdso Liam Howlett
2022-02-15 14:43 ` [PATCH v6 35/71] s390: Remove vma linked list walks Liam Howlett
2022-02-15 14:43 ` [PATCH v6 33/71] parisc: Remove mmap linked list from cache handling Liam Howlett
2022-02-15 14:43 ` [PATCH v6 34/71] powerpc: Remove mmap linked list walks Liam Howlett
2022-02-15 14:43 ` [PATCH v6 37/71] xtensa: Remove vma " Liam Howlett
2022-02-15 14:43 ` [PATCH v6 38/71] cxl: Remove vma linked list walk Liam Howlett
2022-02-15 14:43 ` [PATCH v6 36/71] x86: Remove vma linked list walks Liam Howlett
2022-02-15 14:43 ` [PATCH v6 40/71] um: Remove vma linked list walk Liam Howlett
2022-02-15 14:43 ` [PATCH v6 39/71] optee: " Liam Howlett
2022-02-15 14:43 ` [PATCH v6 41/71] binfmt_elf: " Liam Howlett
2022-02-15 14:43 ` [PATCH v6 43/71] exec: Use VMA iterator instead of linked list Liam Howlett
2022-02-15 14:43 ` [PATCH v6 42/71] coredump: Remove vma linked list walk Liam Howlett
2022-02-15 14:43 ` [PATCH v6 45/71] fs/proc/task_mmu: Stop using linked list and highest_vm_end Liam Howlett
2022-02-15 14:43 ` [PATCH v6 44/71] fs/proc/base: Use maple tree iterators in place of linked list Liam Howlett
2022-02-15 14:43 ` [PATCH v6 47/71] ipc/shm: Use VMA iterator instead " Liam Howlett
2022-02-15 14:43 ` [PATCH v6 46/71] userfaultfd: Use maple tree iterator to iterate VMAs Liam Howlett
2022-02-15 14:43 ` [PATCH v6 48/71] acct: Use VMA iterator instead of linked list Liam Howlett
2022-02-15 14:43 ` [PATCH v6 49/71] perf: Use VMA iterator Liam Howlett
2022-02-15 14:43 ` [PATCH v6 50/71] sched: Use maple tree iterator to walk VMAs Liam Howlett
2022-02-15 14:43 ` [PATCH v6 51/71] fork: Use VMA iterator Liam Howlett
2022-02-15 14:43 ` [PATCH v6 52/71] bpf: Remove VMA linked list Liam Howlett
2022-02-15 14:43 ` [PATCH v6 53/71] mm/gup: Use maple tree navigation instead of " Liam Howlett
2022-02-15 14:43 ` [PATCH v6 55/71] mm/ksm: Use vma iterators instead of vma " Liam Howlett
2022-02-15 14:43 ` [PATCH v6 54/71] mm/khugepaged: Stop using " Liam Howlett
2022-02-15 14:43 ` [PATCH v6 57/71] mm/memcontrol: Stop using mm->highest_vm_end Liam Howlett
2022-02-15 14:43 ` [PATCH v6 56/71] mm/madvise: Use vma_find() instead of vma linked list Liam Howlett
2022-02-15 14:43 ` [PATCH v6 58/71] mm/mempolicy: Use vma iterator & maple state " Liam Howlett
2022-02-15 14:43 ` [PATCH v6 61/71] mm/mremap: Use vma_find_intersection() " Liam Howlett
2022-02-15 14:43 ` [PATCH v6 60/71] mm/mprotect: Use maple tree navigation " Liam Howlett
2022-02-15 14:43 ` [PATCH v6 59/71] mm/mlock: Use vma iterator and " Liam Howlett
2022-02-15 14:43 ` [PATCH v6 62/71] mm/msync: Use vma_find() " Liam Howlett
2022-02-15 14:43 ` [PATCH v6 63/71] mm/oom_kill: Use maple tree iterators " Liam Howlett
2022-02-15 14:43 ` [PATCH v6 64/71] mm/pagewalk: Use vma_find() " Liam Howlett
2022-02-15 14:43 ` [PATCH v6 66/71] i915: Use the VMA iterator Liam Howlett
2022-02-15 14:43 ` [PATCH v6 65/71] mm/swapfile: Use vma iterator instead of vma linked list Liam Howlett
2022-02-15 14:43 ` [PATCH v6 68/71] riscv: Use vma iterator for vdso Liam Howlett
2022-02-15 14:43 ` [PATCH v6 69/71] mm: Remove the vma linked list Liam Howlett
2022-02-15 14:43 ` [PATCH v6 67/71] nommu: Remove uses of VMA " Liam Howlett
2022-02-15 14:43 ` [PATCH v6 70/71] mm/mmap: Drop range_has_overlap() function Liam Howlett
2022-02-15 14:43 ` [PATCH v6 71/71] mm/mmap.c: Pass in mapping to __vma_link_file() Liam Howlett
2022-02-16 19:47 ` [PATCH v6 00/71] Introducing the Maple Tree Andrew Morton
2022-02-16 20:24 ` Matthew Wilcox
2022-02-23 16:35 ` Mel Gorman
2022-02-23 16:45 ` Matthew Wilcox
2022-02-25 3:49 ` Qian Cai
2022-02-25 19:08 ` Liam Howlett
2022-02-25 20:23 ` Liam Howlett
2022-02-25 20:46 ` Qian Cai
2022-02-25 23:00 ` Nathan Chancellor
2022-02-26 1:58 ` Liam Howlett
2022-02-26 23:19 ` Hugh Dickins
2022-02-27 18:32 ` Hugh Dickins
2022-02-28 14:26 ` Liam Howlett
2022-02-28 11:56 ` Qian Cai
2022-02-27 2:22 ` Vasily Gorbik
2022-02-28 14:56 ` Liam Howlett
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