* [PATCH 2/3] mm: use get_i_mmap_root to access the file's i_mmap
2026-04-13 6:20 [PATCH 0/3] mm: split the file's i_mmap tree for NUMA Huang Shijie
2026-04-13 6:20 ` [PATCH 1/3] mm: use mapping_mapped to simplify the code Huang Shijie
@ 2026-04-13 6:20 ` Huang Shijie
2026-04-13 6:20 ` [PATCH 3/3] mm: split the file's i_mmap tree for NUMA Huang Shijie
2 siblings, 0 replies; 4+ messages in thread
From: Huang Shijie @ 2026-04-13 6:20 UTC (permalink / raw)
To: akpm, viro, brauner
Cc: linux-mm, linux-kernel, linux-arm-kernel, linux-fsdevel,
muchun.song, osalvador, linux-trace-kernel, linux-perf-users,
linux-parisc, nvdimm, zhongyuan, fangbaoshun, yingzhiwei,
Huang Shijie
Do not access the file's i_mmap directly, use get_i_mmap_root()
to access it. This patch makes preparations for later patches.
Signed-off-by: Huang Shijie <huangsj@hygon.cn>
---
arch/arm/mm/fault-armv.c | 3 ++-
arch/arm/mm/flush.c | 3 ++-
arch/nios2/mm/cacheflush.c | 3 ++-
arch/parisc/kernel/cache.c | 4 +++-
fs/dax.c | 3 ++-
fs/hugetlbfs/inode.c | 6 +++---
include/linux/fs.h | 5 +++++
include/linux/mm.h | 1 +
kernel/events/uprobes.c | 3 ++-
mm/hugetlb.c | 7 +++++--
mm/khugepaged.c | 6 ++++--
mm/memory-failure.c | 8 +++++---
mm/memory.c | 4 ++--
mm/mmap.c | 2 +-
mm/nommu.c | 9 +++++----
mm/pagewalk.c | 2 +-
mm/rmap.c | 2 +-
mm/vma.c | 14 ++++++++------
18 files changed, 54 insertions(+), 31 deletions(-)
diff --git a/arch/arm/mm/fault-armv.c b/arch/arm/mm/fault-armv.c
index 91e488767783..1b5fe151e805 100644
--- a/arch/arm/mm/fault-armv.c
+++ b/arch/arm/mm/fault-armv.c
@@ -126,6 +126,7 @@ make_coherent(struct address_space *mapping, struct vm_area_struct *vma,
{
const unsigned long pmd_start_addr = ALIGN_DOWN(addr, PMD_SIZE);
const unsigned long pmd_end_addr = pmd_start_addr + PMD_SIZE;
+ struct rb_root_cached *root = get_i_mmap_root(mapping);
struct mm_struct *mm = vma->vm_mm;
struct vm_area_struct *mpnt;
unsigned long offset;
@@ -140,7 +141,7 @@ make_coherent(struct address_space *mapping, struct vm_area_struct *vma,
* cache coherency.
*/
flush_dcache_mmap_lock(mapping);
- vma_interval_tree_foreach(mpnt, &mapping->i_mmap, pgoff, pgoff) {
+ vma_interval_tree_foreach(mpnt, root, pgoff, pgoff) {
/*
* If we are using split PTE locks, then we need to take the pte
* lock. Otherwise we are using shared mm->page_table_lock which
diff --git a/arch/arm/mm/flush.c b/arch/arm/mm/flush.c
index 19470d938b23..b9641901f206 100644
--- a/arch/arm/mm/flush.c
+++ b/arch/arm/mm/flush.c
@@ -238,6 +238,7 @@ void __flush_dcache_folio(struct address_space *mapping, struct folio *folio)
static void __flush_dcache_aliases(struct address_space *mapping, struct folio *folio)
{
struct mm_struct *mm = current->active_mm;
+ struct rb_root_cached *root = get_i_mmap_root(mapping);
struct vm_area_struct *vma;
pgoff_t pgoff, pgoff_end;
@@ -251,7 +252,7 @@ static void __flush_dcache_aliases(struct address_space *mapping, struct folio *
pgoff_end = pgoff + folio_nr_pages(folio) - 1;
flush_dcache_mmap_lock(mapping);
- vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, pgoff_end) {
+ vma_interval_tree_foreach(vma, root, pgoff, pgoff_end) {
unsigned long start, offset, pfn;
unsigned int nr;
diff --git a/arch/nios2/mm/cacheflush.c b/arch/nios2/mm/cacheflush.c
index 8321182eb927..ab6e064fabe2 100644
--- a/arch/nios2/mm/cacheflush.c
+++ b/arch/nios2/mm/cacheflush.c
@@ -78,11 +78,12 @@ static void flush_aliases(struct address_space *mapping, struct folio *folio)
unsigned long flags;
pgoff_t pgoff;
unsigned long nr = folio_nr_pages(folio);
+ struct rb_root_cached *root = get_i_mmap_root(mapping);
pgoff = folio->index;
flush_dcache_mmap_lock_irqsave(mapping, flags);
- vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, pgoff + nr - 1) {
+ vma_interval_tree_foreach(vma, root, pgoff, pgoff + nr - 1) {
unsigned long start;
if (vma->vm_mm != mm)
diff --git a/arch/parisc/kernel/cache.c b/arch/parisc/kernel/cache.c
index 4c5240d3a3c7..920adacaaac2 100644
--- a/arch/parisc/kernel/cache.c
+++ b/arch/parisc/kernel/cache.c
@@ -473,6 +473,7 @@ static inline unsigned long get_upa(struct mm_struct *mm, unsigned long addr)
void flush_dcache_folio(struct folio *folio)
{
struct address_space *mapping = folio_flush_mapping(folio);
+ struct rb_root_cached *root;
struct vm_area_struct *vma;
unsigned long addr, old_addr = 0;
void *kaddr;
@@ -494,6 +495,7 @@ void flush_dcache_folio(struct folio *folio)
return;
pgoff = folio->index;
+ root = get_i_mmap_root(mapping);
/*
* We have carefully arranged in arch_get_unmapped_area() that
@@ -503,7 +505,7 @@ void flush_dcache_folio(struct folio *folio)
* on machines that support equivalent aliasing
*/
flush_dcache_mmap_lock_irqsave(mapping, flags);
- vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, pgoff + nr - 1) {
+ vma_interval_tree_foreach(vma, root, pgoff, pgoff + nr - 1) {
unsigned long offset = pgoff - vma->vm_pgoff;
unsigned long pfn = folio_pfn(folio);
diff --git a/fs/dax.c b/fs/dax.c
index 289e6254aa30..00fe5481accc 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -1101,6 +1101,7 @@ static int dax_writeback_one(struct xa_state *xas, struct dax_device *dax_dev,
struct address_space *mapping, void *entry)
{
unsigned long pfn, index, count, end;
+ struct rb_root_cached *root = get_i_mmap_root(mapping);
long ret = 0;
struct vm_area_struct *vma;
@@ -1164,7 +1165,7 @@ static int dax_writeback_one(struct xa_state *xas, struct dax_device *dax_dev,
/* Walk all mappings of a given index of a file and writeprotect them */
i_mmap_lock_read(mapping);
- vma_interval_tree_foreach(vma, &mapping->i_mmap, index, end) {
+ vma_interval_tree_foreach(vma, root, index, end) {
pfn_mkclean_range(pfn, count, index, vma);
cond_resched();
}
diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
index ab5ac092d8a6..9cf82fba6eb6 100644
--- a/fs/hugetlbfs/inode.c
+++ b/fs/hugetlbfs/inode.c
@@ -400,7 +400,7 @@ static void hugetlb_unmap_file_folio(struct hstate *h,
struct address_space *mapping,
struct folio *folio, pgoff_t index)
{
- struct rb_root_cached *root = &mapping->i_mmap;
+ struct rb_root_cached *root = get_i_mmap_root(mapping);
struct hugetlb_vma_lock *vma_lock;
unsigned long pfn = folio_pfn(folio);
struct vm_area_struct *vma;
@@ -647,7 +647,7 @@ static void hugetlb_vmtruncate(struct inode *inode, loff_t offset)
i_size_write(inode, offset);
i_mmap_lock_write(mapping);
if (mapping_mapped(mapping))
- hugetlb_vmdelete_list(&mapping->i_mmap, pgoff, 0,
+ hugetlb_vmdelete_list(get_i_mmap_root(mapping), pgoff, 0,
ZAP_FLAG_DROP_MARKER);
i_mmap_unlock_write(mapping);
remove_inode_hugepages(inode, offset, LLONG_MAX);
@@ -708,7 +708,7 @@ static long hugetlbfs_punch_hole(struct inode *inode, loff_t offset, loff_t len)
/* Unmap users of full pages in the hole. */
if (hole_end > hole_start) {
if (mapping_mapped(mapping))
- hugetlb_vmdelete_list(&mapping->i_mmap,
+ hugetlb_vmdelete_list(get_i_mmap_root(mapping),
hole_start >> PAGE_SHIFT,
hole_end >> PAGE_SHIFT, 0);
}
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 8b3dd145b25e..a6a99e044265 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -555,6 +555,11 @@ static inline int mapping_mapped(const struct address_space *mapping)
return !RB_EMPTY_ROOT(&mapping->i_mmap.rb_root);
}
+static inline struct rb_root_cached *get_i_mmap_root(struct address_space *mapping)
+{
+ return &mapping->i_mmap;
+}
+
/*
* Might pages of this file have been modified in userspace?
* Note that i_mmap_writable counts all VM_SHARED, VM_MAYWRITE vmas: do_mmap
diff --git a/include/linux/mm.h b/include/linux/mm.h
index abb4963c1f06..15cb1da43eb2 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -3797,6 +3797,7 @@ struct vm_area_struct *vma_interval_tree_iter_first(struct rb_root_cached *root,
struct vm_area_struct *vma_interval_tree_iter_next(struct vm_area_struct *node,
unsigned long start, unsigned long last);
+/* Please use get_i_mmap_root() to get the @root */
#define vma_interval_tree_foreach(vma, root, start, last) \
for (vma = vma_interval_tree_iter_first(root, start, last); \
vma; vma = vma_interval_tree_iter_next(vma, start, last))
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index 923b24b321cc..420035b0cc7b 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -1201,6 +1201,7 @@ static inline struct map_info *free_map_info(struct map_info *info)
static struct map_info *
build_map_info(struct address_space *mapping, loff_t offset, bool is_register)
{
+ struct rb_root_cached *root = get_i_mmap_root(mapping);
unsigned long pgoff = offset >> PAGE_SHIFT;
struct vm_area_struct *vma;
struct map_info *curr = NULL;
@@ -1210,7 +1211,7 @@ build_map_info(struct address_space *mapping, loff_t offset, bool is_register)
again:
i_mmap_lock_read(mapping);
- vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, pgoff) {
+ vma_interval_tree_foreach(vma, root, pgoff, pgoff) {
if (!valid_vma(vma, is_register))
continue;
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 327eaa4074d3..8d27f1b8abb5 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -5396,6 +5396,7 @@ static void unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma,
struct hstate *h = hstate_vma(vma);
struct vm_area_struct *iter_vma;
struct address_space *mapping;
+ struct rb_root_cached *root;
pgoff_t pgoff;
/*
@@ -5406,6 +5407,7 @@ static void unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma,
pgoff = ((address - vma->vm_start) >> PAGE_SHIFT) +
vma->vm_pgoff;
mapping = vma->vm_file->f_mapping;
+ root = get_i_mmap_root(mapping);
/*
* Take the mapping lock for the duration of the table walk. As
@@ -5413,7 +5415,7 @@ static void unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma,
* __unmap_hugepage_range() is called as the lock is already held
*/
i_mmap_lock_write(mapping);
- vma_interval_tree_foreach(iter_vma, &mapping->i_mmap, pgoff, pgoff) {
+ vma_interval_tree_foreach(iter_vma, root, pgoff, pgoff) {
/* Do not unmap the current VMA */
if (iter_vma == vma)
continue;
@@ -6879,6 +6881,7 @@ pte_t *huge_pmd_share(struct mm_struct *mm, struct vm_area_struct *vma,
unsigned long addr, pud_t *pud)
{
struct address_space *mapping = vma->vm_file->f_mapping;
+ struct rb_root_cached *root = get_i_mmap_root(mapping);
pgoff_t idx = ((addr - vma->vm_start) >> PAGE_SHIFT) +
vma->vm_pgoff;
struct vm_area_struct *svma;
@@ -6887,7 +6890,7 @@ pte_t *huge_pmd_share(struct mm_struct *mm, struct vm_area_struct *vma,
pte_t *pte;
i_mmap_lock_read(mapping);
- vma_interval_tree_foreach(svma, &mapping->i_mmap, idx, idx) {
+ vma_interval_tree_foreach(svma, root, idx, idx) {
if (svma == vma)
continue;
diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index 1dd3cfca610d..3a4e81474fe3 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -1740,10 +1740,11 @@ static bool file_backed_vma_is_retractable(struct vm_area_struct *vma)
static void retract_page_tables(struct address_space *mapping, pgoff_t pgoff)
{
+ struct rb_root_cached *root = get_i_mmap_root(mapping);
struct vm_area_struct *vma;
i_mmap_lock_read(mapping);
- vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, pgoff) {
+ vma_interval_tree_foreach(vma, root, pgoff, pgoff) {
struct mmu_notifier_range range;
struct mm_struct *mm;
unsigned long addr;
@@ -2163,7 +2164,8 @@ static enum scan_result collapse_file(struct mm_struct *mm, unsigned long addr,
* not be able to observe any missing pages due to the
* previously inserted retry entries.
*/
- vma_interval_tree_foreach(vma, &mapping->i_mmap, start, end) {
+ vma_interval_tree_foreach(vma, get_i_mmap_root(mapping),
+ start, end) {
if (userfaultfd_missing(vma)) {
result = SCAN_EXCEED_NONE_PTE;
goto immap_locked;
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index ee42d4361309..85196d9bb26c 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -598,7 +598,7 @@ static void collect_procs_file(const struct folio *folio,
if (!t)
continue;
- vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff,
+ vma_interval_tree_foreach(vma, get_i_mmap_root(mapping), pgoff,
pgoff) {
/*
* Send early kill signal to tasks where a vma covers
@@ -650,7 +650,8 @@ static void collect_procs_fsdax(const struct page *page,
t = task_early_kill(tsk, true);
if (!t)
continue;
- vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, pgoff) {
+ vma_interval_tree_foreach(vma, get_i_mmap_root(mapping), pgoff,
+ pgoff) {
if (vma->vm_mm == t->mm)
add_to_kill_fsdax(t, page, vma, to_kill, pgoff);
}
@@ -2251,7 +2252,8 @@ static void collect_procs_pfn(struct pfn_address_space *pfn_space,
t = task_early_kill(tsk, true);
if (!t)
continue;
- vma_interval_tree_foreach(vma, &mapping->i_mmap, 0, ULONG_MAX) {
+ vma_interval_tree_foreach(vma, get_i_mmap_root(mapping),
+ 0, ULONG_MAX) {
pgoff_t pgoff;
if (vma->vm_mm == t->mm &&
diff --git a/mm/memory.c b/mm/memory.c
index 366054435773..1ddd6b55fe7e 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -4298,7 +4298,7 @@ void unmap_mapping_folio(struct folio *folio)
i_mmap_lock_read(mapping);
if (unlikely(mapping_mapped(mapping)))
- unmap_mapping_range_tree(&mapping->i_mmap, first_index,
+ unmap_mapping_range_tree(get_i_mmap_root(mapping), first_index,
last_index, &details);
i_mmap_unlock_read(mapping);
}
@@ -4328,7 +4328,7 @@ void unmap_mapping_pages(struct address_space *mapping, pgoff_t start,
i_mmap_lock_read(mapping);
if (unlikely(mapping_mapped(mapping)))
- unmap_mapping_range_tree(&mapping->i_mmap, first_index,
+ unmap_mapping_range_tree(get_i_mmap_root(mapping), first_index,
last_index, &details);
i_mmap_unlock_read(mapping);
}
diff --git a/mm/mmap.c b/mm/mmap.c
index 843160946aa5..5b0671dff019 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1832,7 +1832,7 @@ __latent_entropy int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm)
flush_dcache_mmap_lock(mapping);
/* insert tmp into the share list, just after mpnt */
vma_interval_tree_insert_after(tmp, mpnt,
- &mapping->i_mmap);
+ get_i_mmap_root(mapping));
flush_dcache_mmap_unlock(mapping);
i_mmap_unlock_write(mapping);
}
diff --git a/mm/nommu.c b/mm/nommu.c
index c3a23b082adb..2e64b6c4c539 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -569,7 +569,7 @@ static void setup_vma_to_mm(struct vm_area_struct *vma, struct mm_struct *mm)
i_mmap_lock_write(mapping);
flush_dcache_mmap_lock(mapping);
- vma_interval_tree_insert(vma, &mapping->i_mmap);
+ vma_interval_tree_insert(vma, get_i_mmap_root(mapping));
flush_dcache_mmap_unlock(mapping);
i_mmap_unlock_write(mapping);
}
@@ -585,7 +585,7 @@ static void cleanup_vma_from_mm(struct vm_area_struct *vma)
i_mmap_lock_write(mapping);
flush_dcache_mmap_lock(mapping);
- vma_interval_tree_remove(vma, &mapping->i_mmap);
+ vma_interval_tree_remove(vma, get_i_mmap_root(mapping));
flush_dcache_mmap_unlock(mapping);
i_mmap_unlock_write(mapping);
}
@@ -1804,6 +1804,7 @@ EXPORT_SYMBOL_GPL(copy_remote_vm_str);
int nommu_shrink_inode_mappings(struct inode *inode, size_t size,
size_t newsize)
{
+ struct rb_root_cached *root = get_i_mmap_root(&inode->mapping);
struct vm_area_struct *vma;
struct vm_region *region;
pgoff_t low, high;
@@ -1816,7 +1817,7 @@ int nommu_shrink_inode_mappings(struct inode *inode, size_t size,
i_mmap_lock_read(inode->i_mapping);
/* search for VMAs that fall within the dead zone */
- vma_interval_tree_foreach(vma, &inode->i_mapping->i_mmap, low, high) {
+ vma_interval_tree_foreach(vma, root, low, high) {
/* found one - only interested if it's shared out of the page
* cache */
if (vma->vm_flags & VM_SHARED) {
@@ -1832,7 +1833,7 @@ int nommu_shrink_inode_mappings(struct inode *inode, size_t size,
* we don't check for any regions that start beyond the EOF as there
* shouldn't be any
*/
- vma_interval_tree_foreach(vma, &inode->i_mapping->i_mmap, 0, ULONG_MAX) {
+ vma_interval_tree_foreach(vma, root, 0, ULONG_MAX) {
if (!(vma->vm_flags & VM_SHARED))
continue;
diff --git a/mm/pagewalk.c b/mm/pagewalk.c
index a94c401ab2cf..c6c1c45df575 100644
--- a/mm/pagewalk.c
+++ b/mm/pagewalk.c
@@ -792,7 +792,7 @@ int walk_page_mapping(struct address_space *mapping, pgoff_t first_index,
return -EINVAL;
lockdep_assert_held(&mapping->i_mmap_rwsem);
- vma_interval_tree_foreach(vma, &mapping->i_mmap, first_index,
+ vma_interval_tree_foreach(vma, get_i_mmap_root(mapping), first_index,
first_index + nr - 1) {
/* Clip to the vma */
vba = vma->vm_pgoff;
diff --git a/mm/rmap.c b/mm/rmap.c
index 391337282e3f..52288d39d8a2 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -3036,7 +3036,7 @@ static void __rmap_walk_file(struct folio *folio, struct address_space *mapping,
i_mmap_lock_read(mapping);
}
lookup:
- vma_interval_tree_foreach(vma, &mapping->i_mmap,
+ vma_interval_tree_foreach(vma, get_i_mmap_root(mapping),
pgoff_start, pgoff_end) {
unsigned long address = vma_address(vma, pgoff_start, nr_pages);
diff --git a/mm/vma.c b/mm/vma.c
index be64f781a3aa..1768e4355a13 100644
--- a/mm/vma.c
+++ b/mm/vma.c
@@ -231,7 +231,7 @@ static void __vma_link_file(struct vm_area_struct *vma,
mapping_allow_writable(mapping);
flush_dcache_mmap_lock(mapping);
- vma_interval_tree_insert(vma, &mapping->i_mmap);
+ vma_interval_tree_insert(vma, get_i_mmap_root(mapping));
flush_dcache_mmap_unlock(mapping);
}
@@ -245,7 +245,7 @@ static void __remove_shared_vm_struct(struct vm_area_struct *vma,
mapping_unmap_writable(mapping);
flush_dcache_mmap_lock(mapping);
- vma_interval_tree_remove(vma, &mapping->i_mmap);
+ vma_interval_tree_remove(vma, get_i_mmap_root(mapping));
flush_dcache_mmap_unlock(mapping);
}
@@ -316,10 +316,11 @@ static void vma_prepare(struct vma_prepare *vp)
if (vp->file) {
flush_dcache_mmap_lock(vp->mapping);
- vma_interval_tree_remove(vp->vma, &vp->mapping->i_mmap);
+ vma_interval_tree_remove(vp->vma,
+ get_i_mmap_root(vp->mapping));
if (vp->adj_next)
vma_interval_tree_remove(vp->adj_next,
- &vp->mapping->i_mmap);
+ get_i_mmap_root(vp->mapping));
}
}
@@ -338,8 +339,9 @@ static void vma_complete(struct vma_prepare *vp, struct vma_iterator *vmi,
if (vp->file) {
if (vp->adj_next)
vma_interval_tree_insert(vp->adj_next,
- &vp->mapping->i_mmap);
- vma_interval_tree_insert(vp->vma, &vp->mapping->i_mmap);
+ get_i_mmap_root(vp->mapping));
+ vma_interval_tree_insert(vp->vma,
+ get_i_mmap_root(vp->mapping));
flush_dcache_mmap_unlock(vp->mapping);
}
--
2.43.0
^ permalink raw reply [flat|nested] 4+ messages in thread* [PATCH 3/3] mm: split the file's i_mmap tree for NUMA
2026-04-13 6:20 [PATCH 0/3] mm: split the file's i_mmap tree for NUMA Huang Shijie
2026-04-13 6:20 ` [PATCH 1/3] mm: use mapping_mapped to simplify the code Huang Shijie
2026-04-13 6:20 ` [PATCH 2/3] mm: use get_i_mmap_root to access the file's i_mmap Huang Shijie
@ 2026-04-13 6:20 ` Huang Shijie
2 siblings, 0 replies; 4+ messages in thread
From: Huang Shijie @ 2026-04-13 6:20 UTC (permalink / raw)
To: akpm, viro, brauner
Cc: linux-mm, linux-kernel, linux-arm-kernel, linux-fsdevel,
muchun.song, osalvador, linux-trace-kernel, linux-perf-users,
linux-parisc, nvdimm, zhongyuan, fangbaoshun, yingzhiwei,
Huang Shijie
In NUMA, there are maybe many NUMA nodes and many CPUs.
For example, a Hygon's server has 12 NUMA nodes, and 384 CPUs.
In the UnixBench tests, there is a test "execl" which tests
the execve system call.
When we test our server with "./Run -c 384 execl",
the test result is not good enough. The i_mmap locks contended heavily on
"libc.so" and "ld.so". For example, the i_mmap tree for "libc.so" can have
over 6000 VMAs, all the VMAs can be in different NUMA mode.
The insert/remove operations do not run quickly enough.
In order to reduce the competition of the i_mmap lock, this patch does
following:
1.) Split the single i_mmap tree into several sibling trees:
Each NUMA node has a tree.
2.) Introduce a new field "tree_idx" for vm_area_struct to save the
sibling tree index for this VMA.
3.) Introduce a new field "vma_count" for address_space.
The new mapping_mapped() will use it.
4.) Rewrite the vma_interval_tree_foreach() for NUMA.
After this patch, the VMA insert/remove operations will work faster,
and we can get 77% (10 times average) performance improvement
with the above test.
Signed-off-by: Huang Shijie <huangsj@hygon.cn>
---
fs/inode.c | 55 +++++++++++++++++++++++++++++++++++++++-
include/linux/fs.h | 35 +++++++++++++++++++++++++
include/linux/mm.h | 32 +++++++++++++++++++++++
include/linux/mm_types.h | 1 +
mm/mmap.c | 3 ++-
mm/nommu.c | 6 +++--
mm/vma.c | 34 +++++++++++++++++++------
mm/vma_init.c | 1 +
8 files changed, 155 insertions(+), 12 deletions(-)
diff --git a/fs/inode.c b/fs/inode.c
index cc12b68e021b..3067cb2558da 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -215,6 +215,56 @@ static int no_open(struct inode *inode, struct file *file)
return -ENXIO;
}
+#ifdef CONFIG_NUMA
+static void free_mapping_i_mmap(struct address_space *mapping)
+{
+ int i;
+
+ if (!mapping->i_mmap)
+ return;
+
+ for (i = 0; i < nr_node_ids; i++)
+ kfree(mapping->i_mmap[i]);
+
+ kfree(mapping->i_mmap);
+ mapping->i_mmap = NULL;
+}
+
+static int init_mapping_i_mmap(struct address_space *mapping)
+{
+ struct rb_root_cached *root;
+ int i;
+
+ /* The extra one is used as terminator in vma_interval_tree_foreach() */
+ mapping->i_mmap = kzalloc(sizeof(root) * (nr_node_ids + 1), GFP_KERNEL);
+ if (!mapping->i_mmap)
+ return -ENOMEM;
+
+ for (i = 0; i < nr_node_ids; i++) {
+ root = kzalloc_node(sizeof(*root), GFP_KERNEL, i);
+ if (!root)
+ goto no_mem;
+
+ *root = RB_ROOT_CACHED;
+ mapping->i_mmap[i] = root;
+ }
+ return 0;
+
+no_mem:
+ free_mapping_i_mmap(mapping);
+ return -ENOMEM;
+}
+#else
+static int init_mapping_i_mmap(struct address_space *mapping)
+{
+ mapping->i_mmap = RB_ROOT_CACHED;
+ return 0;
+}
+static void free_mapping_i_mmap(struct address_space *mapping)
+{
+}
+#endif
+
/**
* inode_init_always_gfp - perform inode structure initialisation
* @sb: superblock inode belongs to
@@ -307,6 +357,9 @@ int inode_init_always_gfp(struct super_block *sb, struct inode *inode, gfp_t gfp
if (unlikely(security_inode_alloc(inode, gfp)))
return -ENOMEM;
+ if (init_mapping_i_mmap(mapping))
+ return -ENOMEM;
+
this_cpu_inc(nr_inodes);
return 0;
@@ -383,6 +436,7 @@ void __destroy_inode(struct inode *inode)
if (inode->i_default_acl && !is_uncached_acl(inode->i_default_acl))
posix_acl_release(inode->i_default_acl);
#endif
+ free_mapping_i_mmap(&inode->i_data);
this_cpu_dec(nr_inodes);
}
EXPORT_SYMBOL(__destroy_inode);
@@ -486,7 +540,6 @@ static void __address_space_init_once(struct address_space *mapping)
init_rwsem(&mapping->i_mmap_rwsem);
INIT_LIST_HEAD(&mapping->i_private_list);
spin_lock_init(&mapping->i_private_lock);
- mapping->i_mmap = RB_ROOT_CACHED;
}
void address_space_init_once(struct address_space *mapping)
diff --git a/include/linux/fs.h b/include/linux/fs.h
index a6a99e044265..34064c1cbd10 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -477,7 +477,12 @@ struct address_space {
/* number of thp, only for non-shmem files */
atomic_t nr_thps;
#endif
+#ifdef CONFIG_NUMA
+ struct rb_root_cached **i_mmap;
+ unsigned long vma_count;
+#else
struct rb_root_cached i_mmap;
+#endif
unsigned long nrpages;
pgoff_t writeback_index;
const struct address_space_operations *a_ops;
@@ -547,6 +552,27 @@ static inline void i_mmap_assert_write_locked(struct address_space *mapping)
lockdep_assert_held_write(&mapping->i_mmap_rwsem);
}
+#ifdef CONFIG_NUMA
+static inline int mapping_mapped(const struct address_space *mapping)
+{
+ return READ_ONCE(mapping->vma_count);
+}
+
+static inline void inc_mapping_vma(struct address_space *mapping)
+{
+ mapping->vma_count++;
+}
+
+static inline void dec_mapping_vma(struct address_space *mapping)
+{
+ mapping->vma_count--;
+}
+
+static inline struct rb_root_cached *get_i_mmap_root(struct address_space *mapping)
+{
+ return (struct rb_root_cached *)mapping->i_mmap;
+}
+#else
/*
* Might pages of this file be mapped into userspace?
*/
@@ -555,10 +581,19 @@ static inline int mapping_mapped(const struct address_space *mapping)
return !RB_EMPTY_ROOT(&mapping->i_mmap.rb_root);
}
+static inline void inc_mapping_vma(struct address_space *mapping)
+{
+}
+
+static inline void dec_mapping_vma(struct address_space *mapping)
+{
+}
+
static inline struct rb_root_cached *get_i_mmap_root(struct address_space *mapping)
{
return &mapping->i_mmap;
}
+#endif
/*
* Might pages of this file have been modified in userspace?
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 15cb1da43eb2..c7f26eb34322 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -913,6 +913,9 @@ static inline void vma_init(struct vm_area_struct *vma, struct mm_struct *mm)
vma->vm_ops = &vma_dummy_vm_ops;
INIT_LIST_HEAD(&vma->anon_vma_chain);
vma_lock_init(vma, false);
+#ifdef CONFIG_NUMA
+ vma->tree_idx = numa_node_id();
+#endif
}
/* Use when VMA is not part of the VMA tree and needs no locking */
@@ -3783,6 +3786,8 @@ extern atomic_long_t mmap_pages_allocated;
extern int nommu_shrink_inode_mappings(struct inode *, size_t, size_t);
/* interval_tree.c */
+struct rb_root_cached *get_rb_root(struct vm_area_struct *vma,
+ struct address_space *mapping);
void vma_interval_tree_insert(struct vm_area_struct *node,
struct rb_root_cached *root);
void vma_interval_tree_insert_after(struct vm_area_struct *node,
@@ -3798,9 +3803,36 @@ struct vm_area_struct *vma_interval_tree_iter_next(struct vm_area_struct *node,
unsigned long start, unsigned long last);
/* Please use get_i_mmap_root() to get the @root */
+#ifdef CONFIG_NUMA
+/* Find the first valid VMA in the sibling trees */
+static inline struct vm_area_struct *first_vma(struct rb_root_cached ***__r,
+ unsigned long start, unsigned long last)
+{
+ struct vm_area_struct *vma = NULL;
+ struct rb_root_cached **tree = *__r;
+
+ while (*tree) {
+ vma = vma_interval_tree_iter_first(*tree++, start, last);
+ if (vma)
+ break;
+ }
+
+ /* Save for the next loop */
+ *__r = tree;
+ return vma;
+}
+
+/* @_tmp is referenced to avoid unused variable warning. */
+#define vma_interval_tree_foreach(vma, root, start, last) \
+ for (struct rb_root_cached **_r = (void *)(root), \
+ **_tmp = (vma = first_vma(&_r, start, last)) ? _r : NULL;\
+ ((_tmp && vma) || (vma = first_vma(&_r, start, last))); \
+ vma = vma_interval_tree_iter_next(vma, start, last))
+#else
#define vma_interval_tree_foreach(vma, root, start, last) \
for (vma = vma_interval_tree_iter_first(root, start, last); \
vma; vma = vma_interval_tree_iter_next(vma, start, last))
+#endif
void anon_vma_interval_tree_insert(struct anon_vma_chain *node,
struct rb_root_cached *root);
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 3cc8ae722886..4982e20ce27c 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -984,6 +984,7 @@ struct vm_area_struct {
#endif
#ifdef CONFIG_NUMA
struct mempolicy *vm_policy; /* NUMA policy for the VMA */
+ int tree_idx; /* The sibling tree index for the VMA */
#endif
#ifdef CONFIG_NUMA_BALANCING
struct vma_numab_state *numab_state; /* NUMA Balancing state */
diff --git a/mm/mmap.c b/mm/mmap.c
index 5b0671dff019..81a2f4932ca8 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1832,8 +1832,9 @@ __latent_entropy int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm)
flush_dcache_mmap_lock(mapping);
/* insert tmp into the share list, just after mpnt */
vma_interval_tree_insert_after(tmp, mpnt,
- get_i_mmap_root(mapping));
+ get_rb_root(mpnt, mapping));
flush_dcache_mmap_unlock(mapping);
+ inc_mapping_vma(mapping);
i_mmap_unlock_write(mapping);
}
diff --git a/mm/nommu.c b/mm/nommu.c
index 2e64b6c4c539..6553cfcb6683 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -569,8 +569,9 @@ static void setup_vma_to_mm(struct vm_area_struct *vma, struct mm_struct *mm)
i_mmap_lock_write(mapping);
flush_dcache_mmap_lock(mapping);
- vma_interval_tree_insert(vma, get_i_mmap_root(mapping));
+ vma_interval_tree_insert(vma, get_rb_root(vma, mapping));
flush_dcache_mmap_unlock(mapping);
+ inc_mapping_vma(mapping);
i_mmap_unlock_write(mapping);
}
}
@@ -585,8 +586,9 @@ static void cleanup_vma_from_mm(struct vm_area_struct *vma)
i_mmap_lock_write(mapping);
flush_dcache_mmap_lock(mapping);
- vma_interval_tree_remove(vma, get_i_mmap_root(mapping));
+ vma_interval_tree_remove(vma, get_rb_root(vma, mapping));
flush_dcache_mmap_unlock(mapping);
+ dec_mapping_vma(mapping);
i_mmap_unlock_write(mapping);
}
}
diff --git a/mm/vma.c b/mm/vma.c
index 1768e4355a13..5aa3915d183b 100644
--- a/mm/vma.c
+++ b/mm/vma.c
@@ -224,6 +224,16 @@ static bool can_vma_merge_after(struct vma_merge_struct *vmg)
return false;
}
+struct rb_root_cached *get_rb_root(struct vm_area_struct *vma,
+ struct address_space *mapping)
+{
+#ifdef CONFIG_NUMA
+ return mapping->i_mmap[vma->tree_idx];
+#else
+ return &mapping->i_mmap;
+#endif
+}
+
static void __vma_link_file(struct vm_area_struct *vma,
struct address_space *mapping)
{
@@ -231,8 +241,9 @@ static void __vma_link_file(struct vm_area_struct *vma,
mapping_allow_writable(mapping);
flush_dcache_mmap_lock(mapping);
- vma_interval_tree_insert(vma, get_i_mmap_root(mapping));
+ vma_interval_tree_insert(vma, get_rb_root(vma, mapping));
flush_dcache_mmap_unlock(mapping);
+ inc_mapping_vma(mapping);
}
/*
@@ -245,8 +256,9 @@ static void __remove_shared_vm_struct(struct vm_area_struct *vma,
mapping_unmap_writable(mapping);
flush_dcache_mmap_lock(mapping);
- vma_interval_tree_remove(vma, get_i_mmap_root(mapping));
+ vma_interval_tree_remove(vma, get_rb_root(vma, mapping));
flush_dcache_mmap_unlock(mapping);
+ dec_mapping_vma(mapping);
}
/*
@@ -317,10 +329,13 @@ static void vma_prepare(struct vma_prepare *vp)
if (vp->file) {
flush_dcache_mmap_lock(vp->mapping);
vma_interval_tree_remove(vp->vma,
- get_i_mmap_root(vp->mapping));
- if (vp->adj_next)
+ get_rb_root(vp->vma, vp->mapping));
+ dec_mapping_vma(vp->mapping);
+ if (vp->adj_next) {
vma_interval_tree_remove(vp->adj_next,
- get_i_mmap_root(vp->mapping));
+ get_rb_root(vp->adj_next, vp->mapping));
+ dec_mapping_vma(vp->mapping);
+ }
}
}
@@ -337,11 +352,14 @@ static void vma_complete(struct vma_prepare *vp, struct vma_iterator *vmi,
struct mm_struct *mm)
{
if (vp->file) {
- if (vp->adj_next)
+ if (vp->adj_next) {
vma_interval_tree_insert(vp->adj_next,
- get_i_mmap_root(vp->mapping));
+ get_rb_root(vp->adj_next, vp->mapping));
+ inc_mapping_vma(vp->mapping);
+ }
vma_interval_tree_insert(vp->vma,
- get_i_mmap_root(vp->mapping));
+ get_rb_root(vp->vma, vp->mapping));
+ inc_mapping_vma(vp->mapping);
flush_dcache_mmap_unlock(vp->mapping);
}
diff --git a/mm/vma_init.c b/mm/vma_init.c
index 3c0b65950510..5735868b1ad4 100644
--- a/mm/vma_init.c
+++ b/mm/vma_init.c
@@ -71,6 +71,7 @@ static void vm_area_init_from(const struct vm_area_struct *src,
#endif
#ifdef CONFIG_NUMA
dest->vm_policy = src->vm_policy;
+ dest->tree_idx = src->tree_idx;
#endif
#ifdef __HAVE_PFNMAP_TRACKING
dest->pfnmap_track_ctx = NULL;
--
2.43.0
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