The patch titled
Subject: XArray: Set the marks correctly when splitting an entry
has been added to the -mm mm-hotfixes-unstable branch. Its filename is
xarray-set-the-marks-correctly-when-splitting-an-entry.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/xarray-set-the-marks-correctly-when-splitting-an-entry.patch
This patch will later appear in the mm-hotfixes-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx>
Subject: XArray: Set the marks correctly when splitting an entry
Date: Wed, 1 May 2024 16:31:18 +0100
If we created a new node to replace an entry which had search marks set,
we were setting the search mark on every entry in that node. That works
fine when we're splitting to order 0, but when splitting to a larger
order, we must not set the search marks on the sibling entries.
Link: https://lkml.kernel.org/r/20240501153120.4094530-1-willy@xxxxxxxxxxxxx
Fixes: c010d47f107f ("mm: thp: split huge page to any lower order pages")
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Reported-by: Luis Chamberlain <mcgrof@xxxxxxxxxx>
Link: https://lore.kernel.org/r/ZjFGCOYk3FK_zVy3@xxxxxxxxxxxxxxxxxxxxxx
Tested-by: Luis Chamberlain <mcgrof@xxxxxxxxxx>
Cc: Zi Yan <ziy@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
lib/test_xarray.c | 14 +++++++++++++-
lib/xarray.c | 23 +++++++++++++++++++----
2 files changed, 32 insertions(+), 5 deletions(-)
--- a/lib/test_xarray.c~xarray-set-the-marks-correctly-when-splitting-an-entry
+++ a/lib/test_xarray.c
@@ -1788,9 +1788,11 @@ static void check_split_1(struct xarray
unsigned int order, unsigned int new_order)
{
XA_STATE_ORDER(xas, xa, index, new_order);
- unsigned int i;
+ unsigned int i, found;
+ void *entry;
xa_store_order(xa, index, order, xa, GFP_KERNEL);
+ xa_set_mark(xa, index, XA_MARK_1);
xas_split_alloc(&xas, xa, order, GFP_KERNEL);
xas_lock(&xas);
@@ -1807,6 +1809,16 @@ static void check_split_1(struct xarray
xa_set_mark(xa, index, XA_MARK_0);
XA_BUG_ON(xa, !xa_get_mark(xa, index, XA_MARK_0));
+ xas_set_order(&xas, index, 0);
+ found = 0;
+ rcu_read_lock();
+ xas_for_each_marked(&xas, entry, ULONG_MAX, XA_MARK_1) {
+ found++;
+ XA_BUG_ON(xa, xa_is_internal(entry));
+ }
+ rcu_read_unlock();
+ XA_BUG_ON(xa, found != 1 << (order - new_order));
+
xa_destroy(xa);
}
--- a/lib/xarray.c~xarray-set-the-marks-correctly-when-splitting-an-entry
+++ a/lib/xarray.c
@@ -969,8 +969,22 @@ static unsigned int node_get_marks(struc
return marks;
}
+static inline void node_mark_slots(struct xa_node *node, unsigned int sibs,
+ xa_mark_t mark)
+{
+ int i;
+
+ if (sibs == 0)
+ node_mark_all(node, mark);
+ else {
+ for (i = 0; i < XA_CHUNK_SIZE; i += sibs + 1)
+ node_set_mark(node, i, mark);
+ }
+}
+
static void node_set_marks(struct xa_node *node, unsigned int offset,
- struct xa_node *child, unsigned int marks)
+ struct xa_node *child, unsigned int sibs,
+ unsigned int marks)
{
xa_mark_t mark = XA_MARK_0;
@@ -978,7 +992,7 @@ static void node_set_marks(struct xa_nod
if (marks & (1 << (__force unsigned int)mark)) {
node_set_mark(node, offset, mark);
if (child)
- node_mark_all(child, mark);
+ node_mark_slots(child, sibs, mark);
}
if (mark == XA_MARK_MAX)
break;
@@ -1077,7 +1091,8 @@ void xas_split(struct xa_state *xas, voi
child->nr_values = xa_is_value(entry) ?
XA_CHUNK_SIZE : 0;
RCU_INIT_POINTER(child->parent, node);
- node_set_marks(node, offset, child, marks);
+ node_set_marks(node, offset, child, xas->xa_sibs,
+ marks);
rcu_assign_pointer(node->slots[offset],
xa_mk_node(child));
if (xa_is_value(curr))
@@ -1086,7 +1101,7 @@ void xas_split(struct xa_state *xas, voi
} else {
unsigned int canon = offset - xas->xa_sibs;
- node_set_marks(node, canon, NULL, marks);
+ node_set_marks(node, canon, NULL, 0, marks);
rcu_assign_pointer(node->slots[canon], entry);
while (offset > canon)
rcu_assign_pointer(node->slots[offset--],
_
Patches currently in -mm which might be from willy@xxxxxxxxxxxxx are
xarray-set-the-marks-correctly-when-splitting-an-entry.patch
doc-improve-the-description-of-__folio_mark_dirty.patch
buffer-add-kernel-doc-for-block_dirty_folio.patch
buffer-add-kernel-doc-for-try_to_free_buffers.patch
buffer-fix-__bread-and-__bread_gfp-kernel-doc.patch
buffer-add-kernel-doc-for-brelse-and-__brelse.patch
buffer-add-kernel-doc-for-bforget-and-__bforget.patch
buffer-improve-bdev_getblk-documentation.patch
doc-split-bufferrst-out-of-api-summaryrst.patch
doc-split-bufferrst-out-of-api-summaryrst-fix.patch
mm-memory-failure-remove-fsdax_pgoff-argument-from-__add_to_kill.patch
mm-memory-failure-pass-addr-to-__add_to_kill.patch
mm-return-the-address-from-page_mapped_in_vma.patch
mm-make-page_mapped_in_vma-conditional-on-config_memory_failure.patch
mm-memory-failure-convert-shake_page-to-shake_folio.patch
mm-convert-hugetlb_page_mapping_lock_write-to-folio.patch
mm-memory-failure-convert-memory_failure-to-use-a-folio.patch
mm-memory-failure-convert-hwpoison_user_mappings-to-take-a-folio.patch
mm-memory-failure-add-some-folio-conversions-to-unpoison_memory.patch
mm-memory-failure-use-folio-functions-throughout-collect_procs.patch
mm-memory-failure-pass-the-folio-to-collect_procs_ksm.patch
fscrypt-convert-bh_get_inode_and_lblk_num-to-use-a-folio.patch
f2fs-convert-f2fs_clear_page_cache_dirty_tag-to-use-a-folio.patch
memory-failure-remove-calls-to-page_mapping.patch
migrate-expand-the-use-of-folio-in-__migrate_device_pages.patch
userfault-expand-folio-use-in-mfill_atomic_install_pte.patch
mm-remove-page_cache_alloc.patch
mm-remove-put_devmap_managed_page.patch
mm-convert-put_devmap_managed_page_refs-to-put_devmap_managed_folio_refs.patch
mm-remove-page_ref_sub_return.patch
gup-use-folios-for-gup_devmap.patch
mm-add-kernel-doc-for-folio_mark_accessed.patch
mm-remove-pagereferenced.patch
mm-simplify-thp_vma_allowable_order.patch
mm-assert-the-mmap_lock-is-held-in-__anon_vma_prepare.patch
mm-delay-the-check-for-a-null-anon_vma.patch
mm-fix-some-minor-per-vma-lock-issues-in-userfaultfd.patch
mm-optimise-vmf_anon_prepare-for-vmas-without-an-anon_vma.patch
squashfs-convert-squashfs_symlink_read_folio-to-use-folio-apis.patch
squashfs-remove-calls-to-set-the-folio-error-flag.patch
