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| author | Sidhartha Kumar <sidhartha.kumar@oracle.com> | 2023-12-13 21:50:57 +0100 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2023-12-20 22:46:19 +0100 |
| commit | 4249f13c11be8b8b7bf93204185e150c3bdc968d (patch) | |
| tree | 0a7d225b9579f9b3c23e94f267cd041f7895b857 /lib/maple_tree.c | |
| parent | mm/filemap: avoid buffered read/write race to read inconsistent data (diff) | |
| download | linux-4249f13c11be8b8b7bf93204185e150c3bdc968d.tar.xz linux-4249f13c11be8b8b7bf93204185e150c3bdc968d.zip | |
maple_tree: do not preallocate nodes for slot stores
mas_preallocate() defaults to requesting 1 node for preallocation and then
,depending on the type of store, will update the request variable. There
isn't a check for a slot store type, so slot stores are preallocating the
default 1 node. Slot stores do not require any additional nodes, so add a
check for the slot store case that will bypass node_count_gfp(). Update
the tests to reflect that slot stores do not require allocations.
User visible effects of this bug include increased memory usage from the
unneeded node that was allocated.
Link: https://lkml.kernel.org/r/20231213205058.386589-1-sidhartha.kumar@oracle.com
Fixes: 0b8bb544b1a7 ("maple_tree: update mas_preallocate() testing")
Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: <stable@vger.kernel.org> [6.6+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'lib/maple_tree.c')
| -rw-r--r-- | lib/maple_tree.c | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/lib/maple_tree.c b/lib/maple_tree.c index bb24d84a4922..684689457d77 100644 --- a/lib/maple_tree.c +++ b/lib/maple_tree.c @@ -5501,6 +5501,17 @@ int mas_preallocate(struct ma_state *mas, void *entry, gfp_t gfp) mas_wr_end_piv(&wr_mas); node_size = mas_wr_new_end(&wr_mas); + + /* Slot store, does not require additional nodes */ + if (node_size == wr_mas.node_end) { + /* reuse node */ + if (!mt_in_rcu(mas->tree)) + return 0; + /* shifting boundary */ + if (wr_mas.offset_end - mas->offset == 1) + return 0; + } + if (node_size >= mt_slots[wr_mas.type]) { /* Split, worst case for now. */ request = 1 + mas_mt_height(mas) * 2; |