diff options
author | Kent Overstreet <kent.overstreet@gmail.com> | 2022-04-04 01:09:26 -0400 |
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committer | Kent Overstreet <kent.overstreet@linux.dev> | 2023-10-22 17:09:30 -0400 |
commit | d1d7737fd9df0cc57cd276b0189faf8c92c1426f (patch) | |
tree | 351c9884cb6f7b7f47dcfdf955ca6b1e04fe5e71 /fs/bcachefs/util.h | |
parent | 7c7e071d90ac278e462640570d739dd165d3acd0 (diff) |
bcachefs: Gap buffer for journal keys
Btree updates before we go RW work by inserting into the array of keys
that journal replay will insert - but inserting into a flat array is
O(n), meaning if btree_gc needs to update many alloc keys, we're O(n^2).
Fortunately, the updates btree_gc does happens in sequential order,
which means a gap buffer works nicely here - this patch implements a gap
buffer for journal keys.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Diffstat (limited to 'fs/bcachefs/util.h')
-rw-r--r-- | fs/bcachefs/util.h | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/fs/bcachefs/util.h b/fs/bcachefs/util.h index 1629d279f494..74bfa5faf470 100644 --- a/fs/bcachefs/util.h +++ b/fs/bcachefs/util.h @@ -826,6 +826,31 @@ do { \ #define array_remove_item(_array, _nr, _pos) \ array_remove_items(_array, _nr, _pos, 1) +static inline void __move_gap(void *array, size_t element_size, + size_t nr, size_t size, + size_t old_gap, size_t new_gap) +{ + size_t gap_end = old_gap + size - nr; + + if (new_gap < old_gap) { + size_t move = old_gap - new_gap; + + memmove(array + element_size * (gap_end - move), + array + element_size * (old_gap - move), + element_size * move); + } else if (new_gap > old_gap) { + size_t move = new_gap - old_gap; + + memmove(array + element_size * old_gap, + array + element_size * gap_end, + element_size * move); + } +} + +/* Move the gap in a gap buffer: */ +#define move_gap(_array, _nr, _size, _old_gap, _new_gap) \ + __move_gap(_array, sizeof(_array[0]), _nr, _size, _old_gap, _new_gap) + #define bubble_sort(_base, _nr, _cmp) \ do { \ ssize_t _i, _end; \ |