During swapoff, try_to_unuse() makes sure that zswap_invalidate() is
called for all swap entries before zswap_swapoff() is called. This means
that all zswap entries should already be removed from the tree. Simplify
zswap_swapoff() by removing the trees cleanup code, and leave an
assertion in its place.
Signed-off-by: Yosry Ahmed <[email protected]>
---
mm/zswap.c | 16 +++-------------
1 file changed, 3 insertions(+), 13 deletions(-)
diff --git a/mm/zswap.c b/mm/zswap.c
index dcdd5ecfedb09..78df16d307aa8 100644
--- a/mm/zswap.c
+++ b/mm/zswap.c
@@ -1808,19 +1808,9 @@ void zswap_swapoff(int type)
if (!trees)
return;
- for (i = 0; i < nr_zswap_trees[type]; i++) {
- struct zswap_tree *tree = trees + i;
- struct zswap_entry *entry, *n;
-
- /* walk the tree and free everything */
- spin_lock(&tree->lock);
- rbtree_postorder_for_each_entry_safe(entry, n,
- &tree->rbroot,
- rbnode)
- zswap_free_entry(entry);
- tree->rbroot = RB_ROOT;
- spin_unlock(&tree->lock);
- }
+ /* try_to_unuse() invalidated all the entries already */
+ for (i = 0; i < nr_zswap_trees[type]; i++)
+ WARN_ON_ONCE(!RB_EMPTY_ROOT(&trees[i].rbroot));
kvfree(trees);
nr_zswap_trees[type] = 0;
--
2.43.0.429.g432eaa2c6b-goog
On Tue, Jan 23, 2024 at 8:51 PM Yosry Ahmed <[email protected]> wrote:
>
> During swapoff, try_to_unuse() makes sure that zswap_invalidate() is
> called for all swap entries before zswap_swapoff() is called. This means
> that all zswap entries should already be removed from the tree. Simplify
> zswap_swapoff() by removing the trees cleanup code, and leave an
> assertion in its place.
>
> Signed-off-by: Yosry Ahmed <[email protected]>
Johannes, Nhat, I didn't carry the Acks forward after the rebase as
the code changed significantly.
On 2024/1/24 12:51, Yosry Ahmed wrote:
> During swapoff, try_to_unuse() makes sure that zswap_invalidate() is
> called for all swap entries before zswap_swapoff() is called. This means
> that all zswap entries should already be removed from the tree. Simplify
> zswap_swapoff() by removing the trees cleanup code, and leave an
> assertion in its place.
>
> Signed-off-by: Yosry Ahmed <[email protected]>
Looks good to me, thanks!
Reviewed-by: Chengming Zhou <[email protected]>
> ---
> mm/zswap.c | 16 +++-------------
> 1 file changed, 3 insertions(+), 13 deletions(-)
>
> diff --git a/mm/zswap.c b/mm/zswap.c
> index dcdd5ecfedb09..78df16d307aa8 100644
> --- a/mm/zswap.c
> +++ b/mm/zswap.c
> @@ -1808,19 +1808,9 @@ void zswap_swapoff(int type)
> if (!trees)
> return;
>
> - for (i = 0; i < nr_zswap_trees[type]; i++) {
> - struct zswap_tree *tree = trees + i;
> - struct zswap_entry *entry, *n;
> -
> - /* walk the tree and free everything */
> - spin_lock(&tree->lock);
> - rbtree_postorder_for_each_entry_safe(entry, n,
> - &tree->rbroot,
> - rbnode)
> - zswap_free_entry(entry);
> - tree->rbroot = RB_ROOT;
> - spin_unlock(&tree->lock);
> - }
> + /* try_to_unuse() invalidated all the entries already */
> + for (i = 0; i < nr_zswap_trees[type]; i++)
> + WARN_ON_ONCE(!RB_EMPTY_ROOT(&trees[i].rbroot));
>
> kvfree(trees);
> nr_zswap_trees[type] = 0;