On Fri, Jan 19, 2024 at 6:40 PM Yosry Ahmed <yosryahmed@xxxxxxxxxx> 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 tree cleanup loop, and leaving an
> assertion in its place.
>
> Signed-off-by: Yosry Ahmed <yosryahmed@xxxxxxxxxx>
> ---
> Chengming, Chris, I think this should make the tree split and the xarray
> conversion patches simpler (especially the former). If others agree,
> both changes can be rebased on top of this.
> ---
> mm/zswap.c | 9 ++-------
> 1 file changed, 2 insertions(+), 7 deletions(-)
>
> diff --git a/mm/zswap.c b/mm/zswap.c
> index f8bc9e0892687..9675c3c27f9d1 100644
> --- a/mm/zswap.c
> +++ b/mm/zswap.c
> @@ -1790,17 +1790,12 @@ void zswap_swapon(int type)
> void zswap_swapoff(int type)
> {
> struct zswap_tree *tree = zswap_trees[type];
> - struct zswap_entry *entry, *n;
>
> if (!tree)
> return;
>
> - /* 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 entries already */
> + WARN_ON_ONCE(!RB_EMPTY_ROOT(&tree->rbroot));
> kfree(tree);
> zswap_trees[type] = NULL;
> }
> --
> 2.43.0.429.g432eaa2c6b-goog
>
Oh man this is sweet! FWIW:
Acked-by: Nhat Pham <nphamcs@xxxxxxxxx>
