diff options
| author | Christian Brauner <brauner@kernel.org> | 2024-12-15 21:17:06 +0100 |
|---|---|---|
| committer | Christian Brauner <brauner@kernel.org> | 2025-01-09 16:58:54 +0100 |
| commit | 2ce23285d704f6a8d90207ae8f115f5db93d3541 (patch) | |
| tree | 080356af151f07f9a31e568b77802cc6a87b5973 /fs/namespace.c | |
| parent | c7bb042031b4890b1c5e733dd1ef6484565d174a (diff) | |
fs: cache first and last mount
Speed up listmount() by caching the first and last node making retrieval
of the first and last mount of each mount namespace O(1).
Link: https://lore.kernel.org/r/20241215-vfs-6-14-mount-work-v1-2-fd55922c4af8@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
Diffstat (limited to 'fs/namespace.c')
| -rw-r--r-- | fs/namespace.c | 17 |
1 files changed, 13 insertions, 4 deletions
diff --git a/fs/namespace.c b/fs/namespace.c index a382be402f62..5336e5f09996 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -1155,16 +1155,25 @@ static void mnt_add_to_ns(struct mnt_namespace *ns, struct mount *mnt) { struct rb_node **link = &ns->mounts.rb_node; struct rb_node *parent = NULL; + bool mnt_first_node = true, mnt_last_node = true; WARN_ON(mnt_ns_attached(mnt)); mnt->mnt_ns = ns; while (*link) { parent = *link; - if (mnt->mnt_id_unique < node_to_mount(parent)->mnt_id_unique) + if (mnt->mnt_id_unique < node_to_mount(parent)->mnt_id_unique) { link = &parent->rb_left; - else + mnt_last_node = false; + } else { link = &parent->rb_right; + mnt_first_node = false; + } } + + if (mnt_last_node) + ns->mnt_last_node = &mnt->mnt_node; + if (mnt_first_node) + ns->mnt_first_node = &mnt->mnt_node; rb_link_node(&mnt->mnt_node, parent, link); rb_insert_color(&mnt->mnt_node, &ns->mounts); } @@ -5563,9 +5572,9 @@ static ssize_t do_listmount(struct mnt_namespace *ns, u64 mnt_parent_id, if (!last_mnt_id) { if (reverse) - first = node_to_mount(rb_last(&ns->mounts)); + first = node_to_mount(ns->mnt_last_node); else - first = node_to_mount(rb_first(&ns->mounts)); + first = node_to_mount(ns->mnt_first_node); } else { if (reverse) first = mnt_find_id_at_reverse(ns, last_mnt_id - 1); |