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| author | Amir Goldstein <amir73il@gmail.com> | 2021-03-04 13:48:25 +0300 |
|---|---|---|
| committer | Jan Kara <jack@suse.cz> | 2021-03-16 18:37:51 +0300 |
| commit | 94e00d28a680dff18805ca472b191364347d2234 (patch) | |
| tree | d1b50fca5c1d57faf50a0a387552385dde90975f /fs/notify/fanotify/fanotify.h | |
| parent | 7e3e5c6943994943eb76cab2d3a1806bc10b9045 (diff) | |
| download | linux-94e00d28a680dff18805ca472b191364347d2234.tar.xz | |
fsnotify: use hash table for faster events merge
In order to improve event merge performance, hash events in a 128 size
hash table by the event merge key.
The fanotify_event size grows by two pointers, but we just reduced its
size by removing the objectid member, so overall its size is increased
by one pointer.
Permission events and overflow event are not merged so they are also
not hashed.
Link: https://lore.kernel.org/r/20210304104826.3993892-5-amir73il@gmail.com
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Diffstat (limited to 'fs/notify/fanotify/fanotify.h')
| -rw-r--r-- | fs/notify/fanotify/fanotify.h | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/fs/notify/fanotify/fanotify.h b/fs/notify/fanotify/fanotify.h index 9871f76cd9c2..4a5e555dc3d2 100644 --- a/fs/notify/fanotify/fanotify.h +++ b/fs/notify/fanotify/fanotify.h @@ -3,6 +3,7 @@ #include <linux/path.h> #include <linux/slab.h> #include <linux/exportfs.h> +#include <linux/hashtable.h> extern struct kmem_cache *fanotify_mark_cache; extern struct kmem_cache *fanotify_fid_event_cachep; @@ -150,6 +151,7 @@ enum fanotify_event_type { struct fanotify_event { struct fsnotify_event fse; + struct hlist_node merge_list; /* List for hashed merge */ u32 mask; struct { unsigned int type : FANOTIFY_EVENT_TYPE_BITS; @@ -162,6 +164,7 @@ static inline void fanotify_init_event(struct fanotify_event *event, unsigned int hash, u32 mask) { fsnotify_init_event(&event->fse); + INIT_HLIST_NODE(&event->merge_list); event->hash = hash; event->mask = mask; event->pid = NULL; @@ -299,3 +302,25 @@ static inline struct path *fanotify_event_path(struct fanotify_event *event) else return NULL; } + +/* + * Use 128 size hash table to speed up events merge. + */ +#define FANOTIFY_HTABLE_BITS (7) +#define FANOTIFY_HTABLE_SIZE (1 << FANOTIFY_HTABLE_BITS) +#define FANOTIFY_HTABLE_MASK (FANOTIFY_HTABLE_SIZE - 1) + +/* + * Permission events and overflow event do not get merged - don't hash them. + */ +static inline bool fanotify_is_hashed_event(u32 mask) +{ + return !fanotify_is_perm_event(mask) && !(mask & FS_Q_OVERFLOW); +} + +static inline unsigned int fanotify_event_hash_bucket( + struct fsnotify_group *group, + struct fanotify_event *event) +{ + return event->hash & FANOTIFY_HTABLE_MASK; +} |