objectid is only used by fanotify backend and it is just an optimization
for event merge before comparing all fields in event.
Move the objectid member from common struct fsnotify_event into struct
fanotify_event and reduce it to 29-bit hash to cram it together with the
3-bit event type.
Events of different types are never merged, so the combination of event
type and hash form a 32-bit key for fast compare of events.
This reduces the size of events by one pointer and paves the way for
adding hashed queue support for fanotify.
Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx>
---
fs/notify/fanotify/fanotify.c | 25 ++++++++++++-------------
fs/notify/fanotify/fanotify.h | 16 +++++++++++++---
fs/notify/inotify/inotify_fsnotify.c | 2 +-
fs/notify/inotify/inotify_user.c | 2 +-
include/linux/fsnotify_backend.h | 5 +----
5 files changed, 28 insertions(+), 22 deletions(-)
diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c
index 1192c9953620..8a2bb6954e02 100644
--- a/fs/notify/fanotify/fanotify.c
+++ b/fs/notify/fanotify/fanotify.c
@@ -88,16 +88,12 @@ static bool fanotify_name_event_equal(struct fanotify_name_event *fne1,
return fanotify_info_equal(info1, info2);
}
-static bool fanotify_should_merge(struct fsnotify_event *old_fsn,
- struct fsnotify_event *new_fsn)
+static bool fanotify_should_merge(struct fanotify_event *old,
+ struct fanotify_event *new)
{
- struct fanotify_event *old, *new;
+ pr_debug("%s: old=%p new=%p\n", __func__, old, new);
- pr_debug("%s: old=%p new=%p\n", __func__, old_fsn, new_fsn);
- old = FANOTIFY_E(old_fsn);
- new = FANOTIFY_E(new_fsn);
-
- if (old_fsn->objectid != new_fsn->objectid ||
+ if (old->hash != new->hash ||
old->type != new->type || old->pid != new->pid)
return false;
@@ -133,10 +129,9 @@ static bool fanotify_should_merge(struct fsnotify_event *old_fsn,
static int fanotify_merge(struct list_head *list, struct fsnotify_event *event)
{
struct fsnotify_event *test_event;
- struct fanotify_event *new;
+ struct fanotify_event *old, *new = FANOTIFY_E(event);
pr_debug("%s: list=%p event=%p\n", __func__, list, event);
- new = FANOTIFY_E(event);
/*
* Don't merge a permission event with any other event so that we know
@@ -147,8 +142,9 @@ static int fanotify_merge(struct list_head *list, struct fsnotify_event *event)
return 0;
list_for_each_entry_reverse(test_event, list, list) {
- if (fanotify_should_merge(test_event, event)) {
- FANOTIFY_E(test_event)->mask |= new->mask;
+ old = FANOTIFY_E(test_event);
+ if (fanotify_should_merge(old, new)) {
+ old->mask |= new->mask;
return 1;
}
}
@@ -533,6 +529,7 @@ static struct fanotify_event *fanotify_alloc_event(struct fsnotify_group *group,
struct mem_cgroup *old_memcg;
struct inode *child = NULL;
bool name_event = false;
+ unsigned int hash = 0;
if ((fid_mode & FAN_REPORT_DIR_FID) && dirid) {
/*
@@ -600,8 +597,10 @@ static struct fanotify_event *fanotify_alloc_event(struct fsnotify_group *group,
* Use the victim inode instead of the watching inode as the id for
* event queue, so event reported on parent is merged with event
* reported on child when both directory and child watches exist.
+ * Hash object id for queue merge.
*/
- fanotify_init_event(event, (unsigned long)id, mask);
+ hash = hash_ptr(id, FANOTIFY_EVENT_HASH_BITS);
+ fanotify_init_event(event, hash, mask);
if (FAN_GROUP_FLAG(group, FAN_REPORT_TID))
event->pid = get_pid(task_pid(current));
else
diff --git a/fs/notify/fanotify/fanotify.h b/fs/notify/fanotify/fanotify.h
index 896c819a1786..d531f0cfa46f 100644
--- a/fs/notify/fanotify/fanotify.h
+++ b/fs/notify/fanotify/fanotify.h
@@ -135,19 +135,29 @@ enum fanotify_event_type {
FANOTIFY_EVENT_TYPE_PATH,
FANOTIFY_EVENT_TYPE_PATH_PERM,
FANOTIFY_EVENT_TYPE_OVERFLOW, /* struct fanotify_event */
+ __FANOTIFY_EVENT_TYPE_NUM
};
+#define FANOTIFY_EVENT_TYPE_BITS \
+ (ilog2(__FANOTIFY_EVENT_TYPE_NUM - 1) + 1)
+#define FANOTIFY_EVENT_HASH_BITS \
+ (32 - FANOTIFY_EVENT_TYPE_BITS)
+
struct fanotify_event {
struct fsnotify_event fse;
u32 mask;
- enum fanotify_event_type type;
+ struct {
+ unsigned int type : FANOTIFY_EVENT_TYPE_BITS;
+ unsigned int hash : FANOTIFY_EVENT_HASH_BITS;
+ };
struct pid *pid;
};
static inline void fanotify_init_event(struct fanotify_event *event,
- unsigned long id, u32 mask)
+ unsigned int hash, u32 mask)
{
- fsnotify_init_event(&event->fse, id);
+ fsnotify_init_event(&event->fse);
+ event->hash = hash;
event->mask = mask;
event->pid = NULL;
}
diff --git a/fs/notify/inotify/inotify_fsnotify.c b/fs/notify/inotify/inotify_fsnotify.c
index 1901d799909b..0533bacbd584 100644
--- a/fs/notify/inotify/inotify_fsnotify.c
+++ b/fs/notify/inotify/inotify_fsnotify.c
@@ -107,7 +107,7 @@ int inotify_handle_inode_event(struct fsnotify_mark *inode_mark, u32 mask,
mask &= ~IN_ISDIR;
fsn_event = &event->fse;
- fsnotify_init_event(fsn_event, 0);
+ fsnotify_init_event(fsn_event);
event->mask = mask;
event->wd = i_mark->wd;
event->sync_cookie = cookie;
diff --git a/fs/notify/inotify/inotify_user.c b/fs/notify/inotify/inotify_user.c
index a6c95bd64618..98f61b31745a 100644
--- a/fs/notify/inotify/inotify_user.c
+++ b/fs/notify/inotify/inotify_user.c
@@ -641,7 +641,7 @@ static struct fsnotify_group *inotify_new_group(unsigned int max_events)
return ERR_PTR(-ENOMEM);
}
group->overflow_event = &oevent->fse;
- fsnotify_init_event(group->overflow_event, 0);
+ fsnotify_init_event(group->overflow_event);
oevent->mask = FS_Q_OVERFLOW;
oevent->wd = -1;
oevent->sync_cookie = 0;
diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h
index 7eb979bfc141..fc98f9f88d12 100644
--- a/include/linux/fsnotify_backend.h
+++ b/include/linux/fsnotify_backend.h
@@ -167,7 +167,6 @@ struct fsnotify_ops {
*/
struct fsnotify_event {
struct list_head list;
- unsigned long objectid; /* identifier for queue merges */
};
/*
@@ -582,11 +581,9 @@ extern void fsnotify_put_mark(struct fsnotify_mark *mark);
extern void fsnotify_finish_user_wait(struct fsnotify_iter_info *iter_info);
extern bool fsnotify_prepare_user_wait(struct fsnotify_iter_info *iter_info);
-static inline void fsnotify_init_event(struct fsnotify_event *event,
- unsigned long objectid)
+static inline void fsnotify_init_event(struct fsnotify_event *event)
{
INIT_LIST_HEAD(&event->list);
- event->objectid = objectid;
}
#else
--
2.30.0
