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fanotify: reduce event objectid to 29-bit hash

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[ Upstream commit 8988f11abb820bacfcc53d498370bfb30f792ec4 ]

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.

Link: https://lore.kernel.org/r/20210304104826.3993892-3-amir73il@gmail.com
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Amir Goldstein
2021-03-04 12:48:23 +02:00
committed by Greg Kroah-Hartman
parent 4f14948942
commit 5b57a2b74d
5 changed files with 28 additions and 22 deletions
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5
include/linux/fsnotify_backend.h
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@@ -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