fanotify: reduce event objectid to 29-bit hash

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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>

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Amir Goldstein 2021-03-04 12:48:23 +02:00 • committed by Jan Kara

parent 6f73171e19

commit 8988f11abb

5 changed files with 28 additions and 22 deletions

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include/linux/fsnotify_backend.h

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