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| author | Amir Goldstein <amir73il@gmail.com> | 2021-03-04 14:29:20 +0300 |
|---|---|---|
| committer | Jan Kara <jack@suse.cz> | 2021-03-16 18:49:31 +0300 |
| commit | 5b8fea65d197f408bb00b251c70d842826d6b70b (patch) | |
| tree | 0dbad0feb14654368cf8d2873887fec1c451864d /include/linux/fanotify.h | |
| parent | b8cd0ee8cda68a888a317991c1e918a8cba1a568 (diff) | |
| download | linux-5b8fea65d197f408bb00b251c70d842826d6b70b.tar.xz | |
fanotify: configurable limits via sysfs
fanotify has some hardcoded limits. The only APIs to escape those limits
are FAN_UNLIMITED_QUEUE and FAN_UNLIMITED_MARKS.
Allow finer grained tuning of the system limits via sysfs tunables under
/proc/sys/fs/fanotify, similar to tunables under /proc/sys/fs/inotify,
with some minor differences.
- max_queued_events - global system tunable for group queue size limit.
Like the inotify tunable with the same name, it defaults to 16384 and
applies on initialization of a new group.
- max_user_marks - user ns tunable for marks limit per user.
Like the inotify tunable named max_user_watches, on a machine with
sufficient RAM and it defaults to 1048576 in init userns and can be
further limited per containing user ns.
- max_user_groups - user ns tunable for number of groups per user.
Like the inotify tunable named max_user_instances, it defaults to 128
in init userns and can be further limited per containing user ns.
The slightly different tunable names used for fanotify are derived from
the "group" and "mark" terminology used in the fanotify man pages and
throughout the code.
Considering the fact that the default value for max_user_instances was
increased in kernel v5.10 from 8192 to 1048576, leaving the legacy
fanotify limit of 8192 marks per group in addition to the max_user_marks
limit makes little sense, so the per group marks limit has been removed.
Note that when a group is initialized with FAN_UNLIMITED_MARKS, its own
marks are not accounted in the per user marks account, so in effect the
limit of max_user_marks is only for the collection of groups that are
not initialized with FAN_UNLIMITED_MARKS.
Link: https://lore.kernel.org/r/20210304112921.3996419-2-amir73il@gmail.com
Suggested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Diffstat (limited to 'include/linux/fanotify.h')
| -rw-r--r-- | include/linux/fanotify.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/include/linux/fanotify.h b/include/linux/fanotify.h index 3e9c56ee651f..031a97d8369a 100644 --- a/include/linux/fanotify.h +++ b/include/linux/fanotify.h @@ -2,8 +2,11 @@ #ifndef _LINUX_FANOTIFY_H #define _LINUX_FANOTIFY_H +#include <linux/sysctl.h> #include <uapi/linux/fanotify.h> +extern struct ctl_table fanotify_table[]; /* for sysctl */ + #define FAN_GROUP_FLAG(group, flag) \ ((group)->fanotify_data.flags & (flag)) |