On Tue 19-10-21 08:38:34, Amir Goldstein wrote:

On Tue, Oct 19, 2021 at 3:03 AM Gabriel Krisman Bertazi
[off-list ref] wrote:

quoted

Pre-allocate slots for file system errors to have greater chances of
succeeding, since error events can happen in GFP_NOFS context.  This
patch introduces a group-wide mempool of error events, shared by all
FAN_FS_ERROR marks in this group.

For now, just allocate 128 positions.  A future patch allows this
array to be dynamically resized when a new mark is added.

Signed-off-by: Gabriel Krisman Bertazi <redacted>

---
Changes since v7:
  - Expand limit to 128. (Amir)

I am not sure if Jan was also on board with this request but otherwise

Reviewed-by: Amir Goldstein <amir73il@gmail.com>

I don't really care. I don't see a strong reason to go above original 32
(so I'd slightly prefer that) but OTOH I also don't think those few KB per
notification group using FS_ERROR matter since I don't expect such groups
to be that common.

quoted

diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
index 66ee3c2805c7..f77581c5b97f 100644
--- a/fs/notify/fanotify/fanotify_user.c
+++ b/fs/notify/fanotify/fanotify_user.c

@@ -30,6 +30,7 @@
 #define FANOTIFY_DEFAULT_MAX_EVENTS    16384
 #define FANOTIFY_OLD_DEFAULT_MAX_MARKS 8192
 #define FANOTIFY_DEFAULT_MAX_GROUPS    128
+#define FANOTIFY_DEFAULT_MAX_FEE_POOL  128

Perhaps FANOTIFY_DEFAULT_FEE_POOL_SIZE would better describe what this
constant is about?

Otherwise feel free to add:

Reviewed-by: Jan Kara <jack@suse.cz>

								Honza
-- 
Jan Kara [off-list ref]
SUSE Labs, CR