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Date: Tue, 19 Oct 2021 08:50:23 +0300 From: Amir Goldstein <amir73il@...il.com> To: Gabriel Krisman Bertazi <krisman@...labora.com> Cc: Jan Kara <jack@...e.com>, "Darrick J. Wong" <djwong@...nel.org>, Theodore Tso <tytso@....edu>, Dave Chinner <david@...morbit.com>, David Howells <dhowells@...hat.com>, Khazhismel Kumykov <khazhy@...gle.com>, linux-fsdevel <linux-fsdevel@...r.kernel.org>, Ext4 <linux-ext4@...r.kernel.org>, Linux API <linux-api@...r.kernel.org>, kernel@...labora.com Subject: Re: [PATCH v8 20/32] fanotify: Dynamically resize the FAN_FS_ERROR pool On Tue, Oct 19, 2021 at 3:03 AM Gabriel Krisman Bertazi <krisman@...labora.com> wrote: > > Allow the FAN_FS_ERROR group mempool to grow up to an upper limit > dynamically, instead of starting already at the limit. This doesn't > bother resizing on mark removal, but next time a mark is added, the slot > will be either reused or resized. Also, if several marks are being > removed at once, most likely the group is going away anyway. > > Signed-off-by: Gabriel Krisman Bertazi <krisman@...labora.com> > --- > fs/notify/fanotify/fanotify_user.c | 26 +++++++++++++++++++++----- > include/linux/fsnotify_backend.h | 1 + > 2 files changed, 22 insertions(+), 5 deletions(-) > > diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c > index f77581c5b97f..a860c286e885 100644 > --- a/fs/notify/fanotify/fanotify_user.c > +++ b/fs/notify/fanotify/fanotify_user.c > @@ -959,6 +959,10 @@ static int fanotify_remove_mark(struct fsnotify_group *group, > > removed = fanotify_mark_remove_from_mask(fsn_mark, mask, flags, > umask, &destroy_mark); > + > + if (removed & FAN_FS_ERROR) > + group->fanotify_data.error_event_marks--; > + > if (removed & fsnotify_conn_mask(fsn_mark->connector)) > fsnotify_recalc_mask(fsn_mark->connector); > if (destroy_mark) > @@ -1057,12 +1061,24 @@ static struct fsnotify_mark *fanotify_add_new_mark(struct fsnotify_group *group, > > static int fanotify_group_init_error_pool(struct fsnotify_group *group) > { > - if (mempool_initialized(&group->fanotify_data.error_events_pool)) > - return 0; > + int ret; > + > + if (group->fanotify_data.error_event_marks >= > + FANOTIFY_DEFAULT_MAX_FEE_POOL) > + return -ENOMEM; > > - return mempool_init_kmalloc_pool(&group->fanotify_data.error_events_pool, > - FANOTIFY_DEFAULT_MAX_FEE_POOL, > - sizeof(struct fanotify_error_event)); > + if (!mempool_initialized(&group->fanotify_data.error_events_pool)) > + ret = mempool_init_kmalloc_pool( > + &group->fanotify_data.error_events_pool, > + 1, sizeof(struct fanotify_error_event)); > + else > + ret = mempool_resize(&group->fanotify_data.error_events_pool, > + group->fanotify_data.error_event_marks + 1); > + > + if (!ret) > + group->fanotify_data.error_event_marks++; > + > + return ret; > } This is not what I had in mind. I was thinking start with ~32 and double each time limit is reached. And also, this code grows the pool to infinity with add/remove mark loop. Anyway, since I clearly did not understand how mempool works and Jan had some different ideas I would leave it to Jan to explain how he wants the mempool init limit and resize to be implemented. Thanks, Amir.
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