On Mon, Jun 11, 2018 at 7:03 PM, Jan Kara <jack@xxxxxxx> wrote: > On Mon 11-06-18 16:58:14, Amir Goldstein wrote: >> On Mon, Jun 11, 2018 at 4:36 PM, Jan Kara <jack@xxxxxxx> wrote: >> > > I reworked the cleanup patches to get rid of fsnotify_obj and pushed to: >> > > https://github.com/amir73il/linux.git fsnotify-cleanup >> > >> > Thanks! >> > >> > > Only last 5 patches from fsnotify_for_v4.18-rc1 have been modified >> > > and I removed your S-O-B from the modified patches. >> > > >> > > This leaves struct inode unchanged, in fact no changes to code outside >> > > fsnotify/audit at all. >> > > >> > > mask is now a member of connector for the purpose of generalizing >> > > add/remove mark, but struct inode/mount still have a copy of the mask >> > > for the purpose of the VFS optimizations. >> > >> > Looking through those patches, is it really beneficial to add mask to >> > connector when you keep it in inode / vfsmount? A helper function to get >> > mask from connector would make the same refactoring possible as well, won't >> > it? >> > >> > And adding a helper function to set mask given connector would get rid of >> > the remaining checks for connector type due to mask manipulations... >> > >> >> By moving the checks for object type into the helper? > > Yes, that's what I meant. > >> Anyway, my thinking was: >> >> What do we have to loose from keeping the mask also inside the connector? >> >> Not much. We didn't change the size of connector struct >> and it hardly adds any complexity / performance cost. > > You've actually grown the connector by 1 long on x86_64 - spinlock_t is > just 4 bytes there. Also it seems a bit stupid to me to have the mask in > two places (connector & object) just to save ifs in two helper functions. > Oh! I had CONFIG_DEBUG_LOCK_ALLOC on so hadn't noticed that. >> What do we have to gain from keeping the mask also inside the connector? >> >> We can later get rid of the copy of mask in inode struct as I wrote. >> I will follow up on that. > > If we can get rid of the mask in inode, I'm definitely fine with moving the > mask to the connector. > I'll rework mask back out of connector and will bring that back later if that makes sense. BTW, found a way to shave 8 bytes from struct inode as well as from struct file on x86_64 by shrinking _write_hint to u8 and moving it around. Will test and send an RFC patch. Thanks, Amir.
