Messages in this thread | | | Date | Tue, 6 Mar 2007 16:51:50 -0800 (PST) | From | Linus Torvalds <> | Subject | Re: [patch] epoll use a single inode ... |
| |
[ Al Viro added to Cc: as the arbiter of good taste in the VFS layer. He has veto powers even over my proposals ;^]
On Tue, 6 Mar 2007, Davide Libenzi wrote: > > I currently have the dentry to carry the name of the file* class it is > linked to. I'd prefer to keep it that way, unless there are huge factors > against.
I assume that the *only* reason for having multiple dentries is really just the output in /proc/<pid>/fd/, right? Or is there any other reason to have separate dentries for these pseudo-files?
It's a bit sad to waste that much memory (and time) on something like that. I bet that the dentry setup is a noticeable part of the whole sigfd()/timerfd() setup. It's likely also a big part of any memory footprint if you have lots of them.
So how about just doing: - do a single dentry - make a "struct file_operations" member function that prints out the name of the thing in /proc/<pid>/fd/, and which *defaults* to just doing the d_path() on the dentry, but special filesystems like this could do something else (like print out a fake inode number from the "file->f_private_data" information)
There seems to really be no downsides to that approach. No existing filesystem will even notice (they'll all have NULL in the new f_op member), and it would allow pipes etc to be sped up and use less memory.
Linus - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |