Re: [PATCH] pipe: don't update {a,c,m}time for anonymous pipes

[Linus Torvalds]

On Tue, 4 Feb 2025 at 08:34, Christian Brauner <brauner@xxxxxxxxxx> wrote:
>
> So really that mnt_get_write_access() should be pointless for
> anonymous pipes. In other words, couldn't this also just be:

I bet you'll find that even just inode_update_times() isn't all that cheap.

Yes, the silly "get writability" thing is pointless for pipes, but the
"get current time" really isn't a no-op either. There's all the crazy
"coarse time vs fine time" crud, there's justv a *lot* of overhead.

That's not really noticeable on a "real" file where you never access
just one byte anyway, and where any write costs are elsewhere. But
pipes can be very cheap, so the silly overheads really show up.

                 Linus