Re: [PATCH/RFC] VFS: don't keep disconnected dentries on d_anon
From: Matthew Wilcox
Date: Wed Dec 20 2017 - 17:56:22 EST
On Thu, Dec 21, 2017 at 09:45:40AM +1100, NeilBrown wrote:
> -c/ Helper routines to allocate anonymous dentries, and to help attach
> + prefix. If the refcount on a dentry with this flag set
> + becomes zero, the dentry is immediately discarded, rather than being
> + kept in the dcache. If a dentry that is not already in the dcache
> + is repeatedly accessed by filehandle (as NFSD might do), an new dentry
> + will be a allocated for each access, and discarded at the end of
> + the access. As there is no parent, children, or name in the dentry
> + is it unlikely that there will be any useful information to lose,
> + and allocating a new dentry should normally be fast.
As the dentry is completely unattached, there is little information to
lose, and allocating a new dentry is normally fast.