[linux-cifs-client] [PATCH] cifs: implement drop_inode superblock op

[Steve French]

Cached metadata will still be valid for 1 second - do these still have
dentries pointing to them?

On Thu, May 27, 2010 at 8:38 AM, Jeff Layton <jlayton at redhat.com> wrote:
> On Wed, 26 May 2010 19:19:11 -0400
> Scott Lovenberg <scott.lovenberg at gmail.com> wrote:
>
>>
>> >> Any rough idea of performance or memory savings (even in something
>> >> artificial like dbench run)?
>> >>
>> >>
>> > It's more of a memory savings thing. When I mount with -o noserverino
>> > and run fsstress on the mount, I'd regularly see the size of the
>> > cifs_inode_cache hit 60M or more (on a client with 1G RAM). With this
>> > patch in place, it rarely goes over 2M in size.
>> >
>> > Eventually, memory pressure will force the size to go down, but if we
>> > know that they'll never be used again (which is the case with
>> > noserverino), it's better to go ahead and just free them.
>> >
>> >
>> I take it this overrides the behavior of the vfs_cache_pressure before
>> the memory pressure makes reclaiming cache necessary?
>
> Not exactly. vfs_cache_pressure just governs the way in which the VM
> subsystem will attempt to free memory when it needs it by changing the
> preference for flushing inode and dentry caches.
>
> This patch just aims to delete inodes that we know will never be used
> again as soon as their refcount drops to 0.
>
> --
> Jeff Layton <jlayton at redhat.com>
>



-- 
Thanks,

Steve