On 1/26/25 5:33 PM, NeilBrown wrote:
On Fri, 24 Jan 2025, Chuck Lever wrote:
On 1/22/25 5:10 PM, NeilBrown wrote:
On Thu, 23 Jan 2025, Chuck Lever wrote:
On 1/21/25 10:54 PM, NeilBrown wrote:
The final freeing of nfsd files is done by per-net nfsd threads (which
call nfsd_file_net_dispose()) so it makes some sense to make more of the
freeing infrastructure to be per-net - in struct nfsd_fcache_disposal.
This is a step towards replacing the list_lru with simple lists which
each share the per-net lock in nfsd_fcache_disposal and will require
less list walking.
As the net is always shutdown before there is any chance that the rest
of the filecache is shut down we can removed the tests on
NFSD_FILE_CACHE_UP.
For the filecache stats file, which assumes a global lru, we keep a
separate counter which includes all files in all netns lrus.
Hey Neil -
One of the issues with the current code is that the contention for
the LRU lock has been effectively buried. It would be nice to have a
way to expose that contention in the new code.
Can this patch or this series add some lock class infrastructure to
help account for the time spent contending for these dynamically
allocated spin locks?
Unfortunately I don't know anything about accounting for lock contention
time.
I know about lock classes for the purpose of lockdep checking but not
how they relate to contention tracking.
Could you give me some pointers?
Sticking these locks into a class is all you need to do. When lockstat
is enabled, it automatically accumulates the statistics for all locks
in a class, and treats that as a single lock in /proc/lock_stat.
Ahh thanks. So I don't need to do anything as this lock has it's own
spin_lock_init() so it already has it's own class.
However.... the init call is :
spin_lock_init(&l->lock);
so that appear in /proc/lock_stat as
&l->lock:
or maybe
&l->lock/1:
or even
&l->lock/2:
Well, that's the problem, as I see it. They might all appear separately,
but we want lock_stat to group them together so we can see the aggregate
wait time and contention metrics.
Have a look at svc_reclassify_socket().
Maybe I should change the "l" to something more unique. "nfd" ??
Or I could actually define a lock_class_key and call __spin_lock_init:
__skin_lock_init(&l->lock, "nfsd_fcache_disposal->lock", &key,
false);
There is no precedent for that though.
NeilBrown
--
Chuck Lever
