On 2022-07-04 00:53:06, Dan Aloni wrote:
> On 2018-10-23 12:34:01, Trond Myklebust wrote:
> > @@ -456,32 +495,24 @@ rpcauth_prune_expired(struct list_head *free, int nr_to_scan)
> >
> > if (nr_to_scan-- == 0)
> > break;
> > + if (atomic_read(&cred->cr_count) > 1) {
> > + rpcauth_lru_remove_locked(cred);
> > + continue;
> > + }
> > /*
> > * Enforce a 60 second garbage collection moratorium
> > * Note that the cred_unused list must be time-ordered.
> > */
> > - if (time_in_range(cred->cr_expire, expired, jiffies) &&
> > - test_bit(RPCAUTH_CRED_HASHED, &cred->cr_flags) != 0) {
> > - freed = SHRINK_STOP;
> > - break;
> > - }
> > -
> > - list_del_init(&cred->cr_lru);
> > - number_cred_unused--;
> > - freed++;
> > - if (atomic_read(&cred->cr_count) != 0)
> > + if (!time_in_range(cred->cr_expire, expired, jiffies))
> > + continue;
> > + if (!rpcauth_unhash_cred(cred))
> > continue;
>
> With `!` flipping the `time_in_range(...)` condition in this past
> change, looks like we are skipping the head of the LRU which should be
> pruned, so actual expiry does not happen at all in case there are more
> than about 100 old items in the LRU.
>
> Reverting this, I saw the correct behavior taking place.
v2: Made a better explanation in the commit message.
-- >8 --
Subject: [PATCH] sunrpc: fix expiry of auth creds
Before this commit, with a large enough LRU of expired items (100), the
loop skipped all the expired items and was entirely ineffectual in
trimming the LRU list.
Fixes: 95cd623250ad ('SUNRPC: Clean up the AUTH cache code')
Signed-off-by: Dan Aloni <dan.aloni@xxxxxxxxxxxx>
---
net/sunrpc/auth.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/sunrpc/auth.c b/net/sunrpc/auth.c
index 682fcd24bf43..2324d1e58f21 100644
--- a/net/sunrpc/auth.c
+++ b/net/sunrpc/auth.c
@@ -445,7 +445,7 @@ rpcauth_prune_expired(struct list_head *free, int nr_to_scan)
* Enforce a 60 second garbage collection moratorium
* Note that the cred_unused list must be time-ordered.
*/
- if (!time_in_range(cred->cr_expire, expired, jiffies))
+ if (time_in_range(cred->cr_expire, expired, jiffies))
continue;
if (!rpcauth_unhash_cred(cred))
continue;
--
2.23.0
--
Dan Aloni
