This is a note to let you know that I've just added the patch titled
NFSD: Streamline the rare "found" case
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
nfsd-streamline-the-rare-found-case.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 49784760ed07c22ffb4b09937f4cf10aac3dd438
Author: Chuck Lever <chuck.lever@xxxxxxxxxx>
Date: Tue Sep 28 11:40:59 2021 -0400
NFSD: Streamline the rare "found" case
[ Upstream commit add1511c38166cf1036765f8c4aa939f0275a799 ]
Move a rarely called function call site out of the hot path.
This is an exceptionally small improvement because the compiler
inlines most of the functions that nfsd_cache_lookup() calls.
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
diff --git a/fs/nfsd/nfscache.c b/fs/nfsd/nfscache.c
index 1523d2e3dae97..7da88bdc0d6c3 100644
--- a/fs/nfsd/nfscache.c
+++ b/fs/nfsd/nfscache.c
@@ -448,11 +448,8 @@ int nfsd_cache_lookup(struct svc_rqst *rqstp)
b = nfsd_cache_bucket_find(rqstp->rq_xid, nn);
spin_lock(&b->cache_lock);
found = nfsd_cache_insert(b, rp, nn);
- if (found != rp) {
- nfsd_reply_cache_free_locked(NULL, rp, nn);
- rp = found;
+ if (found != rp)
goto found_entry;
- }
nfsd_stats_rc_misses_inc();
rqstp->rq_cacherep = rp;
@@ -470,8 +467,10 @@ int nfsd_cache_lookup(struct svc_rqst *rqstp)
found_entry:
/* We found a matching entry which is either in progress or done. */
+ nfsd_reply_cache_free_locked(NULL, rp, nn);
nfsd_stats_rc_hits_inc();
rtn = RC_DROPIT;
+ rp = found;
/* Request being processed */
if (rp->c_state == RC_INPROG)
