diff options
| author | NeilBrown <neilb@suse.de> | 2024-12-12 08:47:07 +1100 |
|---|---|---|
| committer | Chuck Lever <chuck.lever@oracle.com> | 2025-01-06 09:37:38 -0500 |
| commit | 60aa6564317db29ea72b6db821b5bbb45f1e879d (patch) | |
| tree | d0ca7e4c63702dcd48d300536644f356f2936247 | |
| parent | 601c8cb349c2d9a3a6cea6f53e0bf838e2e60893 (diff) | |
nfsd: allocate new session-based DRC slots on demand.
If a client ever uses the highest available slot for a given session,
attempt to allocate more slots so there is room for the client to use
them if wanted. GFP_NOWAIT is used so if there is not plenty of
free memory, failure is expected - which is what we want. It also
allows the allocation while holding a spinlock.
Each time we increase the number of slots by 20% (rounded up). This
allows fairly quick growth while avoiding excessive over-shoot.
We would expect to stablise with around 10% more slots available than
the client actually uses.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
| -rw-r--r-- | fs/nfsd/nfs4state.c | 37 |
1 files changed, 32 insertions, 5 deletions
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c index bdfe791b02f1..fcc0153b6b90 100644 --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -4235,11 +4235,6 @@ nfsd4_sequence(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate, slot = xa_load(&session->se_slots, seq->slotid); dprintk("%s: slotid %d\n", __func__, seq->slotid); - /* We do not negotiate the number of slots yet, so set the - * maxslots to the session maxreqs which is used to encode - * sr_highest_slotid and the sr_target_slot id to maxslots */ - seq->maxslots = session->se_fchannel.maxreqs; - trace_nfsd_slot_seqid_sequence(clp, seq, slot); status = check_slot_seqid(seq->seqid, slot->sl_seqid, slot->sl_flags & NFSD4_SLOT_INUSE); @@ -4289,6 +4284,38 @@ nfsd4_sequence(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate, cstate->session = session; cstate->clp = clp; + /* + * If the client ever uses the highest available slot, + * gently try to allocate another 20%. This allows + * fairly quick growth without grossly over-shooting what + * the client might use. + */ + if (seq->slotid == session->se_fchannel.maxreqs - 1 && + session->se_fchannel.maxreqs < NFSD_MAX_SLOTS_PER_SESSION) { + int s = session->se_fchannel.maxreqs; + int cnt = DIV_ROUND_UP(s, 5); + + do { + /* + * GFP_NOWAIT both allows allocation under a + * spinlock, and only succeeds if there is + * plenty of memory. + */ + slot = kzalloc(slot_bytes(&session->se_fchannel), + GFP_NOWAIT); + if (slot && + !xa_is_err(xa_store(&session->se_slots, s, slot, + GFP_NOWAIT))) { + s += 1; + session->se_fchannel.maxreqs = s; + } else { + kfree(slot); + slot = NULL; + } + } while (slot && --cnt > 0); + } + seq->maxslots = session->se_fchannel.maxreqs; + out: switch (clp->cl_cb_state) { case NFSD4_CB_DOWN: |