diff options
| author | Jeff Layton <jlayton@kernel.org> | 2026-07-06 09:29:25 -0400 |
|---|---|---|
| committer | Chuck Lever <cel@kernel.org> | 2026-08-10 09:54:35 -0400 |
| commit | 91141b8eb9c9d2580b073688c6b0ee2ba3718b34 (patch) | |
| tree | 5c159c2bb04ce54819c20455dd64858973c74ed8 /include/linux | |
| parent | 0e024f580b171fb60c04118fef32977f84e3d3ea (diff) | |
sunrpc: derive the pool count instead of caching it in sv_nrpools
Now that the pool mode is always pernode, svc_serv.sv_nrpools is
redundant with sv_is_pooled: an unpooled service always has a single
pool, and a pooled service has svc_pool_map.npools pools (which is one on
a single-node host). sv_nrpools cannot distinguish an unpooled service
from a pooled service that happens to have one pool, so it is sv_nrpools,
not sv_is_pooled, that carries no unique information.
Replace the cached field with a svc_serv_nrpools() helper that derives
the count from sv_is_pooled and the pool map, and convert all readers to
it. svc_pool_map is file-local to svc.c, so export the helper for the
svc_xprt.c and nfsd callers.
Reading svc_pool_map.npools without svc_pool_map_mutex is safe: the
mutex protects only svc_pool_map.count, and npools is already read
locklessly in svc_pool_for_cpu().
A pooled service holds a map reference for its whole lifetime, so npools
is stable while any reader could observe it. The hot path
(svc_pool_for_cpu()) already dereferences svc_pool_map for to_pool, and
npools shares that cacheline, so there is no new locking or coherence
cost.
__svc_create() keeps using its local npools argument for the sv_pools[]
allocation, since sv_is_pooled is not set until svc_create_pooled() has
returned from it.
Doing this also removes a modulus operation from svc_pool_for_cpu(),
which should make for more efficient RPC queueing.
Assisted-by: Claude:claude-opus-4-8
Suggested-by: NeilBrown <neilb@ownmail.net>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://patch.msgid.link/20260706-sunrpc-pool-mode-v5-5-6c4ee7cd89aa@kernel.org
Signed-off-by: Chuck Lever <cel@kernel.org>
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/sunrpc/svc.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/include/linux/sunrpc/svc.h b/include/linux/sunrpc/svc.h index 3a0152d926fb..3c885ab6ad41 100644 --- a/include/linux/sunrpc/svc.h +++ b/include/linux/sunrpc/svc.h @@ -85,7 +85,6 @@ struct svc_serv { char * sv_name; /* service name */ - unsigned int sv_nrpools; /* number of thread pools */ bool sv_is_pooled; /* is this a pooled service? */ struct svc_pool * sv_pools; /* array of thread pools */ int (*sv_threadfn)(void *data); @@ -480,6 +479,7 @@ void svc_wake_up(struct svc_serv *); void svc_reserve(struct svc_rqst *rqstp, int space); void svc_pool_wake_idle_thread(struct svc_pool *pool); struct svc_pool *svc_pool_for_cpu(struct svc_serv *serv); +unsigned int svc_serv_nrpools(const struct svc_serv *serv); char * svc_print_addr(struct svc_rqst *, char *, size_t); const char * svc_proc_name(const struct svc_rqst *rqstp); int svc_encode_result_payload(struct svc_rqst *rqstp, |