diff options
| author | Chuck Lever <chuck.lever@oracle.com> | 2026-02-26 09:47:39 -0500 |
|---|---|---|
| committer | Chuck Lever <chuck.lever@oracle.com> | 2026-03-29 21:25:09 -0400 |
| commit | d7f3efd9ff474867b04e1ea784690f02450a245b (patch) | |
| tree | 9b7b29faf3aa65993f1642c6f06d42d72034bc8a | |
| parent | 7ed7504287a627834f2a35ef04e5dfd26d1c8986 (diff) | |
SUNRPC: Optimize rq_respages allocation in svc_alloc_arg
svc_alloc_arg() invokes alloc_pages_bulk() with the full rq_maxpages
count (~259 for 1MB messages) for the rq_respages array, causing a
full-array scan despite most slots holding valid pages.
svc_rqst_release_pages() NULLs only the range
[rq_respages, rq_next_page)
after each RPC, so only that range contains NULL entries. Limit the
rq_respages fill in svc_alloc_arg() to that range instead of
scanning the full array.
svc_init_buffer() initializes rq_next_page to span the entire
rq_respages array, so the first svc_alloc_arg() call fills all
slots.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
| -rw-r--r-- | include/linux/sunrpc/svc.h | 4 | ||||
| -rw-r--r-- | net/sunrpc/svc.c | 1 | ||||
| -rw-r--r-- | net/sunrpc/svc_xprt.c | 8 |
3 files changed, 12 insertions, 1 deletions
diff --git a/include/linux/sunrpc/svc.h b/include/linux/sunrpc/svc.h index c3399cf64524..669c944eaf7f 100644 --- a/include/linux/sunrpc/svc.h +++ b/include/linux/sunrpc/svc.h @@ -152,6 +152,10 @@ extern u32 svc_max_payload(const struct svc_rqst *rqstp); * still in transport use, and set rq_pages_nfree to the count. * svc_alloc_arg() refills only that many rq_pages entries. * + * For rq_respages, svc_rqst_release_pages() NULLs entries in + * [rq_respages, rq_next_page) after each RPC. svc_alloc_arg() + * refills only that range. + * * xdr_buf holds responses; the structure fits NFS read responses * (header, data pages, optional tail) and enables sharing of * client-side routines. diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c index 6e57e35fa6d6..5e0b5ec2fd52 100644 --- a/net/sunrpc/svc.c +++ b/net/sunrpc/svc.c @@ -656,6 +656,7 @@ svc_init_buffer(struct svc_rqst *rqstp, const struct svc_serv *serv, int node) } rqstp->rq_pages_nfree = rqstp->rq_maxpages; + rqstp->rq_next_page = rqstp->rq_respages + rqstp->rq_maxpages; return true; } diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c index 795b5729525f..b16e710926c1 100644 --- a/net/sunrpc/svc_xprt.c +++ b/net/sunrpc/svc_xprt.c @@ -686,8 +686,14 @@ static bool svc_alloc_arg(struct svc_rqst *rqstp) rqstp->rq_pages_nfree = 0; } - if (!svc_fill_pages(rqstp, rqstp->rq_respages, pages)) + if (WARN_ON_ONCE(rqstp->rq_next_page < rqstp->rq_respages)) return false; + nfree = rqstp->rq_next_page - rqstp->rq_respages; + if (nfree) { + if (!svc_fill_pages(rqstp, rqstp->rq_respages, nfree)) + return false; + } + rqstp->rq_next_page = rqstp->rq_respages; rqstp->rq_page_end = &rqstp->rq_respages[pages]; /* svc_rqst_replace_page() dereferences *rq_next_page even |