[v2,00/13] Put struct nfsd4_copy on a diet

Message

Chuck Lever July 27, 2022, 6:39 p.m. UTC

While testing NFSD for-next, I noticed svc_generic_init_request()
was an unexpected hot spot on NFSv4 workloads. Drilling into the
perf report, it shows that the hot path in there is:

1208         memset(rqstp->rq_argp, 0, procp->pc_argsize);
1209         memset(rqstp->rq_resp, 0, procp->pc_ressize);

For an NFSv4 COMPOUND,

	procp->pc_argsize = sizeof(nfsd4_compoundargs),

struct nfsd4_compoundargs on my system is more than 17KB! This is
due to the size of the iops field:

	struct nfsd4_op                 iops[8];

Each struct nfsd4_op contains a union of the arguments for each
NFSv4 operation. Each argument is typically less than 128 bytes
except that struct nfsd4_copy and struct nfsd4_copy_notify are both
larger than 2KB each.

Changes since v1:
- Fix a compile-time bug spotted by the kernel 0-day robot
- Fix a crasher reported by Dai, then by Olga
- Add two more clean-up patches

---

Chuck Lever (13):
      NFSD: Fix strncpy() fortify warning
      NFSD: nfserrno(-ENOMEM) is nfserr_jukebox
      NFSD: Shrink size of struct nfsd4_copy_notify
      NFSD: Shrink size of struct nfsd4_copy
      NFSD: Reorder the fields in struct nfsd4_op
      NFSD: Make nfs4_put_copy() static
      NFSD: Make boolean fields in struct nfsd4_copy into atomic bit flags
      NFSD: Refactor nfsd4_cleanup_inter_ssc() (1/2)
      NFSD: Refactor nfsd4_cleanup_inter_ssc() (2/2)
      NFSD: Refactor nfsd4_do_copy()
      NFSD: Remove kmalloc from nfsd4_do_async_copy()
      NFSD: Add nfsd4_send_cb_offload()
      NFSD: Move copy offload callback arguments into a separate structure


 fs/nfsd/nfs4callback.c  |  37 +++++----
 fs/nfsd/nfs4proc.c      | 169 ++++++++++++++++++++--------------------
 fs/nfsd/nfs4xdr.c       |  33 +++++---
 fs/nfsd/state.h         |   1 -
 fs/nfsd/xdr4.h          |  54 +++++++++----
 include/linux/nfs_ssc.h |   2 +-
 6 files changed, 167 insertions(+), 129 deletions(-)

--
Chuck Lever