Re: [pnfs] [PATCH 5/5] nfsd41: replace page based DRC with buffer based DRC

William A. (Andy) Adamson
2009-09-01T15:22:23Z

On Tue, Sep 1, 2009 at 11:14 AM, J. Bruce Fields<bfields@fieldses.org> =
wrote:
> On Tue, Sep 01, 2009 at 09:48:41AM -0400, William A. (Andy) Adamson w=
rote:
>> On Fri, Aug 28, 2009 at 5:33 PM, J. Bruce Fields<bfields-uC3wQj2KruMpug/h7KTFAQ@public.gmane.org=
g> wrote:
>> > On Thu, Aug 27, 2009 at 12:07:44PM -0400, andros@netapp.com wrote:
>> >> From: Andy Adamson <andros@netapp.com>
>> >>
>> >> Use NFSD_SLOT_CACHE_SIZE size buffers for sessions DRC instead of=
holding nfsd
>> >> pages in cache.
>> >>
>> >> Connectathon testing has shown that 1024 bytes for encoded compou=
nd operation
>> >> responses past the sequence operation is sufficient, 512 bytes is=
a little too
>> >> small. Set NFSD_SLOT_CACHE_SIZE to 1024.
>> >>
>> >> Allocate memory for the session DRC in the CREATE_SESSION operati=
on
>> >> to guarantee that the memory resource is available for caching re=
sponses.
>> >> Allocate each slot individually in preparation for slot table siz=
e negotiation.
>> >>
>> >> Remove struct nfsd4_cache_entry and helper functions for the old =
page-based
>> >> DRC.
>> >>
>> >> The iov_len calculation in nfs4svc_encode_compoundres is now alwa=
ys
>> >> correct, clean up the nfs4svc_encode_compoundres session logic.
>> >>
>> >> The nfsd4_compound_state statp pointer is also not used.
>> >> Remove nfsd4_set_statp().
>> >>
>> >> Move useful nfsd4_cache_entry fields into nfsd4_slot.
>> >>
>> >> Signed-off-by: Andy Adamson <andros@netapp.com
>> >> ---
>> >> =A0fs/nfsd/nfs4state.c =A0 =A0 =A0 =A0| =A0207 ++++++++++++------=
--------------------------
>> >> =A0fs/nfsd/nfs4xdr.c =A0 =A0 =A0 =A0 =A0| =A0 13 ++--
>> >> =A0fs/nfsd/nfssvc.c =A0 =A0 =A0 =A0 =A0 | =A0 =A04 -
>> >> =A0include/linux/nfsd/state.h | =A0 27 ++----
>> >> =A0include/linux/nfsd/xdr4.h =A0| =A0 =A05 +-
>> >> =A05 files changed, 74 insertions(+), 182 deletions(-)
>> >>
>> >> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
>> >> index 4695cec..2d72d5c 100644
>> >> --- a/fs/nfsd/nfs4state.c
>> >> +++ b/fs/nfsd/nfs4state.c
>> >> @@ -510,12 +510,22 @@ static int init_forechannel_attrs(struct sv=
c_rqst *rqstp,
>> >> =A0 =A0 =A0 return status;
>> >> =A0}
>> >>
>> >> +static void
>> >> +free_session_slots(struct nfsd4_session *ses)
>> >> +{
>> >> + =A0 =A0 int i;
>> >> +
>> >> + =A0 =A0 for (i =3D 0; i < ses->se_fchannel.maxreqs; i++)
>> >> + =A0 =A0 =A0 =A0 =A0 =A0 kfree(ses->se_slots[i]);
>> >> +}
>> >> +
>> >> =A0static int
>> >> =A0alloc_init_session(struct svc_rqst *rqstp, struct nfs4_client =
*clp,
>> >> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0struct nfsd4_create_session *c=
ses)
>> >> =A0{
>> >> =A0 =A0 =A0 struct nfsd4_session *new, tmp;
>> >> - =A0 =A0 int idx, status =3D nfserr_serverfault, slotsize;
>> >> + =A0 =A0 struct nfsd4_slot *sp;
>> >> + =A0 =A0 int idx, status =3D nfserr_serverfault, slotsize, cache=
size, i;
>> >
>> > Just as a style thing: that list's getting a little long. =A0Could=
you
>> > keep at least "status" on a separate line?
>> >
>> >>
>> >> =A0 =A0 =A0 memset(&tmp, 0, sizeof(tmp));
>> >>
>> >> @@ -526,14 +536,23 @@ alloc_init_session(struct svc_rqst *rqstp, =
struct nfs4_client *clp,
>> >> =A0 =A0 =A0 if (status)
>> >> =A0 =A0 =A0 =A0 =A0 =A0 =A0 goto out;
>> >>
>> >> - =A0 =A0 /* allocate struct nfsd4_session and slot table in one =
piece */
>> >> - =A0 =A0 slotsize =3D tmp.se_fchannel.maxreqs * sizeof(struct nf=
sd4_slot);
>> >> + =A0 =A0 /* allocate struct nfsd4_session and slot table pointer=
s in one piece */
>> >> + =A0 =A0 slotsize =3D tmp.se_fchannel.maxreqs * sizeof(struct nf=
sd4_slot *);
>> >> =A0 =A0 =A0 new =3D kzalloc(sizeof(*new) + slotsize, GFP_KERNEL);
>> >
>> > I think this is OK for now, but maybe stick something like:
>> >
>> > =A0 =A0 =A0 =A0BUILD_BUG_ON(NFSD_MAX_SLOTS_PER_SESSION * sizeof(st=
ruct nfsd4_slot)
>> > =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0+ sizeof(struct nfs=
d4_session) > PAGE_SIZE);
>> >
>> > in state.h just to warn anyone who wants to blindly bump up
>> > NFSD_MAX_SLOTS_PER_SESSION. =A0(It's not really forbidden to kmall=
oc more
>> > than a page, but it's also not reliable, and if it becomes necessa=
ry
>> > then we'd rather find some way to code around it.)
>> >
>> >> =A0 =A0 =A0 if (!new)
>> >> =A0 =A0 =A0 =A0 =A0 =A0 =A0 goto out;
>> >>
>> >> =A0 =A0 =A0 memcpy(new, &tmp, sizeof(*new));
>> >>
>> >> + =A0 =A0 /* allocate each struct nfsd4_slot and data cache in on=
e piece */
>> >> + =A0 =A0 cachesize =3D new->se_fchannel.maxresp_cached - NFSD_MI=
N_HDR_SEQ_SZ;
>> >> + =A0 =A0 for (i =3D 0; i < new->se_fchannel.maxreqs; i++) {
>> >> + =A0 =A0 =A0 =A0 =A0 =A0 sp =3D kzalloc(sizeof(*sp) + cachesize,=
GFP_KERNEL);
>> >> + =A0 =A0 =A0 =A0 =A0 =A0 if (!sp)
>> >> + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 goto out_free;
>> >> + =A0 =A0 =A0 =A0 =A0 =A0 new->se_slots[i] =3D sp;
>> >> + =A0 =A0 }
>> >> +
>> >> =A0 =A0 =A0 new->se_client =3D clp;
>> >> =A0 =A0 =A0 gen_sessionid(new);
>> >> =A0 =A0 =A0 idx =3D hash_sessionid(&new->se_sessionid);
>> >> @@ -550,6 +569,10 @@ alloc_init_session(struct svc_rqst *rqstp, s=
truct nfs4_client *clp,
>> >> =A0 =A0 =A0 status =3D nfs_ok;
>> >> =A0out:
>> >> =A0 =A0 =A0 return status;
>> >> +out_free:
>> >> + =A0 =A0 free_session_slots(new);
>> >> + =A0 =A0 kfree(new);
>> >> + =A0 =A0 goto out;
>> >> =A0}
>> >>
>> >> =A0/* caller must hold sessionid_lock */
>> >> @@ -592,22 +615,16 @@ release_session(struct nfsd4_session *ses)
>> >> =A0 =A0 =A0 nfsd4_put_session(ses);
>> >> =A0}
>> >>
>> >> -static void nfsd4_release_respages(struct page **respages, short=
resused);
>> >> -
>> >> =A0void
>> >> =A0free_session(struct kref *kref)
>> >> =A0{
>> >> =A0 =A0 =A0 struct nfsd4_session *ses;
>> >> - =A0 =A0 int i;
>> >>
>> >> =A0 =A0 =A0 ses =3D container_of(kref, struct nfsd4_session, se_r=
ef);
>> >> - =A0 =A0 for (i =3D 0; i < ses->se_fchannel.maxreqs; i++) {
>> >> - =A0 =A0 =A0 =A0 =A0 =A0 struct nfsd4_cache_entry *e =3D &ses->s=
e_slots[i].sl_cache_entry;
>> >> - =A0 =A0 =A0 =A0 =A0 =A0 nfsd4_release_respages(e->ce_respages, =
e->ce_resused);
>> >> - =A0 =A0 }
>> >> =A0 =A0 =A0 spin_lock(&nfsd_drc_lock);
>> >> =A0 =A0 =A0 nfsd_drc_mem_used -=3D ses->se_fchannel.maxreqs * NFS=
D_SLOT_CACHE_SIZE;
>> >> =A0 =A0 =A0 spin_unlock(&nfsd_drc_lock);
>> >> + =A0 =A0 free_session_slots(ses);
>> >> =A0 =A0 =A0 kfree(ses);
>> >> =A0}
>> >>
>> >> @@ -964,116 +981,32 @@ out_err:
>> >> =A0 =A0 =A0 return;
>> >> =A0}
>> >>
>> >> -void
>> >> -nfsd4_set_statp(struct svc_rqst *rqstp, __be32 *statp)
>> >> -{
>> >> - =A0 =A0 struct nfsd4_compoundres *resp =3D rqstp->rq_resp;
>> >> -
>> >> - =A0 =A0 resp->cstate.statp =3D statp;
>> >> -}
>> >> -
>> >> -/*
>> >> - * Dereference the result pages.
>> >> - */
>> >> -static void
>> >> -nfsd4_release_respages(struct page **respages, short resused)
>> >> -{
>> >> - =A0 =A0 int i;
>> >> -
>> >> - =A0 =A0 dprintk("--> %s\n", __func__);
>> >> - =A0 =A0 for (i =3D 0; i < resused; i++) {
>> >> - =A0 =A0 =A0 =A0 =A0 =A0 if (!respages[i])
>> >> - =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 continue;
>> >> - =A0 =A0 =A0 =A0 =A0 =A0 put_page(respages[i]);
>> >> - =A0 =A0 =A0 =A0 =A0 =A0 respages[i] =3D NULL;
>> >> - =A0 =A0 }
>> >> -}
>> >> -
>> >> -static void
>> >> -nfsd4_copy_pages(struct page **topages, struct page **frompages,=
short count)
>> >> -{
>> >> - =A0 =A0 int i;
>> >> -
>> >> - =A0 =A0 for (i =3D 0; i < count; i++) {
>> >> - =A0 =A0 =A0 =A0 =A0 =A0 topages[i] =3D frompages[i];
>> >> - =A0 =A0 =A0 =A0 =A0 =A0 if (!topages[i])
>> >> - =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 continue;
>> >> - =A0 =A0 =A0 =A0 =A0 =A0 get_page(topages[i]);
>> >> - =A0 =A0 }
>> >> -}
>> >> -
>> >> =A0/*
>> >> - * Cache the reply pages up to NFSD_PAGES_PER_SLOT + 1, clearing=
the previous
>> >> - * pages. We add a page to NFSD_PAGES_PER_SLOT for the case wher=
e the total
>> >> - * length of the XDR response is less than se_fmaxresp_cached
>> >> - * (NFSD_PAGES_PER_SLOT * PAGE_SIZE) but the xdr_buf pages is us=
ed for a
>> >> - * of the reply (e.g. readdir).
>> >> - *
>> >> - * Store the base and length of the rq_req.head[0] page
>> >> - * of the NFSv4.1 data, just past the rpc header.
>> >> + * Cache a reply. nfsd4_check_drc_limit() has bounded the cache =
size.
>> >> =A0 */
>> >> =A0void
>> >> =A0nfsd4_store_cache_entry(struct nfsd4_compoundres *resp)
>> >> =A0{
>> >> - =A0 =A0 struct nfsd4_cache_entry *entry =3D &resp->cstate.slot-=
>sl_cache_entry;
>> >> - =A0 =A0 struct svc_rqst *rqstp =3D resp->rqstp;
>> >> - =A0 =A0 struct kvec *resv =3D &rqstp->rq_res.head[0];
>> >> -
>> >> - =A0 =A0 dprintk("--> %s entry %p\n", __func__, entry);
>> >> + =A0 =A0 struct nfsd4_slot *slot =3D resp->cstate.slot;
>> >> + =A0 =A0 unsigned int base;
>> >>
>> >> - =A0 =A0 nfsd4_release_respages(entry->ce_respages, entry->ce_re=
sused);
>> >> - =A0 =A0 entry->ce_opcnt =3D resp->opcnt;
>> >> - =A0 =A0 entry->ce_status =3D resp->cstate.status;
>> >> + =A0 =A0 dprintk("--> %s slot %p\n", __func__, slot);
>> >>
>> >> - =A0 =A0 /*
>> >> - =A0 =A0 =A0* Don't need a page to cache just the sequence opera=
tion - the slot
>> >> - =A0 =A0 =A0* does this for us!
>> >> - =A0 =A0 =A0*/
>> >> + =A0 =A0 slot->sl_opcnt =3D resp->opcnt;
>> >> + =A0 =A0 slot->sl_status =3D resp->cstate.status;
>> >>
>> >> =A0 =A0 =A0 if (nfsd4_not_cached(resp)) {
>> >> - =A0 =A0 =A0 =A0 =A0 =A0 entry->ce_resused =3D 0;
>> >> - =A0 =A0 =A0 =A0 =A0 =A0 entry->ce_rpchdrlen =3D 0;
>> >> - =A0 =A0 =A0 =A0 =A0 =A0 dprintk("%s Just cache SEQUENCE. ce_cac=
hethis %d\n", __func__,
>> >> - =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 resp->cstate.slot->sl_c=
ache_entry.ce_cachethis);
>> >> + =A0 =A0 =A0 =A0 =A0 =A0 slot->sl_datalen =3D 0;
>> >> =A0 =A0 =A0 =A0 =A0 =A0 =A0 return;
>> >> =A0 =A0 =A0 }
>> >> - =A0 =A0 entry->ce_resused =3D rqstp->rq_resused;
>> >> - =A0 =A0 if (entry->ce_resused > NFSD_PAGES_PER_SLOT + 1)
>> >> - =A0 =A0 =A0 =A0 =A0 =A0 entry->ce_resused =3D NFSD_PAGES_PER_SL=
OT + 1;
>> >> - =A0 =A0 nfsd4_copy_pages(entry->ce_respages, rqstp->rq_respages=
,
>> >> - =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0entry->ce_resused);
>> >> - =A0 =A0 entry->ce_datav.iov_base =3D resp->cstate.statp;
>> >> - =A0 =A0 entry->ce_datav.iov_len =3D resv->iov_len - ((char *)re=
sp->cstate.statp -
>> >> - =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 (char *=
)page_address(rqstp->rq_respages[0]));
>> >> - =A0 =A0 /* Current request rpc header length*/
>> >> - =A0 =A0 entry->ce_rpchdrlen =3D (char *)resp->cstate.statp -
>> >> - =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 (char *=
)page_address(rqstp->rq_respages[0]);
>> >> -}
>> >> -
>> >> -/*
>> >> - * We keep the rpc header, but take the nfs reply from the reply=
cache.
>> >> - */
>> >> -static int
>> >> -nfsd41_copy_replay_data(struct nfsd4_compoundres *resp,
>> >> - =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 struct nfsd4_cache_entr=
y *entry)
>> >> -{
>> >> - =A0 =A0 struct svc_rqst *rqstp =3D resp->rqstp;
>> >> - =A0 =A0 struct kvec *resv =3D &resp->rqstp->rq_res.head[0];
>> >> - =A0 =A0 int len;
>> >> -
>> >> - =A0 =A0 /* Current request rpc header length*/
>> >> - =A0 =A0 len =3D (char *)resp->cstate.statp -
>> >> - =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 (char *)page_address(rq=
stp->rq_respages[0]);
>> >> - =A0 =A0 if (entry->ce_datav.iov_len + len > PAGE_SIZE) {
>> >> - =A0 =A0 =A0 =A0 =A0 =A0 dprintk("%s v41 cached reply too large =
(%Zd).\n", __func__,
>> >> - =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 entry->ce_datav.iov_len=
);
>> >> - =A0 =A0 =A0 =A0 =A0 =A0 return 0;
>> >> - =A0 =A0 }
>> >> - =A0 =A0 /* copy the cached reply nfsd data past the current rpc=
header */
>> >> - =A0 =A0 memcpy((char *)resv->iov_base + len, entry->ce_datav.io=
v_base,
>> >> - =A0 =A0 =A0 =A0 =A0 =A0 entry->ce_datav.iov_len);
>> >> - =A0 =A0 resv->iov_len =3D len + entry->ce_datav.iov_len;
>> >> - =A0 =A0 return 1;
>> >> + =A0 =A0 slot->sl_datalen =3D (char *)resp->p - (char *)resp->cs=
tate.datap;
>> >> + =A0 =A0 base =3D (char *)resp->cstate.datap -
>> >> + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0=
=A0 =A0 (char *)resp->xbuf->head[0].iov_base;
>> >> + =A0 =A0 if (read_bytes_from_xdr_buf(resp->xbuf, base, slot->sl_=
data,
>> >> + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0=
slot->sl_datalen))
>> >> + =A0 =A0 =A0 =A0 =A0 =A0 printk(KERN_WARNING
>> >> + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 "nfsd: sessions DRC cou=
ld not cache compound\n");
>> >
>> > I'd make this WARN("nfsd:...") just to make it completely clear it=
's a
>> > kernel bug. =A0(This case should be caught by nfsd4_check_drc_limi=
t unless
>> > we've messed something up, right?)
>> >
>> >> + =A0 =A0 return;
>> >> =A0}
>> >>
>> >> =A0/*
>> >> @@ -1091,14 +1024,14 @@ nfsd4_enc_sequence_replay(struct nfsd4_co=
mpoundargs *args,
>> >> =A0 =A0 =A0 struct nfsd4_slot *slot =3D resp->cstate.slot;
>> >>
>> >> =A0 =A0 =A0 dprintk("--> %s resp->opcnt %d cachethis %u \n", __fu=
nc__,
>> >> - =A0 =A0 =A0 =A0 =A0 =A0 resp->opcnt, resp->cstate.slot->sl_cach=
e_entry.ce_cachethis);
>> >> + =A0 =A0 =A0 =A0 =A0 =A0 resp->opcnt, resp->cstate.slot->sl_cach=
ethis);
>> >>
>> >> =A0 =A0 =A0 /* Encode the replayed sequence operation */
>> >> =A0 =A0 =A0 op =3D &args->ops[resp->opcnt - 1];
>> >> =A0 =A0 =A0 nfsd4_encode_operation(resp, op);
>> >>
>> >> =A0 =A0 =A0 /* Return nfserr_retry_uncached_rep in next operation=
=2E */
>> >> - =A0 =A0 if (args->opcnt > 1 && slot->sl_cache_entry.ce_cachethi=
s =3D=3D 0) {
>> >> + =A0 =A0 if (args->opcnt > 1 && slot->sl_cachethis =3D=3D 0) {
>> >> =A0 =A0 =A0 =A0 =A0 =A0 =A0 op =3D &args->ops[resp->opcnt++];
>> >> =A0 =A0 =A0 =A0 =A0 =A0 =A0 op->status =3D nfserr_retry_uncached_=
rep;
>> >> =A0 =A0 =A0 =A0 =A0 =A0 =A0 nfsd4_encode_operation(resp, op);
>> >> @@ -1107,57 +1040,29 @@ nfsd4_enc_sequence_replay(struct nfsd4_co=
mpoundargs *args,
>> >> =A0}
>> >>
>> >> =A0/*
>> >> - * Keep the first page of the replay. Copy the NFSv4.1 data from=
the first
>> >> - * cached page. =A0Replace any futher replay pages from the cach=
e.
>> >> + * The sequence operation is not cached because we can use the s=
lot and
>> >> + * session values.
>> >> =A0 */
>> >> =A0__be32
>> >> =A0nfsd4_replay_cache_entry(struct nfsd4_compoundres *resp,
>> >> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0struct nfsd4_seque=
nce *seq)
>> >> =A0{
>> >> - =A0 =A0 struct nfsd4_cache_entry *entry =3D &resp->cstate.slot-=
>sl_cache_entry;
>> >> + =A0 =A0 struct nfsd4_slot *slot =3D resp->cstate.slot;
>> >> =A0 =A0 =A0 __be32 status;
>> >>
>> >> - =A0 =A0 dprintk("--> %s entry %p\n", __func__, entry);
>> >> -
>> >> - =A0 =A0 /*
>> >> - =A0 =A0 =A0* If this is just the sequence operation, we did not=
keep
>> >> - =A0 =A0 =A0* a page in the cache entry because we can just use =
the
>> >> - =A0 =A0 =A0* slot info stored in struct nfsd4_sequence that was=
checked
>> >> - =A0 =A0 =A0* against the slot in nfsd4_sequence().
>> >> - =A0 =A0 =A0*
>> >> - =A0 =A0 =A0* This occurs when seq->cachethis is FALSE, or when =
the client
>> >> - =A0 =A0 =A0* session inactivity timer fires and a solo sequence=
operation
>> >> - =A0 =A0 =A0* is sent (lease renewal).
>> >> - =A0 =A0 =A0*/
>> >> + =A0 =A0 dprintk("--> %s slot %p\n", __func__, slot);
>> >>
>> >> =A0 =A0 =A0 /* Either returns 0 or nfserr_retry_uncached */
>> >> =A0 =A0 =A0 status =3D nfsd4_enc_sequence_replay(resp->rqstp->rq_=
argp, resp);
>> >> =A0 =A0 =A0 if (status =3D=3D nfserr_retry_uncached_rep)
>> >> =A0 =A0 =A0 =A0 =A0 =A0 =A0 return status;
>> >>
>> >> - =A0 =A0 if (!nfsd41_copy_replay_data(resp, entry)) {
>> >> - =A0 =A0 =A0 =A0 =A0 =A0 /*
>> >> - =A0 =A0 =A0 =A0 =A0 =A0 =A0* Not enough room to use the replay =
rpc header, send the
>> >> - =A0 =A0 =A0 =A0 =A0 =A0 =A0* cached header. Release all the all=
ocated result pages.
>> >> - =A0 =A0 =A0 =A0 =A0 =A0 =A0*/
>> >> - =A0 =A0 =A0 =A0 =A0 =A0 svc_free_res_pages(resp->rqstp);
>> >> - =A0 =A0 =A0 =A0 =A0 =A0 nfsd4_copy_pages(resp->rqstp->rq_respag=
es, entry->ce_respages,
>> >> - =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 entry->ce_resused);
>> >> - =A0 =A0 } else {
>> >> - =A0 =A0 =A0 =A0 =A0 =A0 /* Release all but the first allocated =
result page */
>> >> -
>> >> - =A0 =A0 =A0 =A0 =A0 =A0 resp->rqstp->rq_resused--;
>> >> - =A0 =A0 =A0 =A0 =A0 =A0 svc_free_res_pages(resp->rqstp);
>> >> -
>> >> - =A0 =A0 =A0 =A0 =A0 =A0 nfsd4_copy_pages(&resp->rqstp->rq_respa=
ges[1],
>> >> - =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0&ent=
ry->ce_respages[1],
>> >> - =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0entr=
y->ce_resused - 1);
>> >> - =A0 =A0 }
>> >> + =A0 =A0 /* The sequence operation has been encoded, cstate->dat=
ap set. */
>> >> + =A0 =A0 memcpy(resp->cstate.datap, slot->sl_data, slot->sl_data=
len);
>> >>
>> >> - =A0 =A0 resp->rqstp->rq_resused =3D entry->ce_resused;
>> >> - =A0 =A0 resp->opcnt =3D entry->ce_opcnt;
>> >> - =A0 =A0 resp->cstate.iovlen =3D entry->ce_datav.iov_len + entry=
->ce_rpchdrlen;
>> >> - =A0 =A0 status =3D entry->ce_status;
>> >> + =A0 =A0 resp->opcnt =3D slot->sl_opcnt;
>> >> + =A0 =A0 resp->p =3D resp->cstate.datap + XDR_QUADLEN(slot->sl_d=
atalen);
>> >> + =A0 =A0 status =3D slot->sl_status;
>> >>
>> >> =A0 =A0 =A0 return status;
>> >> =A0}
>> >> @@ -1489,7 +1394,7 @@ nfsd4_sequence(struct svc_rqst *rqstp,
>> >> =A0 =A0 =A0 if (seq->slotid >=3D session->se_fchannel.maxreqs)
>> >> =A0 =A0 =A0 =A0 =A0 =A0 =A0 goto out;
>> >>
>> >> - =A0 =A0 slot =3D &session->se_slots[seq->slotid];
>> >> + =A0 =A0 slot =3D session->se_slots[seq->slotid];
>> >> =A0 =A0 =A0 dprintk("%s: slotid %d\n", __func__, seq->slotid);
>> >>
>> >> =A0 =A0 =A0 /* We do not negotiate the number of slots yet, so se=
t the
>> >> @@ -1502,7 +1407,7 @@ nfsd4_sequence(struct svc_rqst *rqstp,
>> >> =A0 =A0 =A0 =A0 =A0 =A0 =A0 cstate->slot =3D slot;
>> >> =A0 =A0 =A0 =A0 =A0 =A0 =A0 cstate->session =3D session;
>> >> =A0 =A0 =A0 =A0 =A0 =A0 =A0 /* Return the cached reply status and=
set cstate->status
>> >> - =A0 =A0 =A0 =A0 =A0 =A0 =A0* for nfsd4_svc_encode_compoundres p=
rocessing */
>> >> + =A0 =A0 =A0 =A0 =A0 =A0 =A0* for nfsd4_proc_compound processing=
*/
>> >> =A0 =A0 =A0 =A0 =A0 =A0 =A0 status =3D nfsd4_replay_cache_entry(r=
esp, seq);
>> >> =A0 =A0 =A0 =A0 =A0 =A0 =A0 cstate->status =3D nfserr_replay_cach=
e;
>> >> =A0 =A0 =A0 =A0 =A0 =A0 =A0 goto replay_cache;
>> >> @@ -1513,7 +1418,7 @@ nfsd4_sequence(struct svc_rqst *rqstp,
>> >> =A0 =A0 =A0 /* Success! bump slot seqid */
>> >> =A0 =A0 =A0 slot->sl_inuse =3D true;
>> >> =A0 =A0 =A0 slot->sl_seqid =3D seq->seqid;
>> >> - =A0 =A0 slot->sl_cache_entry.ce_cachethis =3D seq->cachethis;
>> >> + =A0 =A0 slot->sl_cachethis =3D seq->cachethis;
>> >>
>> >> =A0 =A0 =A0 cstate->slot =3D slot;
>> >> =A0 =A0 =A0 cstate->session =3D session;
>> >> diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
>> >> index fdf632b..49824ea 100644
>> >> --- a/fs/nfsd/nfs4xdr.c
>> >> +++ b/fs/nfsd/nfs4xdr.c
>> >> @@ -3064,6 +3064,7 @@ nfsd4_encode_sequence(struct nfsd4_compound=
res *resp, int nfserr,
>> >> =A0 =A0 =A0 WRITE32(0);
>> >>
>> >> =A0 =A0 =A0 ADJUST_ARGS();
>> >> + =A0 =A0 resp->cstate.datap =3D p; /* DRC cache data pointer */
>> >> =A0 =A0 =A0 return 0;
>> >> =A0}
>> >>
>> >> @@ -3166,7 +3167,7 @@ static int nfsd4_check_drc_limit(struct nfs=
d4_compoundres *resp)
>> >> =A0 =A0 =A0 =A0 =A0 =A0 =A0 return status;
>> >>
>> >> =A0 =A0 =A0 session =3D resp->cstate.session;
>> >> - =A0 =A0 if (session =3D=3D NULL || slot->sl_cache_entry.ce_cach=
ethis =3D=3D 0)
>> >> + =A0 =A0 if (session =3D=3D NULL || slot->sl_cachethis =3D=3D 0)
>> >> =A0 =A0 =A0 =A0 =A0 =A0 =A0 return status;
>> >>
>> >> =A0 =A0 =A0 if (resp->opcnt >=3D args->opcnt)
>> >> @@ -3291,6 +3292,7 @@ nfs4svc_encode_compoundres(struct svc_rqst =
*rqstp, __be32 *p, struct nfsd4_compo
>> >> =A0 =A0 =A0 /*
>> >> =A0 =A0 =A0 =A0* All that remains is to write the tag and operati=
on count...
>> >> =A0 =A0 =A0 =A0*/
>> >> + =A0 =A0 struct nfsd4_compound_state *cs =3D &resp->cstate;
>> >> =A0 =A0 =A0 struct kvec *iov;
>> >> =A0 =A0 =A0 p =3D resp->tagp;
>> >> =A0 =A0 =A0 *p++ =3D htonl(resp->taglen);
>> >> @@ -3304,14 +3306,11 @@ nfs4svc_encode_compoundres(struct svc_rqs=
t *rqstp, __be32 *p, struct nfsd4_compo
>> >> =A0 =A0 =A0 =A0 =A0 =A0 =A0 iov =3D &rqstp->rq_res.head[0];
>> >> =A0 =A0 =A0 iov->iov_len =3D ((char*)resp->p) - (char*)iov->iov_b=
ase;
>> >> =A0 =A0 =A0 BUG_ON(iov->iov_len > PAGE_SIZE);
>> >> - =A0 =A0 if (nfsd4_has_session(&resp->cstate)) {
>> >> - =A0 =A0 =A0 =A0 =A0 =A0 if (resp->cstate.status =3D=3D nfserr_r=
eplay_cache &&
>> >> - =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 !nfsd4_=
not_cached(resp)) {
>> >> - =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 iov->iov_len =3D resp->=
cstate.iovlen;
>> >> - =A0 =A0 =A0 =A0 =A0 =A0 } else {
>> >> + =A0 =A0 if (nfsd4_has_session(cs)) {
>> >> + =A0 =A0 =A0 =A0 =A0 =A0 if (cs->status !=3D nfserr_replay_cache=
) {
>> >> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 nfsd4_store_cache_ent=
ry(resp);
>> >> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 dprintk("%s: SET SLOT=
STATE TO AVAILABLE\n", __func__);
>> >> - =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 resp->cstate.slot->sl_i=
nuse =3D 0;
>> >> + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 resp->cstate.slot->sl_i=
nuse =3D false;
>> >> =A0 =A0 =A0 =A0 =A0 =A0 =A0 }
>> >> =A0 =A0 =A0 =A0 =A0 =A0 =A0 nfsd4_put_session(resp->cstate.sessio=
n);
>> >> =A0 =A0 =A0 }
>> >> diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c
>> >> index d68cd05..944ef01 100644
>> >> --- a/fs/nfsd/nfssvc.c
>> >> +++ b/fs/nfsd/nfssvc.c
>> >> @@ -576,10 +576,6 @@ nfsd_dispatch(struct svc_rqst *rqstp, __be32=
*statp)
>> >> =A0 =A0 =A0 =A0 =A0 =A0 =A0 + rqstp->rq_res.head[0].iov_len;
>> >> =A0 =A0 =A0 rqstp->rq_res.head[0].iov_len +=3D sizeof(__be32);
>> >>
>> >> - =A0 =A0 /* NFSv4.1 DRC requires statp */
>> >> - =A0 =A0 if (rqstp->rq_vers =3D=3D 4)
>> >> - =A0 =A0 =A0 =A0 =A0 =A0 nfsd4_set_statp(rqstp, statp);
>> >> -
>> >> =A0 =A0 =A0 /* Now call the procedure handler, and encode NFS sta=
tus. */
>> >> =A0 =A0 =A0 nfserr =3D proc->pc_func(rqstp, rqstp->rq_argp, rqstp=
->rq_resp);
>> >> =A0 =A0 =A0 nfserr =3D map_new_errors(rqstp->rq_vers, nfserr);
>> >> diff --git a/include/linux/nfsd/state.h b/include/linux/nfsd/stat=
e.h
>> >> index ff0b771..e745100 100644
>> >> --- a/include/linux/nfsd/state.h
>> >> +++ b/include/linux/nfsd/state.h
>> >> @@ -94,30 +94,23 @@ struct nfs4_cb_conn {
>> >>
>> >> =A0/* Maximum number of slots per session. 160 is useful for long=
haul TCP */
>> >> =A0#define NFSD_MAX_SLOTS_PER_SESSION =A0 =A0 160
>> >> -/* Maximum number of pages per slot cache entry */
>> >> -#define NFSD_PAGES_PER_SLOT =A01
>> >> -#define NFSD_SLOT_CACHE_SIZE =A0 =A0 =A0 =A0 PAGE_SIZE
>> >> =A0/* Maximum number of operations per session compound */
>> >> =A0#define NFSD_MAX_OPS_PER_COMPOUND =A0 =A016
>> >> +/* Maximum =A0session per slot cache size */
>> >> +#define NFSD_SLOT_CACHE_SIZE =A0 =A0 =A0 =A0 1024
>> >> =A0/* Maximum number of NFSD_SLOT_CACHE_SIZE slots per session */
>> >> =A0#define NFSD_CACHE_SIZE_SLOTS_PER_SESSION =A0 =A032
>> >> =A0#define NFSD_MAX_MEM_PER_SESSION =A0\
>> >> =A0 =A0 =A0 =A0 =A0 =A0 =A0 (NFSD_CACHE_SIZE_SLOTS_PER_SESSION * =
NFSD_SLOT_CACHE_SIZE)
>> >>
>> >> -struct nfsd4_cache_entry {
>> >> - =A0 =A0 __be32 =A0 =A0 =A0 =A0 =A0ce_status;
>> >> - =A0 =A0 struct kvec =A0 =A0 ce_datav; /* encoded NFSv4.1 data i=
n rq_res.head[0] */
>> >> - =A0 =A0 struct page =A0 =A0 *ce_respages[NFSD_PAGES_PER_SLOT + =
1];
>> >> - =A0 =A0 int =A0 =A0 =A0 =A0 =A0 =A0 ce_cachethis;
>> >> - =A0 =A0 short =A0 =A0 =A0 =A0 =A0 ce_resused;
>> >> - =A0 =A0 int =A0 =A0 =A0 =A0 =A0 =A0 ce_opcnt;
>> >> - =A0 =A0 int =A0 =A0 =A0 =A0 =A0 =A0 ce_rpchdrlen;
>> >> -};
>> >> -
>> >> =A0struct nfsd4_slot {
>> >> - =A0 =A0 bool =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0=
=A0sl_inuse;
>> >> - =A0 =A0 u32 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0=
=A0 sl_seqid;
>> >> - =A0 =A0 struct nfsd4_cache_entry =A0 =A0 =A0 =A0sl_cache_entry;
>> >> + =A0 =A0 bool =A0 =A0sl_inuse;
>> >> + =A0 =A0 u32 =A0 =A0 sl_seqid;
>> >> + =A0 =A0 int =A0 =A0 sl_cachethis;
>> >> + =A0 =A0 int =A0 =A0 sl_opcnt;
>> >> + =A0 =A0 __be32 =A0sl_status;
>> >> + =A0 =A0 u32 =A0 =A0 sl_datalen;
>> >> + =A0 =A0 char =A0 =A0sl_data[];
>> >
>> > Could you just move sl_inuse to the end? =A0It'll save a few bytes=
in the
>> > structure (because the compiler will probably stick 3 bytes after =
it to
>> > align sl_seqid.)
>>
>> How about this?
>>
>> struct nfsd4_slot {
>> - =A0 =A0 =A0 bool =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0=
=A0sl_inuse;
>> - =A0 =A0 =A0 u32 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0=
=A0 sl_seqid;
>> - =A0 =A0 =A0 struct nfsd4_cache_entry =A0 =A0 =A0 =A0sl_cache_entry=
;
>> + =A0 =A0 =A0 bool =A0 =A0sl_inuse;
>> + =A0 =A0 =A0 bool =A0 =A0sl_cachethis;
>> + =A0 =A0 =A0 u16 =A0 =A0 sl_opcnt;
>> + =A0 =A0 =A0 u32 =A0 =A0 sl_seqid;
>> + =A0 =A0 =A0 __be32 =A0sl_status;
>> + =A0 =A0 =A0 u32 =A0 =A0 sl_datalen;
>> + =A0 =A0 =A0 char =A0 =A0sl_data[];
>> =A0};
>
> Looks OK to me! =A0By the way, on recent distro's you should be able =
to
> run apt-get install/yum install dwarves, then
>
> =A0 =A0 =A0 =A0pahole fs/nfsd/nfsd.o
>
> and look through the output for the struct of interest:
>
> struct nfsd4_slot {
> =A0 =A0 =A0 =A0bool =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 sl_in=
use; =A0 =A0 =A0 =A0 =A0 =A0 /* =A0 =A0 0 =A0 =A0 1 */
>
> =A0 =A0 =A0 =A0/* XXX 3 bytes hole, try to pack */
>
> =A0 =A0 =A0 =A0u32 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0sl_=
seqid; =A0 =A0 =A0 =A0 =A0 =A0 /* =A0 =A0 4 =A0 =A0 4 */
> =A0 =A0 =A0 =A0struct nfsd4_cache_entry =A0 sl_cache_entry; =A0 =A0 =A0=
/* =A0 =A0 8 =A0 =A036 */
>
> =A0 =A0 =A0 =A0/* size: 44, cachelines: 1 */
> =A0 =A0 =A0 =A0/* sum members: 41, holes: 1, sum holes: 3 */
> =A0 =A0 =A0 =A0/* last cacheline: 44 bytes */
> }; =A0 =A0 =A0/* definitions: 3 */
>
> (But no point obsessing over this kind of thing; I just happened to
> notice the problem in this patch and figured for such a common struct=
ure
> it might be worth mentioning.)

Cool! - thanks for the pointer

-->Andy
>
> --b.
>
>>
>> -->Andy
>>
>> > --b.
>> >
>> >> =A0};
>> >>
>> >> =A0struct nfsd4_channel_attrs {
>> >> @@ -159,7 +152,7 @@ struct nfsd4_session {
>> >> =A0 =A0 =A0 struct nfs4_sessionid =A0 se_sessionid;
>> >> =A0 =A0 =A0 struct nfsd4_channel_attrs se_fchannel;
>> >> =A0 =A0 =A0 struct nfsd4_channel_attrs se_bchannel;
>> >> - =A0 =A0 struct nfsd4_slot =A0 =A0 =A0 se_slots[]; =A0 =A0 /* fo=
rward channel slots */
>> >> + =A0 =A0 struct nfsd4_slot =A0 =A0 =A0 *se_slots[]; =A0 =A0/* fo=
rward channel slots */
>> >> =A0};
>> >>
>> >> =A0static inline void
>> >> diff --git a/include/linux/nfsd/xdr4.h b/include/linux/nfsd/xdr4.=
h
>> >> index 3f71660..73164c2 100644
>> >> --- a/include/linux/nfsd/xdr4.h
>> >> +++ b/include/linux/nfsd/xdr4.h
>> >> @@ -51,7 +51,7 @@ struct nfsd4_compound_state {
>> >> =A0 =A0 =A0 /* For sessions DRC */
>> >> =A0 =A0 =A0 struct nfsd4_session =A0 =A0*session;
>> >> =A0 =A0 =A0 struct nfsd4_slot =A0 =A0 =A0 *slot;
>> >> - =A0 =A0 __be32 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0*statp;
>> >> + =A0 =A0 __be32 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0*datap;
>> >> =A0 =A0 =A0 size_t =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0iovlen;
>> >> =A0 =A0 =A0 u32 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 minorvers=
ion;
>> >> =A0 =A0 =A0 u32 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 status;
>> >> @@ -472,8 +472,7 @@ static inline bool nfsd4_is_solo_sequence(str=
uct nfsd4_compoundres *resp)
>> >>
>> >> =A0static inline bool nfsd4_not_cached(struct nfsd4_compoundres *=
resp)
>> >> =A0{
>> >> - =A0 =A0 return !resp->cstate.slot->sl_cache_entry.ce_cachethis =
||
>> >> - =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 nfsd4_is_solo_sequence(=
resp);
>> >> + =A0 =A0 return !resp->cstate.slot->sl_cachethis || nfsd4_is_sol=
o_sequence(resp);
>> >> =A0}
>> >>
>> >> =A0#define NFS4_SVC_XDRSIZE =A0 =A0 =A0 =A0 =A0 =A0 sizeof(struct=
nfsd4_compoundargs)
>> >> --
>> >> 1.6.2.5
>> >>
>> > _______________________________________________
>> > pNFS mailing list
>> > pNFS@linux-nfs.org
>> > http://linux-nfs.org/cgi-bin/mailman/listinfo/pnfs
>> >
>