On Tue, Sep 1, 2009 at 11:14 AM, J. Bruce Fields<bfields@xxxxxxxxxxxx> wrote:
> On Tue, Sep 01, 2009 at 09:48:41AM -0400, William A. (Andy) Adamson wrote:
>> On Fri, Aug 28, 2009 at 5:33 PM, J. Bruce Fields<bfields@xxxxxxxxxxxx> wrote:
>> > On Thu, Aug 27, 2009 at 12:07:44PM -0400, andros@xxxxxxxxxx wrote:
>> >> From: Andy Adamson <andros@xxxxxxxxxx>
>> >>
>> >> 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 compound 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 operation
>> >> to guarantee that the memory resource is available for caching responses.
>> >> Allocate each slot individually in preparation for slot table size 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 always
>> >> 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@xxxxxxxxxx
>> >> ---
>> >> fs/nfsd/nfs4state.c | 207 ++++++++++++--------------------------------
>> >> fs/nfsd/nfs4xdr.c | 13 ++--
>> >> fs/nfsd/nfssvc.c | 4 -
>> >> include/linux/nfsd/state.h | 27 ++----
>> >> include/linux/nfsd/xdr4.h | 5 +-
>> >> 5 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 svc_rqst *rqstp,
>> >> return status;
>> >> }
>> >>
>> >> +static void
>> >> +free_session_slots(struct nfsd4_session *ses)
>> >> +{
>> >> + int i;
>> >> +
>> >> + for (i = 0; i < ses->se_fchannel.maxreqs; i++)
>> >> + kfree(ses->se_slots[i]);
>> >> +}
>> >> +
>> >> static int
>> >> alloc_init_session(struct svc_rqst *rqstp, struct nfs4_client *clp,
>> >> struct nfsd4_create_session *cses)
>> >> {
>> >> struct nfsd4_session *new, tmp;
>> >> - int idx, status = nfserr_serverfault, slotsize;
>> >> + struct nfsd4_slot *sp;
>> >> + int idx, status = nfserr_serverfault, slotsize, cachesize, i;
>> >
>> > Just as a style thing: that list's getting a little long. Could you
>> > keep at least "status" on a separate line?
>> >
>> >>
>> >> memset(&tmp, 0, sizeof(tmp));
>> >>
>> >> @@ -526,14 +536,23 @@ alloc_init_session(struct svc_rqst *rqstp, struct nfs4_client *clp,
>> >> if (status)
>> >> goto out;
>> >>
>> >> - /* allocate struct nfsd4_session and slot table in one piece */
>> >> - slotsize = tmp.se_fchannel.maxreqs * sizeof(struct nfsd4_slot);
>> >> + /* allocate struct nfsd4_session and slot table pointers in one piece */
>> >> + slotsize = tmp.se_fchannel.maxreqs * sizeof(struct nfsd4_slot *);
>> >> new = kzalloc(sizeof(*new) + slotsize, GFP_KERNEL);
>> >
>> > I think this is OK for now, but maybe stick something like:
>> >
>> > BUILD_BUG_ON(NFSD_MAX_SLOTS_PER_SESSION * sizeof(struct nfsd4_slot)
>> > + sizeof(struct nfsd4_session) > PAGE_SIZE);
>> >
>> > in state.h just to warn anyone who wants to blindly bump up
>> > NFSD_MAX_SLOTS_PER_SESSION. (It's not really forbidden to kmalloc more
>> > than a page, but it's also not reliable, and if it becomes necessary
>> > then we'd rather find some way to code around it.)
>> >
>> >> if (!new)
>> >> goto out;
>> >>
>> >> memcpy(new, &tmp, sizeof(*new));
>> >>
>> >> + /* allocate each struct nfsd4_slot and data cache in one piece */
>> >> + cachesize = new->se_fchannel.maxresp_cached - NFSD_MIN_HDR_SEQ_SZ;
>> >> + for (i = 0; i < new->se_fchannel.maxreqs; i++) {
>> >> + sp = kzalloc(sizeof(*sp) + cachesize, GFP_KERNEL);
>> >> + if (!sp)
>> >> + goto out_free;
>> >> + new->se_slots[i] = sp;
>> >> + }
>> >> +
>> >> new->se_client = clp;
>> >> gen_sessionid(new);
>> >> idx = hash_sessionid(&new->se_sessionid);
>> >> @@ -550,6 +569,10 @@ alloc_init_session(struct svc_rqst *rqstp, struct nfs4_client *clp,
>> >> status = nfs_ok;
>> >> out:
>> >> return status;
>> >> +out_free:
>> >> + free_session_slots(new);
>> >> + kfree(new);
>> >> + goto out;
>> >> }
>> >>
>> >> /* caller must hold sessionid_lock */
>> >> @@ -592,22 +615,16 @@ release_session(struct nfsd4_session *ses)
>> >> nfsd4_put_session(ses);
>> >> }
>> >>
>> >> -static void nfsd4_release_respages(struct page **respages, short resused);
>> >> -
>> >> void
>> >> free_session(struct kref *kref)
>> >> {
>> >> struct nfsd4_session *ses;
>> >> - int i;
>> >>
>> >> ses = container_of(kref, struct nfsd4_session, se_ref);
>> >> - for (i = 0; i < ses->se_fchannel.maxreqs; i++) {
>> >> - struct nfsd4_cache_entry *e = &ses->se_slots[i].sl_cache_entry;
>> >> - nfsd4_release_respages(e->ce_respages, e->ce_resused);
>> >> - }
>> >> spin_lock(&nfsd_drc_lock);
>> >> nfsd_drc_mem_used -= ses->se_fchannel.maxreqs * NFSD_SLOT_CACHE_SIZE;
>> >> spin_unlock(&nfsd_drc_lock);
>> >> + free_session_slots(ses);
>> >> kfree(ses);
>> >> }
>> >>
>> >> @@ -964,116 +981,32 @@ out_err:
>> >> return;
>> >> }
>> >>
>> >> -void
>> >> -nfsd4_set_statp(struct svc_rqst *rqstp, __be32 *statp)
>> >> -{
>> >> - struct nfsd4_compoundres *resp = rqstp->rq_resp;
>> >> -
>> >> - resp->cstate.statp = statp;
>> >> -}
>> >> -
>> >> -/*
>> >> - * Dereference the result pages.
>> >> - */
>> >> -static void
>> >> -nfsd4_release_respages(struct page **respages, short resused)
>> >> -{
>> >> - int i;
>> >> -
>> >> - dprintk("--> %s\n", __func__);
>> >> - for (i = 0; i < resused; i++) {
>> >> - if (!respages[i])
>> >> - continue;
>> >> - put_page(respages[i]);
>> >> - respages[i] = NULL;
>> >> - }
>> >> -}
>> >> -
>> >> -static void
>> >> -nfsd4_copy_pages(struct page **topages, struct page **frompages, short count)
>> >> -{
>> >> - int i;
>> >> -
>> >> - for (i = 0; i < count; i++) {
>> >> - topages[i] = frompages[i];
>> >> - if (!topages[i])
>> >> - continue;
>> >> - get_page(topages[i]);
>> >> - }
>> >> -}
>> >> -
>> >> /*
>> >> - * 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 where 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 used 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.
>> >> */
>> >> void
>> >> nfsd4_store_cache_entry(struct nfsd4_compoundres *resp)
>> >> {
>> >> - struct nfsd4_cache_entry *entry = &resp->cstate.slot->sl_cache_entry;
>> >> - struct svc_rqst *rqstp = resp->rqstp;
>> >> - struct kvec *resv = &rqstp->rq_res.head[0];
>> >> -
>> >> - dprintk("--> %s entry %p\n", __func__, entry);
>> >> + struct nfsd4_slot *slot = resp->cstate.slot;
>> >> + unsigned int base;
>> >>
>> >> - nfsd4_release_respages(entry->ce_respages, entry->ce_resused);
>> >> - entry->ce_opcnt = resp->opcnt;
>> >> - entry->ce_status = resp->cstate.status;
>> >> + dprintk("--> %s slot %p\n", __func__, slot);
>> >>
>> >> - /*
>> >> - * Don't need a page to cache just the sequence operation - the slot
>> >> - * does this for us!
>> >> - */
>> >> + slot->sl_opcnt = resp->opcnt;
>> >> + slot->sl_status = resp->cstate.status;
>> >>
>> >> if (nfsd4_not_cached(resp)) {
>> >> - entry->ce_resused = 0;
>> >> - entry->ce_rpchdrlen = 0;
>> >> - dprintk("%s Just cache SEQUENCE. ce_cachethis %d\n", __func__,
>> >> - resp->cstate.slot->sl_cache_entry.ce_cachethis);
>> >> + slot->sl_datalen = 0;
>> >> return;
>> >> }
>> >> - entry->ce_resused = rqstp->rq_resused;
>> >> - if (entry->ce_resused > NFSD_PAGES_PER_SLOT + 1)
>> >> - entry->ce_resused = NFSD_PAGES_PER_SLOT + 1;
>> >> - nfsd4_copy_pages(entry->ce_respages, rqstp->rq_respages,
>> >> - entry->ce_resused);
>> >> - entry->ce_datav.iov_base = resp->cstate.statp;
>> >> - entry->ce_datav.iov_len = resv->iov_len - ((char *)resp->cstate.statp -
>> >> - (char *)page_address(rqstp->rq_respages[0]));
>> >> - /* Current request rpc header length*/
>> >> - entry->ce_rpchdrlen = (char *)resp->cstate.statp -
>> >> - (char *)page_address(rqstp->rq_respages[0]);
>> >> -}
>> >> -
>> >> -/*
>> >> - * We keep the rpc header, but take the nfs reply from the replycache.
>> >> - */
>> >> -static int
>> >> -nfsd41_copy_replay_data(struct nfsd4_compoundres *resp,
>> >> - struct nfsd4_cache_entry *entry)
>> >> -{
>> >> - struct svc_rqst *rqstp = resp->rqstp;
>> >> - struct kvec *resv = &resp->rqstp->rq_res.head[0];
>> >> - int len;
>> >> -
>> >> - /* Current request rpc header length*/
>> >> - len = (char *)resp->cstate.statp -
>> >> - (char *)page_address(rqstp->rq_respages[0]);
>> >> - if (entry->ce_datav.iov_len + len > PAGE_SIZE) {
>> >> - dprintk("%s v41 cached reply too large (%Zd).\n", __func__,
>> >> - entry->ce_datav.iov_len);
>> >> - return 0;
>> >> - }
>> >> - /* copy the cached reply nfsd data past the current rpc header */
>> >> - memcpy((char *)resv->iov_base + len, entry->ce_datav.iov_base,
>> >> - entry->ce_datav.iov_len);
>> >> - resv->iov_len = len + entry->ce_datav.iov_len;
>> >> - return 1;
>> >> + slot->sl_datalen = (char *)resp->p - (char *)resp->cstate.datap;
>> >> + base = (char *)resp->cstate.datap -
>> >> + (char *)resp->xbuf->head[0].iov_base;
>> >> + if (read_bytes_from_xdr_buf(resp->xbuf, base, slot->sl_data,
>> >> + slot->sl_datalen))
>> >> + printk(KERN_WARNING
>> >> + "nfsd: sessions DRC could not cache compound\n");
>> >
>> > I'd make this WARN("nfsd:...") just to make it completely clear it's a
>> > kernel bug. (This case should be caught by nfsd4_check_drc_limit unless
>> > we've messed something up, right?)
>> >
>> >> + return;
>> >> }
>> >>
>> >> /*
>> >> @@ -1091,14 +1024,14 @@ nfsd4_enc_sequence_replay(struct nfsd4_compoundargs *args,
>> >> struct nfsd4_slot *slot = resp->cstate.slot;
>> >>
>> >> dprintk("--> %s resp->opcnt %d cachethis %u \n", __func__,
>> >> - resp->opcnt, resp->cstate.slot->sl_cache_entry.ce_cachethis);
>> >> + resp->opcnt, resp->cstate.slot->sl_cachethis);
>> >>
>> >> /* Encode the replayed sequence operation */
>> >> op = &args->ops[resp->opcnt - 1];
>> >> nfsd4_encode_operation(resp, op);
>> >>
>> >> /* Return nfserr_retry_uncached_rep in next operation. */
>> >> - if (args->opcnt > 1 && slot->sl_cache_entry.ce_cachethis == 0) {
>> >> + if (args->opcnt > 1 && slot->sl_cachethis == 0) {
>> >> op = &args->ops[resp->opcnt++];
>> >> op->status = nfserr_retry_uncached_rep;
>> >> nfsd4_encode_operation(resp, op);
>> >> @@ -1107,57 +1040,29 @@ nfsd4_enc_sequence_replay(struct nfsd4_compoundargs *args,
>> >> }
>> >>
>> >> /*
>> >> - * Keep the first page of the replay. Copy the NFSv4.1 data from the first
>> >> - * cached page. Replace any futher replay pages from the cache.
>> >> + * The sequence operation is not cached because we can use the slot and
>> >> + * session values.
>> >> */
>> >> __be32
>> >> nfsd4_replay_cache_entry(struct nfsd4_compoundres *resp,
>> >> struct nfsd4_sequence *seq)
>> >> {
>> >> - struct nfsd4_cache_entry *entry = &resp->cstate.slot->sl_cache_entry;
>> >> + struct nfsd4_slot *slot = resp->cstate.slot;
>> >> __be32 status;
>> >>
>> >> - dprintk("--> %s entry %p\n", __func__, entry);
>> >> -
>> >> - /*
>> >> - * If this is just the sequence operation, we did not keep
>> >> - * a page in the cache entry because we can just use the
>> >> - * slot info stored in struct nfsd4_sequence that was checked
>> >> - * against the slot in nfsd4_sequence().
>> >> - *
>> >> - * This occurs when seq->cachethis is FALSE, or when the client
>> >> - * session inactivity timer fires and a solo sequence operation
>> >> - * is sent (lease renewal).
>> >> - */
>> >> + dprintk("--> %s slot %p\n", __func__, slot);
>> >>
>> >> /* Either returns 0 or nfserr_retry_uncached */
>> >> status = nfsd4_enc_sequence_replay(resp->rqstp->rq_argp, resp);
>> >> if (status == nfserr_retry_uncached_rep)
>> >> return status;
>> >>
>> >> - if (!nfsd41_copy_replay_data(resp, entry)) {
>> >> - /*
>> >> - * Not enough room to use the replay rpc header, send the
>> >> - * cached header. Release all the allocated result pages.
>> >> - */
>> >> - svc_free_res_pages(resp->rqstp);
>> >> - nfsd4_copy_pages(resp->rqstp->rq_respages, entry->ce_respages,
>> >> - entry->ce_resused);
>> >> - } else {
>> >> - /* Release all but the first allocated result page */
>> >> -
>> >> - resp->rqstp->rq_resused--;
>> >> - svc_free_res_pages(resp->rqstp);
>> >> -
>> >> - nfsd4_copy_pages(&resp->rqstp->rq_respages[1],
>> >> - &entry->ce_respages[1],
>> >> - entry->ce_resused - 1);
>> >> - }
>> >> + /* The sequence operation has been encoded, cstate->datap set. */
>> >> + memcpy(resp->cstate.datap, slot->sl_data, slot->sl_datalen);
>> >>
>> >> - resp->rqstp->rq_resused = entry->ce_resused;
>> >> - resp->opcnt = entry->ce_opcnt;
>> >> - resp->cstate.iovlen = entry->ce_datav.iov_len + entry->ce_rpchdrlen;
>> >> - status = entry->ce_status;
>> >> + resp->opcnt = slot->sl_opcnt;
>> >> + resp->p = resp->cstate.datap + XDR_QUADLEN(slot->sl_datalen);
>> >> + status = slot->sl_status;
>> >>
>> >> return status;
>> >> }
>> >> @@ -1489,7 +1394,7 @@ nfsd4_sequence(struct svc_rqst *rqstp,
>> >> if (seq->slotid >= session->se_fchannel.maxreqs)
>> >> goto out;
>> >>
>> >> - slot = &session->se_slots[seq->slotid];
>> >> + slot = 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
>> >> @@ -1502,7 +1407,7 @@ nfsd4_sequence(struct svc_rqst *rqstp,
>> >> cstate->slot = slot;
>> >> cstate->session = session;
>> >> /* Return the cached reply status and set cstate->status
>> >> - * for nfsd4_svc_encode_compoundres processing */
>> >> + * for nfsd4_proc_compound processing */
>> >> status = nfsd4_replay_cache_entry(resp, seq);
>> >> cstate->status = nfserr_replay_cache;
>> >> goto replay_cache;
>> >> @@ -1513,7 +1418,7 @@ nfsd4_sequence(struct svc_rqst *rqstp,
>> >> /* Success! bump slot seqid */
>> >> slot->sl_inuse = true;
>> >> slot->sl_seqid = seq->seqid;
>> >> - slot->sl_cache_entry.ce_cachethis = seq->cachethis;
>> >> + slot->sl_cachethis = seq->cachethis;
>> >>
>> >> cstate->slot = slot;
>> >> cstate->session = 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_compoundres *resp, int nfserr,
>> >> WRITE32(0);
>> >>
>> >> ADJUST_ARGS();
>> >> + resp->cstate.datap = p; /* DRC cache data pointer */
>> >> return 0;
>> >> }
>> >>
>> >> @@ -3166,7 +3167,7 @@ static int nfsd4_check_drc_limit(struct nfsd4_compoundres *resp)
>> >> return status;
>> >>
>> >> session = resp->cstate.session;
>> >> - if (session == NULL || slot->sl_cache_entry.ce_cachethis == 0)
>> >> + if (session == NULL || slot->sl_cachethis == 0)
>> >> return status;
>> >>
>> >> if (resp->opcnt >= args->opcnt)
>> >> @@ -3291,6 +3292,7 @@ nfs4svc_encode_compoundres(struct svc_rqst *rqstp, __be32 *p, struct nfsd4_compo
>> >> /*
>> >> * All that remains is to write the tag and operation count...
>> >> */
>> >> + struct nfsd4_compound_state *cs = &resp->cstate;
>> >> struct kvec *iov;
>> >> p = resp->tagp;
>> >> *p++ = htonl(resp->taglen);
>> >> @@ -3304,14 +3306,11 @@ nfs4svc_encode_compoundres(struct svc_rqst *rqstp, __be32 *p, struct nfsd4_compo
>> >> iov = &rqstp->rq_res.head[0];
>> >> iov->iov_len = ((char*)resp->p) - (char*)iov->iov_base;
>> >> BUG_ON(iov->iov_len > PAGE_SIZE);
>> >> - if (nfsd4_has_session(&resp->cstate)) {
>> >> - if (resp->cstate.status == nfserr_replay_cache &&
>> >> - !nfsd4_not_cached(resp)) {
>> >> - iov->iov_len = resp->cstate.iovlen;
>> >> - } else {
>> >> + if (nfsd4_has_session(cs)) {
>> >> + if (cs->status != nfserr_replay_cache) {
>> >> nfsd4_store_cache_entry(resp);
>> >> dprintk("%s: SET SLOT STATE TO AVAILABLE\n", __func__);
>> >> - resp->cstate.slot->sl_inuse = 0;
>> >> + resp->cstate.slot->sl_inuse = false;
>> >> }
>> >> nfsd4_put_session(resp->cstate.session);
>> >> }
>> >> 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)
>> >> + rqstp->rq_res.head[0].iov_len;
>> >> rqstp->rq_res.head[0].iov_len += sizeof(__be32);
>> >>
>> >> - /* NFSv4.1 DRC requires statp */
>> >> - if (rqstp->rq_vers == 4)
>> >> - nfsd4_set_statp(rqstp, statp);
>> >> -
>> >> /* Now call the procedure handler, and encode NFS status. */
>> >> nfserr = proc->pc_func(rqstp, rqstp->rq_argp, rqstp->rq_resp);
>> >> nfserr = map_new_errors(rqstp->rq_vers, nfserr);
>> >> diff --git a/include/linux/nfsd/state.h b/include/linux/nfsd/state.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 {
>> >>
>> >> /* Maximum number of slots per session. 160 is useful for long haul TCP */
>> >> #define NFSD_MAX_SLOTS_PER_SESSION 160
>> >> -/* Maximum number of pages per slot cache entry */
>> >> -#define NFSD_PAGES_PER_SLOT 1
>> >> -#define NFSD_SLOT_CACHE_SIZE PAGE_SIZE
>> >> /* Maximum number of operations per session compound */
>> >> #define NFSD_MAX_OPS_PER_COMPOUND 16
>> >> +/* Maximum session per slot cache size */
>> >> +#define NFSD_SLOT_CACHE_SIZE 1024
>> >> /* Maximum number of NFSD_SLOT_CACHE_SIZE slots per session */
>> >> #define NFSD_CACHE_SIZE_SLOTS_PER_SESSION 32
>> >> #define NFSD_MAX_MEM_PER_SESSION \
>> >> (NFSD_CACHE_SIZE_SLOTS_PER_SESSION * NFSD_SLOT_CACHE_SIZE)
>> >>
>> >> -struct nfsd4_cache_entry {
>> >> - __be32 ce_status;
>> >> - struct kvec ce_datav; /* encoded NFSv4.1 data in rq_res.head[0] */
>> >> - struct page *ce_respages[NFSD_PAGES_PER_SLOT + 1];
>> >> - int ce_cachethis;
>> >> - short ce_resused;
>> >> - int ce_opcnt;
>> >> - int ce_rpchdrlen;
>> >> -};
>> >> -
>> >> struct nfsd4_slot {
>> >> - bool sl_inuse;
>> >> - u32 sl_seqid;
>> >> - struct nfsd4_cache_entry sl_cache_entry;
>> >> + bool sl_inuse;
>> >> + u32 sl_seqid;
>> >> + int sl_cachethis;
>> >> + int sl_opcnt;
>> >> + __be32 sl_status;
>> >> + u32 sl_datalen;
>> >> + char sl_data[];
>> >
>> > Could you just move sl_inuse to the end? It'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 {
>> - bool sl_inuse;
>> - u32 sl_seqid;
>> - struct nfsd4_cache_entry sl_cache_entry;
>> + bool sl_inuse;
>> + bool sl_cachethis;
>> + u16 sl_opcnt;
>> + u32 sl_seqid;
>> + __be32 sl_status;
>> + u32 sl_datalen;
>> + char sl_data[];
>> };
>
> Looks OK to me! By the way, on recent distro's you should be able to
> run apt-get install/yum install dwarves, then
>
> pahole fs/nfsd/nfsd.o
>
> and look through the output for the struct of interest:
>
> struct nfsd4_slot {
> bool sl_inuse; /* 0 1 */
>
> /* XXX 3 bytes hole, try to pack */
>
> u32 sl_seqid; /* 4 4 */
> struct nfsd4_cache_entry sl_cache_entry; /* 8 36 */
>
> /* size: 44, cachelines: 1 */
> /* sum members: 41, holes: 1, sum holes: 3 */
> /* last cacheline: 44 bytes */
> }; /* 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 structure
> it might be worth mentioning.)
Cool! - thanks for the pointer
-->Andy
>
> --b.
>
>>
>> -->Andy
>>
>> > --b.
>> >
>> >> };
>> >>
>> >> struct nfsd4_channel_attrs {
>> >> @@ -159,7 +152,7 @@ struct nfsd4_session {
>> >> struct nfs4_sessionid se_sessionid;
>> >> struct nfsd4_channel_attrs se_fchannel;
>> >> struct nfsd4_channel_attrs se_bchannel;
>> >> - struct nfsd4_slot se_slots[]; /* forward channel slots */
>> >> + struct nfsd4_slot *se_slots[]; /* forward channel slots */
>> >> };
>> >>
>> >> static 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 {
>> >> /* For sessions DRC */
>> >> struct nfsd4_session *session;
>> >> struct nfsd4_slot *slot;
>> >> - __be32 *statp;
>> >> + __be32 *datap;
>> >> size_t iovlen;
>> >> u32 minorversion;
>> >> u32 status;
>> >> @@ -472,8 +472,7 @@ static inline bool nfsd4_is_solo_sequence(struct nfsd4_compoundres *resp)
>> >>
>> >> static inline bool nfsd4_not_cached(struct nfsd4_compoundres *resp)
>> >> {
>> >> - return !resp->cstate.slot->sl_cache_entry.ce_cachethis ||
>> >> - nfsd4_is_solo_sequence(resp);
>> >> + return !resp->cstate.slot->sl_cachethis || nfsd4_is_solo_sequence(resp);
>> >> }
>> >>
>> >> #define NFS4_SVC_XDRSIZE sizeof(struct nfsd4_compoundargs)
>> >> --
>> >> 1.6.2.5
>> >>
>> > _______________________________________________
>> > pNFS mailing list
>> > pNFS@xxxxxxxxxxxxx
>> > http://linux-nfs.org/cgi-bin/mailman/listinfo/pnfs
>> >
>
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