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[];
};
-->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
>>
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