nfsd: track memory utilization by the DRC
Jeff Layton [Wed, 27 Mar 2013 14:15:38 +0000 (10:15 -0400)]
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

fs/nfsd/nfscache.c

index 48f5ef9..1f45b33 100644 (file)
@@ -38,6 +38,9 @@ static unsigned int           num_drc_entries;
 /* cache misses due only to checksum comparison failures */
 static unsigned int            payload_misses;
 
+/* amount of memory (in bytes) currently consumed by the DRC */
+static unsigned int            drc_mem_usage;
+
 /*
  * Calculate the hash index from an XID.
  */
@@ -112,12 +115,15 @@ nfsd_reply_cache_alloc(void)
 static void
 nfsd_reply_cache_free_locked(struct svc_cacherep *rp)
 {
-       if (rp->c_type == RC_REPLBUFF)
+       if (rp->c_type == RC_REPLBUFF && rp->c_replvec.iov_base) {
+               drc_mem_usage -= rp->c_replvec.iov_len;
                kfree(rp->c_replvec.iov_base);
+       }
        if (!hlist_unhashed(&rp->c_hash))
                hlist_del(&rp->c_hash);
        list_del(&rp->c_lru);
        --num_drc_entries;
+       drc_mem_usage -= sizeof(*rp);
        kmem_cache_free(drc_slab, rp);
 }
 
@@ -372,8 +378,10 @@ nfsd_cache_lookup(struct svc_rqst *rqstp)
        spin_unlock(&cache_lock);
        rp = nfsd_reply_cache_alloc();
        spin_lock(&cache_lock);
-       if (likely(rp))
+       if (likely(rp)) {
                ++num_drc_entries;
+               drc_mem_usage += sizeof(*rp);
+       }
 
 search_cache:
        found = nfsd_cache_search(rqstp, csum);
@@ -415,6 +423,7 @@ search_cache:
 
        /* release any buffer */
        if (rp->c_type == RC_REPLBUFF) {
+               drc_mem_usage -= rp->c_replvec.iov_len;
                kfree(rp->c_replvec.iov_base);
                rp->c_replvec.iov_base = NULL;
        }
@@ -483,6 +492,7 @@ nfsd_cache_update(struct svc_rqst *rqstp, int cachetype, __be32 *statp)
        struct svc_cacherep *rp = rqstp->rq_cacherep;
        struct kvec     *resv = &rqstp->rq_res.head[0], *cachv;
        int             len;
+       size_t          bufsize = 0;
 
        if (!rp)
                return;
@@ -504,19 +514,21 @@ nfsd_cache_update(struct svc_rqst *rqstp, int cachetype, __be32 *statp)
                break;
        case RC_REPLBUFF:
                cachv = &rp->c_replvec;
-               cachv->iov_base = kmalloc(len << 2, GFP_KERNEL);
+               bufsize = len << 2;
+               cachv->iov_base = kmalloc(bufsize, GFP_KERNEL);
                if (!cachv->iov_base) {
                        nfsd_reply_cache_free(rp);
                        return;
                }
-               cachv->iov_len = len << 2;
-               memcpy(cachv->iov_base, statp, len << 2);
+               cachv->iov_len = bufsize;
+               memcpy(cachv->iov_base, statp, bufsize);
                break;
        case RC_NOCACHE:
                nfsd_reply_cache_free(rp);
                return;
        }
        spin_lock(&cache_lock);
+       drc_mem_usage += bufsize;
        lru_put_end(rp);
        rp->c_secure = rqstp->rq_secure;
        rp->c_type = cachetype;