3 files changed, 28 insertions, 0 deletions

diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c
index b5168d1898ec..b53a098e97a4 100644
--- a/fs/nfsd/nfssvc.c
+++ b/fs/nfsd/nfssvc.c
@@ -22,6 +22,7 @@
 #include <linux/freezer.h>
 #include <linux/fs_struct.h>
 #include <linux/kthread.h>
+#include <linux/swap.h>
 
 #include <linux/sunrpc/types.h>
 #include <linux/sunrpc/stats.h>
@@ -197,6 +198,26 @@ void nfsd_reset_versions(void)
         }
 }
 
+/*
+ * Each session guarantees a negotiated per slot memory cache for replies
+ * which in turn consumes memory beyond the v2/v3/v4.0 server. A dedicated
+ * NFSv4.1 server might want to use more memory for a DRC than a machine
+ * with mutiple services.
+ *
+ * Impose a hard limit on the number of pages for the DRC which varies
+ * according to the machines free pages. This is of course only a default.
+ *
+ * For now this is a #defined shift which could be under admin control
+ * in the future.
+ */
+static void set_max_drc(void)
+{
+        nfsd_serv->sv_drc_max_pages = nr_free_buffer_pages()
+                                                >> NFSD_DRC_SIZE_SHIFT;
+        nfsd_serv->sv_drc_pages_used = 0;
+        dprintk("%s svc_drc_max_pages %u\n", __func__,
+                nfsd_serv->sv_drc_max_pages);
+}
 
 int nfsd_create_serv(void)
 {
@@ -229,6 +250,8 @@ int nfsd_create_serv(void)
                                       nfsd_last_thread, nfsd, THIS_MODULE);
         if (nfsd_serv == NULL)
                 err = -ENOMEM;
+        else
+                set_max_drc();
 
         do_gettimeofday(&nfssvc_boot);          /* record boot time */
         return err;
diff --git a/include/linux/nfsd/nfsd.h b/include/linux/nfsd/nfsd.h
index ab9616d09204..1f063d495159 100644
--- a/include/linux/nfsd/nfsd.h
+++ b/include/linux/nfsd/nfsd.h
@@ -331,6 +331,9 @@ extern struct timeval	nfssvc_boot;
 #define NFSD_LEASE_TIME                 (nfs4_lease_time())
 #define NFSD_LAUNDROMAT_MINTIMEOUT      10   /* seconds */
 
+/* The percent of nr_free_buffer_pages used by the V4.1 server DRC */
+#define NFSD_DRC_SIZE_SHIFT     7
+
 /*
  * The following attributes are currently not supported by the NFSv4 server:
  *    ARCHIVE       (deprecated anyway)
diff --git a/include/linux/sunrpc/svc.h b/include/linux/sunrpc/svc.h
index 815dd589d4db..d209c630a4a1 100644
--- a/include/linux/sunrpc/svc.h
+++ b/include/linux/sunrpc/svc.h
@@ -95,6 +95,8 @@ struct svc_serv {
         struct module *         sv_module;      /* optional module to count when
                                                  * adding threads */
         svc_thread_fn           sv_function;    /* main function for threads */
+        unsigned int            sv_drc_max_pages; /* Total pages for DRC */
+        unsigned int            sv_drc_pages_used;/* DRC pages used */
 };
 
 /*