fuse: make background queue length configurable

* also make 'congestion_threshold' an option
* make 'congestion_threshold' as 75% of background queue length if
  not explicitely specified
* in glusterfsd.c, moved all the fuse option dictionary setting
  code to separate function

Change-Id: Ie1680eefaed9377720770a09222282321bd4132e
Signed-off-by: Amar Tumballi <amarts@redhat.com>
BUG: 845214
Reviewed-on: https://code.engineering.redhat.com/gerrit/1860
Reviewed-by: Vijay Bellur <vbellur@redhat.com>
Tested-by: Vijay Bellur <vbellur@redhat.com>

3 files changed, 54 insertions, 3 deletions

diff --git a/xlators/mount/fuse/src/fuse-bridge.c b/xlators/mount/fuse/src/fuse-bridge.c
index 07859c60a4a..8b93a4d1fb0 100644
--- a/xlators/mount/fuse/src/fuse-bridge.c
+++ b/xlators/mount/fuse/src/fuse-bridge.c
@@ -3389,8 +3389,8 @@ fuse_init (xlator_t *this, fuse_in_header_t *finh, void *msg)
         }
         if (fini->minor >= 13) {
                 /* these values seemed to work fine during testing */
-                fino.max_background = 64;
-                fino.congestion_threshold = 48;
+                fino.max_background = priv->background_qlen;
+                fino.congestion_threshold = priv->congestion_threshold;
         }
         if (fini->minor < 9)
                 *priv->msg0_len_p = sizeof(*finh) + FUSE_COMPAT_WRITE_IN_SIZE;
@@ -4574,6 +4574,32 @@ init (xlator_t *this_xl)
 		goto cleanup_exit;
 	}
 
+        /* default values seemed to work fine during testing */
+	GF_OPTION_INIT ("background-qlen", priv->background_qlen, int32,
+                        cleanup_exit);
+	GF_OPTION_INIT ("congestion-threshold", priv->congestion_threshold,
+                        int32, cleanup_exit);
+
+        if (dict_get (this_xl->options, "background-qlen") &&
+            !dict_get (this_xl->options, "congestion-threshold")) {
+                /* user has set only background-qlen, not congestion-threshold,
+                   use the fuse kernel driver formula to set congestion,
+                   ie, 75% */
+                priv->congestion_threshold = (priv->background_qlen * 3) / 4;
+                gf_log (this_xl->name, GF_LOG_INFO,
+                        "setting congestion control as 75%% of "
+                        "background-queue length (ie, (.75 * %d) = %d",
+                        priv->background_qlen, priv->congestion_threshold);
+        }
+        /* congestion should not be higher than background queue length */
+        if (priv->congestion_threshold > priv->background_qlen) {
+                gf_log (this_xl->name, GF_LOG_INFO,
+                        "setting congestion control same as "
+                        "background-queue length (%d)",
+                        priv->background_qlen);
+                priv->congestion_threshold = priv->background_qlen;
+        }
+
         cmd_args = &this_xl->ctx->cmd_args;
         fsname = cmd_args->volfile;
         if (!fsname && cmd_args->volfile_server) {
@@ -4742,5 +4768,17 @@ struct volume_options options[] = {
 	  .type = GF_OPTION_TYPE_INT,
 	  .default_value = "0"
 	},
+        { .key  = {"background-qlen"},
+          .type = GF_OPTION_TYPE_INT,
+          .default_value = "64",
+          .min = 16,
+          .max = (64 * GF_UNIT_KB),
+        },
+        { .key  = {"congestion-threshold"},
+          .type = GF_OPTION_TYPE_INT,
+          .default_value = "48",
+          .min = 12,
+          .max = (64 * GF_UNIT_KB),
+        },
         { .key = {NULL} },
 };
diff --git a/xlators/mount/fuse/src/fuse-bridge.h b/xlators/mount/fuse/src/fuse-bridge.h
index f9d897c3037..d5b57e068df 100644
--- a/xlators/mount/fuse/src/fuse-bridge.h
+++ b/xlators/mount/fuse/src/fuse-bridge.h
@@ -122,6 +122,10 @@ struct fuse_private {
 
         /* For communicating with separate mount thread. */
         int                  status_pipe[2];
+
+        /* for fuse queue length and congestion threshold */
+        int background_qlen;
+        int congestion_threshold;
 };
 typedef struct fuse_private fuse_private_t;
 
diff --git a/xlators/mount/fuse/utils/mount.glusterfs.in b/xlators/mount/fuse/utils/mount.glusterfs.in
index f3d3839e8fa..833013abc76 100755
--- a/xlators/mount/fuse/utils/mount.glusterfs.in
+++ b/xlators/mount/fuse/utils/mount.glusterfs.in
@@ -109,6 +109,14 @@ start_glusterfs ()
 	cmd_line=$(echo "$cmd_line --gid-timeout=$gid_timeout");
     fi
 
+    if [ -n "$bg_qlen" ]; then
+	cmd_line=$(echo "$cmd_line --background-qlen=$bg_qlen");
+    fi
+
+    if [ -n "$cong_threshold" ]; then
+	cmd_line=$(echo "$cmd_line --congestion-threshold=$cong_threshold");
+    fi
+
     if [ -z "$volfile_loc" ]; then
         if  [ -n "$server_ip" ]; then
             if [ -n "$server_port" ]; then
@@ -137,7 +145,6 @@ start_glusterfs ()
     err=0;
     $cmd_line;
 
-
     inode=$(stat -c %i $mount_point 2>/dev/null);
 
     # this is required if the stat returns error
@@ -284,6 +291,8 @@ main ()
                             "backupvolfile-server")
                                 backupvolfile_server=$value ;;
 			    "gid-timeout")	gid_timeout=$value ;;
+			    "background-qlen")	bg_qlen=$value ;;
+			    "congestion-threshold")	cong_threshold=$value ;;
                             *) echo "unknown option $key (ignored)" ;;
                         esac
                 esac