Drop -namespacesize option, related code, update related doc

Maintaining multiple fixed-size namespaces does not add value,
so let's create a single namespace per namespace mode (fsdax, sector).
Modify DeviceMode diagrams of README to show less namespaces

DEVELOPMENT.md

@@ -119,7 +119,6 @@ Specific arguments to pmem-ns-init
 
 argument name      | meaning                                                | type | range
 -------------------|--------------------------------------------------------|------|---
--namespacesize in  | Namespace size in GB (default 32)                      | int  | set to 2 if less than 2
 -useforfsdax int   | Percentage of total to use in Fsdax mode (default 100) | int  | 0..100
 -useforsector int  | Percentage of total to use in Sector mode (default 0)  | int  | 0..100
 

README.md

@@ -76,10 +76,8 @@ initialization stages and a third API-serving stage.
 
 During startup, the driver scans persistent memory for regions and
 namespaces, and tries to create more namespaces using all or part
-(selectable via option) of the remaining available space. The
-namespace size can be specified as a driver parameter and defaults to
-32 GB. This first stage is performed by a separate entity
-_pmem-ns-init_.
+(selectable via option) of the remaining available space. This first
+stage is performed by a separate entity _pmem-ns-init_.
 
 The second stage of initialization arranges physical volumes provided
 by namespaces into LVM volume groups. This is performed by a separate

deploy/kubernetes-1.13/pmem-csi-lvm-testing.yaml

@@ -350,7 +350,6 @@ spec:
       initContainers:
       - args:
         - -v=3
-        - -namespacesize=9
         - -v=5
         - -coverprofile=/var/lib/pmem-csi-coverage/pmem-ns-init-*.out
         command:

deploy/kubernetes-1.13/pmem-csi-lvm.yaml

@@ -268,7 +268,6 @@ spec:
       initContainers:
       - args:
         - -v=3
-        - -namespacesize=9
         command:
         - /go/bin/pmem-ns-init
         env:

deploy/kubernetes-1.14/pmem-csi-lvm-testing.yaml

@@ -370,7 +370,6 @@ spec:
       initContainers:
       - args:
         - -v=3
-        - -namespacesize=9
         - -v=5
         - -coverprofile=/var/lib/pmem-csi-coverage/pmem-ns-init-*.out
         command:

deploy/kubernetes-1.14/pmem-csi-lvm.yaml

@@ -288,7 +288,6 @@ spec:
       initContainers:
       - args:
         - -v=3
-        - -namespacesize=9
         command:
         - /go/bin/pmem-ns-init
         env:

deploy/kustomize/patches/lvm-patch.yaml

@@ -11,7 +11,7 @@
     imagePullPolicy: Always
     image: PMEM_REGISTRY/pmem-csi-driver:canary
     command: ["/go/bin/pmem-ns-init"]
-    args: [ "-v=3", "-namespacesize=9" ]
+    args: [ "-v=3" ]
     env:
       - name: TERMINATION_LOG_PATH
         value: /tmp/pmem-ns-init-termination-log

pkg/pmem-ns-init/main.go

@@ -15,10 +15,9 @@ var (
 	/* generic options */
 	//TODO: reading name configuration not yet supported
 	//configFile    = flag.String("configfile", "/etc/pmem-csi/config", "PMEM CSI driver namespace configuration file")
-	namespacesize = flag.Int("namespacesize", 32, "Namespace size in GB")
-	useforfsdax   = flag.Int("useforfsdax", 100, "Percentage of total to use in Fsdax mode")
-	useforsector  = flag.Int("useforsector", 0, "Percentage of total to use in Sector mode")
-	showVersion   = flag.Bool("version", false, "Show release version and exit")
+	useforfsdax  = flag.Int("useforfsdax", 100, "Percentage of total to use in Fsdax mode")
+	useforsector = flag.Int("useforsector", 0, "Percentage of total to use in Sector mode")
+	showVersion  = flag.Bool("version", false, "Show release version and exit")
 
 	version = "unknown"
 )
@@ -36,7 +35,7 @@ func Main() int {
 
 	glog.V(3).Info("Version: ", version)
 
-	if err := CheckArgs(*namespacesize, *useforfsdax, *useforsector); err != nil {
+	if err := CheckArgs(*useforfsdax, *useforsector); err != nil {
 		pmemcommon.ExitError("invalid arguments", err)
 		return 1
 	}
@@ -46,11 +45,11 @@ func Main() int {
 		return 1
 	}
 
-	initNVdimms(ctx, *namespacesize, *useforfsdax, *useforsector)
+	initNVdimms(ctx, *useforfsdax, *useforsector)
 	return 0
 }
 
-func CheckArgs(namespacesize int, useforfsdax int, useforsector int) error {
+func CheckArgs(useforfsdax int, useforsector int) error {
 	if useforfsdax < 0 || useforfsdax > 100 {
 		return fmt.Errorf("useforfsdax value must be 0..100")
 	}
@@ -60,25 +59,19 @@ func CheckArgs(namespacesize int, useforfsdax int, useforsector int) error {
 	if useforfsdax+useforsector > 100 {
 		return fmt.Errorf("useforfsdax and useforsector combined must not exceed 100")
 	}
-	if namespacesize < 2 {
-		return fmt.Errorf("namespacesize has to be at least 2 GB")
-	}
 	return nil
 }
 
-func initNVdimms(ctx *ndctl.Context, namespacesize int, useforfsdax int, useforsector int) {
-	glog.V(4).Infof("Configured namespacesize; %v GB", namespacesize)
-	// we get 1GB smaller than we ask so lets ask for 1GB more
-	nsSize := uint64(namespacesize+1) * 1024 * 1024 * 1024
+func initNVdimms(ctx *ndctl.Context, useforfsdax int, useforsector int) {
 	for _, bus := range ctx.GetBuses() {
 		for _, r := range bus.ActiveRegions() {
-			createNS(r, nsSize, useforfsdax, ndctl.FsdaxMode)
-			createNS(r, nsSize, useforsector, ndctl.SectorMode)
+			createNS(r, useforfsdax, ndctl.FsdaxMode)
+			createNS(r, useforsector, ndctl.SectorMode)
 		}
 	}
 }
 
-func createNS(r *ndctl.Region, nsSize uint64, uselimit int, nsmode ndctl.NamespaceMode) {
+func createNS(r *ndctl.Region, uselimit int, nsmode ndctl.NamespaceMode) {
 	// uselimit is the percentage we can use
 	canUse := uint64(uselimit) * r.Size() / 100
 	glog.V(3).Infof("Create %s-namespaces in %v, allowed %d %%:\ntotal       : %16d\navail       : %16d\ncan use     : %16d",
@@ -90,43 +83,28 @@ func createNS(r *ndctl.Region, nsSize uint64, uselimit int, nsmode ndctl.Namespa
 			canUse -= ns.Size()
 		}
 	}
-	glog.V(4).Infof("%v bytes calculated available after scan for existing %s-mode namespaces", canUse, nsmode)
-	// cast to signed, otherwise can never be negative and risks forever-looping,
-	// broken only by break stmt below which happens after a failed creation attempt
-	for int64(canUse) > 0 {
-		if nsSize > canUse {
-			// this creates one last smaller namespace in leftover space
-			nsSize = canUse
-			glog.V(4).Infof("Less than configured namespacesize remaining, change desired size to %v", nsSize)
-		}
-		glog.V(4).Infof("Calculated canUse:%v, available by Region info:%v", canUse, r.AvailableSize())
-		// Because of overhead by alignement and extra space for page mapping, calculated available may show more than actual
-		if r.AvailableSize() < nsSize {
-			glog.V(4).Infof("Available in Region:%v is less than desired nsSize, limit nsSize to that", r.AvailableSize())
-			nsSize = r.AvailableSize()
-		}
-		// Should not happen easily, fragmented space could lead to r.MaxAvailableExtent() being less than r.AvailableSize()
-		if r.MaxAvailableExtent() < nsSize {
-			glog.V(4).Infof("MaxAvailableExtent in Region:%v is less than desired nsSize, limit nsSize to that", r.MaxAvailableExtent())
-			nsSize = r.MaxAvailableExtent()
-		}
-		// If NSize drops to less than 2GB, stop as creation would fail
-		if nsSize < 2*1024*1024*1024 {
-			glog.V(4).Infof("nsSize:%v is less then 2 GB, stop creating", nsSize)
-			break
-		}
-		glog.V(3).Infof("Create next %v-bytes %s-namespace", nsSize, nsmode)
+	glog.V(4).Infof("Calculated canUse:%v, available by Region info:%v", canUse, r.AvailableSize())
+	// Because of overhead by alignement and extra space for page mapping, calculated available may show more than actual
+	if r.AvailableSize() < canUse {
+		glog.V(4).Infof("Available in Region:%v is less than desired size, limit to that", r.AvailableSize())
+		canUse = r.AvailableSize()
+	}
+	// Should not happen often: fragmented space could lead to r.MaxAvailableExtent() being less than r.AvailableSize()
+	if r.MaxAvailableExtent() < canUse {
+		glog.V(4).Infof("MaxAvailableExtent in Region:%v is less than desired size, limit to that", r.MaxAvailableExtent())
+		canUse = r.MaxAvailableExtent()
+	}
+	// If less than 2GB usable, don't attempt as creation would fail
+	if canUse >= 2*1024*1024*1024 {
+		glog.V(3).Infof("Create %v-bytes %s-namespace", canUse, nsmode)
 		_, err := r.CreateNamespace(ndctl.CreateNamespaceOpts{
 			Name:  "pmem-csi",
 			Mode:  nsmode,
-			Size:  nsSize,
+			Size:  canUse,
 			Align: 1024 * 1024 * 1024,
 		})
 		if err != nil {
 			glog.Warning("Failed to create namespace:", err.Error())
-			/* ??? something went wrong, leave this region ??? */
-			break
 		}
-		canUse -= nsSize
 	}
 }

pkg/pmem-ns-init/main_test.go

@@ -26,37 +26,34 @@ var _ = AfterSuite(func() {
 var _ = Describe("pmem-ns-init", func() {
 	Context("Check arguments", func() {
 		type cases struct {
-			name                                     string
-			namespacesize, useforfsdax, useforsector int
+			name                      string
+			useforfsdax, useforsector int
 		}
 		goodcases := []cases{
-			{"namespacesize ok", 32, 0, 0},
-			{"useforfsdax ok", 32, 50, 0},
-			{"useforsector ok", 32, 0, 50},
-			{"useforfsdax and useforsector combined 100", 32, 70, 30},
-			{"useforfsdax and useforsector combined less than 100", 32, 40, 30},
+			{"useforfsdax ok", 50, 0},
+			{"useforsector ok", 0, 50},
+			{"useforfsdax and useforsector combined 100", 70, 30},
+			{"useforfsdax and useforsector combined less than 100", 40, 30},
 		}
 		badcases := []cases{
-			{"namespacesize negative", -1, 0, 0},
-			{"namespacesize too small", 1, 0, 0},
-			{"useforfsdax negative", 32, -1, 0},
-			{"useforsector negative", 32, 0, -1},
-			{"useforfsdax too large", 32, 101, 0},
-			{"useforsector too large", 32, 0, 101},
-			{"useforfsdax and useforsector combined too large", 32, 51, 51},
+			{"useforfsdax negative", -1, 0},
+			{"useforsector negative", 0, -1},
+			{"useforfsdax too large", 101, 0},
+			{"useforsector too large", 0, 101},
+			{"useforfsdax and useforsector combined too large", 51, 51},
 		}
 
 		for _, c := range goodcases {
 			c := c
 			It(c.name, func() {
-				err := pmemnsinit.CheckArgs(c.namespacesize, c.useforfsdax, c.useforsector)
+				err := pmemnsinit.CheckArgs(c.useforfsdax, c.useforsector)
 				Expect(err).NotTo(HaveOccurred())
 			})
 		}
 		for _, c := range badcases {
 			c := c
 			It(c.name, func() {
-				err := pmemnsinit.CheckArgs(c.namespacesize, c.useforfsdax, c.useforsector)
+				err := pmemnsinit.CheckArgs(c.useforfsdax, c.useforsector)
 				Expect(err).To(HaveOccurred())
 			})
 		}