Translate Memory Limit to Swap in API

in specgen, CLI path uses the given memory limit to define the swap value (if not already specified)
add a route to this piece of code from within the api handlers

resolves #13145

Signed-off-by: cdoern <cdoern@redhat.com>

2 files changed, 29 insertions, 8 deletions

diff --git a/pkg/api/handlers/libpod/containers_create.go b/pkg/api/handlers/libpod/containers_create.go
index 4f9dc008d..1043dec4d 100644
--- a/pkg/api/handlers/libpod/containers_create.go
+++ b/pkg/api/handlers/libpod/containers_create.go
@@ -4,6 +4,7 @@ import (
 	"context"
 	"encoding/json"
 	"net/http"
+	"strconv"
 
 	"github.com/containers/podman/v4/libpod"
 	"github.com/containers/podman/v4/pkg/api/handlers/utils"
@@ -11,6 +12,7 @@ import (
 	"github.com/containers/podman/v4/pkg/domain/entities"
 	"github.com/containers/podman/v4/pkg/specgen"
 	"github.com/containers/podman/v4/pkg/specgen/generate"
+	"github.com/containers/podman/v4/pkg/specgenutil"
 	"github.com/pkg/errors"
 )
 
@@ -39,6 +41,20 @@ func CreateContainer(w http.ResponseWriter, r *http.Request) {
 		t := true
 		sg.Passwd = &t
 	}
+
+	// need to check for memory limit to adjust swap
+	if sg.ResourceLimits != nil && sg.ResourceLimits.Memory != nil {
+		s := ""
+		var l int64 = 0
+		if sg.ResourceLimits.Memory.Swap != nil {
+			s = strconv.Itoa(int(*sg.ResourceLimits.Memory.Swap))
+		}
+		if sg.ResourceLimits.Memory.Limit != nil {
+			l = *sg.ResourceLimits.Memory.Limit
+		}
+		specgenutil.LimitToSwap(sg.ResourceLimits.Memory, s, l)
+	}
+
 	warn, err := generate.CompleteSpec(r.Context(), runtime, &sg)
 	if err != nil {
 		utils.InternalServerError(w, err)
@@ -54,6 +70,7 @@ func CreateContainer(w http.ResponseWriter, r *http.Request) {
 		utils.InternalServerError(w, err)
 		return
 	}
+
 	response := entities.ContainerCreateResponse{ID: ctr.ID(), Warnings: warn}
 	utils.WriteJSON(w, http.StatusCreated, response)
 }
diff --git a/pkg/specgenutil/specgen.go b/pkg/specgenutil/specgen.go
index c86af7295..00de99817 100644
--- a/pkg/specgenutil/specgen.go
+++ b/pkg/specgenutil/specgen.go
@@ -126,6 +126,16 @@ func getIOLimits(s *specgen.SpecGenerator, c *entities.ContainerCreateOptions) (
 	return io, nil
 }
 
+func LimitToSwap(memory *specs.LinuxMemory, swap string, ml int64) {
+	if ml > 0 {
+		memory.Limit = &ml
+		if swap == "" {
+			limit := 2 * ml
+			memory.Swap = &(limit)
+		}
+	}
+}
+
 func getMemoryLimits(s *specgen.SpecGenerator, c *entities.ContainerCreateOptions) (*specs.LinuxMemory, error) {
 	var err error
 	memory := &specs.LinuxMemory{}
@@ -135,14 +145,8 @@ func getMemoryLimits(s *specgen.SpecGenerator, c *entities.ContainerCreateOption
 		if err != nil {
 			return nil, errors.Wrapf(err, "invalid value for memory")
 		}
-		if ml > 0 {
-			memory.Limit = &ml
-			if c.MemorySwap == "" {
-				limit := 2 * ml
-				memory.Swap = &(limit)
-			}
-			hasLimits = true
-		}
+		LimitToSwap(memory, c.MemorySwap, ml)
+		hasLimits = true
 	}
 	if m := c.MemoryReservation; len(m) > 0 {
 		mr, err := units.RAMInBytes(m)