allow pre-allocating buffers to reduce frequent GCs during growth (#18686)

This PR also increases per node bpool memory from 1024 entries
to 2048 entries; along with that, it also moves the byte pool
centrally instead of being per pool.

cmd/globals.go

@@ -30,6 +30,7 @@ import (
 	"github.com/minio/madmin-go/v3"
 	"github.com/minio/minio-go/v7"
 	"github.com/minio/minio-go/v7/pkg/set"
+	"github.com/minio/minio/internal/bpool"
 	"github.com/minio/minio/internal/bucket/bandwidth"
 	"github.com/minio/minio/internal/config"
 	"github.com/minio/minio/internal/handlers"
@@ -141,6 +142,7 @@ type serverCtxt struct {
 	JSON, Quiet               bool
 	Anonymous                 bool
 	StrictS3Compat            bool
+	PreAllocate               bool
 	Addr, ConsoleAddr         string
 	ConfigDir, CertsDir       string
 	configDirSet, certsDirSet bool
@@ -225,6 +227,7 @@ var (
 	globalBucketMonitor     *bandwidth.Monitor
 	globalPolicySys         *PolicySys
 	globalIAMSys            *IAMSys
+	globalBytePoolCap       *bpool.BytePoolCap
 
 	globalLifecycleSys       *LifecycleSys
 	globalBucketSSEConfigSys *BucketSSEConfigSys