minio/pkg/sys/stats_linux.go

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// +build linux,!arm,!386
/*
* MinIO Cloud Storage, (C) 2016,2017 MinIO, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package sys
import (
"os"
"syscall"
"github.com/minio/minio/pkg/cgroup"
)
// Get the final system memory limit chosen by the user.
// by default without any configuration on a vanilla Linux
// system you would see physical RAM limit. If cgroup
// is configured at some point in time this function
// would return the memory limit chosen for the given pid.
func getMemoryLimit() (sysLimit uint64, err error) {
if sysLimit, err = getSysinfoMemoryLimit(); err != nil {
// Physical memory info is not accessible, just exit here.
return 0, err
}
// Following code is deliberately ignoring the error.
cGroupLimit, gerr := cgroup.GetMemoryLimit(os.Getpid())
if gerr != nil {
// Upon error just return system limit.
return sysLimit, nil
}
// cgroup limit is lesser than system limit means
// user wants to limit the memory usage further
// treat cgroup limit as the system limit.
if cGroupLimit <= sysLimit {
sysLimit = cGroupLimit
}
// Final system limit.
return sysLimit, nil
}
// Get physical RAM size of the node.
func getSysinfoMemoryLimit() (limit uint64, err error) {
var si syscall.Sysinfo_t
if err = syscall.Sysinfo(&si); err != nil {
return 0, err
}
// Some fields in syscall.Sysinfo_t have different integer sizes
// in different platform architectures. Cast all fields to uint64.
unit := si.Unit
totalRAM := si.Totalram
// Total RAM is always the multiplicative value
// of unit size and total ram.
return uint64(unit) * totalRAM, nil
}
// GetStats - return system statistics, currently only
// supported value is TotalRAM.
func GetStats() (stats Stats, err error) {
var limit uint64
limit, err = getMemoryLimit()
if err != nil {
return Stats{}, err
}
stats.TotalRAM = limit
return stats, nil
}