VictoriaMetrics/lib/memory/memory.go

66 lines
2.3 KiB
Go

package memory
import (
"flag"
"fmt"
"sync"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/flagutil"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/logger"
)
var (
allowedPercent = flag.Float64("memory.allowedPercent", 60, "Allowed percent of system memory VictoriaMetrics caches may occupy. "+
"See also -memory.allowedBytes. "+
"Too low value may increase cache miss rate, which usually results in higher CPU and disk IO usage. "+
"Too high value may evict too much data from OS page cache, which will result in higher disk IO usage")
allowedBytes = flagutil.NewBytes("memory.allowedBytes", 0, "Allowed size of system memory VictoriaMetrics caches may occupy. "+
"This option overrides -memory.allowedPercent if set to non-zero value. "+
"Too low value may increase cache miss rate, which usually results in higher CPU and disk IO usage. "+
"Too high value may evict too much data from OS page cache, which will result in higher disk IO usage")
)
var (
allowedMemory int
remainingMemory int
)
var once sync.Once
func initOnce() {
if !flag.Parsed() {
// Do not use logger.Panicf here, since logger may be uninitialized yet.
panic(fmt.Errorf("BUG: memory.Allowed must be called only after flag.Parse call"))
}
mem := sysTotalMemory()
if allowedBytes.N <= 0 {
if *allowedPercent < 1 || *allowedPercent > 200 {
logger.Panicf("FATAL: -memory.allowedPercent must be in the range [1...200]; got %g", *allowedPercent)
}
percent := *allowedPercent / 100
allowedMemory = int(float64(mem) * percent)
remainingMemory = mem - allowedMemory
logger.Infof("limiting caches to %d bytes, leaving %d bytes to the OS according to -memory.allowedPercent=%g", allowedMemory, remainingMemory, *allowedPercent)
} else {
allowedMemory = allowedBytes.N
remainingMemory = mem - allowedMemory
logger.Infof("limiting caches to %d bytes, leaving %d bytes to the OS according to -memory.allowedBytes=%s", allowedMemory, remainingMemory, allowedBytes.String())
}
}
// Allowed returns the amount of system memory allowed to use by the app.
//
// The function must be called only after flag.Parse is called.
func Allowed() int {
once.Do(initOnce)
return allowedMemory
}
// Remaining returns the amount of memory remaining to the OS.
//
// This function must be called only after flag.Parse is called.
func Remaining() int {
once.Do(initOnce)
return remainingMemory
}