VictoriaMetrics/lib/memory/memory.go
Roman Khavronenko 80768d53dd
docs: follow-up after aec4b5db81 ()
Signed-off-by: hagen1778 <roman@victoriametrics.com>
2023-07-19 14:48:17 -07:00

65 lines
2.5 KiB
Go

package memory
import (
"flag"
"fmt"
"sync"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/flagutil"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/logger"
"github.com/VictoriaMetrics/metrics"
)
var (
allowedPercent = flag.Float64("memory.allowedPercent", 60, `Allowed percent of system memory VictoriaMetrics caches may occupy. See also -memory.allowedBytes. Too low a value may increase cache miss rate usually resulting in higher CPU and disk IO usage. Too high a value may evict too much data from the 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 a non-zero value. Too low a value may increase the cache miss rate usually resulting in higher CPU and disk IO usage. Too high a value may evict too much data from the OS page cache resulting in higher disk IO usage`)
)
var _ = metrics.NewGauge("process_memory_limit_bytes", func() float64 {
return float64(memoryLimit)
})
var (
allowedMemory int
remainingMemory int
memoryLimit 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"))
}
memoryLimit = sysTotalMemory()
if allowedBytes.N <= 0 {
if *allowedPercent < 1 || *allowedPercent > 100 {
logger.Fatalf("FATAL: -memory.allowedPercent must be in the range [1...100]; got %g", *allowedPercent)
}
percent := *allowedPercent / 100
allowedMemory = int(float64(memoryLimit) * percent)
remainingMemory = memoryLimit - 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.IntN()
remainingMemory = memoryLimit - 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
}