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// Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package com.yahoo.vespa.hosted.node.admin.cgroup;
import java.util.List;
import java.util.Optional;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import java.util.stream.Stream;
/**
* Represents a cgroup v2 memory controller, i.e. all memory.* files.
*
* @author hakonhall
*/
public class MemoryController {
private final Cgroup cgroup;
MemoryController(Cgroup cgroup) {
this.cgroup = cgroup;
}
/** @return Maximum amount of memory that can be used by the cgroup and its descendants. */
public Size readMax() {
return cgroup.readSize("memory.max");
}
/** @return The total amount of memory currently being used by the cgroup and its descendants, in bytes. */
public Size readCurrent() {
return cgroup.readSize("memory.current");
}
/** @return The total amount of memory currently being used by the cgroup and its descendants, in bytes. */
public Optional<Size> readCurrentIfExists() {
return cgroup.readIfExists("memory.current").map(Size::from);
}
public Stats readStat() {
var lines = cgroup.readLines("memory.stat");
return new Stats(
Size.from(readField(lines, "file")), Size.from(readField(lines, "sock")), Size.from(readField(lines, "slab")),
Size.from(readField(lines, "slab_reclaimable")), Size.from(readField(lines, "anon")));
}
public Optional<Pressure> readPressureIfExists() {
return cgroup.readIfExists("memory.pressure")
.map(fileContent ->
new Pressure(
readPressureField(fileContent, "some"),
readPressureField(fileContent, "full")
)
);
}
private static String readField(List<String> lines, String fieldName) {
return lines.stream()
.map(line -> line.split("\\s+"))
.filter(fields -> fields.length == 2)
.filter(fields -> fieldName.equals(fields[0]))
.map(fields -> fields[1])
.findFirst()
.orElseThrow(() -> new IllegalArgumentException("No such field: " + fieldName));
}
/**
* Fetches the avg60 value from the specified type, i.e. "some" or "full".
*/
private static Double readPressureField(String fileContent, String type) {
var pattern = Pattern.compile(type + ".*avg60=(?<avg60>\\d+\\.\\d+).*");
return Stream.of(fileContent.split("\n"))
.map(pattern::matcher)
.filter(Matcher::matches)
.map(matcher -> matcher.group("avg60"))
.findFirst()
.map(Double::parseDouble)
.orElseThrow(() -> new IllegalArgumentException("No such field: " + type));
}
/**
* @param file Number of bytes used to cache filesystem data, including tmpfs and shared memory.
* @param sock Amount of memory used in network transmission buffers.
* @param slab Amount of memory used for storing in-kernel data structures.
* @param slabReclaimable Part of "slab" that might be reclaimed, such as dentries and inodes.
* @param anon Amount of memory used in anonymous mappings such as brk(), sbrk(), and mmap(MAP_ANONYMOUS).
*/
public record Stats(Size file, Size sock, Size slab, Size slabReclaimable, Size anon) {}
/**
* @param some The avg60 value of the "some" pressure level.
* @param full The avg60 value of the "full" pressure level.
*/
public record Pressure(double some, double full) {}
}
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