jschoubben
3a84044ece
With THP 'always' journald's mmapped journal files sit in 2 MiB folios, so each small journal write dirties and writes back 2 MiB; on the control node that saturated the root mirror holding the bus store and the store, and the controller lost its lease. The module sets the mode from a per-machine setting (default always, the kernel's own, so assigning it changes nothing until a machine sets madvise), verifies it took, rotates the journal once so new files are mapped under the new mode, gives back what it found when stopped, and serves kernel_huge_pages to measure file_thp per unit.
66 lines
1.6 KiB
Go
66 lines
1.6 KiB
Go
package main
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// The machine as the tools see it: the files they read, under a root that tests replace with a stand-in
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// tree. Everything read here is readable by the runtime's account; nothing is escalated.
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import (
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"fmt"
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"io/fs"
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"os"
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"path/filepath"
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)
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// Machine reads this machine's kernel files under Root ("/" on the machine).
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type Machine struct {
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Root string
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}
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// ThisMachine is the machine the runtime launched this bundle on.
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func ThisMachine() *Machine { return &Machine{Root: "/"} }
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func (m *Machine) path(p string) string { return filepath.Join(m.Root, p) }
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func (m *Machine) read(p string) (string, error) {
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b, err := os.ReadFile(m.path(p))
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return string(b), err
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}
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func (m *Machine) dirs(p string) ([]string, error) {
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entries, err := os.ReadDir(m.path(p))
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if err != nil {
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return nil, err
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}
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var out []string
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for _, e := range entries {
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if e.IsDir() || e.Type()&fs.ModeSymlink != 0 {
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out = append(out, e.Name())
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}
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}
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return out, nil
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}
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// whole is a whole-number argument with a default, kept within bounds.
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func whole(args map[string]any, key string, def, least, most int) (int, error) {
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raw, present := args[key]
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if !present || raw == nil {
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return def, nil
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}
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f, ok := raw.(float64)
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if !ok || f != float64(int(f)) {
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return 0, fmt.Errorf("%s must be a whole number", key)
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}
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n := int(f)
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if n < least {
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return 0, fmt.Errorf("%s must be at least %d", key, least)
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}
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if n > most {
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n = most
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}
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return n, nil
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}
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// schema is a tool's input: its properties.
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func schema(properties map[string]any) map[string]any {
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return map[string]any{"type": "object", "properties": properties}
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}
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