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54 lines
1.3 KiB
Go
54 lines
1.3 KiB
Go
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// +build !windows,!plan9,!solaris
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package tsdb
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// import (
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// "fmt"
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// "syscall"
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// "unsafe"
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// )
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// // mmap memory maps a DB's data file.
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// func mmap(db *DB, sz int) error {
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// // Map the data file to memory.
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// b, err := syscall.Mmap(int(db.file.Fd()), 0, sz, syscall.PROT_READ, syscall.MAP_SHARED|db.MmapFlags)
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// if err != nil {
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// return err
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// }
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// // Advise the kernel that the mmap is accessed randomly.
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// if err := madvise(b, syscall.MADV_RANDOM); err != nil {
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// return fmt.Errorf("madvise: %s", err)
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// }
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// // Save the original byte slice and convert to a byte array pointer.
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// db.dataref = b
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// db.data = (*[maxMapSize]byte)(unsafe.Pointer(&b[0]))
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// db.datasz = sz
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// return nil
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// }
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// // munmap unmaps a DB's data file from memory.
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// func munmap(db *DB) error {
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// // Ignore the unmap if we have no mapped data.
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// if db.dataref == nil {
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// return nil
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// }
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// // Unmap using the original byte slice.
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// err := syscall.Munmap(db.dataref)
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// db.dataref = nil
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// db.data = nil
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// db.datasz = 0
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// return err
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// }
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// // NOTE: This function is copied from stdlib because it is not available on darwin.
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// func madvise(b []byte, advice int) (err error) {
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// _, _, e1 := syscall.Syscall(syscall.SYS_MADVISE, uintptr(unsafe.Pointer(&b[0])), uintptr(len(b)), uintptr(advice))
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// if e1 != 0 {
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// err = e1
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// }
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// return
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// }
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