44 lines
965 B
Go
44 lines
965 B
Go
// +build !windows,!plan9
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package tsm1
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import (
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"os"
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"syscall"
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"golang.org/x/sys/unix"
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)
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func mmap(f *os.File, offset int64, length int) ([]byte, error) {
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// anonymous mapping
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if f == nil {
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return unix.Mmap(-1, 0, length, syscall.PROT_READ|syscall.PROT_WRITE, syscall.MAP_ANON|syscall.MAP_PRIVATE)
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}
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mmap, err := unix.Mmap(int(f.Fd()), 0, length, syscall.PROT_READ, syscall.MAP_SHARED)
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if err != nil {
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return nil, err
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}
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return mmap, nil
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}
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func munmap(b []byte) (err error) {
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return unix.Munmap(b)
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}
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// madviseWillNeed gives the kernel the mmap madvise value MADV_WILLNEED, hinting
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// that we plan on using the provided buffer in the near future.
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func madviseWillNeed(b []byte) error {
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return madvise(b, syscall.MADV_WILLNEED)
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}
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func madviseDontNeed(b []byte) error {
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return madvise(b, syscall.MADV_DONTNEED)
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}
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// From: github.com/boltdb/bolt/bolt_unix.go
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func madvise(b []byte, advice int) (err error) {
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return unix.Madvise(b, advice)
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}
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