38027c8f52
This PR brings two optimizations mainly for page-cache build-up and how to avoid getting OOM killed in the process. Although these memories are reclaimable Linux is not fast enough to reclaim them as needed on a very busy system. fadvise is a system call implemented in Linux to advise page-cache to avoid overload as we get significant amount of requests on the server. - FADV_SEQUENTIAL tells that all I/O from now is going to be sequential, allowing for more resposive throughput. - FADV_NOREUSE tells kernel to start removing things for this 'fd' from page-cache.
55 lines
1.9 KiB
Go
55 lines
1.9 KiB
Go
//go:build linux
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// +build linux
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// Copyright (c) 2015-2021 MinIO, Inc.
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//
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// This file is part of MinIO Object Storage stack
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//
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// This program is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Affero General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// This program is distributed in the hope that it will be useful
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Affero General Public License for more details.
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//
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// You should have received a copy of the GNU Affero General Public License
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// along with this program. If not, see <http://www.gnu.org/licenses/>.
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package disk
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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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// Fdatasync - fdatasync() is similar to fsync(), but does not flush modified metadata
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// unless that metadata is needed in order to allow a subsequent data retrieval
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// to be correctly handled. For example, changes to st_atime or st_mtime
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// (respectively, time of last access and time of last modification; see inode(7))
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// do not require flushing because they are not necessary for a subsequent data
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// read to be handled correctly. On the other hand, a change to the file size
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// (st_size, as made by say ftruncate(2)), would require a metadata flush.
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//
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// The aim of fdatasync() is to reduce disk activity for applications that
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// do not require all metadata to be synchronized with the disk.
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func Fdatasync(f *os.File) error {
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return syscall.Fdatasync(int(f.Fd()))
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}
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// fdavise advice constants
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const (
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FadvSequential = unix.FADV_SEQUENTIAL
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FadvNoReuse = unix.FADV_NOREUSE
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)
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// Fadvise implements possibility of choosing
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// offset: 0, length: 0
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func Fadvise(f *os.File, advice int) error {
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return unix.Fadvise(int(f.Fd()), 0, 0, advice)
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}
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