本文選題：操作系統(tǒng)　切入點(diǎn)：內(nèi)存文件系統(tǒng)　出處：《南京大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：內(nèi)存去冗余化一直是計算機(jī)高性能領(lǐng)域研究的一個熱點(diǎn),在服務(wù)器上特別是云計算中,各類的服務(wù)或者虛擬機(jī)對內(nèi)存的需求很高,在傳統(tǒng)的虛擬機(jī)技術(shù)中,每個虛擬機(jī)(VM)都需要有一塊獨(dú)立的內(nèi)存,不能的虛擬機(jī)內(nèi)存之間存在著相同頁面;而在輕量級的容器技術(shù)中,不同容器之間,容器與主機(jī)之間會存在著不少的文件和內(nèi)存數(shù)據(jù)是重復(fù)的;在內(nèi)存計算中,對內(nèi)存的需求尤其大。其他包括個人計算機(jī)和終端設(shè)備如手機(jī)也存在著內(nèi)存緊張的問題。因此不僅有必要,也有需求提高內(nèi)存利用率。因而,探究更好的去除內(nèi)存冗余度的方法將有很大的應(yīng)用前景。內(nèi)存去冗余就是消除內(nèi)存中的相似或是相同的內(nèi)存區(qū)域,把存儲多份冗余的內(nèi)存變?yōu)橹淮鎯σ环莸囊环N方法。系統(tǒng)中可能會存在大量的冗余內(nèi)存,當(dāng)前主要有內(nèi)存壓縮和內(nèi)存去冗余兩種方法,并且都已經(jīng)成功應(yīng)用在Linux內(nèi)核中。內(nèi)存去冗余的代表作是UKSM,內(nèi)存壓縮的代表作是Zswap。然而,現(xiàn)在Linux內(nèi)核中的這兩種機(jī)制是由不同的團(tuán)隊(duì)設(shè)計并且實(shí)現(xiàn)的,它們?nèi)コ齼?nèi)存冗余的速度和方式不相同,因而不能相互替代,在內(nèi)存緊張時,同步Zswap會先壓縮內(nèi)存,會導(dǎo)致UKSM無法掃描到被壓縮的頁面。這時需要一種協(xié)同工作機(jī)制能夠協(xié)調(diào)這兩種方法運(yùn)行。文件系統(tǒng)的文件緩存存在于內(nèi)存中,當(dāng)前沒有方法能夠消除文件系統(tǒng)中文件緩存的冗余數(shù)據(jù)。主要原因是文件緩存存在于內(nèi)存中,涉及與I/O交互的塊設(shè)備,設(shè)計一種方法統(tǒng)一消除所有文件系統(tǒng)中文件緩存的冗余是個很困難的任務(wù)。但是如果可以消除內(nèi)存中文件緩存的冗余數(shù)據(jù),就可以有效提高系統(tǒng)內(nèi)存利用率。本文對上述兩個問題進(jìn)行研究,針對第一個問題提出了內(nèi)存壓縮和內(nèi)存去冗協(xié)同工作機(jī)制,協(xié)調(diào)兩種方法的運(yùn)行,具體設(shè)計了一種同步機(jī)制,在進(jìn)行內(nèi)存壓縮前首先進(jìn)行內(nèi)存去冗余掃描,確保所有相同的頁面都被合并。同時考慮了不對整個系統(tǒng)的性能造成過大影響。針對第二個問題,結(jié)合UKSM設(shè)計了種包含文件數(shù)據(jù)切片,頁面合并,頁面拆分的文件系統(tǒng)去冗余方法。本文的主要成果如下:1.同機(jī)制,考慮了內(nèi)存壓縮和內(nèi)存去冗余這兩種方法的特性,也考慮了協(xié)同機(jī)制對系統(tǒng)性能的影響,并且在Linux內(nèi)核中實(shí)現(xiàn)了這種機(jī)制。2.設(shè)計對比實(shí)驗(yàn)測試了協(xié)同運(yùn)行機(jī)制,豐富的實(shí)驗(yàn)結(jié)果證明了這個機(jī)制的有效性,并且在高CPU負(fù)荷和高內(nèi)存需求時都表現(xiàn)良好。在給系統(tǒng)帶來快速合并內(nèi)存頁面的性能優(yōu)勢時,對CPU占用的增加并不明顯。3.針對特定的內(nèi)存文件系統(tǒng),本文設(shè)計了文件緩存的去冗余機(jī)制。結(jié)合UKSM的掃描設(shè)計,根據(jù)虛擬文件系統(tǒng)的設(shè)計(VFS),對文件(inode)切片,分割成適合采樣、掃描的小塊。設(shè)計了中斷安全的頁面比較合并機(jī)制和頁面拆分的寫時拷貝技術(shù)。在Linux內(nèi)核中實(shí)現(xiàn)。4.根據(jù)內(nèi)存文件系統(tǒng)文件緩存去冗余機(jī)制,設(shè)計對比實(shí)驗(yàn),在實(shí)驗(yàn)中對文件緩存頁面的去冗余速度高達(dá)2.28MB/s。
[Abstract]:To memory redundancy is a hot research area of high performance computer, especially on the server in the cloud, all kinds of services or virtual machine memory demand is very high, in the traditional virtual machine technology, each virtual machine (VM) are required to have a separate memory, there are the same the page between the virtual machine memory cannot; and in the lightweight container technology in different containers, between the container and the host will have a lot of documents and data memory is repeated; in memory computing, the memory requirement is particularly large. Others include personal computer and terminal devices such as mobile phone also has the memory stress the problem is not only necessary. Therefore, there is also a demand to improve memory utilization. Therefore, the removal method of memory redundancy into better will have great application prospect. To eliminate redundant memory is in memory or similar The same area of memory, to store multiple copies of the redundant memory becomes a method of a stores only. There may be a large number of redundant memory systems, currently there are two methods to redundant memory compression and memory, and have been successfully applied in the Linux kernel. On behalf of the redundant memory to UKSM that representative memory compression is Zswap., however, now the two mechanisms in the Linux kernel is implemented and designed by a team of different speed and the way they remove redundant memory are not the same, so it can not replace each other in memory, tense, synchronous Zswap will be compressed memory, will cause UKSM to be unable to scan compression of the page. Then we need a collaborative work mechanism to coordinate operation of the two methods. The file system cache file exists in memory, currently there is no way to eliminate redundant files in a file system cache The main reason is the data. The file cache exists in memory, to interact with the I/O block device, design a unified method to eliminate redundant files of all the file system cache is a very difficult task. But if you can eliminate the redundant data in the file cache memory, can effectively improve the system memory utilization in this paper. Research on these two problems, put forward to solve the first problem of memory compression and memory redundancy to collaborative work mechanism, coordination of two methods of operation, the specific design of a synchronization mechanism in memory compression before the first memory to redundant scanning, ensure all the same pages are merged. Considering the performance the whole system does not cause too much influence. Aiming at the second problems, combined with the UKSM file containing the data slice, the design of the page to merge the file system page split redundancy method. The main results are as follows: 1. the same mechanism, considering the characteristics of these two kinds of methods to redundant memory compression and memory, also consider the influence of cooperative mechanism on the performance of the system, and in the Linux kernel implements the mechanism design of.2. experiment mechanism test, abundant experimental results prove the validity of this the mechanism, and CPU in high load and high memory requirements are in good performance. Bring the performance advantages of fast merge memory page, the increase of CPU is not obvious for.3. memory occupy a particular file system, this paper designed to redundancy mechanism of the file cache. Combined with UKSM scan design, based on Virtual design the file system (VFS), the file (inode) were divided into small pieces for sampling, scanning is designed. Compared with the Security page interrupt mechanism and page split copy on write technology. In the Linux kernel,.4. is implemented according to the memory redundancy mechanism of memory file system file, and a contrast experiment is designed. In experiment, the redundancy speed of file cache page is as high as 2.28MB/s..

【學(xué)位授予單位】：南京大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TP333.1

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1 姜承祥;基于UKSM的高效內(nèi)存合并技術(shù)的研究和實(shí)現(xiàn)[D];南京大學(xué);2017年

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本文編號：1649647