Good going Amey, contributions to open source are always appreciated. As you are a new to kernel, you need to understand the working of kernel so that you can associate things and how kernel works. Remember my words, don't just jump into any topic before clearing the basics. :) Refer UTLK, LKD etc.. If you insist on Memory management just study ch 8 from UTLK and you will get a basic idea of memory management unit and you check the code for the same in linux/mm/ and figure out thing for yourself. Check lwn.net articles. Read this pdf, a good one. www.ecsl.cs.sunysb.edu/elibrary/linux/mm/mm.pdf And you always hav kernelnewbies for help. :) Dont decide your project in a hurry, understand the kernel and you will have many other areas to work upon, you can work upon file systems as well. All the best. On Mon, Sep 15, 2008 at 4:45 AM, Rik van Riel <riel@xxxxxxxxxxx> wrote: > On Fri, 12 Sep 2008 19:06:49 +0530 > "amey mahamuni" <ameymahamuni@xxxxxxxxx> wrote: > >> I am ameya and I want to do a 3-4 month project in linux memory >> management >> I am interested in page replacement policy.as I am new to linux kernel I not >> able to select particular page replacement algorithm for study. >> so, I would like to know any enhancement or any improvement in present >> algorithm . what page replacement algorithm is used by latest kernel version > > The latest kernel from Linus uses a complex combination of > replacement algorithms. There are two pageout lists (active > and inactive), with different policies for pages, depending > on whether they are swap backed, anonymous, filesystem backed > and mapped or unmapped. > > The -mm tree has the split LRU VM, which has more pageout > lists: active anon, inactive anon, active file, inactive file > and unevictable. > > Anonymous (and other swap backed) pages use a simple two-handed > clock replacement algorithm, while file backed pages use a > use-once algorithm that somewhat resembles 2Q. Pages that cannot > be evicted are placed on the unevictable list, to keep them out > of the way of the VM. > > The split LRU VM has a fairly simple balancing scheme to put > different pageout pressure on the two sets of lists (anon and file) > depending on the fraction of pages on each list that were recently > referenced. > > One thing missing is good tests for a page replacement system. > > With hard disks having latencies around 100,000 times higher than > RAM latencies, the old "this algorithm has a 95% hit rate, while > this one has an 80% hit rate" measurement strategies are no longer > adequate, since either hit rate would result in absolutely > atrocious performance. > > The lack of a good way to test page replacements systems means it > is very difficult to decide whether one page replacement system is > better than another. > > This lack of information, in turn, makes it difficult to decide on > an implementation for the VM's pageout mechanism. > > Some of the problems (but no real solutions) have been gathered here: > > http://linux-mm.org/AdvancedPageReplacement > > -- > All rights reversed. > > -- > To unsubscribe from this list: send an email with > "unsubscribe kernelnewbies" to ecartis@xxxxxxxxxxxx > Please read the FAQ at http://kernelnewbies.org/FAQ > > -- To unsubscribe from this list: send an email with "unsubscribe kernelnewbies" to ecartis@xxxxxxxxxxxx Please read the FAQ at http://kernelnewbies.org/FAQ
