Messages in this thread | | | Date | Sat, 28 Mar 1998 05:48:37 +0300 | From | Itai Nahshon <> | Subject | Re: 2.1.91 swap performance: jerky. |
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Linus Torvalds wrote: > > On Sat, 28 Mar 1998, Itai Nahshon wrote: > > > > The idea sounds right, I have questions regarding limitation on > > current implementation: > > 1. If something is swapped out but the pages that it occupied > > never used later, will it have to be paged-in from disk or can > > the copy in memory be reused without any farter io? > > If the page is never used again, it will never be paged in: an exit of the > process will just free up the page on disk, and a "fork()" will duplicate > the pointer to the disk rather than page it in in order to duplicate it.
I did not phrase my question right... Suppose a page was swapped out, but the physical memory that it occupied was not used for something else. Now the process page-faults in that address. Can the page be reclaimed from memory (the data is still in the main memory?) or do we need to page-in from disk?
Thanks, Itai -- Itai Nahshon nahshon@actcom.co.il Also nahshon@vnet.ibm.com
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