Tom Duerbusch wrote: > If you read a page from the swap disk, and you don't modify it, and it > becomes a least recently used page, will it be rewritten or just deleted > (and use the existing on the swap dataset)? If it is still clean [not modified since last time reading it from disk] it does just get discarded - we do have an up-to-date copy on disk so there is no need to write it again.
> VM use to just leave the existing page alone. But people have been > telling me that even pages that have not been modified are rewritten to > the paging subsystem for efficiency sake. I dunno how z/VM handles this. > If the pages are being rewritten, then pages will migrate from your low > priority swap to higher priority swap. No. Even when the page was modified: When a page gets swapped out for the very first time, Linux tries to find a slot on high-order swap. If it cannot, it assigns a swap-slot on low-order swap. From that time on, the page will _always_ be paged to this swap slot, regardless of whether or not a high-prio slot has become available in the meantime... -- Carsten Otte IBM Linux technology center ARCH=s390 ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390
