> > proposes extensions to , which will make swap reservation and > > locked memory resource controls easy to configure on a zone via > > zonecfg(1m). > > I'm not sure if this is exactly the right place to bring this up, > but > there needs to be some clarity to the user community about the > definition of swap. Due to the fact that it is not essential to the > discussion of the particular ARC case, PSARC-EXT has not been Cc'd. > > The key places that the term "swap" is exposed to users currently is > vmstat(1M) and swap(1M). A search through the relevant sysadmin > guides and grepping through /usr/share/man turns up this somewhat > unapproachable definition in "System Aministration Guide: Devices > and > File Systems": > > The Solaris OS uses the concept of virtual swap space, a > layer between anonymous memory pages and the physical > storage (or disk-backed swap space) that actually back these > pages. A system's virtual swap space is equal to the sum of > all its physical (disk-backed) swap space plus a portion of > the currently available physical memory. > > The man pages for vmstat and swap are not especially clear as to > whether they are talking about swap space (blocks in a swap device) > or > "virtual swap space", a term that I have only seen in the Devices > and > File Systems book. That, combined with the fact that "devices and > file systems" is not the first place a person would expect to find > this information, frequently leads to a misunderstanding of what the > definition of "swap" is. > > As prstat is changed and resource controls are added to limit swap > reservations, it would be extremely helpful to ensure that swap is > clearly defined. This likely includes a definition in a man page > (time for swapfs(7s)?) and references to that definition in relevant > man pages.
I agree that "swap" is generally poorly defined and misunderstood. Hopefully, a future "memory sets + swap sets" feature make the components of swap easier to understand and manage. It seems reasonable to file bugs to get the appropriate manpages updated with better definitions: vmstat(1m) swap(1m) prstat(1) swap(1m) sort of defines this in the "-s" case, but it could be better. vmstat(1m) is lacking, and of course prstat(1) will need to be updated anyhow for this change. We will also update the zones/rm/container admin guide with a swap overview when we document zone.max-swap. -Steve > > Mike > > -- > Mike Gerdts > http://mgerdts.blogspot.com/ _______________________________________________ zones-discuss mailing list firstname.lastname@example.org