Eric W. Biederman wrote: > Herbert Poetzl <[EMAIL PROTECTED]> writes: > > >>On Mon, Mar 12, 2007 at 09:50:08AM -0700, Dave Hansen wrote: >> >>>On Mon, 2007-03-12 at 19:23 +0300, Kirill Korotaev wrote: >>> >>>>For these you essentially need per-container page->_mapcount counter, >>>>otherwise you can't detect whether rss group still has the page >>>>in question being mapped in its processes' address spaces or not. >> >>>What do you mean by this? You can always tell whether a process has a >>>particular page mapped. Could you explain the issue a bit more. I'm >>>not sure I get it. >> >>OpenVZ wants to account _shared_ pages in a guest >>different than separate pages, so that the RSS >>accounted values reflect the actual used RAM instead >>of the sum of all processes RSS' pages, which for >>sure is more relevant to the administrator, but IMHO >>not so terribly important to justify memory consuming >>structures and sacrifice performance to get it right >> >>YMMV, but maybe we can find a smart solution to the >>issue too :) > > > I will tell you what I want. > > I want a shared page cache that has nothing to do with RSS limits. > > I want an RSS limit that once I know I can run a deterministic > application with a fixed set of inputs in I want to know it will > always run. > > First touch page ownership does not guarantee give me anything useful > for knowing if I can run my application or not. Because of page > sharing my application might run inside the rss limit only because > I got lucky and happened to share a lot of pages with another running > application. If the next I run and it isn't running my application > will fail. That is ridiculous.
Let's be practical here, what you're asking is basically impossible. Unless by deterministic you mean that it never enters the a non trivial syscall, in which case, you just want to know about maximum RSS of the process, which we already account). > I don't want sharing between vservers/VE/containers to affect how many > pages I can have mapped into my processes at once. You seem to want total isolation. You could use virtualization? > Now sharing is sufficiently rare that I'm pretty certain that problems > come up rarely. So maybe these problems have not shown up in testing > yet. But until I see the proof that actually doing the accounting for > sharing properly has intolerable overhead. I want proper accounting > not this hand waving that is only accurate on the third Tuesday of the > month. It is basically handwaving anyway. The only approach I've seen with a sane (not perfect, but good) way of accounting memory use is this one. If you care to define "proper", then we could discuss that. -- SUSE Labs, Novell Inc. Send instant messages to your online friends http://au.messenger.yahoo.com _______________________________________________ Containers mailing list [EMAIL PROTECTED] https://lists.osdl.org/mailman/listinfo/containers _______________________________________________ Devel mailing list Devel@openvz.org https://openvz.org/mailman/listinfo/devel
