Messages in this thread | | | Subject | Re: RSS accounting (was: Re: 2.6.19-rc1-mm1) | From | Arjan van de Ven <> | Date | Wed, 11 Oct 2006 15:55:13 +0200 |
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On Wed, 2006-10-11 at 06:07 -0600, Eric W. Biederman wrote: > Arjan van de Ven <arjan@infradead.org> writes: > > > On Tue, 2006-10-10 at 17:54 -0600, Eric W. Biederman wrote: > > > >> For processes shared pages are not special. > > Actually the above is not quite true you can map a shared page twice > into the same process but in practice it rarely happens.
yeah I'm entirely fine with ignoring that case (or making the person who does it pay for it :)
> > > depends on what question you want to answer with RSS. > > If the question is "workload working set size" then you are right. If > > the question is "how much ram does my application cause to be used" the > > answer is FAR less clear.... > > There are two basic concerns. How do you keep an application from > going crazy and trashing the rest of your system? A question on what > number do you need to implement a resource limit.
yet at the same time if 2 apps mmap a shared file, and app 1 keeps it in pagecache, it doesn't cause app2 to trash, or rather, it's not like if app 2 did NOT have the page from that file, the system wouldn't trash.
> > You seem to have an implicit definition on what RSS should mean; but > > it's implicit. Mind making an explicit definition of what RSS should be > > in your opinion? I think that's the biggest problem we have right now; > > several people have different ideas about what it should/could be, and > > as such we're not talking about the same thing. Lets first agree/specify > > what it SHOULD mean, and then we can figure out what gets counted for > > that ;) > > Well I tried to defined it in terms of what you can use it for. > > I would define the resident set size as the total number of bytes > of physical RAM that a process (or set of processes) is using, > irrespective of the rest of the system. > > > So I think the counting should be primarily about what is mapped into > the page tables. But other things can be added as is appropriate or > easy. > > The practical effect should be that an application that needs more > pages than it's specified RSS to avoid thrashing should thrash but > it shouldn't take the rest of the system with it.
so by your definition, hugepages are part of RSS.
Ken: what is your definition of RSS ?
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