Messages in this thread | | | Date | Tue, 31 Oct 2006 12:25:13 +0300 | From | Pavel Emelianov <> | Subject | Re: [ckrm-tech] RFC: Memory Controller |
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Balbir Singh wrote: > Pavel Emelianov wrote: >> [snip] >> >>>> But in general I agree, these are the three important resources for >>>> accounting and control >>> I missed out to mention, I hope you were including the page cache in >>> your definition of reclaimable memory. >> As far as page cache is concerned my opinion is the following. >> (If I misunderstood you, please correct me.) >> >> Page cache is designed to keep in memory as much pages as >> possible to optimize performance. If we start limiting the page >> cache usage we cut the performance. What is to be controlled is >> _used_ resources (touched pages, opened file descriptors, mapped >> areas, etc), but not the cached ones. I see nothing bad if the >> page that belongs to a file, but is not used by ANY task in BC, >> stays in memory. I think this is normal. If kernel wants it may >> push this page out easily it won't event need to try_to_unmap() >> it. So cached pages must not be accounted. >> > > The idea behind limiting the page cache is this > > 1. Lets say one container fills up the page cache. > 2. The other containers will not be able to allocate memory (even > though they are within their limits) without the overhead of having > to flush the page cache and freeing up occupied cache. The kernel > will have to pageout() the dirty pages in the page cache. > > Since it is easy to push the page out (as you said), it should be > easy to impose a limit on the page cache usage of a container.
If a group is limited with memory _consumption_ it won't fill the page cache...
>> I've also noticed that you've [snip]-ed on one of my questions. >> >> > How would you allocate memory on NUMA in advance? >> >> Please, clarify this. > > I am not quite sure I understand the question. Could you please rephrase > it and highlight some of the difficulty?
I'd like to provide a guarantee for a newly created group. According to your idea I have to preallocate some pages in advance. OK. How to select a NUMA node to allocate them from? - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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