On Thu, 17 Aug 2006 16:53:01 -0700
Daniel Phillips [off-list ref] wrote:

Andrew Morton wrote:

quoted

Daniel Phillips [off-list ref] wrote:

quoted

What happened to the case where we just fill memory full of dirty file
pages backed by a remote disk?

Processes which are dirtying those pages throttle at
/proc/sys/vm/dirty_ratio% of memory dirty.  So it is not possible to "fill"
memory with dirty pages.  If the amount of physical memory which is dirty
exceeds 40%: bug.

Hi Andrew,

So we make 400 MB of a 1 GB system

by default - it's runtime configurable.

unavailable for write caching just to
get around the network receive starvation issue?

No, it's mainly to avoid latency: to prevent tasks which want to allocate
pages from getting stuck behind writeback.

What happens if some in kernel user grabs 68% of kernel memory to do some
very important thing, does this starvation avoidance scheme still work?

Well something has to give way.  The process might get swapped out a bit,
or it might stall in the page allocator because of all the dirty memory.

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